***Parts availability announcement***
I was emailing Bruce about the thread size for the air inlet fitting when, in passing, he let me know that newly manufactured aluminum joints are now available. The price will be $225, incl. shipping.
I run mainly MM carts and I've been meaning to acquire an aluminum arm wand (I own the carbon and magnesium wands) to see whether it would better match with my carts. So, I ask Bruce between the alu wand and alu joint which should I get first.
He answers, "I would go with the aluminum joint first, I think this will make the biggest improvement in the low frequency sound with a MM cartridge."
Sold!
I know that contributors to this thread once got together and did a short run on the joint. Perhaps they can discuss the merits of Bruce's assertion?
Incidentally, the air inlet fitting has 10-32l threads (not sure what the 'l' denotes, but I do know that 10-32unf does NOT work) and, like the leaf springs, Bruce offers them for free. This is magnanimous of him especially given that the fitting was impossible for me to find.
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Richard et al, I came across a good video showing the Timeter pump in action. https://www.youtube.com/watch?v=rzNO_iYeopcWith this one the two air outputs have been set up differently. Not for an air bearing tonearm :^) I found this video while looking for a second pump. The video is really good at showing how loud it is, and its operation. A close up shot of the performance gauge can be seen. It’s the indicator of the air quality going out - Amazon humid - to Arizona dry - depending on the patient’s requirements. In this case Arizona please for the ET 2.5 baby. Baby is a good word I think, since my 19 PSI ET 2.5 from Bruce is younger, tighter, and very picky with what it’s inhaling. More so than my older ET 2.0 with High Pressure Manifold in the other room. If you watch the fellow start it - it builds PSI and when used with my main ET 2.5; pump adjustments can be made so the performance gauge needle stays in the green - indicating dry air output. It uses 4 heavy duty caster wheels which allow for it to be easily moved around when not in use, and placed in the room of your choice when listening to records. It’s not a good idea to leave it running in your wife’s TV room. I want a second one; everything seems to come in two’s for me. But the shipping is too damn much to justify for those I have found. As you know my older Timeter pump has had some past surgery. So would be nice to have a backup. I laughed when the guy in the video showed a close up of the hours count on that one. Cheers . |
But then the ET locked up and it began spitting out water. 8^0 I have known of some people who pull off the air hose at the manifold casing - pour some isopropyl down the tube - reconnect and start up the air. This must be the equivalent of drinking home made Slivovitch. (google it). Anyone reading pls take the manifold apart and clean per the manual if needed. I was lucky with my ET tonearm water incident. I casually looked over and saw the water trap bowl was what looked like 3/4 full ! Normally there is nothing there as the timeter drains all moisture. The nozzle on the drain tube on the timeter pump had plugged up and was not exhausting water any more so water starting going down the airline. Soaking the exhaust nozzle in CLR fixed it. Actually, the same sort of thing happened to my wife’s car. She found the passenger side footwell soaked one day. Turns out pine needles/leaves entered and blocked the AC drain tube on her car - entered from passenger side front windshield area. Dealer wanted to charge me an hours labor to fix it so I took off the footwell carpeting/panel and saw the the drain hose coming through and exiting below the floor. Pulled it out, used wire and blew out debris with air.
high humidity pulling down the bias voltage on the stats, a known issue.
Richard I learned about this about 5 years ago, The Quad 57’s were kept in a Toronto space with no air conditioning / humidity control in summer. The first time I experienced it I thought they were Kaput. I spoke with Ken at Electrostatic Solutions who explained the phenomena to me. They left that space shortly after that and came home. The other interesting thing I learned from Ken going by memory, is that the the Quad 63’s and 57’s are opposite builds. The 57’s are actually a hardy build in comparison to the 63’s in regards to humidity; even though high humidity can make them sound like transistor radios it doesn’t hurt them. The Quad 63’s in a couple years of high humidity will self destruct/fall apart. |
Chris. I can relate to the water in the air comment. Here in Auckland, New Zealand, it gets pretty humid in the summer months. Many years ago I was listening with a few Friends and we all commented on the sound quality being sub par. It was put down to the high humidity pulling down the bias voltage on the stats, a known issue. But then the ET locked up and it began spitting out water. Quite shocking to see this in action. I have used a water separator and drainable tank ever since that night.
cheers .
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RichardKrebs
It shows all over again that the arm is very sensitive to the quality of the air supply. Richard - obvious agreement from me. I got sidetracked for a number of years (elapsed time) in my Audiophile phase PUMP journeys. Where does one stop ? It can be addicting. I did learn a lot about how different pump technologies work though. ******************************************** I think it is worth noting for newer readers, a couple important thread quotes from Bruce on Air Supply and Setting Manifold PSI Values. 1) Air Supply (Quality - PSI and Mositure/Dirt) Bruce Thigpen
More than air pressure, the air supply will change the sound of the tonearm. if it is bad, allowing pressure pulsations to enter the manifold. Increasing pressure slightly and a big enough surge tank are the best things that could be added to the tonearm in terms of performance. The key words to me from Bruce is increase pressure slightly, and it implies one knows what PSI your ET2 manifold was built for. If someone buys an ET2 on the used market we have discussed here how to find out the PSI/Bar it was designed for. As a guideline if a regular manifold - 3 psi. If a High Pressure manifold 8-10 psi unless it was a Custom Build. Once consistent PSI is achieved (think pulsations), the big other factor is moisture and dirt. What helped me understand how important this moisture and dirt were, was to think about air brush painting and what happens if dirt/moisture get in the air line for the person doing the spraying. Now I don't air brush myself but there are many air brush painting forums to get an understanding. For me personally. My Timeter pump is designed for keeping people/patients comfortable. It therefore has controls that allow me to vary the moisture being sent out as it has an integral drying system. The pump is affected by humidity and going from very dry winter air, to humid spring/summer air forces me to make pump adjustments to the level of drying. I have found in my room on a few occasions during the season change from winter to spring (going dry to humid) I could have been listening to digital for a while, then switched to vinyl, the system itself is warmed up; at times the vinyl sounded wrong. Almost how reproduced music in a room can sound with cold solid state gear if you know what I mean. When the music sounds like this, it makes me think of wires and the gear. Not the music at all. Going to the pump I notice the dryness level needle has dropped some so I need to crank up the dryness factor a bit on the pump. So the PSI was just fine but there was some moisture in the air line - it affected the sound. And this is moisture "vapor" that is hard to be trapped by filters. Again the air brush forums help to get an understanding of this. Our audio expectation is nice music we enjoy. Their expectation is the finish on their painted product. Its all visual. For those running with tanks of compressed air - don't forget to drain the water in the tank before using (bringing the tank to its PSI level). My Timeter Aridyne pump is tankless. The fact of the matter is if you live in a hot, humid place (I wish I was there now) you will have more challenges with air supply than the guy in a drier, colder environment. So many environmental factors can affect the sound that are never discussed on Audiophile forums. 2) Setting the Manifold PSI on ET 2.0 and 2.5 for specific customer requirements. In the past customers have had Bruce design the manifold PSI for their pump's specific requirements. This is discussed on the Eminent Technology website when one is looking to buy the tonearm, as the pump system is not supplied with tonearm when you purchase it. Bruce Thigpen
The pressure drop across the set screws define the restoring force and part of the stiffness of the air bearing.
The tolerance between the Manifold Inner Diameter and the Spindle Outer Diameter determines the lifting pressure as a function of flow rate through the set screw. Without a restoring force or pressure drop across the set screw, the bearing will lock up, so you always need a higher air pressure in the manifold housing as compared to the pressure at the surface of the spindle.
The high pressure manifolds have a slightly tighter tolerance between the spindle and manifold, they also use a set screw with more plating to restrict the air flow around the threads to create the increased pressure drop (the difference between the pressure in the manifold housing and the pressure at the surface of the spindle).
It does not hurt to slide the spindle in the manifold bore without air, the resistance you feel may be the surface finish roughness on the hard coat anodizing as well as tolerance.
I hope this helps, thank you very much.
-brucet ************************************************ Fnding the ET2 Yellow Sticky Thread Posts. Here's the ET2 thread Yellow Sticky for the setting of manifold PSI values https://forum.audiogon.com/discussions/eminent-technology-et-2-tonearm-owners/post?highlight=et2%2By... The new Audiogon system allows one to find the Yellow Sticky Posts on this ET2 thread easily now. Just enter Yellow Sticky in the forums search field. |
Hi All
I have just finished testing a precision pressure regulator in the air supply for the arm.
I replaced a Norgren B07-201-A1KG reg with a Norgren 11-818-101
Findings in my rig...,
Was there an improvement? Yes. Things were a little clearer, more three dimensional and impactful.
A big change? No, but worthwhile.
All comparative testing was done when the compressor had cycled off, drawing air from the reservoir only.
The old reg has a built in filter/water seperator the new reg doesn't, so a seperate filter/ seperator was also installed before the new reg. So technically two things were changed.
Did this have an impact on the results?
Maybe
Whatever, the new configuration is staying firmly in place.
The bleed off needle valves before and after the reg, that I posted some time ago, were retained and their beneficial impact confirmed.
It shows all over again that the arm is very sensitive to the quality of the air supply.
Cheers
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Dear ct0517: Yes, I remember the first time that I saw that very good picture and was my wife who took my attention about.
Obviously that tha beautiful house is a house where the owner likes music and know what this means in a home audio system ( I'm talking not of RR but the real owner. ).
IMHO, the ET tonearm is today an icon/sign in the audio history.
Regards and enjoy the music,
R. |
My 21 year old son sent me a couple links today. I think inspired by his girlfriend..... I started laughing when I opened them up and I thought for a moment, maybe there is some hope for him ? had to post. http://imcedb.com/images/1/12/Indecent_stereo.pnghttp://imcedb.com/images/1/1c/Indecent_turntable.pngIndecent Proposal - Robert Redford - TNT turntable and ET 2.0 My son always liked my old TNT - told me it looked like a tarantula spider. Black is beautiful. When Bruce told me he was going to be making parts in aluminum I thought for a second maybe he was about to add some bling to the ET 2 tonearm in the form of shiny aluminum. But he stayed true to his low key self with the blacked out aluminum mounting plate. ET 2 owners - notice the correct placement of weights for bass in the first link.. Anyone know what the cartridge is in the second link.....a Benz ?
Happy Listening |
Hello Raul - Feliz año nuevo and welcome to the thread. If I may make some comments to your post. Rauliruegas
One critical subject in the sound generated by any subwoofer is that we at home need enough cubic area for the bass soundwave can be in real way developed, if that cubic area does not exist any one can't " hear "/ feel a 5 hz soundwave. We need " hundred of m. to those very low bass sounwafes really be formed. Yes, I agree you can't defy physics when it comes to bass especially when someone is making a Subwoofer inside a BOX (enclosure) and placing it in a larger box "the room". One of the latest audiophile darlings. The Gotham by JL Audio reproduces 19hz - 200hz (+-) 3db Dimensions* (H x W x D): 34.13 in. x 21.50 in. x 24.00 in. 867 mm x 546 mm x 610 mm 360 lbs. (163 kg) $12,000 plus $3500 for the crossover. US dollars. Now in regards to this ET Rotary Subwoofer - it is thinking "outside of the box" and it is designed to take over where that JL Audio Gotham stops producing below 20hz. It uses that "extra room in a persons house" meaning , the basement, the attic, side room that the rotary woofer gets installed in - the room, space itself becomes the BOX - the infinite baffle ....the sealed enclosure..... Rauliruegas
Yes the ET unit is something really different of what we normal mortal audiophiles know So who is the customer for this? This rotary woofer is now being used in theme park attractions, concert venues, professional audio applications and research projects. But I think there are also possible clients for this product right here at Audiogon. Any potential customer for a start would need to have $12,000 US dollars for the Rotary Woofer which is similar to the JL Audio Gotham price. But from there an additional $8k -$12k for the design and installation. So approx $20k - $25K US dollars total which includes crossover and external amp. And of course this person (client) has a house with the space available for the installation of the Rotary Woofer to create this infinite baffle. For this, the person gets to hear and feel "the 11hz hertz fundamental frequency from a helicopter rotor, the low frequency rumble of wind, the space of a concert hall or infrasonic information contained in an explosion." taken from the website. Well this client is not me. But let us just imagine; this "guy" male customer (no woman would do such a thing right? ) but .......imagine this guys wife, spouse, better half coming home to see the inside walls of their beloved home doing this. http://www.rotarywoofer.com/africa%20photos/Africa%20Video%20Snapshots/Kombi%20Roof.gifthe above is from the Africa segment linked earlier. I got a good laugh - the video shows outside the van containing the Rotary Woofer working inside the van to attract the Elephants. And from that link's description. "With the rotary woofer playing a thunderstorm recording, the elephants all stopped eating and turned toward the camper van." Cheers |
Dear ct0517: One critical subject in the sound generated by any subwoofer is that we at home need enough cubic area for the bass soundwave can be in real way developed, if that cubic area does not exist any one can't " hear "/ feel a 5 hz soundwave. We need " hundred of m. to those very low bass sounwafes really be formed.
Yes the ET unit is something really different of what we normal mortal audiophiles know.
Very good links.
Regards and enjoy the music,
R. |
If you guys recall, there was mention a while back on this thread that Bruce and his team were going to Africa with the BBC to test the hearing of Elephants using his TRW - 17 Rotary Sub. I've noticed some really cool pictures and footage of the trip to Africa have been uploaded to his rotary woofer website. I've linked them here. Infrasonic interaction with Elephants http://www.rotarywoofer.com/Africa.htmlBruce' team then went with the BBC to Florida to do testing with alligators. Provoking a mating dance from an alligator. http://www.rotarywoofer.com/Gators.htmlRotary Woofer Website http://www.rotarywoofer.com/Happy and safe New Year to everyone. |
Bruce' new aluminum mounting plate weighs 39 grams on its own.
40 grams with the three spikes.
The original mounting plate 23 grams and 24 grams with spikes.
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Here is a picture of Bruce’ new ET 2.0, 2.5 Aluminum Mounting Plate. https://goo.gl/photos/YMrLEFY46Rno5cs6AThere is also a picture of it on my Audiogon system link. unfortunately the new Audiogon format does not allow me to link to it in posts - yet. Mine is on its way. Cheers |
Banquo363
I conjecture that the cause is the lack of rigidity at the contact point between the base and the two levelng screws. This holds especially for arms that have had their base abused by owners who overtighten the leveling screws and leave indentations in the base. Yes from my experience The ET2 has three, well four areas that are sensitive to setup abuse by new owners, and those who are not aware of how it works. The one you mention with the base and indentations from the vertical bolts from not being aware of how hard one has screwed those vertical screws down. All leveling should be done after bringing them both up to reset. They should never have to touched again after that. if they do, the base is warped from abuse and/or there is a good possibility a users turntable is going out of level. check there first. Anyway the aluminum base fixes this problem so is welcome. Very excessive force on the Post bolts and VTA block screws being over tightened and even closed. I ask what kind of madman causes something like this to happen ? http://cgim.audiogon.com/i/vs/i/f/1415022707.jpgThe VTA block rack of teeth have been stripped by using it when the block was shut closed, and the VTA block case itself destroyed but excessive force on the bolts. . A third being tightening the end cap I Beam cap bolt too tight could cause it to crack at the opening . I did this once years ago. A fourth extreme is the gooseneck. Maybe tightened too tight and left on for years. A user when going to remove the armtube, puts incorrect torque in the wrong place and could snap off the cueing lever. |
thanks for the head's up, ct0517. Mine is on its way. I've been wanting to replace mine ever since I bought my arm (used) a few years back. Alas, Bruce had no more to sell. So, this is a most welcome development.
The decision to use aluminum hopefully solves a problem I've had with using my et2: every time I adjust vta, the arm goes out of level and needs to be reset. I conjecture that the cause is the lack of rigidity at the contact point between the base and the two levelng screws. This holds especially for arms that have had their base abused by owners who overtighten the leveling screws and leave indentations in the base.
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Big news ET 2’rs. Remember this? http://cgim.audiogon.com/i/vs/i/f/1366738930.jpgThe "joint" affectionately called the Gooseneck here. It will soon be available for the ET 2.0, 2.5 tonearm as a match up with both Carbon Fiber and Magnesium armtubes. The really big news. The ET2 base that holds up the entire Et2 tonearm is ready now in Aluminum. Please contact Bruce directly if interested. ******************************************** IMO this would not have been possible without the increasing interest in the ET 2.0, 2.5. Air Bearing Tonearm. Some background When I was speaking with Bruce in late October and posted the last ET 2 Yellow Sticky ******* YELLOW STICKY ET 2 THREAD - FACTORY SETTING OF PSI - REGULAR AND HIGH PRESSURE MANIFOLDS ************ https://forum.audiogon.com/discussions/eminent-technology-et-2-tonearm-owners?page=30(See the October 31 post on the linked page. This new format no longer allows one to link posts, just pages ) He did mention his plans for this; but wanted me to hold off until the first parts were ready. Very happy to pass this news to you all. |
Probably a better deal: hereSold as a 2.0 but there's reason to believe it's a 2.5. How many of these are out there languishing on shelves? |
- So what is a brand new "Old Stock" base ET2 from 1985 worth ? Here is an original from 1985 New Old Stock Seeing the year 1985 in the ad I got curious. So using an online inflation calculator. It's original new price of $850 in 1985; is just under $1900 US dollars today. He is taking offers :^) If anyone here is one of the ad watchers - good luck Not affiliated with the ad. |
So you listen on Quad ESL 57? Yes. in Room B Room A is using Matrix 800 speakers. Room A is my main room since '94 with my main turntable. The pic is from recent discussions on my system thread of successfully integrating the sub nearfield with the Quad 57. I am very excited about this :^) The arrows point to sub locations I have tried. More pictures of both rooms with equipment lists can be seen if you click on my system link. My wife does not share my audio passion but she recognizes the audio problem, so she lets me use the basement. :^) Dedicated space (The Room) is very important for optimizing music. But what is more important long term, and what can not be see by pictures is how the dedicated space can keep your marriage together in a case like this. Well so far...lol...How do you put a value on that ? I guess it depends o the marriage. Word on the street....married guys are in general a happier lot......they are just more willing to die :^) There were some highly regarded german SS amps that worked as a current source. This is interesting. I would of been very interested to hear them if they were available here. After SS amps - American, Canadian, Japanese, plus also Quad's own SS plus a couple tube amps; I am using an American tube amplifier - Music Reference RM10. The designer Roger Modjeski designed and built the RM10 for his own Quad 57 speakers. A total new world of listening opened up with this amp/57 combo. For those more interested in this ESL /Amp requirements world, Roger Modjeski does IMO a very good short one page summary here See the first post. A couple good points from the link. Recognize he is pushing his own direct drive amps in the 3rd paragraph.
Roger Modjeski
2. This second class of ESL speakers is multi way using panels of different dimensions and often different voltages to obtain line source dispersion. By adjusting the panel size and shape flat response can be obtained without the need for EQ. All the QUAD speakers do this having much larger area for the bass than the treble. The 57 is a 3 way line source where the 63 is a two way point source. I prefer the 57.
The Quad 57s are only 200 pF and the 63's are low also. In general the ESLs that use full range panels have the highest capacitance and are therefore least efficient. The multi-way ESLs (that means mulit-way in the electrostatics themselves) tend to be low capacitance and much more efficient. The extremes are the QUAD 57 needing 15 watts of drive and the Beveridge needing 1,500. Trumpet music is most demanding. Being a little in disbelief about the 1500 watt number I measured a half amp at 3000 volts. No wonder these speakers can't be driven any other way. The QUAD on the other hand needs the voltage of a 15 watt amplifier (at 16 ohms) but from a 4 ohm tap. In my experience that although the QUAD 22 amp was made to drive the 57 speaker, it was rather rolled off at the top due to the fact that the speaker impedance did fall to about 4 ohms. Not everything QUAD did was exactly as they said, contrary to the rather perfectionist philosophy proposed in the QUAD book.
One nice thing about my direct drive system is that by changing just 2 capacitors in my crossover one can set the brightness of the speaker to his desires either more or less than the standard by as much as 12 dB in either direction. Far more than one would need.
I am using the 8 ohm tap on my RM10. The room is made with the heavy right curtain in the pic, into an irregular 20 x 22 feet (6 x 7 meters). Speakers are 7 feet from the front wall. I am able to do an easy 90 db at the chair + peaks with the RM10 and nearfield sub. I listen around a 80 - 85 average db average. |
- Ct 0517: The funny thing with ESLs, Quad etc. is that they do much better with something closer to a current source, this means they deliver much more voltage on high impedance than a low one. Doubling the power in each halving of impedance is the definition of a perfect voltage source. A voltage source gets tricked out on the voltage increase needed for the bass impedances (except if one uses insanely powerful amps). And it delivers the current in the highs (doubling, doubling, doubling the power) like a preussian soldier by executing it's order - but there is an intrinsic stress in that, of which thermal stress is not the least.
There were some highly regarded german SS amps that worked as a current source. It's a pity I never heard one or could try one.
So you listen on Quad ESL 57? |
Thanks for the reply Pegasus. I enjoy reading your posts. My previous post was a generic example, and specific for only one type of SS situation. Although the specs I mentioned for the amps and speakers in the previous post are common in today's audiophile market place. Something stood out to me in what you said and if I may make one more point here. And which design optimisation has to take places with which compromises to reach the intended goal. It has been my personal experience over the years, that in talking with about 1/2 dozen or so amplifier manufacturers and doing research on them; I discovered that they each had a target speaker design (brand and/or model) that their amplifier was based around. They have to after all hook up their amps to something right ? Amplifier makers are forthcoming usually on what speakers they are using for current testing. Likewise for speaker makers on the amps they use. Those looking for answers should give them a call directly. With this method business partner relationships are also discovered. There are a few rules (guidelines) in audio. The rules that revolve around the speakers themselves, have a big effect on the amplifier design. For example if we put our experiences aside and, come into this as if we were new to the hobby. Consider these three questions. Consider each as a separate consideration onto itself. A sort of silo. 1) What if a person wants to reproduce full range music. What majority would not want this ? To hear all that was recorded. 2) What if a person wants good efficiency - again who doesn't really want this...no different than installing a furnace/air conditioner ? We check off the high efficiency box if we can. This also leads to lower utility bills, saving the planet, just make sense... 3) What if the person wants the reproducers "speakers" to take up a small area - un-obtrusive. Bookshelf size - Again if you could why not ? Who really wants 8 foot towers in their living room? Or those huge speakers that need to be disguised as huge sculptures in the dwelling to work - really ? Well you can only have two of the three above. If someone doesn't believe it; run through the math and the scenarios of the 3 options. If a friend asks me today for an opinion, and I know he has not already been made biased by reviews, dealers, forums, etc... I will say take your pick of the two that most appeal to you. Then look at the one that got left out. Whichever one it is - go the opposite to it in design - and if you can accept that, you're done. Your path is clear. Go find that speaker ! All choices in between are a compromise - Leading back to Pegasus' quote above. To me the speaker is the Alpha over the amplifier. This also explains my speaker problem (multiple pairs). I see an amplifier/s as nothing more than a mechanical device that needs to gets the job done and does not break down over time. The amplifier needs to serve the speaker and allow it to make music. The order of my points above do happen to show my personal order choice. My full range speakers are 93db, and can make nice music with a small tube amp. But they are also kinda big. Pegasus - It's BTW a question too, how desirable a wide bandwidth is for a power transformer, which is an inherent property of the general winding technique of toroidals. @Pegasus - my personal midrange reference speakers are unique for 2015. This is because they have a design from 1957 - which is older than me. They do not follow the above rules I posted. They are fairly large, not full range, and their efficiency ? The speakers need 30 + ohms from an amp....in order to do the proper bass and as you can see from the graph, 2-3-4 ohms for proper high frequencies. How is that for bandwidth requirement ? Through research and empirical means I have already found a perfect tube amp for them, for my room. Pegasus et al I don't think a SS amp exists that can serve them properly ? Again through empirical means the SS ones I have tried seem to choke - become so pooped out on the 30+ ohm load reqt for bass - that they seem to have nothing left to give at the requirement needed to reproduce the high frequencies. This leads to the band-aid - external tweeter. ************************************************ Audio Hangman - The Big Rocks -----------------------Room------------------------------ ---------------------/-------------------------------------- -------------------/---------------------------------------- ---------------Speakers ---Source--------------------- ----------------/------------------\------------------------ ---------------/--------------------\----------------------- ---------Amplifier--<<<-----Pre-Amp/Phono------ ------------------------------------------------------------- I sure hope this neat doodling feature is not taken away away when the new Audiogon forums go live in two weeks. An editing feature once post goes in would help though. Sorry for any mistakes. My previous post that said Impressive thought process ! (Should have read - Impressive thought process Frogman!) |
Transformer saturation is one of two main loss factors with transformers, magnetic and ohmic losses. The doubling of the power in high power amps with low impedances highlights the problem of ohmic losses. There are two questions about reducing transformer losses: Does it correlate with better sound, and at which output power levels? And which design optimisation has to take places with which compromises to reach the intended goal. Think also about the sonic qualities of single ended amps, some tube amps too with extremely good bass, but no doubling of the power to lower impedances. The optimisation of audio quality in the major signal range is important - even with considerably compressed music the main energy range is at -10 dBU rel. level, which means at one tenth the peak power. With better material it's rather around -20dB and more. In a normal listening situation one is inclined to reduce the replay level. Generally 90dB medium level, except peaks is very loud. My speakers need less than one Watt average for this. Everything that improves sound quality from zero up to this power range has a lot to do with sound quality. Doubling the power into half of the impedance would be desirable, if there were no inherent sonic compromises. I know this flies in the face of orthodox engineering, but there is some empiric and well thought through truth to it.
Reducing ohmic losses leads to an extremely high current path for the capcitor / rectifier path, with considerable problems, exacerbated by "stable, high energy" designs with huge load capacitance.
Interestingly one of the better sounding Goldmund transistor amps as well as some Cello designs did search for an *optimal*, not maximal load capacitance, with very good results.
One of the reasons is reducing the stress factor inherent in increasing charge current peaks with increased capacitance. The same design compromise is involved with low loss transformers.
There is a way of thinking (shared by some famous names) that a "transformer only provides voltage & current and has no influence on the sound whatsoever". If one starts to experiment with different (brand) transformers, one finds the opposite is true.
This has - in empirical evidence - strongly to do with the magnetic circuit, and wire diameters (and rectifier and power supply design). This is a wide - empiric - research field of patient work, which very few people have done from both sides, the producing and listening side. Most any "normal" transformer is built following general design rules, strongly economical ones, which overlook some key factors, which are relevant "only" to audio. Optics are sometimes also optimised.
It's BTW a question too, how desirable a wide bandwidth is for a power transformer, which is an inherent property of the general winding technique of toroidals. |
Pegasus
Regarding EI (there are several other "square" cores BTW) vs. toroidal transformers: Things are not that simple. While a toroidal has the advantage of a more simple "flowing" magnetic circuit, it's main "advantage" is the absence of an air gap - an economic advantage. This makes for considerably less iron for a toroidal, and more inductivity with less windings. This makes for a low (ohmic !) loss transformer, with low impedance windings.
However this creates disadvantages: The saturation of a toroidal is very sharp, and with the industry practice (and the practice of almost all audiophile transformer builders) of driving the transformers too close to the magnetic saturation point of the cores ("Efficient" ! Bling!) they are *the* achilles heel of excessive sonic mains sensitivity.
And within these issues DC on the mains (a strong disturbance of high variability) drives a toroidal transformers very easily into saturation, a massive disadvantage!
The last related disadvantage of a toroidal is the inherently lower ohmic loss: It produces (much) higher charging current spikes, which on their own magnetize the (hard limited) toroidal core much harder, and again pull away reserves from the iron core. Low loss is not per se better, on magnetic circuits it creates very audible problems. What if; You have two Solid State Amps Class A/B that both put out 100 wpc *** at 8 ohms and both have toroidal transformers. Their specs look like this. Amp A 2 - ohms - n/a 4 - ohms - 125 wpc 8 - ohms - 100 wpc *** 16- ohms - 50 wpc 32 - ohms - 25 wpc Amp B 2 - ohms - 400 wpc 4 - ohms - 200 wpc 8 - ohms - 100 wpc *** 16- ohms - 50 wpc 32 - ohms - 25 wpc. If both are driving full range speakers at a decent SPL level. These speakers dip to 2 ohms for the low bass requirement. Question: Is transformer saturation the right word to describe what is going to happen to Amp A first ? Just asking .... |
Frogman - Wait, this is a trick question..... If I provided "e) all of the above" - it would have made it too easy for all you sharpshooters on the thread. Impressive thought process ! Pegasus
We suspected already during an earlier listening sessions, that the slowly increasing amount of dry air exiting the tonearm creates - a lot! - of static charge on the vinyl surfaces. And it had a considerable effect sonically. The ionizer, building up a certain reserve of air ions (smells also a bit like Ozone), seems to eliminate this problem. Hmmm... An interesting comment Pegasus. I have humidity gauge right next to the TT, One foot away. The needle doesn't move during the hours I am in there. But that is maybe too macro a level.... Have you ever tried a smoke pencil puffer under the sides of the manifold to see the air stream pattern ? 1) With a still record and 2) with a record in play which is playing big bass Good air movement is ...good :^) now where did I put that smoke pen .... "Smoke 'em if you got 'em" - - |
My LFD MM0 looks like it has the same circuit board as the LFD Mistral, but has a double mono power supply fed by a very generous toroidal transformer. It's switchable between MM and MC, it seems to sound very good on both inputs. I saw that one was sold on ebay for 275£, and another one advertised in spain vor ca. 310€. These are extremely attractive prices. Sonically, to my ears it plays well into the 2000$ phono stage league. |
^^^^^^^ Pegasus - I am not an amplifier-preamplifier-phono manufacturer; but someone who bases all products I own (not just audio) on design, construction, operability, reliability, and with my audio products together - making music (lets call this part implementation). I don't tolerate downtime, hiccups, or operability problems especially with any products that are supposed to, with others as part of a whole - bring me pleasure for leisure activities. It has been my experience with all products (not just audio), that a good design to start does not guarantee a good implementation. In fact. The lesser design implemented well; can have better end results than a better design not implemented well. The setting up of a vinyl turntable system - especially the tonearm - being a perfect example ? Now I do own audio amplifiers with both type of transformers. It is my general understanding that a toroidal transformer by design is better to minimize hum and buzz. So it makes it ideal I would think for a preamp / phono design. But in reality my understanding is it is in fact much more difficult to implement a toroidal design. Harder to make. It stands to reason then that to implement this type of design will cost more. Pegasus
The LFD, with some hum and interference problem in our test, has toroidal transformers ;-) Interesting. Is this the one ? LFDThere are toroidal transformers and then there are toroidal transformers. True Story Was finishing the basement space adjacent to my main music room - to hold my extra gear and it became music room B. I assembled some gear and started listening in the unfinished room space. This gives you a good idea "with your gear", how much damping and other room treatment is going to be needed. Now, with no music playing, whenever I would get up to change the lp or cd I would hear a hum as i walked close to the gear. I followed all the normal procedures to find and eliminate the hum. It was not audible at the listening position. It did not come from the speakers or individual components that were turned on. Frustration set in. Then one day when I was standing between the speakers with no music playing my right ear got fixed on the hum. It was a transformer that I discovered was for the front door bell. It had been mounted to the side of one of wood beams supporting the main floor. Only visible from a certain angle. I followed the cord unplugged it and the buzzing transformer stopped. What relief ! My wife was not as happy as me about this event. I promised my wife I would re-locate it to the back of the house. But I like not having a door bell ....... There is a knocker on the door. But I also discovered that people have forgot how to use those things. They need to see buttons now. Moral of the story and Lesson Learned for me. When trying to eliminate hum and buzz... Look straight ahead; look to the left; look to the right; look down. Don't forget to look up. btw... it was not a toroidal transformer :^) |
Regarding EI (there are several other "square" cores BTW) vs. toroidal transformers: Things are not that simple. While a toroidal has the advantage of a more simple "flowing" magnetic circuit, it's main "advantage" is the absence of an air gap - an economic advantage. This makes for considerably less iron for a toroidal, and more inductivity with less windings. This makes for a low (ohmic !) loss transformer, with low impedance windings.
However this creates disadvantages: The saturation of a toroidal is very sharp, and with the industry practice (and the practice of almost all audiophile transformer builders) of driving the transformers too close to the magnetic saturation point of the cores ("Efficient" ! Bling!) they are *the* achilles heel of excessive sonic mains sensitivity.
And within these issues DC on the mains (a strong disturbance of high variability) drives a toroidal transformers very easily into saturation, a massive disadvantage!
The last related disadvantage of a toroidal is the inherently lower ohmic loss: It produces (much) higher charging current spikes, which on their own magnetize the (hard limited) toroidal core much harder, and again pull away reserves from the iron core. Low loss is not per se better, on magnetic circuits it creates very audible problems.
A correct air gap of a well made EI transformer (not the usual cheap chinese ones) makes it much more linear, and it absorbs DC on the mains with much less hickups. And yes, it usually sounds better.
As does a well designed "artisanal" insulation transformer with EI core.
One example more of reality vs. hype and hypothesis.
And a toroidal "out of reserve" creates very strong hum fields BTW.
In my system, there is a low count of transformers (and an increasing count of batteries). The LFD, with some hum and interference problem in our test, has toroidal transformers ;-) Close to my phono front end (1m) there is only one transformer plus the phono stage transformer, if there is one. |
(D), of course. Although, (A) is pretty general and applicable; the ET2 has corrected mistakes found in other arm designs.
However, and a bit of a stretch to be sure, but (B) the function of a surge tank can be said to convert the pulses in the airstream of a pump (alternating current) to a smooth airstream (direct current). Moreover, and an even bigger stretch, a desiccant air filter can be said to refine (C) the air (substance) through distillation. So, yes, rectification is a good word. Wait, this is a trick question.....
Some thoughts with my wine (red, and probably too much of it) :^)
My amps' transformers? EI, all the way. However, being monoblocs they are a good distance from my front end (via 15' ics). My phono preamp uses a toroidal and is much closer..
What did my wife do with that last bottle of Malbec? :-) |
Pegasus - The power supply is one of the places where rectification "happens" (yes, it does), Rectification is a really good word - ET2 thread readers Quiz Question :^) What is the best meaning of rectification for this audio thread ? a. the act of offering an improvement to replace a mistake; setting right b. the conversion of alternating current to direct current c. the process of refinement or purification of a substance by distillation d. determination of the length of a curve; finding a straight line equal in length to a given curve Pegasus - Regarding RF: It was only a problem with one phono stage, that might have some issue in the power supply (while still sounding very impressive). Some thoughts with my coffee (black) :^) Interesting - when I think power supply I think Transformers - Toroidal and EI - This is the one of the big secrets IMO , well, as well as not living next door to a neighbor running an underground radio station; to setting up unshielded phono wires with no noise/hum. How about looking at the perspective of the phono stage. Which is better ? Toroidal transformer. Major advantage is that they do not radiate much magnetic field. James Bond prefers this type of transformer. :^) EI transformer. Radiate a significant magnetic field from the exposed windings. Low level phono audio signals and gain stages prior to the output stage of amplifiers are small enough, I think, in strength, that if they pass through a decent sized magnetic field, will cause hum in what you hear out of the speaker. What about amplifiers. Should we choose Toroidal transformer or EI power transformers in amps, preamps, phono stages ? My amplifiers are always quite a distance from the preamp/phono stage. I have seen setups where audiophiles cram everything into one rack or closed in space. So what type of transformer is used in your Amplifier ? Does it use an EI transformers ? Is it anywhere near your phono stage ? Here is a fun video that was shown on the Discovery Channel. Making McIntosh Tube AmpWatch how they make the transformers starting at the 2:00 minute mark . Do you think you will be able to use unshielded wires if this amplifier is placed near your phono stage setup ? James Bond you have your work cut out for you. I think maybe we will need to bring back Sean Connery for this effort ? btw - myself, I am not feeling good about how they make the transformers and also in this video toward the end; how they join the inside guts to the outside jacks. By solder on a circuit board ? Another discussion ! No more coffee for me ..... |
The real fun in research is the reality. It has a certain from time to time recurring character trait of disrespecting the holy truth of any hypothesis. Without that, life would be pontifical s***. :-)
Regarding RF: It was only a problem with one phono stage, that might have some issue in the power supply (while still sounding very impressive). The power supply is one of the places where rectification "happens" (yes, it does), the others are nonlinearities in active devices or shaky contacts. No problem even with ca. 1.5m of twisted non screened solid core wires. That's my experience in the context of my system.
Very important: I compared the phonostages with a superb insulation transformer that does a lot (by sounding like less devices in the signal path).
I placed a Stadler air cleaner / ionizer in my listening room, that ran for very few hours (1-2) but was unplugged while listening. After experimenting ca. three weeks with "high quality" water in a humidifier which improved the "atmosphere" or energy but made the sound somewhat dull. The results with the ionizer are amazing: Remarkably more full and transparent - and no charged LPs... !!
We suspected already during an earlier listening sessions, that the slowly increasing amount of dry air exiting the tonearm creates - a lot! - of static charge on the vinyl surfaces. And it had a considerable effect sonically. The ionizer, building up a certain reserve of air ions (smells also a bit like Ozone), seems to eliminate this problem. Hmmm...
The Decca continues to amaze - fantastic! And this already with the Lehmann Black Cube... :-) |
Pegasus
"Somehow a "better" insulation with thinner litz wires should be "capable" of better radio reception :-/ ;-) "
"While I had a big issue with some intermittent RF signals ( ;-), probably radar " You are one funny guy Pegasus. :^) So much possible comedic material when analyzing audiophilia. I would pay to go see you perform it at Just For Laughs. |
- ct0517: It's interesting what you quote about the wire loom. While radial tonearms have the advantage of leverage on the point where the wire exits the tonearm tube and enters the base (tube), the distance is short, and the wires are somehow uncontrollable in their movement, so they are inclined to rub / stick / jump - and this "out of sight". The latter problem is nonexistent in tangential arms, if the wires are properly arranged. Thales' Micha Huber prefers *very* thin wires (ca. 0.07mm), probably to have the arm movement as free as possible. If this is necessary "even" with radial arms, not even a trace of a problem will remain regarding freedom of movement will remain with such wires for tangential arms either. IMO even two twisted 0.15mm wires, carefully arranged, do not create a problem.
- Dover: The silk wires are interesting, as these have much more electrostatic "field" surface covered with natural insulation than the compared solid core wire, this might (on sinister or twisted paths) affect RF sensitivity...
Somehow a "better" insulation with thinner litz wires should be "capable" of better radio reception :-/ ;-) In this case: The opposite!
Isn't reality from time to time baffling us?
Actually it's more of a surprise if we actually and really *know* something for sure.
- Decca: I had a first try yesterday with a artisanally rebuilt Decca, in the Garrot tradition. Yes, it's still a bit of a hassle concerning hum and screening. My 1.25m unscreened solid core wires are too long, but the hum with one phono stage we compared yesterday was quite acceptable even in my suboptimal situation (the Lehmann Audio Black Cube).
The first results are extremely impressive - in a truly musical way. This cartridges liquidity, high resolution, ambience retrieval (not 1:1 = big spaces) and grainfree transparency is *hugely* impressive!
Yes, there is a slight upper mid forwardness (but still in the range of "realistic") and yes, there is a certain upper limit in tracing (now, in my present setup), which is slightly modulated by the very low horizontal LF resonance (not yet damped enough). I will experiment with different spring / counterweight settings.
Still my rebuilt Koetsu Black is - as yet - more general purpose, and extremely natural too, and as yet it traces better.
- Phono stages, in short: The Black Cube is good enough by far to show off the superb qualities of the Decca. It seems to sound better on MM than MC and it's good. The Lehmann was a trace gray on MC, but well organised, generally transparent, dynamically stable and transparent. I had some issues with the Koetsu on high level historical horns (on fff).
. The same issue on blasting horns did arise with an austrian phono stage from pure dynamics. This one was very good, transparent and open, with very good stage in all dimensions. The bass was very good too, and it was fuss free in setup. (It costs around or below 1000$)
. The real stunner was an older LFD MM0, same circuit as the LFD Mistral and later basic LFD phono stages (but with a much beefier power supply). While I had a big issue with some intermittent RF signals ( ;-), probably radar, it was truly superb in timbre, agility, space, musicality and dynamics with a very natural, open bass. My feeling is that the LFDs phono stages might be considerably underrated in the press.
. My Audio Synthesis Passion phono had probably an issue with the supply connections, resulting in a not typical slightly opaque and undedamped quality in the bass, and a slight haze. The Passion Phono was still very transparent and true to instrument characteristics with wide and high stage, depth was a bit shortened probably by the mentioned issue. Generally and over long years this is a superb Phono stage. |
11-04-15: Ct0517
Pegasus - Generally, I find that one considerable advantage of low impedance MCs is that they don't need screening through bypassing / dumping external EM-fields through their low impedance.
+1 Just to add, for those who will be attempting the James Bond maneuvers; use a higher signal / noise MM or other cartridge if possible. If you can make that one work, the MC will be a breeze. btw - any one going to go see the new Bond flick "Spectre" ? I saw "The Martian" last week. Cheers |
Pegasus - Generally, I find that one considerable advantage of low impedance MCs is that they don't need screening through bypassing / dumping external EM-fields through their low impedance. +1 Dover - Also I did not have the arm grounded either. No hum or noise with Shure V15vxmr or various LOMC's. In many talks with the fellow that made my Wire Loom a few years ago now. He has confirmed to me that from his own professional experience/discussions with his customers; that in his opinion air bearing tonearms provide a level of isolation that pivot arms can not match. He has not had one customer with a pivot arm be able to use a loom like this. He makes similar looms for pivot arm customers; but they plug into the back of the pivot arm hub and there is a faraday cage the last foot or two near the phono stage. Depending on the design of the preamp/ phono. My preamp sits to the immediate right of the TT on the next rack. I sit beside the preamp. (hence no need for remote) . The design of the preamp/phono has the phono to the back right. If it was on the left I could have used wiring about a foot shorter. Just sayin... also Regarding shielded cables, I still own some Purist Audio Venustas phono cables. They are nice cables and are well made. On the "audiophile perception" used market, they are worth as much as a used base ET2 in decent shape. With that very small phono signal, once you have made it work good "naked" you realize (can hear) what all that material in the cables is doing to the sound in a comparison after - in your own system. What' s that you are asking ? the Venustas ...how did they sound in comparison ? In my room sounded "sweeter", like adding a little sugar on top, but with also a perceived smaller pipe of sound. Hey - not a bad thing at all really ...a little sweeter .. right ? I happen to be someone who takes my morning coffee black. I'm pretty sure that someone who takes a double - double coffee will like something else better. Afterall ... all is fair, as far as what you want to use for rope with this Audio Hangman Game .... right ? And remember the Cables Forum at Audiogon has almost 9400 separate threads |
Pegasus -
The copper litz I used was the same wire as used in the Sumiko headshell wires - each of the +R -R +L -L legs consisting of multi stranded litz - each strand within the bundle being individually insulated with silk. This ran from the cartridge pins to the side of the TT and was soldered directly into a very short pair of stripped ( unshielded ) MIT MI330- total loom was about 15" to phono. Also I did not have the arm grounded either. No hum or noise with Shure V15vxmr or various LOMC's. Like you I am not a fan of shielding signal wires where possible.
Is your TT chassis & platter grounded ? If so how ?
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Hi all - interesting bits & pieces!
Ct0517: interesting to hear more from internal design parameters of Bruces bearings. Some time I'll make photographs of my wiring etc.
Dover: The wire experiences are very interesting, as they are real findings. I'm not convinced however that the reason for the RF issue is solid core or silver, it could be the insulation environment of the wires affecting HF reception too, or the smaller wire diameters. As always the observations are true, the causes sometimes can be more complex than expected.
Were the silk litz wires individually isolated (HF litz) or just the whole bunch? (Besides HF detection / diode-property could also be a cold soldering joint, but I don't suppose that).
My turntable still has the original alu plinth (not too long anymore), but the motor is fed by batteries and the tt as such has no connection with the mains when running. grounding a "raw" alu plinth surface is a PITA...
The Deccas by definition have each channel ground connected ("matrix" summed through the vertical coil). So the ground loop is there for the small EM-field buggers to sneek behind and find. Luckily they oversee the possibilty under certain circumstances - but which? Hum is a dark asian martial art, teached under monumentally wound trees and learned by the nasty little buggers. There is some hope though in the light swords of master Yoda...
Your check list will be very helpful for many in trouble! Like a friend who messed up the ground connection on his new, outstanding phono stage, complaining about everything except his wiring arts.
- Generally, I find that one considerable advantage of low impedance MCs is that they don't need screening through bypassing / dumping external EM-fields through their low impedance.
It's certainly a drawback that exactly the type of cartridge that is more sensitive to capacitive loading - and therefore the sound of the dielectric too - needs screened interconnects. IMO & IME screening doesn't help the sound quality except for eliminating potential hum. |
"It ain't over 'till it's over" yes - they are in deep doo doo now - Down like the Jays were 3-1. In today's game have your pitcher like in game 1 - once again throw close to their lead off batter (who always swings on the first pitch) This time - make it even closer. Moustakas will really lose his cool this time and run into the field at your pitcher. He will be ejected. One up Mets. All is fair in sport - that's why there are rules. Cheering from this side of the border :^) more Billy Joel Until the Night One of my favorites. The lead up from the 4:00 minute mark to the climax gets to me every time. For the romantic - a good one to crank up for those times when you put yourself in big doo doo with the wife. You know...a successful marriage requires 1/2 dozen songs like this ...ready to play at any moments notice :^) - |
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Oops! Sorry; this new iPhone is driving me nuts. Go Mets! |
Chris, that is exactly what I did . It helped a great deal with MM's which tended to have grounding issues although not nearly as severe as with the Decca, but with the Decca it is still a problem. MC's have never been a problem. For anyone who is interested, Michael Percy (website) stocks all necessary items including Teflon tubing, copper mesh and sleeving. |
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******* YELLOW STICKY ET 2 THREAD - FACTORY SETTING OF PSI - REGULAR AND HIGH PRESSURE MANIFOLDS ************
I reached out to Bruce to help shed more light on how our manifolds work - both regular and high pressure HPM models. He responded and I believe answers the questions for our thread. Comments welcome.
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Hi Bruce
Was hoping to shed some light for ET2 owners on our thread regarding how the setting of PSI on our manifolds was done.
A couple of questions.
1) Are the set screws in the manifolds set up differently for different PSI's ?
2) Does setting a higher minimum PSI manifold (i.e. 19 PSI minimum), mean the spindle/manifold (gap) is smaller, tighter. How I came to ask this.
My ET 2.5 which you set up for highest possible psi 19. It continues to dominate over my digital. I also own an older ET2 High Pressure Manifold. I have noticed without air applied, that pushing my spindle through the manifold on the ET 2.5 is tighter, than the spindle going through the older ET2 manifold. The older ET2 HPM will also work with a lower psi, example 7 psi.
Appreciate any information you can provide.
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Chris,
The pressure drop across the set screws define the restoring force and part of the stiffness of the air bearing.
The tolerance between the Manifold Inner Diameter and the Spindle Outer Diameter determines the lifting pressure as a function of flow rate through the set screw. Without a restoring force or pressure drop across the set screw, the bearing will lock up, so you always need a higher air pressure in the manifold housing as compared to the pressure at the surface of the spindle.
The high pressure manifolds have a slightly tighter tolerance between the spindle and manifold, they also use a set screw with more plating to restrict the air flow around the threads to create the increased pressure drop (the difference between the pressure in the manifold housing and the pressure at the surface of the spindle).
It does not hurt to slide the spindle in the manifold bore without air, the resistance you feel may be the surface finish roughness on the hard coat anodizing as well as tolerance.
I hope this helps, thank you very much.
-brucet
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Happy Listening |
- Frogman - as u r a New Yorker, I wanted to mention I was very touched last night watching the NY Mets - KC Royals baseball game; when the camera focused on Billy Joel and the PA system played "Piano Man" with everyone singing. What class ! Go Mets Go - those damn Royals took out our Toronto Blue Jays..... :^( ***** Pegasus
Yes I have two twisted silver wires running left and right of the tonearm. Another example of how the ET2 design allows you to be inventive and ingenious with the wiring. In this case Pegasus a picture would be worth a thousand words. Dover....Started picking up local radio stations and all sorts of rf. Twisting the wires helped but did not eliminate the rf...... Attention Attention. We seem to picking up radio and RF. Immediately invoke 007 maneuvering. and while at it please bring up that Faraday cage up from the vault as a backup. This seems to be a very persistent strain Sounds like disco(love the Bee Gees btw) :^) |
Pegasus - a few suggestions for hum
TT Checks :
Check the chassis/motor earthing on your SL1210- is it earthed to the wall ?
If so, then earthing to pre will create ground loop.
Check for continuity between TT earth and spindle to ensure platter is earthed. If not then there is an internal earth lead in the TT not connected.
Personally I've always got lowest noise by earthing the TT chassis/platter/motor through the power cable. If the TT chassis etc is earthed to the preamp you are putting noise into the phono ( assuming a single ended system ).
Arm Checks :
Unplug the phono cables/earths etc from the pre.
Check for continuity between your tonearm earth and the earth on your Decca phono cable with the arm not plugged into anything. If it is continuous then you will have an earth loop if you connect both the tonearm earth and signal cables to preamp. It is a long time since I had a Decca, but if I recall correctly some had the body and signal earth strapped at the cartridge end.
If the tonearm earth is truly separated electrically from the cartridge signal earths, then I would take the arm earth to the chassis and wall rather than the preamp. This is because any noise picked up by the tonearm earth would be dumped into the signal path in a single ended phono if you connect the tonearm earth to the phono pre.
ET2 Wiring :
My experience with single stranded silver wire was bad. Started picking up local radio stations and all sorts of rf. Twisting the wires helped but did not eliminate the rf.
I eliminated the rf completely by going to a silk copper litz wire. Even without twisting it in pairs there was no rf.
In both cases the wiring was continuous between cartridge and phono input.
Hope thats some help.
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Chris, that is exactly what I did . It helped a great deal with MM's which tended to have grounding issues although not nearly as severe as with the Decca, but with the Decca it is still a problem. MC's have never been a problem. For anyone who is interested, Michael Percy (website) stocks all necessary items including Teflon tubing, copper mesh and sleeving. |
Pegasus et al
have u considered using a DIY Faraday cage for the last part of the wire loom - the part that doesn't affect the spindle movement right after the wire loop to where the wires go into your phono.
A sample Faraday cage recipe. For around wires.
1) Small teflon tube.
2) Larger teflon tube around smaller tube.
3) Brass / copper around wires to which a ground cable is attached at the end furthest from the phono.
4) Finish off with attractive audiophile sleeving :^) - optional.
The cage will capture all the crap and send it to the ground wire that you attach to your preamp/phono ground.
This is good option if your rack/gear setup design does not allow for the James Bond maneuvers I discussed in my previous post. :^) |
Richard
Yes i have two twisted silver wires running left and right of the tonearm. They are mounted to the tube via three very small pieces of double sided adhesive foam strips, to hold the wires and prevent them from touching the metal arm tube. They "exit" the arm connection bending a bit up and then down in a wide radius to the plinth, where they are supported again with an adhesive foam pad. And there is a separate ground wire to one of the arm screws.
With careful wiring dressing the arm is completely free in movement, and very sensitive to the smallest lateral imbalances, as it should be. |
Oops, one other thing: London's put out not only a lot of mechanical energy, but electrical as well---5mV! You will need a phono stage with a pretty high overload margin, and lower than average gain, about 40dB being a good figure. |
One aspect of the London/Decca cartridge design that influences arm choice is the differing lateral vs. vertical compliance figures, they being 10 X 10 (-6) cm/dyne Vertical and 15 Lateral. I know the ET arm has differing moving mass figures in the two planes, but whether or not they align (or conflict) with the London compliance figures I don't know. Whatever arm is used with London's, it has to have as stiff and non-resonant an arm tube as possible, and the best bearings one can afford. That benefits all cartridges of course, but London's put a LOT of energy into the arm.
Another thing to know about the cartridge is that it likes to be loaded with unique amounts of resistance and capacitance. The Reference model is at it's best with 15k resistance and about 220 pF capacitance. I was tutored in Decca's in the 80's by Harvey Rosenberg, and he liked the Decca's of that time with a LOT of capacitance, like 0.5 mF! |
Pegasus
I may have missed it, but have you made twisted pairs with your naked wire runs?
Cheers |
