Lawrence,
It was magnetism......not RFI/EMI that surprised me on the Cu-180 turntable mat?
The Micro Cu-180 is indeed non-magnetic.
My ignorance levels on electro-magnetism run deep.......but I'm guessing that there are materials which can act as 'conductors' whilst others are 'insulators'?
That's why the stainless steel of the 'cradle' I designed became 'magnetised' by the strong magnetic field and why the non-magnetic aluminium platter of the Victor becomes 'magnetised'.....or at least allows the magnetic field to pass through?
The same effect must be in operation with the Micro copper platter even though it is 3mm thick?
I can understand the rubber platter mat being an 'insulator'.......but a 1mm piece of pigskin being a sufficient insulator bowls me over.....
And why a 2mm thick piece of vinyl is NOT an insulator.....I don't know?
I'm sure someone will educate me?
Where's Al when you really need him?? :-) |
You're right Thuchan,
There appears to be 10 times more Cu-180 platter mats available for sale.....even NOS ones.....than Micro ever made in their day?
Similar story with the Orsonic headshells....:-)
Aren't the Chinese great? |
To be fair to Dertonarm Lew.....he was referring to belt-drive turntables with his 35 lbs platter comment.
His logic.....and that of many other belt-drive designers.....is that greater mass creates sufficient inertia in the revolving platter to overcome stylus drag?
He also advocates non-elastic string or thread drive instead of rubber which means that the platter is not insulated from the cogging of the drive motor.
This of course requires a superb motor design.
For a direct drive turntable with a quartz-locked servo motor.....particularly a positive and negative servo control like the TT-101......the lightest possible platter will make speed changes less perceptible than a heavy one.
A common mistake that critics seem to make when discussing quartz-locked servo control....is that the servo is always 'hunting' for the correct speed?
They disregard the notion that the speed is quartz-LOCKED. The speed is generally spot on and not 'hunting' at all. The only time speed correction may be applied is under localised untoward stylus drag when....as you correctly remark.....good torque and bi-lateral speed control come into their own. |
Which leads me to ask myself. Dynavector is a well respected company. if they thought there was a problem with magnetism would they have built their tonearm to be joined with their cartridges ? Good question Chris. One would think not? |
Thuchan,
Don't get me wrong.......
The Raven AC-2 is an excellent turntable providing very stable speed control and superb analogue performance when set up correctly.
It has audibly kept level with the TT-101 until this last 'nudie' change I have made.
And in my 35 years experience listening to all the best turntables I could access.....the TT-101 is simply the best.
The fact that I have extracted a performance level from the Raven that is so close......speaks volumes I think?
I will not be selling the Raven :-) |
I'm wondering if Idlers exhibit the same 'magnetic' characteristics as DDs seeing how they also have motors etc under the platter?
I suspect that the EMT 927 would react "positive' to a magnet wandering amongst its innards.......especially with its steel supporting frame?
Are you able to confirm this for us Thuchan?
And Lew.....perhaps you could do likewise with your Garrard 301? |
Lewm,
Syntax despises DD turntables and Idlers and eschews the qualities displayed by the big Caliburn belt-drive.
He also abhors MM and MI cartridges so crediting him with any knowledge of the TT-101 is like mistaking him for a man of discernment? |
Dover,
Did you miss the point that with the pigskin platter mat in place....there was no magnetism at the mat nor the vinyl disc? |
I just downloaded the Teslameter 11th App onto my iPhone and it's very interesting.
It measures an electro-magnetic field in either Micro Teslas or Milli-Gauss (1 Tesla=10,000Gauss).
Just sitting in my listening chair gives a reading of 43uT or 590mG whilst at the turntable platter I can get a reading from 92-over 200(cut-out point) uT or 590-over 2000mG.
Readings UNDER the naked TT-101 are all over the 200uT max limit.
The readings change with power on or off so a complex study is required.
Because of my 3 tonearms.....the position of each cartridge traverses a different path with the cartridge passing over the transformer reading the highest.
Of course...all the cartridges at their inner-groove points are directly over the motor coils and the reading goes off the chart in all these cases.
The interesting thing is no difference in sound is heard by me as each cartridge passes over different reading points...and the arm passing over the transformer sounds no different to the other arms in intrinsic quality.
As a side-note....in this months issue of Stereophile with the 2013 Recommended Components.....for turntables ranked A+ and A.......76% have their motors mounted in the plinth close to the platter.
If Thuchan can download this App to his iPhone and demonstrate that the EMT 927 provides plenty of magnetism.......it may be possible to make a case for the beneficial effects of this ingredient? :-) |
Henry, Don't own a Garrard 301 Sorry Lew.....I knew you had an idler and was just too lazy to look-up your System Page..... It would be interesting to check your Technics SP10Mk3 which has the motor with the most torque (power?).....? |
Hi Chris,
The Verdier has always interested me....and as you say......Nude....but also Copernican in concept?
One question I have.........what is the material of the tonearm mounting pods?
They look like wood? And how are they fixed to the base? And how do you organise a different one when you get a different tonearm? |
Nice fish Chris.
Rainbow trout is one of my favourites when done the Cantonese way....steamed with ginger and shallots. Yum......
Have you mentioned the new speaker project before?
Sounds intriguing....knowing you :-) |
A good suggestion Dover......
I will surely be borrowing the QLA7 for comparison sessions once the granite cradle arrives. |
Is it time for some clothes.....ππβ Five years ago I went nude...but don't tell my kids... Three years ago I went nuder...kind of 'Punk Mad Max'.... Sound was good. Inspired some fellow converts and adherents but a small problem arose. Whilst my solid cast bronze armpods at 25lbs each would never move......the rather lightweight cradle could often be nudged in the process of cartridge swapping and the spikes could slide along the hard laminate on the cantilevered wall shelf..π© Tired of re-checking the alignments of three arms, I decided to drill through the laminate at the positions of the three spikes to prevent any further sliding. Mission accomplished but small problem now became BIG problem..π The tips of the spikes now made contact with the shelf substrate and its inherent stresses. These subsonic tensile stresses now induced a resonant frequency response in the stainless steel cradle which transferred to the platter/record interface and could be amplified by the stationary stylus at maximum volume settings. Most turntable designs deal with structure-borne feedback in a combination of various methods with mixed results. Suspending the plinth on springs or trying to isolate it with rubber or other compliant feet or various types of air-inflated supports is one method. Mass is another. Real mass is still another... I have chosen to try a 'mass' solution...π The idea behind the 'mass' approach is the hope that physical vibrations can be absorbed and dissipated as heat within the plinth/platter instead of allowing resonant response characteristics. Sometimes this works and sometimes not.... With the space restrictions of my 'nude' setup I can only create a cylinder of either granite or gunmetal/bronze (wood is simply not massive enough in this small structure). Bronze would weigh 3 times more than granite (19Kg vs 7Kg) but also costs 3 times more...π² So at this time....somewhere in China, there is a CNC machine routing and polishing my turntable 'plinth' cylinder out of a solid block of black granite..π Gosh I hope it works..... |
Hi Lew,
As I'm only concerned about density, slate and granite are pretty similar but granite is more homogeneous as slate is riven. So, it's far easier to know what you will get with granite...π
Also getting polished pure black as a visual finish with granite is simply not possible with slate... |
Granite certainly has a sound to it. I hope not in this situation....? As I'm only using the granite to create a 'mass cradle' in lieu of my stainless steel cradle, I'm hoping for no contribution to the sound of the turntable itself. After all....when I went from the 'nude' table on tiptoes to sitting in the steel cradle, there was no alteration to the tonal characteristics of the table. In other words....the steel cradle had no 'sound' to it so I'm hoping the granite table similarly has no sound to it...π We'll soon know...π |
Thanks for all the feedback guys....π Corian unfortunately is a lightweight in the density scales (1.7g/cm vs 3.0g/cm for granite/slate). It seems many of you think the material of this 'cradle' will have an effect on the sound? I hope you're wrong...ππ½ If I were to physically 'bond' the turntable to the granite, I'd be inclined to agree with this thought but I intend to simply 'rest' the table on three rubber pads just like those on the steel cradle. I have experimented greatly with differing methods and materials in the support of this turntable. I have also recently bought for my son, a Victor TT-71 factory mounted in a heavy wood plinth and compared the sound in detail to my 'nude' mounting. Whilst the superb drive and timing of the Victor decks is untouched by the coupling to the heavy wood, there is a very slight (but inoffensive) colouration to the overall palette which is absent from the 'nude' mounting. There is little doubt that there is truth to the theories of resonances in materials and the effects of combining dissimilar materials to mitigate these resonances. I have my theories regarding the pervasive evil of structure-borne feedback in the turntable loop of analogue audio and the methods for handling it.......and I'm putting my theories to the test...π
I'm not a believer Pryso, in the relationship between the 'ringing' of a material when struck and its performance in resonance dissipation and absorption. Polystyrene beats most materials in the 'ringing' test but is not ideal as a plinth material. And yes....I've tried it π This exercise is not about developing a plinth for my 'nude' DD Victors. The sound of the 'nude' Victors is unsurpassed in my listening experiences. This is about adding mass to my turntable support to prevent it sliding on its supporting shelf. If there are any detrimental sonic changes....including colourations....the 'cradle' will be back...π₯ |
Just picked up my repaired TT-101 yesterday in time for the new granite cradle.
After 3 months without it....it's like a heroin hit...π |
Lew,
I have learnt to respect the Victor engineers when it comes to all things analogue.
From their DD turntables to their tonearms to their cartridges to their pigskin mats....every product appears to have the ineffable quality of analogue knowledge and ingenuity.
I think Dover is correct in his assessment of the plinth construction they used for their quality drives.
I have just spent the afternoon at my son's place listening to the QL-A7 (now with the Empire 1000ZE/X).
There appears to be little masking or colouration to the sound compared with a 'nude' TT-81.
I might add that the turntable/plinth combination is heavy...and I mean boat-anchor heavy.
This seems to give to the sound an authority and low-frequency heft that eludes many other decks.
My advice (and my Tech's advice) to you is......get a good tech to burn out ALL the old solder joints in the TT-101 circuits and carefully re-do them.
If they have already been done.......do it again to those joints on the Power Board Circuit under all the control buttons.
An intermittent fault (or one that starts as such) is indicative of a crack or discontinuity in a solder joint. |
I received the granite cradle and have epoxy'd the three Helicoil inserts into the drilled bottom holes to take the M8 stainless steel levelling spikes. Looks quite nice..π Bit of a squeeze inside.... But is just as I imagined it...π Now for the listening tests..... |
Thanks guys, The Victor sits on 3 hard rubber grommets fixed to the granite edge just as it did on the steel cradle. View 1View 2 |
Aaaaahhhh....π± The feedback problem is still there..... Even worse if anything..π° This wasn't supposed to be like this... In desperation I changed the spikes to more substantial ones and then to Stillpoints Ultra Minis. No difference...βΌοΈ In desperation I went to the hardware store and stocked up on all possible FLEXIBLE supports. No difference with any of them. This simply makes no sense.... My Raven has none of this feedback at all and it sits on exactly the same shelf as the Victor. Any ideas guys...? I need help...π |
It cannot be air-borne feedback Aigenga....
The stylus is in the groove with the turntable motionless and no music coming through the speakers.
When I turn the volume up to a very high level...a low frequency drone begins and then increases in volume without further manual volume input.
The feedback begins when the room is in silence...π |
I went back to my original set-up from 2 years ago and guess what........ No feedback.....ππ Then it dawned on me...... Has it dawned on you.....πβ |
Dover wins the Kewpie Doll...ππ When I changed the support of my Victor to the steel cradle two years ago, I removed the flimsy perforated metal screen surrounding the 'guts'. Well it turns out that this metal screen was acting as a Faraday Cage for the electrical emissions from the motor power supply. Without the screen absorbing and neutralising this energy.....the cartridge apparently picks up the 50/60Hz emitted frequency at very loud amplification levels (I can't imagine that the platter is vibrating at this frequency?). This is why there is no feedback issue with my primitive (sorry Aigenga π) original support system. And yes.....when I place the Victor into the granite cradle with the screen attached.....no feedback πβΌοΈ This however gives me a dilemma.....I would prefer not to have the screen attached as there are audible benefits without it. I also don't believe the screen is as effective (being tight up against the granite inner wall) as I believe a Faraday Cage should have both sides of the metal screen in free air? I have orderred Mu Metal sheet and wondered if this was a possible alternative to the Faraday Cage? Is it OK to wrap the power supply transformer in Mu Metal or will it get too hot? Would it be better to line the inside of the granite cradle with the Mu Metal instead (or also)....or am I doomed to using the metal cover forever? |
Hi Chris, It may be the camera angle....? I think the Dyna is riding just fine...π I hate removing the word 'Nude' from any sentence......π° |
Richardkrebs, Is there a secondary issue here?Could there be acoustic feedback following the initial EMR problem?
I think you're right.... When I play music at loud volume containing 30-60Hz bass drum beats (like Cream's 2005 Royal Albert Hall Concert or Copland's 'Fanfare for the Common Man' Ref. Recordings)....this 50/60Hz feedback loop can take hold. At the same time I can feel the vibrations in the supporting shelf and in the granite cradle...π± As the shelf is directly over the Vandersteen subwoofers, this seems like air-borne sound converting into structure-born feedback. But why only recently...and why is the Raven not similarly affected as it is identically situated? |
When I started this Β exercise over six years ago, I began rather crudely with the Victor TT-81 simply supported on cones. MODEL 2010Β Unsatisfied with the 'flexure' of the motor-unit about the cones, three years later I designed an independent stainless steel cradle to support the now 'fully nude' TT-101 motor unit... MODEL 2013Β Two years after that, still unsatisfied with the vibrational and torsional movement possible with the flimsy steel frame.....I designed a cradle cut from a solid block of black granite and then polished. MODEL 2015Β Despite the fact that my floor is a reinforced concrete slab cast on the ground and the turntable is supported on a thick laminated shelf cantilevered from a solid brick wall.....I know that there are low-frequency vibrations in all building structures and materials particularly materials under stress like suspended floors, shelves and equipment stands. When materials are in stress (particularly tensile stresses)....they actually emit low-frequency vibrations between 2-10Hz and these frequencies are easily transferred through turntable plinths, motor units, spindles, platters, tonearm mounts and thus into the tonearms, cartridges and vinyl records themselves. So for this year....I invested in a Herzan TS-140 Active Isolation for my turntable/armpods combination. MODEL 2017Β This stand is designed for electron microscopes and contains numerous electronic actuators which isolate to 0.5Hz in all six degrees of freedom. HERZANΒ So what is the difference.....? Exactly what I expected.....but still almost unbelievable π₯ The improvements at first seem subtle but are all-encompassing.... Be aware.....this has NO effect on frequency response, But every frequency SEEMS affected by suddenly having a purity, transparency and 'body' that was somewhat 'cloudy' before the Herzan. There is absolutely no strain or stress to any music at any volume and as you turn up the volume...so you want to continue turning it up πΆ I thought perhaps the bass would be deeper or more solid but no.....the bass seems unaffected but all the clarity and delicacy is bestowed upon the midrange and the highs with a singular crystallinity emanating from every cymbal, string, flute and horn. The first casualties of unwanted vibrations in the analogue domain are the tiniest molecular-sized groove modulations which contain the most ephemeral informational DNA. Qualities like body, soundstage, spatial depth and positional indications are simply smeared when other unwanted vibrations are present. So it's been an illuminating and rewarding journey... I hope you all enjoyed it with me.... Am I finally done? I think so π |
Thanks Norm, Five years ago after Thuchan listened to my system, he suggested I look into an isolation stand and I investigated Minus K (I didn't know about Herzan). The trouble with the Minus K (as you would know) is that it requires the load to be more or less centralised and evenly spread. It can't cope with isolated individual loadings. It's large-scale wobble movement was also rather alarming....π± I'm sure it suits your turntable perfectly. Can you remind me what turntable you have mounted on it? The degree of effectiveness in using an active or passive isolation platform largely depends on the amount of air-borne energy in the room. That's a common assumption many make but I doubt its validity. Just think about it.......with the Minus K stand, you have not decreased the amount of 'air-borne' energy one iota and as you turn the volume up.....you are certainly increasing it. Yet isolation stands (of all types) cannot prevent the air-borne energy in the room from interacting with the turntable plinth, platter, tonearms and cartridges directly. The fact is, the air-borne energy is not of a sufficiently low frequency (and amplitude) to be a direct consequence. More likely that some of this air-borne energy is absorbed by the rooms structure (including supporting shelves and stands) and transferred via 'structure-borne' feedback. That's why the Minus K and Herzan stands were designed to combat 'structure-borne' vibrations of the lowest magnitude. The Herzan is certainly a 'plug & play' design as you say..... I just hope the electronic actuators and motor controllers have a long and durable life....ππ½ |
Thanks totem,
Herzan USA is the Distributor for Australia (go figure).....so all dealings were directly with Reid Whitney and Tim Rather who were most helpful.
The unit was shipped via FedEx (when the custom top-plate was ready) and was here in three days....π
As I understand it, if something untoward were to occur, it would most likely need to be shipped back to Switzerland where it was designed and built?
|
Interesting experience pryso......
I wonder if you've tried experimenting with placing the stylus in a stationary groove whilst slowly increasing the volume?
Does any feedback develop and if so....is it different with the turntable on the left of the alcove to when it was positioned at the far right?
|
Thanks for the kind words Jim,
Some think that the Herzan is an 'overkill' for our application......and at the prices for their 'active' bases, it is an option few would contemplate.
I haven't tried any other bases although I wanted to try the Minus K many years ago.
It simply wasn't suited to my isolated turntable/armpods arrangement and I concentrated on making my cantilevered supporting shelf more rigid in the meantime.
I'm sure your Vibraplane gives you most of the same improvements I've described.....
It's hard to describe all the subtle effects one can hear once ALL spurious vibrations are removed.....
Most of the records I own where the high-frequencies at times became strident and even sometimes unbearable.....are now listenable. It doesn't mean one is not aware of 'hot' recording or mastering techniques.....it just clarifies exactly what is occurring.
Glad you enjoyed the Thread Jim and thanks once again.
Regards
Henry
|
Hahaha folkfreak π
I think the Herzan looks like a perfect fit for your turntable.
And yes Lew....it's hard to find the compact TS Series of Herzan on EBayΒ
|
Cost of course is relative.......
Any serious analogue lover who is in the market for an $8,000-$15,000 LOMC cartridge......should seriously consider a Herzan Active Vibration Isolation System and a $300 vintage MM cartridge instead......
There is really no comparison IMHO....π
|
