but I hear a slight negative which does not exist with the mass approach. As I said, I think that it is caused by induced currents circulating the spindle. Hi Richard - Did you try the magnetic damping on belt drive or string drive as well ? Do you really want these currents anywhere near your delicate feed from the cartridge? Richard – in your opinion what would you consider as “near your delicate feed”. Reason I ask. The two little circle magnets I use with my ET 2.5 - the closest one is a good 7 or 8 inches away from where the wire exits the armtube – when at the the end of the record which is the worst case. I should note I am using copper on the ET 2.5 right now. I have silver on the ET 2.0 that is on a brass armpod. No room for trying magnets there. Looking at my analog gear its obvious I am not afraid of magnets. I know some who think magnets cause cancer. Can you give some details on how to go about making that lead slug for inside the spindle? Cheers Chris |
Dgarretson
Dover, can you clarify a few points concerning the effective horizontal mass of ET? The manual states that it is 25-35gms. Is this the mass of the wand plus manifold tube, which is then increased by addition of up to 40gms in counterweights? Hi Dave Page 5 of manual – spindle weight (14 grams) tonearm tube weight (11 gms) plus the counterweights. To give you a reference point I am using one large and one small counterweight with the 420 str. That should be 20 gms. Page 9 ‘By decoupling the counterweights horizontally but not vertically, the mass of the counterweight is not seen by the cartridge above a certain frequency and is lowered. This allows use of heavier (more rigid) components in tonearm design with increasing effective mass. Decoupling mechanism is damped at a 2 – 5hz.” Maybe Dover, Richard or others can add more regarding the horizontal inertia. "lots of variables" YUP :^) Cheers |
Dover.
Magnetic dampening will vary with the speed of horizontal motion..... so does pure mass. The formula F=Ma you quoted in another thread confirms this. Try shaking say a 1kg weight backwards and forwards at 0.55 hz (record hole centering error) and try again at 20 hz, (music). Much more force is required at the higher frequency. If this weren't the case, the R&D dollars speaker driver manufacturers spend on reducing the mass of the moving parts would be for nought. As I said earlier all three dampening methods increase in resistance with rising frequency of excitation.
That said, I agree with you, I do not like the effect of the oil trough.
To be clear, I do like, mostly, what magnetic dampening does. Further it is elegant and kinda cool, but I hear a slight negative which does not exist with the mass approach. As I said, I think that it is caused by induced currents circulating the spindle. Do you really want these currents anywhere near your delicate feed from the cartridge? I would be using mag dampening today if not for this slight negative.
Mag dampening increases cartridge output, yes agree, same holds for mass. My take on this is perhaps different to you. While is reduces micro vibrations which is a good thing, I think that the higher output is because the cartridge has more lateral resistance to work against because it cannot move the arm laterally as much. And move due to the cantilever tracing the groove it must, F=Ma again. More cantilever lateral movement equals more output.
Yes the Dynavector is an arm design that I have studied because it is unusual in using mass and magnetic dampening. But currents near the cartridge output?
Look, I don't actually care if people agree with me on this mass thing. I said earlier that it was contentious. Anyone with a full range system down to the 20s, might want to try it. They could well be surprised at what information is lurking in the grooves. |
Dover, can you clarify a few points concerning the effective horizontal mass of ET? The manual states that it is 25-35gms. Is this the mass of the wand plus manifold tube, which is then increased by addition of up to 40gms in counterweights?
I understand that the mass of hanging decoupled counterweights behaves differently than fixed counterweights. It would be interesting to have the math on this horizontal pendulum effect. In any case, while the design may lower horizontal inertia to an extent, it will also contribute to horizontal inertia to an extent. I would imagine that the effective horizontal mass of the entire moving system is quite a bit higher than 35gm.
In the course of developing the predecessor of the Trans-Fi tonearm, Poul Ladegaard experimented with a pendulum counterweight. For whatever reason that feature was abandoned.
BTW, with a custom lightened CF slider and wand the horizontal mass of my Terminator totals 35gm. This includes custom front and rear wand counterweights designed to vary the wand's vertical effective mass. On my full-range system with a sub to 18Hz, the lighter horizontal assembly sounds better than the heavy one. Also, variations in vertical effective mass are more impactful than relatively large variations in horizontal mass.
Lots of variables. |
Chris/Richard As per my earlier post, both an oil trough and a magnet impose a resistance to lateral movement as seen by the cantilever. They behave much like weight in the lateral plane. I have simply used weight alone. This is incorrect. This is like comparing apples, oranges and pears. Magnetic dampening will vary with the speed of horizontal motion whereas the added mass approach is simply increasing static inertia considerably. The resultant behavior from an additional horizontal force will be quite different. Same for fluid dampening. In terms of sound - with magnetic dampening I have gotten increased cartridge output, which indicates that the cartridge is losing less energy due to micro vibrations being damped. By contrast with all fluid dampening I hear a loss of speed, focus and detail. Dynavector also concur with this view in their discussion of their tonearm design. Despite the high horizontal mass they use eddy current dampening to reduce micro vibrations. In my view the ET2 is the best arm I've used. I changed to a Naim Aro due to problems with a sprung floor and growing tired of pumps, tanks and airhoses running through the house. The ET2 is out on loan, but at some stage it will come back. In engineering terms a unipivot is the most rigid bearing you can get. I chose the Aro because compared to the Graham of the day it had no arm tube dampening, the Graham arm tube was full of crap, and the bearing was the correct way up for energy dissipation to ground ( the Graham had what I call an upside down bearing, point up ). The sound of the Naim Aro is quick, lucid through the mids, excellent soundstage and very musical. The downside is that I believe it has a very narrow operating window in terms of cartridge compliance and mass. The Dynavector Nova 13D sounds excellent as does a Denon 103D. The Koetsu Black sounds awful, unstable in the bottom end. I recently purchased an FR64S to try with my Ikeda Kiwame - this arm is one of the best pivoted arms I have used and due to the detachable headshell I am currently running this so that I can play around with all my cartirdges - Ikeda Kiwame, Dynavector Nova 13D ( freshly rebuilt from the ground up by Dynavector Japan ), Koetsu Black and Denon 103D. No pivoted arm in my experience can match the transparency and presentation of the soundstage as well as the ET2 though. Furthermore as you will be aware, there is plenty of bottom end depth and speed if set up properly, despite reports to the contrary. |
Chris.
Thanks for the offer but I must respectifully decline. I am just dialing in my Shelter and newly renovated enlarged room. More distractions, while delightful, are unfortunately just too much for now.
re my building a new arm. The design would allow for bolting to a flat surface with three screws. Simalar to the ET. It has fully adjustable horizontal mass independant of the counterweight. I am struggling with the wand design at present, which is a little radical. While I can visualise it, I'm not sure I can build it. The whole project may founder on this. If I am to build a new arm, I want to be pretty sure it will be a step up from the present version.
Dover, what did you do, loose your ET2 in a drunken poker game or something? |
Hi Richard – email sent.
Where are my manners ? Do you want to try the 420str cartridge?
Your table and arm would need to be set up for the higher compliance.
I was all ready to send it to NZ anyway.
When you are done you can maybe pass it to Dover? I think Dover misplaced his ET2 - and I think it may have something to do with a drink called Slivovitz from Serbia. Maybe Nandric (Nikola) can provide more details on this.
Hopefully Dover gets it back soon
Glad you guys on the other end of the world have a sense of humor.
Cheers Chris |
Chris.
No I have not measured these forces and would be very interested to read Bruce's comments on same. I assume it is a big file, so can I ask you to email it to me at the contact address on my web page, if not too much trouble. Or if appropriate post it here.
As per my earlier post, both an oil trough and a magnet impose a resistance to lateral movement as seen by the cantilever. They behave much like weight in the lateral plane. I have simply used weight alone.
I did my initial tests on extra horozontal mass by disabelling the leaf springs on the counterweight beam and winding equal lengths of solder around the goose neck and counterweight assembly. This way I kept the lateral balance of the arm static. It didn't look pretty but was informative. I also tried this configuration with and without magnets.
I currently adjust for different cartridge compliances by using a range of counterweights.
Dover, I seem to remember from this thread or another that you no longer use an ET2. If so, we would be intereted in what you are currently using and any reasons for the change. As we all, I think, agree, the ET2 is pretty darn hard to beat. |
Hi Chris - yes I agree with Thigpens comments, but I think Richardkrebs high mass approach throws away the advantage of the ET2 over other tangential arms, that is the light horizontal mass. The ET2 is less than 25gm compared to the 80g of the Terminator. The effective horizontal mass of the ET2 is even lower with a decoupled counterweight. The other problem with adding mass to the ET2 is that not all low compliance cartridges are created equal, as the compliance in the horizontal plane cannot be assumed to be the same. For example the Denon 103 is far more rigid in the horizontal mode than the Koetsu even though they are similar compliance vertically. |
Richardkrebs
With a pivoted arm the horizontal effective mass in multiplied by the head shell offset. Only a percentage of the cantilevers lateral movement is resisted by the arms horizontal mass in trying to rotate the arm the rest of this movement is resisted by the cantilevers efforts trying to bend the arm tube itself. Linear arms do not impose the second characteristic on the cantilever. This I believe is one reason that the pivoted arm guys complain about a lack of gestalt from linear arms. We largely fix that with oil troughs or magnets. Pure mass is another option Hi Richard – Have you actually measured these forces? I find it very interesting that what you say is supported by information I have from BT on actual testing that he has done with pivot and linear arms. His measurements found that this phenomena (horizontal effective mass, multiplied by the head shell offset and the resulting bending of the cantilever) produced a +6 to 12dB bump between 10-15 Hz versus flat response down to 5Hz (the ET-2). He also went on to say that “over the years these parameters have been mathematically analyzed and are well understood. There is an easy measurement to prove all of the above, it is called is wow and flutter. If you take the same turntable, put a straight line tonearm arm on it and a pivoted tonearm, both with the same cartridge, the straight line arm will exhibit about half the measured wow and flutter.” I have his summary findings on this if anyone is interested. Alot of his findings again are in his ET2 manual available publicly. Some of it was posted here already here already. Richard, Dover others ...... any comments on this very basic wow and flutter test ? |
Ketchup
Yes your shim idea is a good one. I wonder if it would be possible to fashion tiny wedge shaped shims and push them in. Could maybe eliminate a bunch of trial and error with individual parallel shims.
And yes I agree, there is considerable compliance in the orings. Also in the original goose neck and arm pillar/ manifold interface.
Chris, yes I have the CAD CAM machines that could make the goose neck and a complete arm. ( excluding spindle and sleeve. ) It would however be costly due to the likely small runs.
The original Counter weight mechanism has been discarded. Adjustment is by means of two knurled discs, either side of the weight, on a M10 threaded rod. You can kinda see this in one of the pics Ketchup found.
Ref horizontal mass, I realize that this is controversial. I simply encourage those of you who feel the urge to try it. Particularly those of you that have full range systems. ( response into the lower 20s )
If we redefine horizontal effective mass as resistance to lateral acceleration we will see that magnetic and oil dampening are similar to " pure mass" all three options resist lateral movement and all three increase this resistance as the lateral movement increases in frequency.
All three impose lateral forces on the cantilever when the record hole is not centered.
The reason that I believe that the rules for horizontal effective mass are different for pivoted and linear arms is this.....
With a pivoted arm the horizontal effective mass in multiplied by the head shell offset. Only a percentage of the cantilevers lateral movement is resisted by the arms horizontal mass in trying to rotate the arm the rest of this movement is resisted by the cantilevers efforts trying to bend the arm tube itself. Linear arms do not impose the second characteristic on the cantilever. This I believe is one reason that the pivoted arm guys complain about a lack of gestalt from linear arms. We largely fix that with oil troughs or magnets. Pure mass is another option
Lead is strategically placed in an ascending hierarchy throughout the arm and TT itself. Tests with a number of soft and hard materials in the head shell and elsewhere convinced me that "local" sinks are beneficial.
While the magnetic dampening was an improvement over the oil trough, it was not as good as the recently added lead slug. It is speculation on my part why this is, but the induced currents seem to be a logical possibility. If they do exist, I suspect that they would be AF in nature, not RF.
I heard this, admittedly, small problem with the original arm wiring, OFC Litz headphone wire I then used and with the silver I now use.
Twisted pairs of wires are less susceptible to RF due to common mode rejection.
In my TT, the arm and motor are rigidly fixed to the same upper acrylic layer.
Dover, are you still running an ET2? |
I'm bowing out, while whatever I offered, maybe, somewhat remembered. ( for what, that is for you to determine) Good luck to you all! .... remember the dragonplate... I'm not associated...> |
Richardkrebs Re: your ET2 mods. Here are a few points for you to consider. I have a view on linear arms in that the rules for pivoted arms and effective horizontal mass do not apply. In fact I have added a lead slug inside the bearing spindle 25 mm long…
This combined with the fixed counterweight means that the arm is HEAVY in the horizontal plane. This view is indeed strange. Many records are off centre. By increasing the horizontal mass of the arm significantly, when you play an eccentric record the increased resistance to motion from the additional mass will result in increased cantilever flex. On eccentric records your approach will result in phase anomalies during play back, increased record wear and probably cartridge damage in the long term. My ET2 has been lightened, no internal dampening, no external tube dampening, decoupled counterweight and have had no issues tracking low compliance cartridges, achieving extended bottom end with speed, articulation and accurate timbre. Magnetic dampening controls lateral motion on eccentric records. The arm is optimized for low compliance carts. As you can see, just, from one of the pics Ketchup found, it has a fixed counterweight. I have found the opposite. Using various Koetsu’s and a Denon 103 Garrott I found that there is an optimum decoupling point. Eliminating the decoupling resulted in more “apparent” bass but with less speed, articulation and timbre. In my decoupling methodology I used teflon pads either side of the spring with the end cap quite loose. This gave a soft lossy quality to the motion as opposed to springy. On the magnetic dampening front the negative I heard was possibly caused by the induced circulating currents interfering with the cartridge output I could not hear any distortions of this nature with the magnets located on the opposite side of the manifold from the cartridge wand and using copper litz arm wiring that exited before the gooseneck and straight into the phono 12” away. Cartridge leads are single strand silver lightly twisted at about one turn per 8 mm. Continuous to the preamp Highly prone to rf, might explain your perceived issues with magnetic dampening. Have removed the Teflon in the head shell and replaced with a square of 1/2 mm thick lead and super glued in place. With low compliance cartridges, there is significant energy generated for the arm to deal with. This energy needs to be wicked away from the cartridge and sunk to ground. To maximize this energy flow away from the cartridge materials should be used that that successively increase propagation speed heading towards ground. This encourages the energy flow away and minimizes reflection of energy back towards the cartridge. Inserting lead into the head shell creates an energy reservoir that will sink energy, but due to the softness of the lead some will be released back into the cartridge out of time with the music. The same argument applies to the use of a lead slug in the bearing tube. This causes smearing and loss of detail. I would not recommend the use of lead. One other question I have on your SP10mk3. You mentioned you are using an acrylic/lead/acrylic plinth. It appears from the photos that you have bolted the motor to the bottom piece of acrylic and the ET2 to the upper piece of acrylic, with the lead layer in between. If so this would compromise the loop rigidity between cartridge/arm/platter required for accurate playback. |
Richard,
It sounds like you have a lot of time into that arm. Very nice! A few months ago I took my ET 2.5 manifold out of the housing to give it a cleaning before I did the flow tests that Chris linked to above and to see how it's built. Upon reassembly, I saw how much give there is in the rubber o-rings and realized that the manifold is not rigidly mounted at all. I thought briefly about a way to stiffen the assembly.
It should be possible to insert three precision shims between the manifold and the manifold housing. They will probably have to be somewhere around .0005" oversized (or less) to get them in without deforming the manifold housing to the point of cracking. Once they're in, there should be no need for set screws which may be a problem for a stock housing. This is not for everyone as you will need a way to slowly creep up to your shim thickness a tenth of a thousandth of an inch at a time unless you happened to get lucky and already have the correct size shim.
Another option is to do what you did (or use three screws instead of one screw and two shims) but put the screw(s) on the inside of the o-rings. A little silicone on the threads may be enough to hold back the 15-20 psi.
Chris,
Nope! It’s got to be a 301 :) |
Ketchup
Anyway, can you believe that I can not find one photo of a Garrard 301 with an ET-2 or ET-2.5 arm? Ketchup - Does a JN Lenco with an ET 2.5 count ? |
Hi Richard – thanks for joining the thread and Ketchup thanks for that link which shows better pictures. Richard - A lot to think about in your post thanks for sharing. I need to digest it some more. A few things that hit me immediately though. Big jumps in performance were the goose neck. This was made from the same grade of aluminum as the wand. The bracket that joins the wand to the spindle. I have always wondered about that Gooseneck – listed as the joint in the ET2 arm parts list. Before I ask Bruce if he can make a special run of aluminum ones for Et2 owners , do you have a source for making them ? If we asked ET2 owners here we could probably come up with a certain number of owners that would want to try an aluminum one? I know I would take two for the different size ET2 and ET 2.5 spindles. The manifold and arm pillar are made from acrylic. Lead is inserted and epoxy glued inside these to sink energy. VTA is adjusted by a removable screw after loosening 4x M5 cap screws. Manifold and pillar are locked solid once these are tightened.
Arm pillar is fused to the plinth effectively making it one assembly. I really like your custom arm as it is sleek and clean looking but that the adjustments have been eliminated that could cause movement. Very solid but you can still make VTA adjustments. Chris you have a regulator, water separator. It looks like it uses brass fittings and appears to be close to the arm. Try soldering a wire to the exit fitting and earthing this. I don't know why this works but it is possibly something to do with static electricity build up in the air stream.
On the topic of static electricity try rubbing the wand with AFC anti static foam cleanser. The stuff they use on photocopier glass. I am definitely going to try both of these ideas - thanks Have removed the Teflon in the head shell and replaced with a square of 1/2 mm thick lead and superglued in place. Others have tried different materials here also with good results. I have not got around to doing this. I remember Dover discussed doing this on his ET2 as well. Its a bit of a pain to remove that Teflon piece ? I have a new arm on the drawing board based on what I have learnt from this one. Richard - Will this custom arm be designed for a specific type of armboard / plinth, or will it be designed to be used with different armboards/surfaces ? Your counterweight is now fixed. I assume you are are not using the leaf spring? We have discussed the advantages of the single, double triple spring here. This would be a very interesting discussion plus the lead slug you mention. Cheers Chris |
Chris
I built this version of the ET2 around 15 years ago. Drawings are long gone but it could be reverse engineered. The arm is optimized for low compliance carts. As you can see, just, from one of the pics Ketchup found, it has a fixed counterweight. I have a view on linear arms in that the rules for pivoted arms and effective horizontal mass do not apply. In fact I have added a lead slug inside the bearing spindle 25 mm long with its OD equalling the ID of the tube. This is glued in place halfway along its length. ( it can be removed if I go to high compliance carts)
This combined with the fixed counterweight means that the arm is HEAVY in the horizontal plane. I have tried magnetic dampening and oil troughs but prefer the pure mass approach. I run at around 12 psi, lower pressures may be problematic when adding so much mass.
On the magnetic dampening front the negative I heard was possibly caused by the induced circulating currents interfering with the cartridge output
The manifold and arm pillar are made from acrylic. Lead is inserted and epoxy glued inside these to sink energy. VTA is adjusted by a removable screw after loosening 4x M5 cap screws. Manifold and pillar are locked solid once these are tightened. The arm was designed with a lifter like the ET but I found a subtle improvement when this was removed. Same goes for the VTA adjustment screw. I. E in its operating form there are no bits to flop about. Arm pillar is fused to the plinth effectively making it one assembly.
Cartridge leads are single strand silver lightly twisted at about one turn per 8 mm. Continuous to the preamp
Big jumps in performance were the goose neck. (This was made from the same grade of aluminum as the wand.) The bracket that joins the wand to the spindle.
There are 2x M2 grub screws outboard of the bearing sleeve orings. These pass thru the manifold and contact the sleeve. Two small pieces of shim metal are inserted at 120 degree increments away from the grub screws. Once tightened the grub screws eliminate the compliance of the orings. There should be nothing soft in the loop between record and cartridge. This is a major improvement. There may be room on the standard manifold to do this but Beware anyone doing this it would be easy to break the manifold.
I use 2x 50 liter containers for the surge tanks. They are stuffed with long hair unspun wool to increase their effective volume. They are seperated by 6 meters of 1/4 hose entry and exit points are at opposite ends of these tanks.
Chris you have a regulator, water separator. It looks like it uses brass fittings and appears to be close to the arm. Try soldering a wire to the exit fitting and earthing this. I don't know why this works but it is possibly something to do with static electricity build up in the air stream.
On the topic of static electricity try rubbing the wand with AFC anti static foam cleanser. The stuff they use on photocopier glass.
Have removed the Teflon in the head shell and replaced with a square of 1/2 mm thick lead and superglued in place. Others have tried different materials here also with good results.
I have a new arm on the drawing board based on what I have learnt from this one. |
Chris, I was Googling images of "Garrard 301" and "ET-2" or something like that today and actually spotted another picture of Richards table. There are a few pictures here near the bottom of the thread. I have thought about making a new manifold housing for mine, but I eventually come to my senses and realize that I should just get the table up and running first! Anyway, can you believe that I can not find one photo of a Garrard 301 with an ET-2 or ET-2.5 arm? |
Richard Krebs ET2 Setup (Custom) Richard Krebs ET2 setup pic 1Richard Krebs ET2 setup pic 2Hi Richard, if you are in a position to discuss many are probably wondering what I am right now from looking at these pictures. I have to ask if any of what we see can be duplicated, made again, or was it a one time effort of passion ? Not your typical counterweight setup ? If you are not in a position to discuss – understand - wonderful setup. Cheers Chris |
The pump talk reminded me that Ketchup provided ET2 flow rates to us back in Nov - here is the link to his post which contains the information from his testing. Thx again Ketchup. ET2 Flow Rates |
Have filters and a pressure gauge, but not sure what a "regulator" is and locally what industry would be the best source for a suitable unit. Hi Grant - this picture shows a regulator (black top dial knob), moisture bulb and trap, pressure gauge They can be purchased separately or as a unit at any hydraulics place typically located in industrial areas. Total cost about $70 us dollars. The regulator allows you to dial the pressure down or up. The one in the picture is portable. You can hold it in your lap sitting in your sweet spot, and adjust the pressure up or down and hear how the music delivery is affected. You open the regulator by lifting up – turn clockwise and counter clockwise. When the music sounds best to you in your room – push it back in to lock – your done. As a kind of tune up I personally recommend anyone with an ET2 send alot more air than is needed to the tonearm so you can determine if you have any leaks from screws/bolts. This tonearm was meant to last forever – its industrial quality just like Bruce’s subwoofer :^) subwooferThe worst thing you can do is blow the tube off. Bruce Thigpen can also replace your low pressure manifold for a high pressure one. This changes out the manifold only – the spindle stays so you are left with a high pressure ET2 not a ET 2.5. I recommend emailing him to get the current price which is very reasonable. The high pressure manifold allows you to run low and high pressure with the ET2. Cheers |
You've just reminded me - I got a big improvement when I put an isolation transformer between the mains and the pumps. Much smoother sound. |
Hi Chris/Dover
Thanks for that information very helpful.
I have an ET2 with original low pressure manifold so I think 12 to 15 PSI if anything may be too high. The original pump did not like 50Hz, managing typically less than 4PSI.
Have filters and a pressure gauge, but not sure what a "regulator" is and locally what industry would be the best source for a suitable unit.
As the pumps are 115V, 50/60Hz I briefly considering running the two pumps in series, one "out of phase". I thought better to run them off a step-down transformer in parallel. Pumps would be housed inside a baffled box so effectively double insulated and isolated from one another, with the surge tank also housed in the same box.
For the surge tank I was going to use PVC pipe and fittings (2 - 300mm lengths of 200mm dia pipe with sealed end caps). Any advice on packing, was going to try some left over "BATTS".
Am I on the right track?
Many thanks for the advice.
Kind Regards
Grant |
Hi Chris/Grant
Yes I used 2 pumps running into a 20 litre surge tank. On the pumps I used, reversing phase & neutral at the transformer inside reversed the phase on one of the pumps. In NZ you must not reverse phase and neutral at the power cord because the mains fuse must be in the phase line. |
Hi Grant – welcome to the thread. Another New Zealander. I wish I was there right now.
With both Mark and yourself discussing Medo’s I dug out my medo ac0110 pumps from the past today and hooked them up separately and together to experiment. I remember I received them with three wires hanging. I cut off the three prong from two power cords and spliced them to make the wall plugs. So I did connect their grounds. I was only using one at the time and the other was a backup.
Separately mine both produce about 12 psi on a pressure gauge inserted within a few feet of tubing to the ET2. A real dynamo of a pump for only being a couple inches by a few inches.
When I connect them together on a T Valve PSI only goes up to about 15 psi as they are working against one another. Hopefully someone else can chime in if they are using two Medo’s. I went to the Timeter pump after the single Medo. The Medos are a linear piston design if that helps. Maybe Dover if he sees this can offer some advice as he used multiple pumps with his ET2 setup.
Cheers Chris |
Picked up two of the medo pumps and pleased to see they are 50/60Hz, so proposing to run them in parallel off a step down transformer, as our mains supply is 230v. There was a suggestion to run two pumps out of phase with each other. What should I do with the earth wires, or should I leave them unconnected?
Any other advice for using these pumps greatly appreciated.
Regards
Grant |
It seems we may be getting into symantics,?
Read between the lines......
My message has been, 'focus on the music'. Why do we need to discuss varionses between this or that component... at this stage... the most important thing is the music. May be, we should be discussing how many times we seach out new music?
Myself, I'm spending $300.00 + per month on LPs!
Yeah, that sounds right?! |
Dear Dgarretson,If you called my 'assumption' the false 'authority consensus' I would agree. We are supposed to share information we have but this does not mean that we
checked everything in the sense of the truth value. I thought that the opinion of the mentioned desiger may be relevant info but my primary intention was to mention this
cheap and available alternative (M 312) for the 420 which is obviously difficult to get. My 'horses' are elswhere btw.
Regards, |
Nandric, Absent direct experience with Terminator, your remark would seem to be a good example of what psychologists call the false consensus effect. |
Slaw - Mark asked for an opinion - I gave one. I am done with cartridges myself. Unfortunately I keep misplacing/losing the damn screws in the carpet. I hear tinkle tinkle sometimes when I vacuum. Hence my post about the screws. Have a nice day. I have to go shovel snow. Haven't seen anything like this in 10 years.
Cheers Chris |
Nandric -I know of course that the Terminator is no match for the ET-2 but both are linear so why not try? Hi Nandric (Nikola) Never heard the Terminator yet alone on the same table as an ET2. Feel free to share your impressions. There are Terminator owners here as you know. I have found personally, and you can confirm this by looking at individual setups. We SL Tonearm owners seem to share one thing in common- a straight line – anywhere on the LP. From there we are all very individualistic. Not one set up is the same. Cheers Chris |
Chris: Regarding your recent reply about the 420str... I'm really not sure what I'm suppose to take from this. Frankly, I love the cart/the sound w/my system. I was the one that initially remarked here or to you privately that the cart pins/angle would be an issue. I'm not one that really wants to try cart after cart. when I find one that sounds this good, I'm good. ( I have thought of a way to remedy my much earlier cart/pin/overhang issue when I decide to take the time). I'm just having too much fun listening and frankly don't want to take the time to change right now. Too much good music, too little time! Yes, it's true! |
The designer/producer of the Terminator tonearm bought one
of my 420 and also 415, 412 and M 312 STR by the 'pizza guy'
in Italy. He was impressed by 420 and M 312 and not
so much by the other two. The 312 is still available on the
Italian ebay ( testina giradichi) for 45 euro + postage (12euro?).
I know of course that the Terminator is no match for the
ET-2 but both are linear so why not try? |
Chris is exactly right, the 412 is not a as linear as the 420; a perfect description. As far as I know, the body ("corpus", thank you Nandric) of the two are identical. The difference between the two is in the stylus assembly. If you don't plan on doing a lot of cartridge swapping, and given how easy it is to swap stylus assemblies, it might be of value to you to have a 412 stylus assembly for casual listening and thus save the stylus life of your 420 stylus assembly. |
Hi Chris,
Thanks for the response. I'm not in the market right now, as I got a 420 from Nandric, but wanted to know for future reference. Maybe if the price is right on the 415, I might try it out for comparison purposes...
Regards,
Mark |
Hi Mark – from the specs in the manual which shows all three the 415 is closest to the 420. I have the 412 not the 415. I found it wasn't as linear as the 420 (hf, mid, lf). Frogman is using a 412 to make a new body for his 420 ? Maybe he will chime in if he sees this. I recommend a quick post on the MM thread asking for a 420 and for someone to pm you. Pretty sure somebody will respond to you. I paid around 70 euros for the 412 from what I recall. Cheers Chris |
Sorry Guys, my bad...
I originally stated that there were a couple of Acutex 412's for sale on eBay, but in reality there is one 412 and one 415. I would copy in links, but am not in a position to do so.
I would be interested in other's opinions on these two cartridges in the ET2...
Regards,
Mark |
Dear Chris, I don't believe that your amount of TT's, tonearms, carts and more in particular speakers can be explained with your mom's upbringing methods. But I must
confess that my both sons whose education cost me a fortune still ask: 'do I got THIS from you or mom?' BTW my youngest (36) never say 'Hi dad' or something similar
but instead : 'any new tonearm dad?'
I think that Dover and I like gossip and that is why we occasionaly participate in 'your thread'(grin).
Regards, |
Hi Guys,
Sorry I've been absent from the thread, but had to travel last week on biz...
Slaw, thanks for the additional input. I purchased a second pump, just to be sure...
Again, thanks to Nikola for selling me his last 420...I am indeed enjoying it very much!
Finally, there have been a couple of NOS 412's on eBay this week...don't know if they are worthy of consideration.
Best regards,
Mark |
02-04-13: Nandric
Dear Dover, I hope you realize that we are again in the wrong thread? Dear Nandric (Nikola) My mother used to say to me. “That is wrong son...don't do that” “Don’t do that son, it is bad for you” “If you keep doing that son, your xxxx will fall off” The funny thing is, I remember that the more she said things like this, the more I ended up wanting to do those things. Back to normal programming. Here is something alien but valuable I think. Alien Screws Just received in the mail the brass screw set. Seems like a good price for the quality. Not affiliated with the site. As a tweak for ET2 owners, if your current cartridge set up does not allow you to get to end of the I Beam with the lead weights putting the next size screw / bolt on may be all that is needed to get there. I keep losing the things myself. Cheers |
Dear Dover, I hope you realize that we are again in the wrong thread? Except of course if we intend to hide our preference for the MC carts from our MM 'comrades'. My
provisional ranking is: 1. Magic Diamond;2. Miyabi Standard (aka Krell KC100);3. Benz LP S 4. Kiseki 'Silver Spot'.
First of all I am informed by an owner that the Magic with a ruby cantilever really exists. So the one we both have seen on ebay.com is not a 'fake'. Second I am not sure if my Kiseki is 'Silver'- or 'Gold spot'. My has 5 screw holes on each side while according to some this should be the 'Gold one'. Anyway the cart is very fast and very dynamic, similar in this regard with the Miyabi. The Magic is, uh, 'magical'. Probable too good for some Balkanes. I would say really 'neutral' and refined. But only the Miyabi is in my main system at present .With Basis Exclusive, Kuzma S.R. the Reed 2 A, etc. The rest I tested in my second system with FR-64S/ SP 10 Mk 2 and Jasmine LP2. Hence my 'provisional' ranking.
Regards, |
Nandric - do you have a ranking for your MC's at this stage. Am very interested to hear what you think of the Magic Diamond. The Kiseki Silver Spot I know well so if you do a comparison to that then I can work it out from there. |
Dear Chris& Slaw, I sold my last 420 to Mark but am still
'loaded' with other ,uh, interesting MM carts. If you
promise not to tell the guys by the MM thread I will
confess to prefer the MC kind. I spend a fortune on those
lately: Kiseki Silver Spot, Shiraz, Benz LP S and Magic
Diamond. The last mentioned really deserves the adjective
'magical'. It is of course not done to try to sell whatever
via our forum but it is also very rewarding if one can help
an co-memeber. Even more so if the person in casu is a
friend of my friend Chris. I hope my address is still by the member list.
Regards, |
Slaw – My first 420 str, I tried out as I did the other MM’s the last year or two on my pivot arms first as they have removeable headshells and make it easy; and another big reason I hesitated putting it on the ET2, as Mark has already pointed out; the angle of the cartridge pins can be a real PITA on the ET2 armtube if your wire leads are long. Here she is on the pivot arm – well sort of a hybrid arm in this case – DV505. http://cgim.audiogon.com/i/vs/i/f/1322856939.jpgI got the 420 to sound good, but it didn’t better a couple other MM cartridges I already owned. It was not until I read Frogman’s post about it on the ET2, that I removed a cartridge that was on it, put the 420str on the ET2 and it was like – holy crappola. BTW - I am not sure if Nandric is coming back here although I hope he does. You have been away for a while. I think it has to do with being on the "wrong thread" and being asked to consider taking a Red Pill. |
Nandric:
I'm an interested party in regards to a second Acutex 420STR. I love mine! If it wasn't for Chris I wouldn't have mine.
I'm enjoying my system more than ever now! No turning back. |
Saubmgc: I had a Medo AC120 (I believe) and while it performed well beyond it's stature, it did run hot. Still no trouble in the long run. It's been gone for quite a while. I'm running 18.5 psi with my current compressor. |
I appreciated Chris's song list earlier, I also agree with a few others there. I've come across an interesting item that I'm currently using. I plan on integrating it into upcoming projects.
www.DragonPlate.com. I'm using the PP core plate.
I can only state the remarkable sonic upgrade it has made under my EAR phono. You can decide for yourself.
|
Hi Mark Wow - thats a great price on these pumps. Here is a direct link to your site. Medo PumpI paid $60 or something like that for each of the two I had. Placing a really small fan next to the pump will alleviate any worries of overheating. Years ago I accidentally left mine on all weekend to return with no problems. Cheers Chris |
Fellow ET-2 owners,
Surplus Center has a quantity of Medo AC0110 pumps available for $19.99 each. I bought one the other day to try out and found that it delivered a steady 6psi to my arm and was fairly quiet compared to my stock Takatsuki pump. The 30 minute duty cycle is a bit troubling, but found that after 30 minutes the pump didn't get too hot. I got a second pump and plan to hook them up to a surge tank and see what happens...Here's the link: https://www.surpluscenter.com/item.asp?item=4-1894&catname=
I would appreciate others thoughts on using this particular pump.
Regards,
Mark |
Antiskating and Frequency Modulation Distortion of Different Tonearm Geometric Hi Guys (gals?) There has been a few different threads on the Gon recently about turntables maintaining their speed - Speed Stability. The effect of stylus drag with turntable speed is always mentioned and acknowledged. I continue to go back to Bruce Thigpens ET2 tonearm manual, and find information that I had either overlooked or forgotten about. IMO - for anyone in this hobby this manual contains important data. Here is BT's information on this subject, the forces involved and some real measurements. The Et2 manual on page 51 says that an LP record contains approximately 40% vertical energy and 60% lateral energy. These are significant and different forces at play. BT did testing of these forces as they applied to different tonearms. The manual section that summarizes these findings follows. Taken from “the Eminent Technology ET2 Tonearm Manual - Pages 46 and 47”. Disclaimer - This is public information and is available online at the Eminent Technology website under support/manuals/ET2 owners manual. Antiskating and Frequency Modulation Distortion of Different Tonearm Geometric
Pivoted tonearms are designed so that the head shell holds the cartridge at an “offset angle” with respect to an imaginary line drawn through the tonearm pivot to the stylus tip. The arc traced by the stylus tip extends past the record center and is defined as “overhang”.
This design approach minimizes tracking error. There have been many articles written about the geometry of this design approach. Pivoted arms create several side effects which reduce phono cartridge performance. The first is a skating force which results from two different parts of pivoted arm design.
There is a force component (vector) that is directed toward the center of the record. It results from the stylus drag force vector not falling in line with the pivot point of the arm. This force pulls the tonearm inward and the stylus can be observed as bending outward. This force and the resulting bending can be demonstrated by connecting a rubber band to a pivoted arm around the cartridge body and pulling it straight (away) from the tonearm. Note: the motion of the tonearm is inward and results in bending of the rubber band (cantilever).
If you corrected these forces with an anti-skating mechanism such that the stylus did not bend (you can not really do this because the frictional force and resultant bending varies with groove modulation, stylus shape, tracking force, etc...) there still exists another component of skating.
This second skating force results because of overhang. There are frictional force vectors that result which are not directly ahead of the stylus. The surface of the record is not really moving straight ahead with respect to the stylus tip. As a result, there are force components directed ahead and toward the center of the record. The magnitude of the inward force depends upon the degree of overhang.
This means that any given cartridge works against lower horizontal forces in the Model Two tonearm (.1 gram or less) compared to a conventional arm (.2 grams/gram vtf). These figures apply if you use records that are not severely out of round. If you like to play severely eccentric records, ones with runout of greater than 1/8”, then we suggest you use a low mass pivoted arm.
For vertical forces while tracking warps, the cartridge suspension system must work against the tonearms moment of inertia about its vertical axis of rotation. For the Model Two, these forces will be similar to those of a conventional tonearm which has low to medium effective mass (10 grams). Fwiw - As an owner of both pivot and straight line tonearms I am aware that stylus drag differences differ with each. I never did take any measurements. It is now possible with software, a test disc and your Android or Iphone to measure things like turntable speeds and tonearm resonances, as discussed in this thread. See the post from Halcro |
