Eminent Technology ET-2 Tonearm Owners

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

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 ?

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 :)

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.

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...>