Eminent Technology ET-2 Tonearm Owners

Richardkrebs/John47

Quote from ET2 Manual – Bruce Thigpen

P29

It is desirable in most cases ( low to medium compliance cartridges 5x10 dynes/cm – 20x10 dynes/cm ) to use the minimum number of weights, far out on the cantilever stem. This decreases the horizontal inertia of the tonearm while increasing its vertical inertia.

This is the exact opposite of what Richardkrebs continues to advocate. Richardkrebs is advocating increasing the horizontal inertia for low compliance cartridges – the opposite of what Thigpen recommends.

Re the comments on the Kuzma

There is a lack of comprehension of what is claimed with the Kuzma.
Frank Kuzma is quoted as follows

Horizontal disturbances of an eccentrically spinning record occur only at 0.55Hz or 0.75Hz (33rpm or 45rpm). This is well out of the Air Line tonearm's resonance in the horizontal plane, which is between 2 and 5Hz and does not cause problems tracking virtually all LPs.

That is all he is saying.
Kuzma does NOT say the cartridge does not see this resonance, it simply means that it does not cause problems tracking. This is because if the resonance of 0.55hz were within the tonearm resonance range the two resonances could at worst sum and “double up” which could cause tracking problems.

I quote Bruce Thigpen

the cartridge will "see" .55Hz mounted in any tonearm, more so in one with higher horizontal inertia

I don't think Kuzma means the stylus does not deflect at all at .55Hz, that would defy physics

Note that Thigpen says that the 0.55hz is seen “more so” with higher horizontal inertia. I would suggest this is one of the contributing reasons for Thigpen recommending a lower horizontal mass for low compliance cartridges.

You continue to ignore Bruce Thigpens' recommendations based on the laws of physics and his extensive testing, because it would appear you do not grasp the physics and engineering principles involved. Unless you understand those principles then you are unable to understand what underpins Thigpens' and Kuzmas' comments and designs, and are speculating at best.

"..... do not appear to grasp the physics and engineering principles involved."

MF wasn't speculating when he heard 1 of the best 2 arms in the world - I guess you'll never be able to look out the door and see blue sky and appreciate that (the Kuzma is just about the best arm on the globe, dispite it contravening your design principles ..... uuuuuuuuuuuum how many arms have designed and manufactured?

I hope Franc Kuzma casts an eye over your 'advice' to correct his fauly design.

Thekong, Richard, I sometimes use brass weights (supplied by Thigpen) instead of, or in combination with, the usual lead weights. IMO, the concern is not so much the possibly inherently-different sound of something like brass as compared to lead, but the fact that using a material with a different density may necessitate placing it on a different spot along the I-beam, since as Dover points out:

****It is desirable in most cases ( low to medium compliance cartridges 5x10 dynes/cm – 20x10 dynes/cm ) to use the minimum number of weights, far out on the cantilever stem. This decreases the horizontal inertia of the tonearm while increasing its vertical inertia.****

In my case, the use of the supplied brass weights usually results in having to place the weights further in along the I-beam. In my set-up, this is usually not ideal, with inferior overall bass performance. I suppose that it would be possible to have the exact size of brass weight machined to match the weight, and hence placement, of the lead. But, that is not the case with the weights that Bruce sent me.

Hi Thekong

Lead is also banned in Canada. Based on the shape and size of the ET2 counterweights here is an easy DIY alternative.

Go to any tire shop and pick up a couple of the lead weights that they use on wheel rims. They are of substantial size. They are easily snipped and the hole drilled to make any size weight you need. To get the nice square look as BT’s take them to a machine shop. Otherwise you could be up and running in the same day with the lead.

Nice speakers btw ! I am glad we have distance and a lot of water separating us otherwise I would be tempted to come over and ask to borrow them for a while.

Some more impressions.

The lead weight reminded me of something.

I “experimented” with a form of higher mass quite a while ago but only at the counterweight end. I had at the time email conversations with a couple of high profile Audigon members who were in this "lets add more weight to the counterweight camp” with their past experiences with the ET2 and ET 2.5. I really hope they see this post.

I added more weight to the counter weight end and tried to get as close to the spindle as I could. I found the sound seemed to get “bigger” each time I did it. It was addicting. I also did not have my Studer at the time for a reference point in my room for the sound. I made extra lead weights sourced from the tire shop I referenced above.

The horizontal mass of the arm may not have been seeing “some” of this extra weight as it was decoupled, but the air bearing spindle itself was. I talked to Bruce about this. Now lets imagine that he has heard every story you can probably think of in the last 20 + years from tweakers, hot rodders and experimenters of his tonearm. He was very clear to me. Try it and see...

So he encouraged me and said at some point I would affect the balance of the spindle, the air would not be able to sustain the spindle weight properly, and rumble would occur. something like that.

I never got as far as actual rumble occurring and then the light came on for me. The ET2 counterweight ” I” Beam is the most misunderstood part of this tonearm and the EASIEST to screw up. The ET2 arm comes with a set of lead weights along with a range described in the manual of the minimum and maximum cartridge weight they can counter. This range can be modified btw - but thats another discussion. How many of you have thought to yourselves, I don’t want to lose them. So lets put them all on the counterweight. Who hasn’t done this when you first started out with the ET2 ?

How many have even done it with a light MM cartridge?

NOW the really big question - imo.

How many Michael Fremer types (professional reviewers) have done the above - used all the weights when they were not needed ?

Has anyone ever read an ET2 review where a description of the weights (how many used/positioning on the I beam was actually described.

There positioning is as critical to the sound as the fine tuning adjustments made to the cartridge itself. Very sensitive. Without the knowledge about this ..

Well as noted in the previous posts from Dover the manual doesn’t say add extra weights like I was doing in the experiment. It says it is preferable to get as far out on the beam as you can. This implies less weight on the I beam itself as its intent is to be decoupled. Think about it – the weight is on a leaf spring. ITS A HORIZONTAL VERSION OF A CAR/TRUCK LEAF SPRING . Get that in your head and your home free with this tonearm – IMO.

So this Iight came on for me around the first couple of pages on this thread. Someone that calls himself Frogman reminded me.

Btw – I thought this person that calls himself Frogman was a scientist that spent his time where its wet; looking for Frogs. Monikers being what they are. Boy was I wrong !

Re-applying less weight further out on the beam; the tuneful bottom end returned with more speed and coherence. Similar wording to one of Dovers previous posts.

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Warning - The above post about adding "mass to the counterweight" does not relate to the mass spindle dampening being discussed. Persons reading this thread do so at their own risk.
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Chris/Frogman -
Thanks for your feedback and comments. I was beginning tho think that analogue heaven consisted of only me and Bruce on a desert island.

I think the key point Chris as you have alluded to is that even if we assumed the Kuzma was the best arm in the world, adding substantive mass to the ET2 is wrong, it is taking it out of its design parameters. To accommodate the mass one would have to redesign the main air bearing and retune the Q of the total system. These factors are being completely ignored by the other folk.

Chris I note that you are also using the carbon fiber arm tube for high compliance cartridges and yet still finding the optimum is only 2 springs with the Benz. This does suggest to err on the more decoupled side of the ledger for LOMC's as well, the only downsides being possibly a fall off below 30hz.
I would be very surprised if many were getting below 30hz in a domestic environment, and if they were it would be unable to be controlled in that environment. To put it another way a roll off below 30hz I would see as an advantage in most domestic environments where room bass response is usually quite uneven and unpredictable.