Eminent Technology ET-2 Tonearm Owners

Frogman,
Thanks for the positive feedback.
With regard to the loosened I beam this is where I got to:

When I first imported the ET2 the spring was prone to coming off. If I recall correctly there used to be a little piece of dampening stuck to the spring.
At that time if I recall correctly Bruce didn't have multiple springs, but offered springs with the dampening stuck to 1 side only or 2 sides.

Basically I found the decoupled methodology I used by trial and error.

I knew rigid coupling didn't work, because somebody told me it was better, I tried it and it was awful. At this point in time I was importing audio and had a shop full of high end TT's. We had Sota/ET2's combo's in three listening rooms with different gear, along with Oracles, Linn's, Pink Triangle's, Roksan's, Well Tempered's etc

In the home system at that time I had the Denon 103 Garrott/ET2/Sota Vacuum - I played around with the looseness of the spring and noticed how changeable the sound was.
So I went to 2 extremes – completely rigid, no good, then completely loose, way way better but not perfect.
Then I just experimented from there,, started with a loose I beam, packed the spring either side with tiny lead shims to dampen the swing motion - results so so, then tried teflon shims - much better.
The teflon shims either side of the spring in conjunction with the loosened end cap bolt gave a very smooth damped motion with the beam, so I stayed with these and then just slowly dialled the pressure up by slowly doing the end bolt up – listening as I went.
The bass timing improved but at a point it lost timing, so I backed off slightly and hey presto.
At the optimum bass speed/timing the I beam could move freely and very smoothly.
A repeat of the procedure with other cartridges seemed to work consistently.

In hindsight it looks like my treatment of the I beam is similar to Bruces and in keeping with the design parameters. My decoupling methodology dampens the I beam movement and most importantly leaves the frequency of the I beam motion very low below the horizontal frequency as outlined in the manual as one of the key design principles.

In case there is any confusion I dont advocate reducing the arm mass substantially. I did remove the heatshrink and sponge foam from the arm wand because in my view soft dampening stores energy and releases it out of time with the music.

Dover, thanks. It appears to me that re coupling/decoupling of the I-beam/weight we are dealing with two issues that, on the surface, may seem to be one and the same, but are actually two separate considerations. We have 1. the degree of coupling due to the stiffness of the spring, and 2. the degree of coupling due to how tightly the I-beam is secured to the arm. I make this distinction because, although I would have thought that the two are effectively the same, I am experiencing different and unexpected results from each approach. I suspect that each has different ramifications as concerns resonance, hence the very different results. As I mentioned above, I have almost always preferred (after much going back and forth) the double spring with most of the cartridges that I have used over the years; these, of every persuasion and compliance. The less compliant double spring usually yielding a more controlled, defined sound with tauter and faster bass. More compliant springs have produced sound that is generally fuller, but less-well defined; fuller mids and lows, but less-well integrated highs.

I usually approach system tuning with the idea that there is always a theoretical ideal, but a necessary practical compromise. I prefer fuller sounding tube amplification, so the perceived leaner sound of the double spring has suited my system well.

This leads me to the issue of perceived bass speed. This relates to (in my fairly non-technical mind, anyway) to the above issues and to the issue you brought up re energy storage of soft dampening. In my experience, perceived speed cannot be completely separated from perceived tonal balance. To be clear, for me speed refers to the ability of a component to let music (or, for the sake of this discussion, the bass range) move as it should; to allow it to swing, rock, crescendo, whatever, with the swagger that it does live. I have always found this aspect of reproduced sound to be THE most elusive of all. I have heard components that were unacceptably dark and excessively full sounding that let the music move as it should with great dynamic nuance; and others that were tight, defined, and sometimes too bright overall that sounded dead, as if the musicians were half-asleep. At the same time, since how a component handles the leading edge of transients has a profound influence on the perceived speed, a system tuned to the darker/fuller side of things can benefit (speed-wise) from a little help by way of what the double spring brings to the table.

A long-winded way of saying that I am a little mystified as to why the loosening the I-beam yields a superior result than simply using a more compliant spring. BTW, I am speaking strictly about bass performance; I need to spend more time, and experiment more in the ways that you suggest, to get a better handle on things.

Thanks again.

Frogman
The less compliant double spring usually yielding a more controlled, defined sound with tauter and faster bass. More compliant springs have produced sound that is generally fuller, but less-well defined; fuller mids and lows, but less-well integrated highs.

Frogman your observations mirror mine. Here are some personal impressions in my specific 2 rooms.

BTW - Bruce has confirmed to me that adding a double spring raises the resonant frequency of the I Beam Counterweight.

Two rooms set up with an ET2 and ET 2.5.

First room

The ET 2.5 is in a room with gear that I am able to pressurize easily and hear the bass nodes by walking around all on fours. I can locate where the bass is fullest and over powering. I can also find the spot where the nulls are. By experimenting over 19 years with multiple speakers I have found for this room only; the spots that give me minimal resonances at my listening chair, based on where I position the speakers. A key to my own audio madness 1) a dedicated room and 2) a listening chair that can be moved forward and backward multiple feet to adjust for soundstage/sweetspot differences between differently engineered music sources (whether they be on lp, cd, or tape) and different cartridges. Anyone that has ever heard a 420 str for the first time is aware of the stark differences in soundstage presentation it provides. I had to move my nearfield listening chair back a few feet from the first listen to the 420 str. What if your chair is up against wall.....

I prefer the double spring in general in this first room. The bass is tighter as you say – mids and highs are clear, the bass nodes don’t last as long with the double spring. The triple spring was even more extreme in this regard. It became too lean however as I posted a couple of posts back.

Second Room – much larger (adjacent to room one)

An ET 2.0 setup with gear that provides for full sound through the mids and highs, but needs help with two subs for the lowest octave with certain music. They are Quad 57 speakers. I cannot pressurize this room no matter what I do – reason is - firstly the space is too big and open and 2) my wifes TV room is close to it above and adjacent to it a ways. :^(

I prefer the single leaf spring in this second room. The bass is fuller as Frogman said, but in my case as the space is larger it allows IMO for bass waves to dissipate, not bounce around causing problems. This also means harder surfaces can be used in the room to allow for clearer highs.

For me the room/space dictate our preferences above everything else.

TORQUING OF THE ET2 LEAF SPRING USING DOVERS METHOD

I untorqued the single leaf spring in room 2 last night per Dovers recent post and the sound seemed to get even more fuller. The change was noticeable. I will experiment more with this.

Dover thanks for this detail it is really appreciated.

Heath Robinson Belt Drive

I really like Grantn's sense of humor :^)

Welcome to the thread Grantn.

I have learned alot from Richard and Dover in the last few weeks.

Cheers Chris

03-23-13: Gnnett
When I look at the pictures of RK's arm I do not see an ET2. It is something specifically crafted and tuned to his system. It is not a universal tonearm. A little bit like the highly modified ET1 that Lloyd Walker uses actually.

Grantn – I thought your observation was a really interesting one.

You mentioned the ET1. It has a very interesting history.

As a reference point here I feel it is important to understand the transition from the ET1 to the ET2.

Especially since we have been debating Rigid versus Sprung I Beams/Counterweights.

ET1 - is Heavier and Rigid

ET2 - Lighter and Sprung

I skipped through the ET1 manual from Bruces’ site.
Anyone interested in Tonearm Resonances and Testing of Resonances should see pages 49 and onward. It is much more detailed than the ET2 manual in this respect and the tests apply to all tonearms in general.

So why did Bruce to go from an ET1 to an ET2. Do the design and specs themselves tell enough story?

There are big differences between the ET1 and ET2.

Actual tonearm tube/headshell weight is more on the ET1.

The small counterweights on the ET1 are actually the large size on the ET2.

The spindle weights are the same.

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ET1 specs.
Spindle Weight 14 grams
Tonearm Tube Weight 14 grams / Headshell weight 5 grams
Counterbalance Weight 15 grams small 30 grams large.

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ET2 specs
Spindle Weight 14 grams
Tonearm Tube Weight 11 grams
Counterbalance weights 5 grams small and 15 grams large.

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Has anyone heard an ET1 versus ET2 ?

Cheers Chris

For me the room/space dictate our preferences above everything else.

Just to be clear - my statement is very "biased" and it is based on my personal audio hobby experiences over the years.

cheers