Eminent Technology ET-2 Tonearm Owners



Where are you? What mods have you done ?

I have been using these ET2's for over 9 years now.
I am still figuring them out and learning from them. They can be modified in so many ways. Bruce Thigpen laid down the GENIUS behind this tonearm over 20 years ago. Some of you have owned them for over 20 years !

Tell us your secrets.

New owners – what questions do you have ?

We may even be able to coax Bruce to post here. :^)

There are so many modifications that can be done.

Dressing of the wire with this arm is critical to get optimum sonics along with proper counterweight setup.

Let me start it off.

Please tell us what you have found to be the best wire for the ET-2 tonearm ? One that is pliable/doesn’t crink or curl. Whats the best way of dressing it so it doesn’t impact the arm. Through the spindle - Over the manifold - Below manifold ? What have you come up with ?
ct0517
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.

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

************************************************************

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

************************************************************

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
My view on a stereo system is that it is just a machine. Actually lots of machines chained together to give an output based on inputs. As such it is logical and the output is predictable provided we have sufficient understanding of the machine. ( none of us have sufficient understanding )
What we are talking about here is a small part of the machine. The coupling, decoupling of a counterweight on a linear arm.

Frogman and Dover say that they prefer a loose connenction and one leaf spring.
Chris says that triple springs produce a sound that is too lean.
Rockport, Walker, Kuzma and I say that there should be no spring at all.
I believe ALL of the above statements as I think that they are actually saying the same thing along a continuum.
It all depends upon the voicing of your system and our biases, and we all have biases.
Also an improvement can actually sound worse as it can expose more clearly problems elsewhere in the machine chain. Sometimes when we open the window wider, we do not like what we see. We then need to work on the new "view" to correct a previously unseen problem. It does not mean that the original change was wrong
I have said that I don't think that it is a good idea to have a mass attached to two dissimilar springs who's resonances are in the same neighbourhood. The transmissibility graph I posted shows the potential nasty consequences of this. At least a 6 x seperation of the two resonant frequencies would a target.
Using one spring lightly coupled to the spindle pushes the resonant frequency down below the arms core resonance. This is good. (As Frogman points out, there may be other factors at play here with the loose screws.) Double or triple springs push the resonant frequency above the core resonance which is also good.
We have to be carefull when using stiffer springs that we don't move too close to the audio spectrum, since the same transmissibility graph data will bite us. We also have to be carefull that we do not go to low with lite springs since we get close to eccentricity frequencies again with possible nasty consequences. So what if we pushed the resonant frequency up above the audio spectrum. We have no risk of any of the issues I raise here.
My early fixed counterweight designs resonated somewhere in the midrange. It was easy to hear adding a nice, but not accurate bloom to voice and midrange instrumemts. If my system was not already "full" in this range I may have stopped experimenting, thinking that the arm was acurate. Increasing its rigidity more, pushed the resonance above the frequency of audibility. This is desirable and is the final logical progression to the tests that have been listed in this thread.

Gnnett. Do you live in AKL? It would be nice to meet. You can contact me directly via my web page if you wish.