Eminent Technology ET-2 Tonearm Owners

05-27-13: Richardkrebs
Dover says.
"....on an undamped standard ET with decoupled counterweight there is a resonant peak at 3 times the fundamental resonant frequency, and that this is reduced with fluid damping on a standard ET with decoupled counterweight."

I say.
"At 3x Fr the rise in response is almost zero."
In response to this question..
In the technical section you talk about phase shift beginning at 2 to 3 times the resonant frequency down to Fr.
Does this mean that there is a resonant peak at 3 x Fr or is this the point where the phase and response errors have reduced to low levels?
Bruce T says...
"This is the point where, above this frequency, the phase shift becomes minimal, as you approach the resonance frequency, the phase shift increases. I hope this helps, thank you very much."

Richardkrebs, you continue to conflate apples and oranges and misrepresent statements.

The technical section you refer to is for a standard ET, with a substantial rise in response below 20hz.

FLUID DYNAMIC DAMPING FOR THE ET-II
If a tonearm/cartridge system has a substantial rise in response below 20 Hz as most do, the phase response at the low end will be shifted and phase shift will occur beginning at 2 to 3 times the resonant frequency down to Fr

One can achieve a flat response by tuning the decoupled counterweight and keeping the horizontal mass and Q low as outlined in the ET manual and demonstrated in the Stereophile testing.

Your ET is not standard. You have doubled the horizontal mass of your arm by adding lead and you have removed the counterweight decoupling mechanism.

The effect of the 2 modifications you made to your arm is to increase the amplitude of the fundamental resonance by some 6-12db as shown by Bruce Thigpens testing.

Bruce Thigpen:
If the weight is coupled the system resonant frequency would be extremely low, a resonant frequency at 3Hz with a significant rise in response (6-12dB) results

The arm Bruce used for testing was deliberately set up with a high Q and very low compliance cartridge. The standard ET when used as outlined in the manual with a decoupled counterweight has a lower Q.

A low frequency sweep was performed twice on the tonearm, once without the damping trough and once with the damping trough. The cartridge used was of very low compliance and the tonearm was set up so that a high amplitude high Q resonance existed. The results of the test show a reduction in the amplitude of the resonance of about 8 dB (horizontal).

You continue to ignore Bruces stated view that increasing horizontal mass increases distortion

Bruce Thigpen:
If the weight is coupled the system resonant frequency would be extremely low, a resonant frequency at 3Hz with a significant rise in response (6-12dB) results, which would affect tracking slightly because of the asymmetric position of the cantilever, we opt for splitting the horizontal resonance frequency into two points and lowering the "Q" which improves tracking.

More important than tracking, the intent was to reduce the modulation effects of low frequency energy (FM and AM) that increase distortion in the cartridge,

Clearly the reduction of 8db is for a standard arm. In the case of your arm to which you have added lead, doubled the horizontal effective mass and removed the decoupling mechanism, all you are achieving is some reduction in the problems and distortions you have built into your arm.

You have misrepresented Bruce’s view on eccentric records,

05-20-13: Richardkrebs
BT uses at 30cu cartridge in his manual to calculate horizontal Fr. The arm weight he uses is 30gm plus 7gm for the cartridge. We have to assume that he is ok with this combination and that he is not worried about cantilever deflection on eccentric records.

This assumption again is just plain wrong. I quote from Bruce Thigpen’s ET website:

ET2 Manual page 47 :
“if you like to play severely eccentric records, ones with run out greater than 1/8th of an inch, then we suggest you use a low mass pivoted arm.”

It would be helpful to move this thread forward if you acknowledged the issues related to adding mass and move away from using examples, maths and quotes that are irrelevant and taken out of context.

Dover - It would be helpful to move this thread forward if you acknowledged the issues related to adding mass and move away from using examples, maths and quotes that are irrelevant and taken out of context.

Actually guys – RK and Dover. I say this with utmost respect. I don’t know about the others here but I am personally totally glazed over with these discussions – back and forth. I would prefer you take it offline?

You see I trust my ears for sound not theory. I don’t need approval of somebody for enjoying my hobby. But as this is a public chat forum and there may be others here that like to dwell in theory I Ieave you as be - this is my opinion only.

Dover - I am really looking forward to your direct experiences again with the the ET2. Or did you get a 2.5 ?

What type of pump are you going to be using?

Dover - ...........Stereophile testing.

What review was that Dover – can you point it out please?

From the one that I read.

From the Stereophile review - "As for other cartridges, I would like to see very specific suggestions from the manufacturer as to the proper combination and location of weights for a given cartridge. The arm is now too adjustable for the consumer or dealer who does not measure low frequency resonance, and I still do not fully understand how the location of the counterweight package best interacts with a given type and compliance of cartridge."

Or to narrow it down.

The arm is now too adjustable for the consumer or dealer who does not measure low frequency resonance

Well - to me it would seem a reviewer that doesn’t trust his own ears or maybe he was rushed on time? Or maybe he should just go seeDorothy

Based on that statement Dover they didn’t even get close.

Like the review that John referenced. Some nice measurements and good reading, but no mention of weight location or how many; counterweight tuning.

IMO – this ET2 and ET2.5 can be tuned to the rest of your room/gear. But you need to live with it for a while to build a reference point. Then you can start tuning. Most audiophile friends I know have no patience.

This is a question for RK and Dover.

Have either of you used a double and/or triple leaf spring with a Low Compliance cartridge on an ET2 with the weights positioned at the end of the decoupled IBeam?

RK - Further I now consider an oil trough to be manditory for this rig.

After some tweaking I am getting excellent results with the damping trough. When I used it years ago I was obviously slugging the paddle through too much oil ! I am only using 1 CC per Bruce’ instructions.

Bruce is clear in the damping trough documentation that the damping trough should NOT BE USED until one becomes familiar with the operation of the ET2 and ET 2.5 without the use of one first. The added benefit I find is the visual confirmation of levelness in the trough. , as the oil in the trough is obviously affected by gravity.

Richard - I don’t like words like mandatory and absolute in this hobby. What we are creating is make believe really? This is why I like to use words like Winnie the Pooh and Goldilocks in my system page :^)

Chris and others.
I can see how our discussion has become tedious for other readers. I apologize for this and will be more considerate moving forward.

On a bit of a side path. What happens when a new better piece of gear is installed, say new speakers.
We set them up, friends come around and after they are run in, all listener's agree that it is a big improvement. We all hear better this and more of that,......for awhile. Then it becomes the new normal and we go on the quest again for "more". Has anyone else thought that this hobby of ours is an addiction?

BTW
When Goldilocks dipped her toe in the bath, she found the temperature to be just right.

I must remember my lines
Richardkrebs .... has an increase of 6-12db at fundamental resonance
I must remember my lines
Richardkrebs .... has an increase of 6-12db at fundamental resonance
I must remember my lines
Richardkrebs .... has an increase of 6-12db at fundamental resonance
I must remember my lines ....................
Dover