Eminent Technology ET-2 Tonearm Owners

Richardkrebs
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 )

Richard - from what I have learned about you, IMO you are one of the few in this hobby that can build and repair your own amps, preamps and TT’s, etc... Fair statement?

As an amateur hobbyist I have my ears and memories of trial and error experiences. I agree with you that the actions and reactions that are happening are more predictable to a degree with some knowledge gained. I also agree that none of us have sufficient understanding. If anyone really did word would get around, and there would be a long audiophile line up at the persons door asking for help.

Now consider this perspective. I refer to the Quad 57 speaker again just as an example.

I have tried multiple amps with them (SS and Tube) out of curiosity; then one day after more research I discovered that Roger Modjeski designed his RM 10 amplifier around their specific needs. I already had his larger RM9 amp which I tried with them briefly, but was concerned about damaging them. Anyway cutting to the result - I now power them with an RM10 and could not be happier. So what I think I have based on what I hear is an amp whose outputs meet the specific needs of this unique speaker. There is a harmony and effortless sound that can be heard. Now consider this.

I have placed these 57’s in 4 different rooms with identical gear in front of the Rm10 amp and the 57’s. One room had hardwood floors, one was tiled, 2 were carpeted. Some rooms had drapes, other s only drywall and some pictures. One had wood panelling on one side. Their dimensions all varied and two of them opened up into other rooms.

Four different music perspectives resulted in the sounds as far as the music presentation goes. This was all with the same CD player. Now add in vinyl with all its variables to the mix...... The stereo system is a slave to the space/room -imo.

Just to be clear here to the readers regarding my impressions I have given. We have been discussing refinements and tweaking for the ET2. In the last 10 years I have owned an ET2 and then added a ET 2.5. In stock form as designed – out of the box this tonearm remains my reference.
And fwiw - The greatest sonic bump with the ET2 came for me, when I introduced air delivery with no (very little) resonance (at the pump) and 19 psi was achieved. The ET2 tonearm setup so far for me has been 40% actual tonearm setup fine tuning, and 60% air delivery tweaking. I am sure with the continued info from this thread it will become 50 – 50 soon.
Cheers

Dover.
:Yes the outcomes are entirely different if the counterweight is fixed....so.
:We have established that it will not be the end of the world for the cartridge if the horizontal mass is increased, this by reference to other arms that are heavy.
:Countary to stated design goals yes.....so.
:While BT designed the cw arm to swing at frequencies below the core arm frequency, it does not neccesariy prove that using 2 springs will result in that criteria being met. It is almost certain that the use of three springs, as Chris did will push the frequency above core.
:I know that BT designed the arm to have the two spring systems, Cart and Counterweight. I just don't think that it is a good idea because they talk to eachother. Has anyone thought about why the CW spring(s) and their damping are so fussy to set up?
:Yes I pulled the resonance graph and math from the net. This because it explains the effects more clearly than the literature we regularly refer to here at my work. Those readers that understand the math will know why I chose a 6 times multiplier.
:My prime reason for fixing the counterweight is to restore the full bass drive. You have in an earlier post talked about not needing response below 30hz and that response in this region can be problematic, or words to that effect. I do want response in that range and yes it can be difficult to sort this area but with effort it can be done and the results are most rewarding.

:We are all biased, it is astonishingly arrogant to suggest that you are not.

Chris.
Agree the room is critical, same for the air feed.

ET 2.0 spindle versus ET 2.5 spindle

I am focusing on the spindle /counterweight. I have some info to share.

It can be difficult from pictures telling the differences between the ET 2.0 and 2.5.

This makes it easier. Pictured is the

ET 2.5 spindle

Significant differences in weight and diameter.
19 gms ET 2.5 versus 11 gms ET 2.0.

Chris,

About 19 grams with the aluminum inserts which are machined from bar stock. The 2.5 tubing has about the same wall thickness as the 2.0.
brucet

Richard/Dover/theKong/Frogman others.

I find this significant based on the recent damping conversations. I will have more information coming from Bruce when he has time to discuss. I feel this info will enlighten us. The only clue I have been given.

"horizontal resonance to be above 2-3Hz but at least 4 to 5Hz below the vertical resonance"



TWEAK

I have also come up with something that I believe is significant as far as sonics are concerned and requires only a one minute adjustment. This is based on only one listening session but is so easy to try I had to share it.

Loosen the end cap bolt (not the leaf spring bolt we have been discussing) just enough to lower the lead weights, so that they are positioned at the bottom half of the spindle; when looking at the arm from the gooseneck side. Once done tighten end cap again.

This increases the VTF significantly.

You will need to adjust by moving the lead farther out on the I Beam. A good thing.

Cheers

Loosen the end cap bolt (not the leaf spring bolt we have been discussing) just enough to lower the lead weights, so that they are positioned at the bottom half of the spindle; when looking at the arm from the gooseneck side.

Hi Ct,

In all the photos I have seen on the Walker turntable, the counterweight set-up was below horizontal. So, I suppose that is intentional and offers some advantages, at least in that design.

I must apologize that due to my schedule, it will take me a while to have the time to do a thorough comparison on the counterweight set-ups in my system. I will report it here at once when I can complete the test!

Chris, thanks for the tip. I will try it and report back.