Eminent Technology ET-2 Tonearm Owners

Good morning Chris,
Thanks for the thorough analysis.  You may just sell me on a loom yet.  My current ICs are so short there is no room to move them more than a couple of inches.  I have a second set that are a little longer I will try moving around a bit.  Yes, I've read the posts and reviews that talk about shielding and coloration.  The Grover Huffmans, however, do get some terrific user reviews.  I should have them next week and will let you know what I hear.

As for the feedback, your idea regarding subwoofer placement is interesting.  I'll try moving mine around.  I don't think I had the feedback with the spring suspension on the HW-19 but I really like the stability and modest sonic improvements the Herbies Tenderfeet brought to the TT.  

Most frustrating is although my two TTs are only two feet apart the Garrard rig is dead quiet and has no feedback.  If a Platine appeared at something I could afford, my VPI would be history.

@vpi: regarding hum:
The Delos has ca. 2.5 dB more output than the Black Beauty in low output configuration, with a quite low source / coil impedance. I suspect the vdH is more in the range of 20-30 Ohms.
I was & am amazed that this information is lacking in all sources I could find, be it van den Huls website, be it eg. Stereophiles / Sculls review! The source impedance is an absolutely essential technical information, as essential as the outpult voltage. There are two reasons:- Stray capacitance couples the static mains voltage field into the tonearms signal wiring and forms a RC voltage divider, the R provided by the source impedance - in this case the source impedance of the cartridge. Ie. a lower source impedance shorts more of the coupled mains field to ground. Shielding should shunt this voltage proportionally to the degree of shielding, and by adding a higher capacitive impedance against the external field.
- For MC transformer compatibility, source impedance is the key parameter (not voltage) - it makes or breaks compatibility.

Assuming a 3x source impedance, this increases stray hum coupling by 9.5 dB, which would result in 12dB more hum with the vdH than the Delos, based on simple and precise signal calculations.
The key issue comparing cartridges is the relationship of the voltages vs. the relationship of the source impedances. This defines in essence the relative hum levels.
Rel. low impedance / rel. high voltage are desirable. The Koetsus are quite good there, with Delos and others. Jan Allaerts and vdH (?) are more tricky in that regard.

Add to that, that the signal shield of the ET2 must be open for the "mobile" wiring loom. The Ortofon arm is almost completely shielded, except maybe 5 mm with visible wires in the horizontal bearing.
In my free external wiring of the ET2 I added a very thin wire from one of the fixing collars of the arm to the ground post. This helps, but not totally cures it.

- A bright timbre of the hum signal hints at stray field coupling (capacitive)
- A dark timbre with sometimes some nasty low harmonics hints at a ground loop, ie. magnetic coupling.

Excellent suggestions and analysis by Chris.

vpi, while I have not used a HW19 for some time and ever since I got my TNT6, I did experience what you describe during the years that I did use it. It was a very low level, volume dependent, hum that I was never able to get rid of. In my case, the cause of it was the HW19’s motor itself; the hum was much worse when the motor was turned off (!). While I could never get rid of it entirely, the level of hum was lowest when I secured a grounding wire to one of the bolts which secure the arm board (ET2, of course) and ran it to the ground lug on the back of my preamp. Hum/grounding issues involve a bit of black magic and the causes and solutions don’t always make sense at first.

In addition to Chris’ excellent suggestions try removing the tt belt and with the stylus resting on an lp turn the motor on and off. Any change in hum level? Then, lift the stylus off the record and do it again to make sure the hum is not simply mechanical noise generated by the motor. Btw, it is not clear from your description of the problem whether you can hear the hum while music is playing. Also, try reversing the orientation of the tt AC plug. These may give you a clue as to what is going on.

Keep in mind that, like Chris, almost from the time I got my ET2, I have used a straight run of wire from cartridge to preamp; no junction box. I also highly recommend this; the sonic benefits are tremendous imo. However, interestingly and unfortunately, while things are dead quite with MC carts, I now (TNT) tend to have noise issues (mostly buzzing) with MM cartridges. Varies cart to cart. My Acutex and Azden are acceptable, the Empire is borderline; and very frustratingly my “Holy Grail MM”, the AT ATML 170 OCC is unusable. With a lot of experimentation and moving wires around as Chris suggests I can get things acceptably quite with most MM’s, but there is always some noise which I wish I could get rid of entirely.

Good luck and I know I am not thinking of some of the other things that I tried. I will post them as I think of them.

**** Excellent suggestions and analysis by Chris. ****; and Pegasus.

Does anyone else use a wall mounted (to the studs of a weight bearing wall) shelf to mount their table? My homebrew turntable shelf consists of heavy duty L brackets from Home Depot and a 1 1/2 inch thick birch plywood shelf. You could stand on my shelf, and no feedback from the floor or woofers. I have a dedicated room and no wife acceptance to worry about. 
-John