Nude Turntable Project


I could not fit the whole story in this Forum so have had to add it to my System Page.
I am attempting to hear if a 'naked' DD turntable can sound as good as Raul claims.
Please click the link below to read the story.
NUDE TT81
128x128halcro
Perhaps a thong. But then one's other turntables would be attracted.

I hope Halcro does not mind this diverting of his thread topic from nude to TT101 nude, but I have a TT101 question for other users: Even after Bill Thalmann blessed mine, I still have the following occasional problem. The TT will start up and go to 33.32. Then after 5-10 seconds, it goes to 33.33. After about a minute or two more, it will go to 33.34. Very shortly thereafter it will shut itself down. The tachometer reading disappears, and the brake effect does not occur. The platter spins freely until it loses momentum. If I manually press the STOP button BEFORE the unpremeditated shutdown, there IS a correct brake effect. I had been thinking that there is a problem with the reverse servo mechanism to explain this, but you guys have me thinking that there may be some inordinate drag on the platter, meaning my bearing may need service. On the other hand, if that were so, I would expect to hear a frictional sound (the table is dead silent) and I would not expect the platter to spin so freely and silently after shutdown. Comments?

I am embarrassed to tell Bill about this glitch, because it worked perfectly in his shop when I picked it up. But of course I will tell him eventually. He is a kind and patient man, moreso than I.
Lewm: My table basically went through all the symptoms you describe and then some. My tech reasoned through and tried testing many of the complex explanations. But in the end, we discovered that it was all attributable to bad solder joints on the 'feed thru eyelets'. He resoldered ALL of them. He said he knew of companies that used such type of boards and that they had reliability problems. Since you're handy with a solder gun, I'd try this brute method first before potentially wasting time investigating the subtler possibilities.

Aigenga: No worries. The thing is, I did note the number of turns and even marked the spot but when I put it back together the platter was completely locked up. Obviously, I screwed up somewhere--but I believe I know how to count, so it's still unclear to me what happened. I have zero plans on doing that again for the next 30 years.

Halcro: I don't have a general problem reproducing bass, but the double basses on that Mahler record, while better after the pantsing, sound far from adequate. I blame my speakers or the lack of subwoofers. Or, for all I know, it's the record itself. I just purchased another better copy of that record so I can test the last possibility soon.

fwiw, I don't have anything invested in the new set up except 15 minutes of time (2 to take the cover off and the rest to realign the tonearm and cartridge). The improvement is remarkable. It's along the same trajectory as the improvements I noted when I moved from my sp10 to the victor.
OK, now I am confused and a bit concerned. I used the Tesla meter to measure stray magnetic fields (as the device tells me) and lo and behold the only area that had high readings was at the top of the platter mostly on the right side of the table. Right where the cartridge tracks the record!

I repeated the measurements with the table grounded and not grounded, with my lead mat on and off, with the platter spinning and stopped, with the power on and off.

I even tried it on a TT-81 that hasn't spun in a year and got similar results! Is this a problem for DD turntables?

There is something in the TT itself that emits a notable magnetic field - I would guess it is the motor. I don't know how to address this but I certainly think that the magnetic operation of the cartridge is affected by this and not in a good way.

I would really like to hear that someone else has repeated this experiment and what they found.

Time to investigate Mu metal and how I can fashion a shield.

Gary
Dover,
I have a stethoscope and have done all the listening you suggest...and more, and hear nothing "revelatory" in regard to 'noise' within my turntable structures.
However this is by no means a scientific or 'white paper approved' form of documentary evidence which laboratory testing could easily provide?
Your use of terms like "noise", "friction" and "vibration" are inexact, undocumented and unquantified.
Hardly a convincing argument regardless of how often you continue to repeat it?
Lewm,
Why re-open the argument?
Errr.....because that is the subject of this Thread? :-)

Incidentally......have you managed to listen to your TT-101 yet?