Hi Norman,
dont apologize, all the responses are very much appreciated and I like problem solving!
I did squeeze some oil under the pulley and worked it down, however I should hit the bottom bearing good call.
However- I think I just figured out from an experiment that it's not the motor causing the rumble:
I took the belt off and put the platter back on. Threw on a record and lowered the stylus onto it. I turned on the (beltless) motor. Total silence from the stereo. Does that suggest the noise is not from the motor, or is my logic flawed?
-Dave |
Mugrug12,
I have a Grace 747, which isn't unlike your BW arm. The Grace is dead silent, and is my favorite. I have it mounted to an old Dual 1229 and their is no rumble or noise anywhere. I would suspect that the noise you are hearing is motor related, not arm related.
I'm not so familar with your Thorens, but if you're handy I would pull the motor and open it and inspect the top and bottom bearings. If you havent serviced it recently it's probably starving for a little oil.
Also, inspect the motor shielding and power cable. This too can cause what you are experiencing, as can poor tonearm leads.
Sorry, but their are several things to consider. Oh, the ADC is an excellent cartridge. I have one in my stable and do enjoy it from time to time..
N.
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It tracks great w the ortofon and im excited for the xlm (though a little nerve racking using thise tiny wires!)
maybe my issue is the thorens itself. But this model is known for having really low rumble I thought...
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Yes, absolute first-hand experience with the Infinity
tonearm many years ago. One of the best combinations was with the ADC XLM II
that you mentioned purchasing NOS. My turntable at the time was a Kenwood
KD-500, which was direct drive and having a fixed suspension. So, very
different from the Thorens. Since what you’re describing is while the tonearm
is not in use it is unlikely having to do with the bearings.
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Thanks that's helpful guys. Is bearing chatter possibly what I'm experiencing then? Or I'm barking up the wrong tree maybe. Have you guys ever owned a thorens td125mkii or BW tonearm? Time to google "bearing chatter" here I go.... |
The arm in its early iterations was susceptible to what was
called at the time “bearing chatter.” As totem395 mentions the damping fluid
tray served to increase cartridge compatibility. It also helped to alleviate
the potential for bearing chatter.
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then what's the damping fluid for on the later models? To allow more flexibility in choice when using lower compliance cartridges. |
I think also maybe I don't fully understand the purpose of tonearm damping. If the mass/compliance is well
matched producing the correct recosnance, like my setup is, then what's the damping fluid for on the later models? |
Yes- The music itself sounds awesome and i think w the xlm mkii it will be even better. I just think the noise floor should be lower. Is tomearm damping strictly to fix resonance from the music, or is it also for mitigating mechanical vibes from the turntable itself? Could it be damped externally somehow? |
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Thank you guys...
the cart is an ortofon super om30. I just got an nos adc xlm ii so I can see if that makes a difference but it seems like it's the arm. For instance if I lift the arm and gently slide a finger down the tube with my other hand I can hear the sound of the finger running come from the speakers. Is this the kind of microphonics that damping mitigates?
the motor doesn't really make noise. Your ear has to literally be an inch from the pulley w no platters on to hear it. I figured that was par for the course, is that wrong?
Dave |
It may make sense to address the motor noise/vibration
first? Admittedly it has been a long time since owning a Thorens turntable, but
I don’t recall it having as much audible noise as you describe.
The first generation Infinity Black Widow tonearm with
knife-edge bearings requires the use of a low mass/high compliance cartridge
for it to perform at its best. (Back in the day think Micro Acoustics, ADC,
Grace, etc.) I would not recommend a “home brew” damping strategy. This does
not necessarily address your issue but should provide the opportunity for best
tonearm/cartridge performance.Watch those original wires, super fragile as you probably already know.
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It's definitely originating in the motor, but due to the microphonics I observe I've the tonearm, I think that is why it's being picked up maybe. The motor can be heard with your ear directly next to the pulley w no platter on which I figured was normal probably? |
Could be the thorens motor? I used to have a td320mk2. Only unwanted noise came from this part. It might amplified by the plint, table it connects on.
There seems to be a modkit for mk125.. |
