Older motor pod vibration control

Older motor pod vibration control

Postby Packgrog » Tue Nov 28, 2017 5:33 pm

Who out there has some interesting motor vibration reduction tweaks to share?

I'm currently using a Scout Jr, thanks in no small part due to Mat's generosity. I have little to no available funds, so unlike many of you folks, I don't really have the option of moving further up the line for better sound. That means that I have to get creative with tweaks to try to improve my sound quality.

One thing that I've done is to damp the motor pod housing using Herbie's Audio Labs grungebuster material that I had laying around. In place of the standard rubber feet, I placed small diameter thick grungebuster dots that I'd used under the motor of a previous turntable. I also noticed a fair bit of ringing when I tapped the top plate of the motor pod housing, so I unscrewed it and placed some scraps of thin grungebuster material both where the top and bottom plates meet when screwed down, as well as the bottom lip of the inner portion of the motor pod (the side that sits under the platter). This changed the ringing to a dull thunk, and actually worked great! Other tweaks that I attempted that were awful included trying a silk thread as a belt instead of the standard belt (much higher noise floor when trying this, very audible hum), as well as a ziplock snack bag filled with playground sand inside the motor pod to try to mass load it (this changed the sound in a really horrible way, and was immediately removed).

This said, after experimenting with voltage reduction with my motor controller (a Phoenix Falcon, sorry, I just cannot afford an SDS or ADS), it seemed that 95V was the sweet spot for keeping some soundstage depth, but this does still mean more vibration than desirable. I placed my hand gently on top of the motor pod and the noise floor dropped substantially. This got me thinking: Can something be placed on top of the motor housing to further damp vibrations while keeping the torque of higher voltage? I've seen mention of Walker Audio Resonance Control Discs, but at $50+ a piece, that's well outside of my financial reach. Would something like a couple of 50g or 100g brass weights placed on the outside corners of the motor pod, potentially with grungebuster dots between them (I still have some left) be a good solution, or would that actually make things worse?

I'm not terribly concerned with appearance (obviously). I just want better sound within my extremely limited budget. Anyone have any interesting tweak ideas to share?

Cheers all!
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Re: Older motor pod vibration control

Postby Ayre Conditioned » Tue Nov 28, 2017 11:57 pm

Packgrog wrote:Who out there has some interesting motor vibration reduction tweaks to share?


I have my motor sitting on 4 Herbie’s Tenderfoot feet. They work great.
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Re: Older motor pod vibration control

Postby Packgrog » Wed Nov 29, 2017 12:33 am

I do have those, but they're under my Nova Phonomena. I originally got them for a Benchmark DAC1 that I had briefly before selling it off. They definitely worked well for that. I tried putting them under my motor, but I'd need to put puckies under the cone feet or something to allow enough clearance between the motor pod and platter. Maybe some day when I have more free cash I'll try that again. Still wondering about top plate damping options first though.
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Re: Older motor pod vibration control

Postby Ayre Conditioned » Wed Nov 29, 2017 9:16 am

If I were you I would either call or email Herbie’s. I know he’ll be able to recommend something for your particular situation.
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Re: Older motor pod vibration control

Postby Packgrog » Wed Nov 29, 2017 9:53 am

I did that before coming here. :P Their email is bouncing back, and they don't seem to be responding to posts on their forum at the moment. And I hate using the phone since it tends to lead to more misunderstanding. That's why I tried posting here for alternate takes. :)
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Re: Older motor pod vibration control

Postby TomD » Wed Nov 29, 2017 12:56 pm

If on a budget, try putting a mousepad underneath the motor as Harry often recommends. Worked surprisingly well for me.

Good luck!
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Re: Older motor pod vibration control

Postby thegage » Wed Nov 29, 2017 1:01 pm

Couple of thoughts. First, how much tension there is on the belt can have an impact. I found that the least amount of tension was best--easy to experiment with motor position. Second, you might try some judicious application of EAR IsoDamp to the motor chassis, or between the motor and the housing and between the stainless retaining plate and the motor (I cut little squares and drilled holes in them so the mounting screws went through them) . I suggest the 0.125" thick sheet, available from Michael Percy for about $12. There's also the possibility that the motor is going bad...

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Re: Older motor pod vibration control

Postby Packgrog » Wed Nov 29, 2017 1:35 pm

Thanks for the feedback, folks, though I think you might have skimmed past the mods I've already made. Here's a little extra emphasis...
Packgrog wrote:One thing that I've done is to damp the motor pod housing using Herbie's Audio Labs grungebuster material that I had laying around. In place of the standard rubber feet, I placed small diameter thick grungebuster dots that I'd used under the motor of a previous turntable. I also noticed a fair bit of ringing when I tapped the top plate of the motor pod housing, so I unscrewed it and placed some scraps of thin grungebuster material both where the top and bottom plates meet when screwed down, as well as the bottom lip of the inner portion of the motor pod (the side that sits under the platter). This changed the ringing to a dull thunk, and actually worked great! Other tweaks that I attempted that were awful included trying a silk thread as a belt instead of the standard belt (much higher noise floor when trying this, very audible hum), as well as a ziplock snack bag filled with playground sand inside the motor pod to try to mass load it (this changed the sound in a really horrible way, and was immediately removed).

Thick grungebusters should be far better than rubber feet and a mousepad. EAR IsoDamp should be very similar to grungebuster material (you can see some of it sticking out of the motor housing in the photo). It is highly unlikely that the motor itself is going bad given that I've only had it since April of this year.

Tension could be a factor, and I might try nudging it back in toward the plinth, but I'd had better overall results with speed stability with the current tension amount, though that was before getting the Falcon and building the tachometer.

Any other thoughts/ideas beyond what's already been covered?
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Re: Older motor pod vibration control

Postby elader » Wed Nov 29, 2017 3:41 pm

Ive been happy with a 70 durometer sorbothane disc under the housing in lieu of feet. It's compressed pretty solid.

Is increasing the mass of the motor housing an answer? I can think of a few ways to do that with lead...
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Re: Older motor pod vibration control

Postby thegage » Wed Nov 29, 2017 3:45 pm

In my experience IsoDamp performs differently from the Grungebuster material, particularly when used in larger patches/sheets covering metal panels. The other option I forgot to mention are Symposium Point Pods: remove the feet from your motor and place it directly on two Point Pods. Though they may be outside of your budget, this pretty much eliminated motor vibration when I had a Scout.

John K.
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