Older motor pod vibration control

Re: Older motor pod vibration control

Postby Packgrog » Wed Nov 29, 2017 4:02 pm

OK, interesting points there, John. Definitely outside of my budget comfort zone for those Symphosium Point Pods, sadly. It'd be interesting to know under which applications that IsoDamp would be a better choice than grungebusters. I've found grungebusters to be excellent for isolation AND synergistic sound improvement compared to most other things, but that doesn't mean that other materials won't work better for certain problems. The rubber feet weren't good, though, and the sand baggie trick that I tried was horrible, so I'm cautious.
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Re: Older motor pod vibration control

Postby Brf » Thu Nov 30, 2017 10:17 am

For vibration suppression, mass is your friend. In the past, I have used lead tape (you can purchase lead tape from most Golf stores) and lined the inside of the motor pod to create more mass. That is why when you move up the VPI line, the motor pods get heavier. In addition, the original rubber feet dry out and no longer provide any usable shock absorption, therefore, you should periodically replace with feet with a softer compound with a 60-90 durometer rating.
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Re: Older motor pod vibration control

Postby Packgrog » Thu Nov 30, 2017 10:27 am

Intriguing... I'm a little wary of non-reversible mods, but that is interesting. Part of my question about brass weights on the top plate was about the prospect of higher mass helping matters, with thin grungebuster in between brass weight and top plate hopefully limiting bad synergy like what I'd had with the playground sand. What about steel and/or lead shot, like some people use in audio rack poles?
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Re: Older motor pod vibration control

Postby elader » Thu Nov 30, 2017 10:29 am

Brf wrote:For vibration suppression, mass is your friend. In the past, I have used lead tape (you can purchase lead tape from most Golf stores) and lined the inside of the motor pod to create more mass. That is why when you move up the VPI line, the motor pods get heavier. In addition, the original rubber feet dry out and no longer provide any usable shock absorption, therefore, you should periodically replace with feet with a softer compound with a 60-90 durometer rating.


how much weight do you think you manage to add with the lead tape? Great idea..

how many of these do you think you could fit in the motor housing? would a pound make a difference?

https://www.amazon.com/Adhesive-Weights ... ead+weight
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Re: Older motor pod vibration control

Postby Packgrog » Thu Nov 30, 2017 11:11 am

I'm still wary of using adhesive, as it would be non-reversible.

But what about something like this in a small baggie inside the motor pod? https://www.amazon.com/Lead-Shot-Balls- ... 01C51OZ2K/ Or would the diameter of that be too large? Would a mix of this and steel pellets be better or worse? I haven't seen much good information about the use of the stuff.

My original idea was a couple of these placed on the top outside corners of the motor pod. Still way less than one of those Walker Audio discs. Better/worse? https://www.amazon.com/100g-Balance-Wei ... 06ZYMT3YB/
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Re: Older motor pod vibration control

Postby Brf » Thu Nov 30, 2017 11:47 am

The motor housing is a simple black metal box. Stuff as much lead tape/weights as humanly possible. Heck, even wrap the lead tape around the actual motor. Don't worry about the adhesive tape or residue if you decide to remove it, it's inside the box or if you want, use goo-gone and remove the adhesive.
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Re: Older motor pod vibration control

Postby Mr_Putty » Wed Jan 24, 2018 2:20 am

I’ve been testing motor isolation on my prime for a while. Mouse pads help isolation at the base but add more horizontal/tilting motion. They are squishy and age quickly so I scrapped them. I now have a stainless disc under the motor roughly 3/16 inch thick and about 8.5 inch diameter. It sits on thin silicone (1/16 inch) slices. In addition my motor has 4 Orings around it. I thought I was hearing too much wow/ flutter so was looking for rotational damping/stability of the motor itself. The base disc is big enough to place a stainless weight on it that touches the motor housing, becoming a mass dampener. I can feel motor vibration with my fingernail, and the added weight seems to help eliminate some rocking in the vertical plane. It’s not just motor isolation you want but greater control of the drive belt pulley. There is a syncing of the platter and motor that I am attempting to “tune”, and this setup seems good to me. There is still more to try. I assume your motor is broken-in and your TT bearing is good. My motor took about 30 hours to settle down, and it does make a difference. I hope my testing has given you some ideas.
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Last edited by Mr_Putty on Wed Jan 24, 2018 5:31 pm, edited 1 time in total.
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Re: Older motor pod vibration control

Postby Golear » Wed Jan 24, 2018 3:48 am

The core issue may be putting the motor unit on the same shelf as the turntable.

How about putting the turntable on one stand, and the motor unit on a completely separate stand.

The stands could be made out of metal, and filled with sand. The sand increases the mass and damps vibrations. A wood stand may also work.

And one might need to avoid a resonance frequency in the 10 Hz to 20 Hz range, since that would be the cartridge-arm resonance.
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Re: Older motor pod vibration control

Postby Packgrog » Wed Jan 24, 2018 10:15 am

I ended up trying a couple of 100g brass weights on top of the motor housing. Noticeable drop in noise, but also ultimately a degradation in sound quality. Everything sounded like an over-driven speaker: sort of flat and distorted. So I removed them. I'd even tried it with thin grungebuster between the weights and the motor housing, and that was even worse! Thus further evidence of my preference for reversible tweaks: Too often I don't actually like the results in the long term.

I changed the footer setup so that the Herbie's Square Fat Dots that I had sitting around are between my maple platform and the extra-thick grungebuster dots on which the motor sits. No real "improvement" per se, but it helps raise the motor back up closer to the normal height. Fun with CLD.

I've seen a fair number of recent comments about people using dual-belt setups. I can't do this because I'm locked in to using the 600RPM motor (I have a Falcon, which only handles up to 5W motors, and can't afford both a new motor and new controller), and the necessary pulley does not exist outside of extremely specialized DIY that's simply out of my reach. But for those of you that can afford the beefier, 7W-motor-friendly controllers, the HRX pulley and dual belt could provide both better torque and better damping.
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