Feedback through turntable

@slaw dude, chill. I’ve had a busy weekend and I just finished installing the springs on Thursday, so I’ve hardly had time to report back. I didn’t realize thread loyalty was a thing.

I bought some 2" compression springs with a spring rate of ~9lbs/inch from Grainger. I then drilled 4 holes in the bottom of my maple butcher block platform approximately 3/4" deep and installed the springs in the holes. To protect my furniture, I put cork discs under the springs.

I also finished mounting the tt motor on the butcher block. I still had the motor circuit board attached to the tt plinth, which made moving it a pain the ass.

So far I like the sound of the butcher block on springs better than on the inner tube. As far as leveling/ mass loading, my butcher block is 2" thick and plenty heavy, especially when the tt is on it. When I drilled the holes for the springs, i made sure they were as equal in đepth as possible. That, combined with the self leveling nature of springs has made leveling a non issue. I also thought of using three springs, but it was too wobbly when I tested it.

I have moved my speakers and sub (crossed at 49Hz) to the adjacent wall - this has helped.  My sub is now approx 15' from TT and furthest speaker cable is 20' from amp.  I made some temp cables using 14/4 in-wall cable to try the relocation prior to outlay of a pair of 20' speaker cables.  without the REL engaged I can now pump the volume up with no feedback (one of my Sf Cremona Auditor Ms is 5' from TT); once I engage the REL I need to adjust the gain to keep from getting some feedback at louder volumes.  So, this does enforce the thought the problem was acoustic and not mechanical.  No shared beams between TT rack and REL now.  Next, I may try putting the REL on a 3" maple base.  Jim Pendleton with Osage Audio has been very helpful and spent many hours helping me tame this wild dog.  I will also replace the OEM inserts on my TT feet with the Symposium inserts.  Thank you everyone for your suggestions.

"So far I like the sound of the butcher block on springs better than on the inner tube. As far as leveling/ mass loading, my butcher block is 2" thick and plenty heavy, especially when the tt is on it. When I drilled the holes for the springs, i made sure they were as equal in đepth as possible. That, combined with the self leveling nature of springs has made leveling a non issue. I also thought of using three springs, but it was too wobbly when I tested it."

sadly the geometry of inner tubes and air bladders is all wrong. The contact surface area is much too large and the rubber material damps too much, compared to springs.

@miner42 thanks for starting this thread. I've definitely made some noticeable improvements with the info here. Good to hear (read) you're making progress too!

Geoff- I will say that I'd try little bowls if there was a believable explanation for how they work and what they do.. I'm not a total reductionist, so I don't shoot things down if they aren't ideas in the mainstream, but my mind does need something to go on, so I can figure out how to implement. Though I suppose it would be pointless since I can't imagine decorating my house with copper bowls.. My lovely wife let's me do what I want with the music room, but she wants input on the rest of the house