A common problem exacerbated by your relatively light weight turntable. Mass being one of the easier ways of controlling vibration. It simply takes a lot more energy to move a large mass than a small one.
Okay so you need more mass. The classic cheap solution is sand, mixed with a little mineral oil to keep the dust down, in a box. The more sand the more mass and the better it works but as little as an inch or two makes a huge improvement and costs next to nothing.
If you don't like that one no problem, next up the food chain in cost and performance, Nobsound springs. These are crazy good for the money but I know people with light turntables need to add mass to make springs work properly. What you want are springs soft enough the load compresses them a lot, at least half way, and when moved the load oscillates very slowly, no more than 2 or 3Hz. Think the way a Linn bounces.
At the top of the pyramid are Townshend Pods. These things are absolutely awesome. Not only under turntables, its surprising how well they work under amps, especially tube amps. If your table is under 15 lbs you may need to add some mass with a board or sand box but it will be worth it. Not only will your feedback be eliminated the sound will be better than you ever heard it on concrete.
All these vibrations are coming from the subs, through the floor and walls, to your system. Nobsound springs under the subs will be a huge improvement. If it was me, I would do Nobsound under all the speakers, and CD, and use Pods under the more critical turntable and amp. That's what I do - all of it including the sand boxes - and it works great. https://systems.audiogon.com/systems/8367
Pods probably seem like overkill in your system. They are expensive, no doubt. You can save a lot with sand and Nobsound. Its hard to believe how well springs work until you try them. That's what I did, and its why I always recommend a gradual incremental type approach like this.
Okay so you need more mass. The classic cheap solution is sand, mixed with a little mineral oil to keep the dust down, in a box. The more sand the more mass and the better it works but as little as an inch or two makes a huge improvement and costs next to nothing.
If you don't like that one no problem, next up the food chain in cost and performance, Nobsound springs. These are crazy good for the money but I know people with light turntables need to add mass to make springs work properly. What you want are springs soft enough the load compresses them a lot, at least half way, and when moved the load oscillates very slowly, no more than 2 or 3Hz. Think the way a Linn bounces.
At the top of the pyramid are Townshend Pods. These things are absolutely awesome. Not only under turntables, its surprising how well they work under amps, especially tube amps. If your table is under 15 lbs you may need to add some mass with a board or sand box but it will be worth it. Not only will your feedback be eliminated the sound will be better than you ever heard it on concrete.
All these vibrations are coming from the subs, through the floor and walls, to your system. Nobsound springs under the subs will be a huge improvement. If it was me, I would do Nobsound under all the speakers, and CD, and use Pods under the more critical turntable and amp. That's what I do - all of it including the sand boxes - and it works great. https://systems.audiogon.com/systems/8367
Pods probably seem like overkill in your system. They are expensive, no doubt. You can save a lot with sand and Nobsound. Its hard to believe how well springs work until you try them. That's what I did, and its why I always recommend a gradual incremental type approach like this.