Rumbly feedback
Hello fellow A'goners. About a year ago I set up a wand 10.3 on the pedestal they sell as my turntable (brinkmann bardo) does not have an option for a second tonearm. Overall, I'm extremely satisfied with the performance. It has an ortofon Winfeld Ti mounted on it and the detail of the cartridge mates to the musicality of The tone arm is a truly magical match. Recently though, I've been listening to a bit more bass, heavy music and a couple of recordings that are mastered at very low levels. When I play these recordings at moderate volumes I get an intermittent bassy rumble that seems to come through. If I turn the volume down it dissipates and additionally, if I place my first two fingers on the pedestal, it goes away immediately. This rumble does not occur if I use my other tone arm which is the brinkman 10.1 with a custom vas cartridge mounted on it. I'm wondering if anybody has any ideas on how I could dampen the pedestal some to try and avoid this feedback.
@dogberry I think that's exactly it. As I said, when I press down onto the pedistal with just a little force the rumble goes away. It's like if I brace it to the HRS platform a little better it solves the problem. I wonder if a heavier pedestal would solve the problem. @mulveling I think the problem is more the last thing you mention, where the woofers are sort of flapping in a pattern and it's audible. What do you mean by rack bracing? |
If you have your turntable atop a tower-style rack (like many of us), freestanding, then it’s actually free to sway when energized - which can easily cause or contribute to that woofer flapping. If you think about it, your turntable is literally cantilevered up into space - a really bad spot for it to be in. The taller the tower, the worse it gets. Adding mass up top can just make the problem WORSE, actually. To brace the rack can be as simple as backing it firmly against a wall, with a little foam or rubber pad wedged in between there to interface. You’re basically clamping it between wall & floor, and making it stop acting as a cantilever. This can help your flapping problem (which can be deadly to woofers - you seriously don’t want this), but may not address your audible rumble / hum feedbacks - for that you’d want to additionally put your turntable & arm pod atop squishy feet or springs. If you have concrete flooring, then your flapping problem possibly has another cause. But usually life with such floors is "easy mode" for vinyl playback. If you struggle to find any mitigating solutions, you can always get a KAB rumble filter - it’s pretty good, and VERY effective, but I found it to not be quite "100% audibly transparent", though it is advertised as such. And it's aways better to address the actual mechanical & structural problems, rather than just slapping an electronic filter on as band-aid. |
@mulveling I think I have pics of my system in my virtual system. It don’t have a big tall rack. I have a lower solid walnut custom piece that weighs a ton. I dont thing it’s flapping from that and, as I mentioned, it’s only the tonearm/cartridge combination mounted on the pedestal, the tonearm attached to the turntable does not have this problem. I’m wondering if bracing the pedista to the HRS platform might solve it since when I press on it it goes away. I just ordered some very long Velcro straps to do this. We’ll see what happens! |
The Bardo tonearm is well coupled to the plinth, the platter, the bearing, So if the TT as a whole entity is disturbed by acoustic feedback, there is little to no aberrant motion of the stylus with respect to the LP. Hence no low frequency noise. The pod is a separate entity from the TT. Hence when it is disturbed by the same amount of acoustic energy, the cartridge mounted on it is much freer to move independently with respect to the LP. That creates the LF noise you hear. You need to move your rig away from your speakers and/or the speakers away from your rack. I disagree with Mulveling’s advice to fasten or lean the rack against the wall, because the wall may also be vibrating. So you might make matters worse. The root cause of your noise is the TT and the pod being separated entities. |
Yes, the separate arm pod is not a variable I’ve dealt with before. That itself might well be the culprit here. Hopefully so, becasue if not, good luck - the hum / rumble types of feedback were the most obnoxious of all gremlins I’ve dealt with. Many times I thought it was finally put to rest, only to come back again. The tables I had the problem with - VPIs - were large enough to not lend themselves easily to spring platforms that could perfectly break the feedback. |
