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Help....subsonic madness

Bkphoto

Bkphoto

Super Member
So,

I'm getting the dreaded speaker bounce...but its odd because its coming from the left speaker, not the right (which is closer to the arm)...TT is in the middle between both speakers...about 3 ft from each speaker...it seems to go away with lowpass filter engaged on my marantz 1060...but I'm using the Project tube box phono pre that is supposed to have a built in subsonic filter...

I'm confused...
 
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Try moving the speaker out from the wall and or corner, also get the speaker if it's a bookshelf size off the floor on stands. Also make sure the table is on a solid/stable shelf/stand/cabinet etc.
 
Bkphoto said:
did all those before my post...
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It's odd that you're getting it from the left but not the right. Is your antiskating set correctly? Is your turntable level?

I have a modest office set up and the turntable is only 6.5 inches from the left speaker....and the speakers are ported...and I don't have any problem with woofer pumping. I'm inclined to agree with other posters about a possible cartridge/arm mismatch.
 
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It's possible that you have some response issue with the electronics, i.e. some defective component or connection that makes the two channels different. As an example, a bad coupling cap could filter out all the lows on one channel.
 
So you think It could be an amp issue...?

I'm going to take the belt off, turn the table on and lower the needle down on a record, then slowly increase volume to see if woofers start to jump again....this should tell me if its the TT or not....

there is no audible hum btw...

so many factors...there is supposed to be a subsonic filter in the phono pre...ugh...
 
Boy, that is a weird one. Does it happen on every album, or only warped ones? If it's only warped records, then it sounds like your subsonic filter isn't working on one channel.

I will say that since I achieved a much better match between cart and arm, in terms of resonance frequency, I don't have any woofer pumping anymore, even on the most extreme warped record. In other words, you shouldn't need a subsonic filter to eliminate woofer pumping -- better to eliminate the low frequency anomalies at the cart, instead of pushing them through your system where they need to be filtered out. Just a thought.
 
Odd, just discovered last night that my right speaker has serious subsonic, and the left absolutely none. This, on a restored SX1010, completely head to toe rebuilt, a Technics SL1400mk2, and a Shure M7-N21D with slightly bent stylus (which I suspect is the culprit)

Gonna switch carts tonight, see if that helps. Did it on every record I played.
 
GreatTone said:
Boy, that is a weird one. Does it happen on every album, or only warped ones? If it's only warped records, then it sounds like your subsonic filter isn't working on one channel.

I will say that since I achieved a much better match between cart and arm, in terms of resonance frequency, I don't have any woofer pumping anymore, even on the most extreme warped record. In other words, you shouldn't need a subsonic filter to eliminate woofer pumping -- better to eliminate the low frequency anomalies at the cart, instead of pushing them through your system where they need to be filtered out. Just a thought.
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i use a record clamp...herbies matt...Blue Jeans IC's....all good stuff....
 
Bkphoto said:
i use a record clamp...herbies matt...Blue Jeans IC's....all good stuff....
Click to expand...

Those are good...I use a Herbie's and Blue Jeans IC's also. But the question is how does your cart match up with your tonearm? You can calculate the resonance point on vinyl engine. But even if they are not well matched, it wouldn't explain why it's only in one channel.
 
GreatTone said:
Those are good...I use a Herbie's and Blue Jeans IC's also. But the question is how does your cart match up with your tonearm? You can calculate the resonance point on vinyl engine. But even if they are not well matched, it wouldn't explain why it's only in one channel.
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exactly....there is supposed to be a subsonic filter in the phono pre...which is from same company...its the tube box s...

unhooked the belt...turned on TT so platter doesn't move, lowered needle on record and slowly turned up volume and the left speaker dances
 
The fact that the pumping is greater on the left channel (there is some on the right too, if you look carefully) is typical of radial arms and is caused by the offset angle. This is related to the skating force and there is nothing you can do about it except install a linear tracker, or a radial arm without offset.

If you're finding it happens even without the platter turning then you have feedback issues. This can be cured with better isolation and damping.

There is still the possibility of an arm/cart mismatch that results in too low a resonant frequency, or it can be that the cart suspension has lost it's temper and is no longer damping the motion of the arm.

I've seen tonarms with a brush damper on the end of the headshell that works to damp the motion much like the brushes on some models of Shure, Stanton and Pickering carts. With a little craftiness it shouldn't be too difficult to make one that bolts under the cart mounting nuts.
 
Well,

just got off the phone with the store I bought it from (online for me)....Its called "ListenUp"...Guy didn't even hesitate and is sending me a new one...Already have tracking info...

good people...
 
Have you played more than one album and noticed this occurrence? I have one album that this happens with so it's not my setup but the vinyl.
 
Tube could be it. Some history: Back in the mono days, the lesson learned was "don't use a speaker cabinet as a stand for your pre-amp, as many times, the first stage pre-amp tubes were microphonic.
So could the "feedback" be picked up from the left speaker by the pre-amp left first stage?
 
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