So Weird- No Stylus Contact Woofer Pumping with Hana ML and Elac PPA-2

@lewm It is not DC… by definition is like a sine wave or really more like a wavelet that is at a period of 33.3/60 of a second.
However it is maybe not a 1/2 Hz sinewave, more likely it is a flat line, with a heart beat that is happening over a just a fraction of the 360 circle.
So maybe it is a 5 or10 Hz thing that happens “at a rate or period” that is 33x/minute.

If it was DC the cone would be pushed out, but the cone was “pumping” and that is a verb or action word that describes something that is not steady-state… and not what a blocking cap or servo is designed to control… assuming that they are used for steady-state control.

…. So, I am dubious that DC generated somehow from the cartridge is causing the problem. But it did occur to me today that maybe the servo in the OP’s preamp is defective when operating in balanced mode. All bets are off.

The thing is perfectly synced to the platter, and the signal has to be coming from the cart, or has to be coming from the ground.

There is no other way the phone stage etc can make the speaker pump perfectly in sync with the platter.

Maybe it could be an intermittent DC shift on the ground, but the “no vinyl” “No mat” discounts that. And a servo will not remove it.

it is a conundrum.

Holmz, I have been saying forever and I’m sure ad nauseam that I don’t think it’s DC. So if you’re addressing me, you’re preaching to the converted. We agree.

Nothing that has been offered as solutions seem viable. Static is random, forget about it. The only suggestion that makes some sense is the the possibility on a weight sensor on the table to detect record weight. The Achromat is much lighter than the rubber stock mat on my old SP-15. 

Nothing that has been offered as solutions seem viable. Static is random, forget about it. The only suggestion that makes some sense is the the possibility on a weight sensor on the table to detect record weight. The Achromat is much lighter than the rubber stock mat on my old SP-15.

Agree @waltroman - but ignoring a solution, how does the static manifest itself into the signal wires?

I would think that both the + and - wires would be elevated equally and in the balanced sense they should then cancel out with the CMRR of a balanced approach.

Weekend results- using a signal generator I input square waves into the phono pre at all three possible inputs, input 1 RCA, input 2 RCA, and input 2 balanced XLR. All three output clean square waves at normal operating frequencies at various amplitudes. I couldn’t trip it up. So I’m eliminating the preamp as a culprit.