Tweet
This post is going to seem strange, but i have had difficulty using search to find precisely what is happening here...
I am noticing a similarity in several of my home builds. (All single channel tube amps). There is oscillation occurring at the midpoint of the volume control; starting with the control off, as i turn up to about half, noise occurs, and as the control reaches maximum, the noise tapers away. This, "noise" is different in each amp, sometimes just a buzz. In a recent build, the noise occurred as a low frequency effect superimposed on the signal...amplitude modulation exactly like tremelo. When i added a tonestack, the oscillation became a high pitched chirping squeal, sill happening at the same point on the control.
In all these builds, the noise occurs as the pot designated as "volume" is increased and is in the middle of the controls range, and it disappears as the control is maxed out.
Has anyone experienced this?
One would expect that any kind of noise would increase as signal level is increased. But this happens in the middle of the pots rotation. It is as if there is some oscillation from the ground side of the circuit.
And Yes i have controlled for tubes, and switched OT leads (although the last 2 amps had no NFB sent back into the circuit)
I don't expect anyone to solve this for me really, but i pose it as a topic of discussion because I've noticed it alot and can't find many people talking about it.
I am noticing a similarity in several of my home builds. (All single channel tube amps). There is oscillation occurring at the midpoint of the volume control; starting with the control off, as i turn up to about half, noise occurs, and as the control reaches maximum, the noise tapers away. This, "noise" is different in each amp, sometimes just a buzz. In a recent build, the noise occurred as a low frequency effect superimposed on the signal...amplitude modulation exactly like tremelo. When i added a tonestack, the oscillation became a high pitched chirping squeal, sill happening at the same point on the control.
In all these builds, the noise occurs as the pot designated as "volume" is increased and is in the middle of the controls range, and it disappears as the control is maxed out.
Has anyone experienced this?
One would expect that any kind of noise would increase as signal level is increased. But this happens in the middle of the pots rotation. It is as if there is some oscillation from the ground side of the circuit.
And Yes i have controlled for tubes, and switched OT leads (although the last 2 amps had no NFB sent back into the circuit)
I don't expect anyone to solve this for me really, but i pose it as a topic of discussion because I've noticed it alot and can't find many people talking about it.
Comment