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previous: Scott Swartz The screen current during overdrive... -- 8/16/2000 3:20 PM	View Thread

Re: Regulated screen supply

8/16/2000 5:34 PM
dpcoyle	Re: Regulated screen supply I have small experience with regulated screens on my Audio Resaearch D 76 amps. They use a fifth 6550 to be a series reg for both channel's screens. It's fairly durable. I have installed Curcio driver cards on the amp, and they employ a low voltage reg "floating" (right!) on top of a high voltage supply for their B+. That configuration is very unstable in startup, when voltages vary. My experience was that it crapped out all the time, until I replaced it with a 6L6, wired like the 6550 topology. I can't tell you the sound of reg screens in guitar amps, but I would guess there will be trivial hum improvement in a push pull amp, because the screen is tracking the B+ . You can expect more power developed before distortion. Conversely, I have gotten rid of hum in non-screen reg amps, like the Deluxe, to the point where the rushing noise dominated the background noise. If you're having hum problems, I doubt that lack of regulation is the cause. Are you star earthed and have you lifted all but one tag to ground for the chassis? Using the chassis as a return path for ground is, IMHO, second choice. Dan

8/16/2000 5:34 PM

dpcoyle

Re: Regulated screen supply

I have small experience with regulated screens on my Audio Resaearch D 76 amps. They use a fifth 6550 to be a series reg for both channel's screens. It's fairly durable.
I have installed Curcio driver cards on the amp, and they employ a low voltage reg "floating" (right!) on top of a high voltage supply for their B+.
That configuration is very unstable in startup, when voltages vary. My experience was that it crapped out all the time, until I replaced it with a 6L6, wired like the 6550 topology.

I can't tell you the sound of reg screens in guitar amps, but I would guess there will be trivial hum improvement in a push pull amp, because the screen is tracking the B+ . You can expect more power developed before distortion.

Conversely, I have gotten rid of hum in non-screen reg amps, like the Deluxe, to the point where the rushing noise dominated the background noise. If you're having hum problems, I doubt that lack of regulation is the cause.
Are you star earthed and have you lifted all but one tag to ground for the chassis? Using the chassis as a return path for ground is, IMHO, second choice.
Dan

Replies:

Kremator HI,thank you for the answer... -- 8/17/2000 9:45 PM