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previous: CL Mathes Does the trem work?You may ... -- 7/27/2000 7:48 PM

Re: Silverface Vibrolux motorboating ?

7/30/2000 3:29 AM
JCS	Re: Silverface Vibrolux motorboating ? Yes the trem works. I discovered the reading on the trem cap was off because the footswitch need to be shorted. I made this amp match the AA270 layout as far as bypass caps etc. It's blackface circuits in the phase inv and bias sections. Cleaned up more lead dress and changed all but 8 res on the board in the process.Normal channel doesn't motorboat at all(less gain). The reverb channel does it at high volume/ bass settings or when extra gain is introduced. ( disconnecting the trem or using a pedal) The plate voltage on the preamp tubes seems to be running high. The schmatic call for 200v and I reading about 240v. This one is really stumping me. All replies are greatly appreciated. JCS

7/30/2000 3:29 AM

JCS

Re: Silverface Vibrolux motorboating ?

Yes the trem works. I discovered the reading on the trem cap was off because the footswitch need to be shorted. I made this amp match the AA270 layout as far as bypass caps etc. It's blackface circuits in the phase inv and bias sections. Cleaned up more lead dress and changed all but 8 res on the board in the process.Normal channel doesn't motorboat at all(less gain). The reverb channel does it at high volume/ bass settings or when extra gain is introduced. ( disconnecting the trem or using a pedal) The plate voltage on the preamp tubes seems to be running high. The schmatic call for 200v and I reading about 240v. This one is really stumping me. All replies are greatly appreciated. JCS

Replies:

JCS I'm going to change the power res i... -- 8/2/2000 12:24 AM
Rebel420 q{ The schmatic call for 200v and I... -- 8/2/2000 6:27 AM