Ampeg Reverbrocket R12R No Tremolo

[SYSDOA]

Hi,

Third post. Still new. Hope someone can offer some direction. I have an R12R that doesn't produce any tremolo. It sounds beautiful other than that. I tested caps and tubes, they're in good shape. Anything else I should be doing before running points everywhere?

[Prairie Dawg]

Hi,

Third post. Still new. Hope someone can offer some direction. I have an R12R that doesn't produce any tremolo. It sounds beautiful other than that. I tested caps and tubes, they're in good shape. Anything else I should be doing before running points everywhere?

Have you tried shorting out the jack to narrow it down to an internal problem? The trem runs off the second section of the first preamp tube, right? So if it's not tubes it's got to be some problem associated with the oscillator circuit, either getting no voltage or maybe one of the caps is gone. There are 3 .05s and a .1, correct? Should be pretty simple to localize the problem, if one of those 50 year old caps has gone open that would do it.

[Rich]

There is a version of this amp that uses what they call a 'Module' which probably performs the function of a Fender Roach. It sits in a clip which is fastened next to a large cap on the extreme left side of the board, wired into v1 and v2.

So the question is which version do you have?

The one I'm thinking of has all 9 pin preamp tubes, a ss rectifier and 7591 tubes.

[jbrew73]

what have you tried so far?

are you sure it has the correct tube for the trem? a 6sn7 in place of a 6sl7 could be the problem.

can you measure the voltages on the trem tube and post them?

[SYSDOA]

Hi Rich, thanks. This one is running off a 5Y3 but I still double checked and didn't find the filthy roach!

[SYSDOA]

Hey J,

I actually ordered more tubes for it, still no luck. I made the mistake before of getting the tubes screwed up and corrected it. I've replaced some caps that were reading off. The rest of the circuit looks really clean. I'll check the voltages on the trem tube tonight and post them.