61 Reverberocket Reverb Problem

[caseyblu]

I recently picked up a '61 Reverberocket (random navy flair covering, 6v6, 5y3, original jensen etc. etc.). I love it, and have been going through troubleshooting various problems with quite a bit of help from this forum (thanks!!)

I have a reverb problem that I haven't found an answer to yet:

The Dimension control is acting as an auxiliary volume whether or not the Reverb is switched in:

-With the reverb switched on turning up the Dimension control increases the level of the dry guitar signal in addition to increasing the level of reverb.

-With the Reverb switched off turning up the Dimension knob still increases the overall level but with no reverb. There is a harsh distortion imparted when turning the Dimension knob past 5 or so in either case.

-The reverb pan is new (accutronics) all caps in the reverb circuit look brand new to me (Xicons).

Is this just the way this reverb system works? Any ideas for troubleshooting?

Thanks!

[jbrew73]

check for dc voltage on the dimension pot. this may be causing the bias to shift on the second half of v2.

[caseyblu]

No DC voltage on the Dimension pot. But to make sure I did this right:

DMM set to DC Volts:

Between Lug One and Two: 0V dc
Between Lug One and Ground: 0V dc
Between Lug Two and Ground: 0V dc
Same results with the Dimension knob all the way up or all the way down...

[jbrew73]

your test looks good to me. did you try swapping v2 with a known good tube?

[caseyblu]

Don't have any spares yet, so I tried swapping V2 and V3 (the 6SN7s). Had the same problem

I noticed that there is a cap that is missing from the circuit: Going from pin 5 of V3 the .02uf cap is there, but the 680pf to ground is nowhere to be found. The closest thing I had to 680pf was a 1000pf ceramic cap, I put this in from lug 1 of the Dimension pot to ground, but this did not change anything (barking up the wrong tree possibly?)

[jbrew73]

could you check and post the dc voltages on pins 1,2,3,4,5and6 of v2?

also check the resistance from pin 3 to ground(2.9k), pin 6 to ground(2k) and between pins 3 and 6(4.4k).

it seems the problem would have to be around v2 but im about out of ideas.

[caseyblu]

DC Voltages for V2 measured as follows:

Pin 1: 0V
Pin 2: 71V
Pin 3: 2.9V
Pin 4: 0V
Pin 5: 79V
Pin 6: 2.8V

Resistances for V2:

Pin 3 to ground: 2.9k
Pin 6 to ground: 2k
Between Pin 3 and 6: 4.4k

btw, thanks so much for all of your help thus far jbrew!!

[jbrew73]

have you tried running it with v3 removed?

[caseyblu]

Just tried it, same problem as before...

[ricach]

Just speaking from my experience with tube amp reverbs, that's a pretty common 'feature'. I say feature and not problem because there isn't anything wrong, just the nature of the beast. Unless the footswitch actually grounds the signal, it will get through. As it is, the dimension pot is the only thing that appears that can stop that signal.

[caseyblu]

Any Reverberocket owners that can verify what ricah is saying regarding this being the nature of the beast? (Significant volume increase and unpleasant distortion upon turning the dimension pot up regardless of whether or not the reverb is switched in...)

I am nearly done recapping the whole amp w/ mallory 150's, and Sprague E-lytics; so far so good, but still having the reverb issue, and weak tremolo although I have recapped the whole tremolo section...

Could some of the issues be resolved by replacing the multi cap?

[ricach]

Sorry, I missed where you said the volume increase was significant, and that it introduces distortion. If that's the case, there is something not quite right going on.

[caseyblu]

Update: Faulty wiring to the multicap. Once I replaced the multicap and wired it according to the schem the reverb worked perfectly.

Tremolo still only works on faster speeds, i.e. stops oscillating at slow speeds.
All caps have been replaced... Could it be a tube?

[ricach]

All caps have been replaced... Could it be a tube?

That's always an easy one to check. Swap V1 with V3 (6SL7's)

[caseyblu]

Swapped the 6SL7's (Valves 1 and 4) and the Trem stopped functioning completely, seems like a good sign in a way...