The Amp Garage

Blackfacing done, I'll check the standby switch as soon as I can. Thanks again.

OK, further exploration revealed that if I remove the 12AX7 for the trem the thumping still happens, but of course no flashing neon. This removes the trem osc. from the cause of the problem. Swapping power tubes didn't do anything either. Screen resistors still in place. This silverface also has the...

I'll check it again this evening, but the caps under the doghouse appear to have been replaced not too long ago. Thanks.

Yep, still thumps exactly with the neon flashes. It seems when thumping it isn't passing any signal to the output section, because the last thump goes through the reverb and sounds bigger - like the 'final thump of doom' or something. Also the tempo of the thump is not changed by the pot settings on...

Yep, the LDR bug was next on my list, but I'll have to order one of those. Don't have a spare.

What's strange is how it settles down and works normally after about 20-30 seconds. That makes no sense to me. Tube changes for the vib changed nothing performance-wise.

I replaced the 3 series caps as suggested, no change. Exact same behavior - thumps for 15-30 seconds, then settles down and works just fine.

Any other ideas?

Thanks again.

Hello Friends, I'm working on a 1972 DR and the vibrato circuit is doing something strange. At startup - once the standby is on, the amp 'thumps' 2-3 times per second for about 15-20 seconds, then settles down and works normally. This thumping coincides with the neon lamp in the vibrato bug flashing...

Again, +1 on Tony.

There is a pdf of the board layout in the Dumble Files section.

Sorry to hear of your layoff. Here's hoping your interviews turn into a great opportunity.

Agreed. I'd check the ground connection(s) for the tone stack as a start.

LeftyStrat, One question, if you will. Do you perceive that greekie's comment was in opposition to what you just said? I most certainly do not. I think you guys are in agreement. Where I live we pay separately for garbage pickup. Here's one example where I'd like to see a change, as it would affect ...

"We want the state to be as weak as not to crush the individual, but at the same time strong enough to help those in dire need". Personally I feel this is very true indeed. I hate paying taxes, because I see what the results are. The poor may have gotten iPads and Playstations, but they are still p...

I believe the tax burden is even more concentrated.

http://www.ntu.org/tax-basics/who-pays- ... taxes.html

Norway is running deficits too.
http://www.datosmacro.com/en/deficit/norway

Their debt is over half of their GDP too.
http://www.indexmundi.com/norway/public_debt.html