New Project Amp

[petesz]

Just reporting back to say that i got my package full of goodies in the mail, and that TubeDepot ships fast and packs the contents really well. I also have a 5% off discount code if anyone wants to order from them soon, as im unlikely to.

Cant wait to get started, but it'll probably have to wait till next weekend.

[jkokura]

I'd take that coupon. I'm thinking about retubing my vibro champ.

jacob

[petesz]

PMd!

[petesz]

quick question.. why would the positive side of an electrolytic go to ground?

i just replaced the power filtering capacitors.. its SO much quieter (less hiss and hum). so good start!

[petesz]

And just replaced about 6 paper in oil capacitors will mallory 150's.. and now the vibrato works!! woohoo! 

[timbo_93631]

quick question.. why would the positive side of an electrolytic go to ground?

i just replaced the power filtering capacitors.. its SO much quieter (less hiss and hum). so good start!

neg side of electro goes to ground....  perhaps whatever cap you are replacing was put in backwards from the get go?  remember to discharge caps when working on it now.  glad to hear it is going well....

[oldhousescott]

The bias cap on fixed-bias amps is backward, positive goes to ground.

[timbo_93631]

Yep, you are right, I wasn't thinking about that this morning!  Just filter caps...  I shouldn't reply to a post before the morning coffee kicks in!

[petesz]

Ok sweet, good thing i didn't reverse it then!

[petesz]

Am i correct in thinking this is 1.2M? Measured with a Multimeter its about 1.5M..

[petesz]

Just finished replacing the rest of the caps, now the vibrato has stopped working again.. damn!

[Scruffie]

Am i correct in thinking this is 1.2M? Measured with a Multimeter its about 1.5M..

You are but Carbon Comp resistors had poorer tollerances than modern resistors and drift in value with age.

[petesz]

Thats a huge drift.. I'll replace it. are 1/2W resistors acceptable?

So the vibrato works with a channel switching pedal plugged into the reverb switch jack at the back of the amp.. i think someones tried modding this before me. I think i'll try and fix that so the reverb is always on and the vibrato has the switching.

Its still very trebley, not that its bad, just different, but if i wanted to allows some more bass back in there, would i be looking mainly at these highlighted values?: