The Amp Garage

OK, so I am envious of being able to do all those calculations but did you, at some point, simply disconnect the LNFB and listen to the amp turned up? Do you hear a difference with it in and out of the circuit? If you don't hear a difference, then all the calculating may show why but if you do hear ...

Are potentiometer casings referenced to ground?
CW

Thanks Martin.
CW

Martin, the primary is 60 ohms and the secondary is 235.3 ohms. I wanted a transformer that would fit the existing cut out and I needed enough filament wind for 3 preamp tubes, so the 40 mA was as much as we could get for secondaries. Bill at Heyboer said he also beefed up the primary a bit. For a 6...

Thanks guys. I can say that the device is a three tube stand alone reverb that Dumble did in the early eighties. It uses two 12ax7s and one 5751 as the reverb driver tube. The cut out for the power transformer is the venerable Triad R-2C, so 15mA DC. The hole spacing for the choke is 1 3/4", pretty ...

Thank you sir. Yeah I have built a few Dumbleators with the 47uf caps with good results. Not sure why I started to wonder about that other than seeing Brandons original post where he stated that they were 100uf. However, that post was almost 20 years ago.
CW

Hello, I have a device that I am restoring and it was missing the power transformer and the choke. I sorted out the power transformer but I could use some help on selecting a choke. I have this in the Dumble section because it is a Dumble device but unfortunately I cannot share much more than that r...

The low plate classic was originally owned by Jackson Browne and lent to SRV.
CW

Hello, I am going way back on this question. The main filtering everyone including myself seems to be using are the two 47uf in series per the schematic in the file section. However, I found a real early Brandon post where he stated that the first two caps were 100uf. So I am wondering, did we decid...

If you want to spend a bunch of money and probably get a good sounding Astron style cap.
http://www.tweeddeluxe.com/recpro-capacitors.cfm
CW

So here is what is going on with this amplifier. Fender has made changes to the circuit that apparently the service department wasn't even aware of. One of the rectifier filament leads (yellow) goes to the tube socket the other (blue) goes to the circuit board. Between the rectifier filament lead an...

Yes, Overdrive Special is trademarked. As is Dumbleator and Overdrive Reverb. The trademarks are held by the Dumble estate.
CW

And then there is the trademark thing.
CW

Guts

https://www.thesubjectmatter.com/dumblearchive.html

CW

Yeah, you would think. This amp has one single yellow power transformer lead going to the filament contact on the tube socket. The other filament contact on the tube socket has a single grey wire going to the board. There is a blue/black lead that comes off the transformer going to the board. The ye...