The Amp Garage

Tom, great to see you back. How goes it? Anything on the bench.

Ange

2 un-used 6AU6 tubes. Maybe tremolo like the Silvertone and a one tube Reverb? Looking into it.

So I found a 5V4 in the stash, and it lit up. Then in go the other tubes since no shorts and adequate voltage and wham, its a guitar amp. Treble and Bass do have a nice response and the volume is substantial into a nice breakup. So just the addition of new caps and input & output jacks did the deed....

So this amp has 6AU6-A preamp tubes, and yes has the 6SN7GT in the PI. Since I do not find a schematic with the actual compliment of preamp tubes, I can look at creating a schematic. I am close to just giving it a try as I have added the input jack and speaker jack and soon will have the new power c...

Steve, how would you proceed with this pentode input? Is it worth having a listen as is? Put in an input jack, speaker jack, power caps..... have a listen. Can I set up the input per the usual with the 1M to ground?

A

yup - looks like the dropping R's got cooked, I pulled them and also getting ready to put 3 prong safety plug and rewire the on/off. The on/off is weird, when you pull it lights up the 6.3v light but the AC is not flowing and when it's off the AC is conducting??? Need to re-do all that with the safe...

Just saw this Tony, way cool and you shared some great tidbits of knowledge. The fixed bias over the cathode bias, now I am looking for more of how you implemented that. You should do some more vids with the Guitologist, great the way you guys were bouncing off each other and getting into stuff.

HI, Looking for the correct schematic for this McGohan amp. It varies somewhat from the M20B schematic that is readily available. The M20B has 6SC7 tubes (triodes) and one 6SQ7 in the preamp section, whereas the M20 has 6AU6-A tubes (pentodes). The PI and power and Rectifier tubes are otherwise the ...

OK done, should last a while longer. Sounds like an Epiphone.

Hi Phil, yup with the switch to the 115 tap I am getting 240v on the plates which I believe is spot on. With the .022 in place of the .005 tone is improved in the bass realm and I am hooked to an 8ohm 2x12 Celestion cab, what a difference. Owner says he like the original sound but he has not heard t...

Yes yes was not sure if that was a good course or not. I can see if it has a great sonic effect.

Thanks

Hi Guys, well damit I got covid and got bored so went to work on the rusty chassis. I reckon it would take many more hours (already have quite few in) than is called for....but it's an improvement. Almost buttoned up. I need a suggestion for a speaker that would improve the overall dynamics, if that...

Hi, using 22uf 450v caps right now.I get 208VDC on the plates, both equal. Very low hum right now and it's not buttoned up. I have the PT at a diagonal position relative to the original so I could make the holes work. Seems to be fine. Let me add that I am at 115VAC on a Variac.

A

Hey Guys, got that PT installed and amp lives again. Looking at maybe a bit of voicing with some suggested cap changes, C6 for .022 and pull C 13, not sure if hum is an issue have to get it in the cab, might swap C12 up to 47uf. Also order a fuse for the Sec CT, have to install. Speaker has a few sm...

Just tested the old 6AQ5's on a rig I have and they are not doing great. One heated up a lot, compared to my usual 6AQ5 and the other one cut out after a bit. They are low cost tubes so I'll source new ones. I need to complete the replacement of the other electrolytic caps and look into the fusing S...