Recent Posts

41

Tube Amp Building - Tweaks - Repairs / Re: 1968 Fender Vibrochamp AA764 Resto

« Last post by shaun on July 24, 2026, 03:30:32 pm »

Beautiful!

42

Tube Amp Building - Tweaks - Repairs / Re: Single tube Reverb headache

« Last post by shaun on July 24, 2026, 03:25:02 pm »

The longer I build amps, the more respect I have for Leo Fender. Which is to say I believe basic lead dress and wiring is my problem all along, as was mentioned earlier.

Being relatively inexperienced with reverb circuits, I assumed the noise that was plaguing me was coming from the power voltage side of things, or maybe a transformer placement issue. I now believe it's simply that I can't run rev send and return lines where I had planned to, even if they are well shielded. I thought shielding would avoid possible noise issues when sending and returning rev signals to the front panel reverb pots. Well, apparently not. I guess I underestimated just how finicky those lines are.

Back to the drawing board for a re-design. When I resolve this, I'll re post.

43

Tube Amp Building - Tweaks - Repairs / Re: Why is this Princeton style amp not loud?

« Last post by sluckey on July 23, 2026, 09:20:55 pm »

The pic that shows the actual PI circuitry does not match the schematic PI circuitry. Do you have a layout drawing?

44

Tube Amp Building - Tweaks - Repairs / Re: Why is this Princeton style amp not loud?

« Last post by Sonny ReVerb on July 23, 2026, 07:46:35 pm »

Some pics

45

Tube Amp Building - Tweaks - Repairs / Why is this Princeton style amp not loud?

« Last post by Sonny ReVerb on July 23, 2026, 07:45:35 pm »

I built this amp with blackface Princeton and brownface Vibrolux channels and a 7591 output section. This is the second version of this amp I've built. The first one is a great amp. This one has a bigger power transformer and a 2x10 cab. It's supposed to be louder than the first one, but it's not. Both channels are relatively low volume until you get to about 7-8 on the volume knob. It starts to get loud at that point, but it's no longer clean. This amp should be 35-40W. I have a Vibrolux Reverb that is very loud at 3-4 on the volume. I know a LTP PI would provide more drive, but the Princeton PI should provide plenty of drive for 7591's. I need another set of eyes to check my work.

46

Tube Amp Building - Tweaks - Repairs / Re: Vox AC15 based on Hoffman AC30 layout

« Last post by Big_Mike on July 23, 2026, 06:25:04 pm »

Yes . Also put a 2.2m between wiper and ground lug of each pot for safety. If you will also have a cut pot then look at page 3 of this pdf to see a neat way to install the mv...
     https://sluckeyamps.com/dual_lite/dual_lite.pdf

Cool, I was wondering how to incorporate a cut pot with a Lar/Mar master and plan to have it with this amp.  Thanks for the info!

47

Tube Amp Building - Tweaks - Repairs / Re: Vox AC15 based on Hoffman AC30 layout

« Last post by sluckey on July 23, 2026, 05:26:43 pm »

Yes . Also put a 2.2m between wiper and ground lug of each pot for safety. If you will also have a cut pot then look at page 3 of this pdf to see a neat way to install the mv...

     https://sluckeyamps.com/dual_lite/dual_lite.pdf

48

Tube Amp Building - Tweaks - Repairs / Re: Vox AC15 based on Hoffman AC30 layout

« Last post by Big_Mike on July 23, 2026, 04:28:54 pm »

Sluckey, to install a Lar/Mar PPIMV, I assume you remove the two 220K resistors after the phase inverter and install a dual gang 250K pot?  Thanks!

Mike

49

Tube Amp Building - Tweaks - Repairs / Re: 1968 Fender Vibrochamp AA764 Resto

« Last post by TIMBO on July 23, 2026, 02:55:51 am »

Hey guys, this one is done



Gave it a quick thrash and sounded pretty good, trem sounded OK as well
I'll be dropping it off to the owner on the weekend so I'll try and get a sound clip done.

50

Tube Amp Building - Tweaks - Repairs / Re: Deville Transformers Reuse

« Last post by sluckey on July 22, 2026, 02:48:04 pm »

https://el34world.com/charts/Schematics/files/Fender/Fender_hotrod_deville.pdf