The Amp Garage

Nice looking chassis! Are you cutting slots on the tablesaw as well? Part of me wants to make this jig, part of me is fine with Hammond chassis... https://www.youtube.com/watch?v=yrb1Oh0aJM4 Bottom line is, I only fab my own chassis if I'm working for myself. It took about two hours for this exampl...

Thanks, Guy. But the cap at the input is for safety, not noise.

As suggested, I'd like to employ a DC blocking cap between input jack and LND150. I need a rating of 300vDC, but what capacitance, to avoid affecting the guitar signal ? And do I need non-polar, or can I get away with electrolytic? The only caps I have on hand that are small in size are a pair of 10...

Yes, this is my first Liverpool-ish build.

I knocked out the chassis today, from 0.080" aluminum with 1/4"-20 rivnuts. I found the Blues Jr's PT's 20-0vAC tap is perfect for powering a 28v dial lamp.

ViperDoc wrote: ↑Sat Mar 09, 2024 4:31 amAlso, did you consider placing the LND150 in the second vs. the first gain stage? I'm curious as to the difference that would make, if any.

No. I don't want to hear distortion from the FET.

I swap an old carbide blade on the table saw to cut 0.080 aluminum. Works fine, but I lack a full face shield, and deflecting aluminum chips with my face is always refreshing...

Updated layout in post #1. Trimmed some fat (empty space), aiming for a compact amp: 15"w x 6"d x 2.5"h

cdemike wrote: ↑Fri Mar 08, 2024 2:07 amBased on the other thread, I take it that the input cap is to protect the MOSFET from DC on the input?

It's more to protect against the LND150 shorting and sending 200+ volts to the guitarist.

Ten Over wrote: ↑Thu Mar 07, 2024 6:28 pmWhat is the two-tone brown thing on the Source?

Bypass cap, value to be determined at runtime.

Ten Over wrote: ↑Thu Mar 07, 2024 6:28 pm50pF seems a little skinny for the treble capacitor.

That 50p value is on both the layout and the schematic, from the Dumble Files section...

I had a chance to swap in an LND150 in place of 12AX7 first gain stage with no other mods in an existing build, and was happy with the results. So I'm going ahead with this Liverpool (nontraditional!) build, using LND150 as first gain stage, thereby eliminating one preamp tube. Layout first. First d...

Remember my failed attempts to repair a DV Mark Little 40 ? I'm looking for a solution to replace the whole circuit with something that can be mounted similarly in the non-traditional chassis. I want to find a PCB for a pair of octal power tubes and three noval preamp tubes, all with tubes-up, PCB-m...

Photos of main PCB, just FYI.

If the imbalance follows the tube, we know the tubes are mismatched, right?

Is this a vintage 1965 amp or a reissue? If it's really 1965, I'd be concerned the 0.1u coupling caps are leaky.

I replaced the pair of post-PI 0.047u coupling caps. Still getting the same bacon frying and pops.