Ok, I finally got a chance to dig into the Pignose G40V yesterday as I weathered the weather here in southern CA. And I have a new issue. It sounds like there's a very faint high gain version of the signal mixed in with the actual signal. It's not a hum or a buzz, it doesn't happen when the guitar's not playing, and it's very quiet compared to the actual signal, but it's definitely there. Any thoughts?

Here's what I did:

I swapped out the input jack and added the 68K resistor there, Removed C9 and C21, swapped out R2 for a 100K pot for adjustable bias added 1 ohm resistors to pin8 on power tubes for bias measurement, and swapped out the olde chinese 6l6GC's for some NOS Jan 5881's I had around. Re-biased to about 34mA on each output tube.

Put it all back in the cab, fired it up and plugged in a guitar. Sounds great! Then...POP. (shit)
Switched it off immediately. Oh crap did I blow a filter Cap?

Opened it back up, turned it on again to inspect, and saw some fireworks under the PSU board. Pulled the board off the standoffs and suspended it to have a look at the underside and tried again. Turns out the power supply was arcing between traces on the PCB. Nice little burn mark (sorry didn't take a pic).

Called my olde man to discuss solutions, and after that consultation scraped off all the carbon from the scorch mark, and applied a coat of readily available brush on lacquer called "nail polish" (thanks wifey). It was even green, though not quite PCB green. Anyway I touched up the scorched spot with about 4 coats in total, and a few other spots that looked like the trace might've been slightly exposed just in case.

Fired it back up and no more fireworks. Cool. Still have the faint sympathetic signal though. Not sure where to start troubleshooting that.

thecr4ne wrote: Tue Jul 25, 2023 11:35 am I have a pignose G40V (similar in design to marshall 2204 I hear) that sounds pretty shrill to me. Like something's not there in the low-mid range, and the highs are murder. Tube swap didn't change this, Pots all do something, but I don't really know where to start to narrow down the cause. Any advice welcome. Schematic below.

thecr4ne wrote: Mon Aug 21, 2023 11:21 am Still have the faint sympathetic signal though. Not sure where to start troubleshooting that.

Might be microphonic preamp or P/I tubes. I'd swap them out one-at-a-time to see if it changes. That's easy enough to do.

However, typically a "ghost" signal like this is from inadequate power supply filtering. Usually replacing the main filter caps solves it.

This is where an oscilloscope comes in handy. You can watch the B+ rails for any modulation/ripple as you apply input signal.

I JUST replaced all the filter caps. I guess I forgot to mention that. But yeah, brand new Nichicons, sigh, I'll start with the tubes and hope it's something there. Thanks

Nate Dort wrote: Mon Aug 21, 2023 11:38 am

thecr4ne wrote: Mon Aug 21, 2023 11:21 am Still have the faint sympathetic signal though. Not sure where to start troubleshooting that.

Might be microphonic preamp or P/I tubes. I'd swap them out one-at-a-time to see if it changes. That's easy enough to do.

However, typically a "ghost" signal like this is from inadequate power supply filtering. Usually replacing the main filter caps solves it.

This is where an oscilloscope comes in handy. You can watch the B+ rails for any modulation/ripple as you apply input signal.

Owen wrote: Sun Aug 20, 2023 9:07 am What do you use to record your shows? I want to get something that is easy to plug into a sound board.

Zoom stuff is fine, no complaints here, but I have a Tascam X8 that I really like. The built-in mics sound way better than they should, it has additional inputs for a board feed and other stuff, it is bluetooth-controllable (you have to buy an adapter but it's worth it. I use it to record live shows (mics @ FOH + board feed) and as a backup recorder for classical gigs.

There's a Tascam X6 that is a little cheaper, smaller, and has stereo mics + two inputs which may be more what you're looking for.

They both have 32-bit capability as well, which is great if you're not as gain savvy - with 32 bits you can basically set it up so it's impossible to clip and has plenty of bits to gain things up in post.

I bought a kinda busted garnet amp the other day and the sale included an unloaded thiele/TL806-style cab (covered in grey carpet no less). I know quite a few folks here are fans of this design, so I figured I should ask about speaker choices. An actual EVM12L or warehouse clone are a bit more than I want to spend just to see if I like the cab - are there cheaper options out there that will make the most of the design?

Is there an EVM12L clone hiding somewhere on aliexpress?

mdc wrote: Wed Aug 23, 2023 9:45 am I bought a kinda busted garnet amp the other day and the sale included an unloaded thiele/TL806-style cab (covered in grey carpet no less). I know quite a few folks here are fans of this design, so I figured I should ask about speaker choices. An actual EVM12L or warehouse clone are a bit more than I want to spend just to see if I like the cab - are there cheaper options out there that will make the most of the design?

Is there an EVM12L clone hiding somewhere on aliexpress?

I’ve got an EVM-12S in mine. FM Pennington had a Swamp Thing in it before I got it. He liked it. I’ve read some stuff online suggesting that these type of ported cabs are hard on your typical speakers at higher volumes but I can’t confirm.

If you deviate, you might look for other “musical instrument” speakers with the same resonant frequency and voice coil size as the EVM-12L to get a better idea of what the cab sounds like.

I believe that’s 55Hz and 2.5 inches respectively.

Having said that, Mesa also uses the Black Shadow MC-90 in these cabs too. That speaker is basically a rebranded Celestion Classic Lead 80. So that might be worth a shot if you can find a used one in your budget.

mdc wrote: Wed Aug 23, 2023 9:45 am I bought a kinda busted garnet amp the other day and the sale included an unloaded thiele/TL806-style cab (covered in grey carpet no less). I know quite a few folks here are fans of this design, so I figured I should ask about speaker choices. An actual EVM12L or warehouse clone are a bit more than I want to spend just to see if I like the cab - are there cheaper options out there that will make the most of the design?

Is there an EVM12L clone hiding somewhere on aliexpress?

I've used EV Force speakers, Eminence Cannabis Rex, Vintage 30, and some other Eminence speaker. I've never driven them to stupid loud level, but I've consistently run them at "with a rock drummer" volume and never had any problems.

TY both!

I think I've just fallen into that internet trap of like "well this cab is designed around these particular speakers and so you need these speakers otherwise it'll sound bad" instead of just putting literally any speaker I have on hand into it and seeing what happens.

mdc wrote: Wed Aug 23, 2023 9:45 am I bought a kinda busted garnet amp the other day and the sale included an unloaded thiele/TL806-style cab (covered in grey carpet no less). I know quite a few folks here are fans of this design, so I figured I should ask about speaker choices. An actual EVM12L or warehouse clone are a bit more than I want to spend just to see if I like the cab - are there cheaper options out there that will make the most of the design?

Is there an EVM12L clone hiding somewhere on aliexpress?

SOME PEOPLE ARE FANS OF THE GARNET DESIGN AND WANT TO KNOW ALL ABOUT THAT INSTEAD

It's an enforcer head, which is similar to the jammer, but has an EL34 power section instead of the 6L6 power section. $300CAD for the head and the empty cab, so I feel like I did pretty well - Garnets are getting PRICY in Canada.

It's an odd duck, one of Gar's later design AFAIK. There's an extra preamp/tube gain stage available via footswitch or a second input jack. The amp sounds a bit borked at the moment - the reverb doesn't work and I think there's some weird grounding nonsense happening. I assume it's the typical garnet spaghetti nightmare inside - I'll bring it by my amp-hobbyist-pal's house sooner than later and have him poke around.

It's missing the footswitch and also the front panel John Reis-style (which is just a plywood rectangle with some tolex on it and will take about 15min to replace). I imagine that also brought the $$$ down.