Recent content by pbrommer

Probably nothing that will be notable. The A/B/C at the end signifies the “gain bucket” of the lot. Looks like lower gain but can withstand higher voltage.

Changing q14 to an mpsa will up the amount of current drive, enough to give signal enough oomph to get the bulb moving. It’s one of those piece of mind things to keep your vibe vibin’

It’s probably not great, but I have a simple 20W stereo power amp running two cabs. If it sounds good there, I usually can get it sounding really good with the rack mount preamp Marshall I built. It’s simple right now but will really get going when I get the preamps done (when there’s time …...

That Harp Attack screams Tube Driver clone without the AC coupling from the mains (using direct +18V power supply)

Seconded with jimilee -- forcing yourself to find the problem makes solving other stupid problems that will show up in the future easier. Don't ask me how I know: I keep making stupid errors.

I’m slowly putting the schematic together to build a board. Should I go 1590BB size or try to go stacked 125B? Personally, I’m aiming for stacked 125B, but I’ve never done that before. Thoughts?

When I read the symptoms of how the potentiometers didn’t quite act right, it makes me wonder if the grounding isn’t solid. Just a thing to check. And don’t shotgun replace the electrolytics. It was only a thought because there are a handful of 10uF connected via a resistor to ground on the...

I did some thinking. I’m wondering if the grounding isn’t solid - as in it’s not all connected together or not well grounded to the chassis. Barring that, I would think a bad capacitor somewhere, like a bad electrolytic

Once you start fooling with stripboards, you’ll start getting into the hard stuff: perfboard, wire wrapping, and dead bugging your prototypes.

Weird shot in the dark - are those ceramic capacitors okay? Sometimes I’ve had leads pull and split the capacitor. Looking at the schematic and where there’s issues, there’s 50pf caps there. Other stab at it - what about the electrolytics? Are they good? Correct orientation? Just a couple...

That’s true (forgot to consider that). I was thinking amps that are similar to where Marshall puts their EQ - Hiwatt, etc. It’s more of an exercise in thinking and experimenting. Probably head in the clouds thinking, but makes the two interconnected hamster cages operating in opposite directions...

So, this got me thinking if this overall topology can be tuned to other amps. I will need to grab a breadboard and some frequency sims.

Maybe check c4? It might have overheated something or you bumped a lead and it broke? Not likely, but another place to look. It might not hurt to reflow the connections after Q3 up to the drive pot. One side of the c4 solder joint looks a bit skimpy on the solder

Om Nom is such a fun character in that silly game.

I jumped to the Facey-books and it sounds like they're out for surgery for a couple months. I just needed to know where to find the build docs in case I want to tweak my Purple Playtpus build to bypass the octave setting (because it still kind of bleeds over) so it's just regular LLama.