Search results

Checked schematic, if you turn mix down and turn volume all way up how is gain compared to bypassed signal? I’ve had bad pots and incorrectly oriented voltage regulator pins :)

Transistor pin orientation checked? Are ICs good, not fake? I know this isn’t what it looks like, but still cannot unsee cracked IC here. :D

4 preamp tubes for one reverb. Really? What I miss here? I know MOD unit aims for compatibility about where it’s placed in chain, but that amount of dual triodes would be enough for a complete preamp with PI included.

Still waiting to hear Ionosphere with a tube amp, but quick test releaved more note clarity than in transistor muffs with sustain dimed.

Cut relief part in half, scrape cord channel clean and glue it back together over a new cord. Or use not-so-approved way with a knot relief mummified in heatshrink flavored with some hot glue. Guess safest would be a clamping relief, that’s my official recommendation. :rolleyes:

500K pot with 500k resistor parallel between pot legs 1&3 could be a solution.

It isn’t safe and yes there is rules to follow. And there’s just plenty to know. First amp I modded did good for 6 months, but went dead after fail in bias circuit which caused tubes to run too hot. There was first heat damage followed by socket arcing on pcb caused by tube failure. The amp...

Maybe rebranded 741? Found this from my stash, white knob underneath:

🤫

Yeah, better to be really prepared for SF rehousing. My rehouse has been sitting on WIP box for a year and half after loosing my intrest on non working circuit. Tried to use rotary switch with option for Fuzz1+Boost&Fuzz2+Boost, but couldn’t get it work. I really should just check every trace...

SF-300? I possess mod doc or a link, just need to dig it. Edit. jackpot, found it bookmarked. https://docs.google.com/document/u/0/d/1U_uanZZQ6463Fj_zyF2kRtD-brLEqN14gemASVcTgUA/mobilebasic?pli=1

Clean build! I have a question about Q2&3, have you measured collector voltages and how they measure? I built this circuit too, tried few different transistors (low and mid gain Ge and Si ones from 200-450), but Q2&3 collector values stay around 6.8-7vdc.

A picture from pcb underside to see component solder joints would be golden. It’s easy to spot solder bridges, cold joints etc from a good picture! Have you double checked component values around charge pumps? Have you set led trimmers according to this: Do one side at a time. Set the rate...

Could be nothing, are the silent ones are without pot lug extension wires?

Remember to post pictures of your build to help troubleshooting, but if what @Cybercow pointed out doesn’t remove the noise it’s good to look into lead dressing. Are in and out wired running near noise emitting components and is shielded i/o wiring needed?

But but but buttt my G(e)FF sounds bit different day to day… Yeah it could be temperature drifting, but it mostly got to do with WHERE I stand in rehersal room, how guitar feedbacks on that particular spot. And this whole sensitivity changes with how my amp gain stages are set, but the most...

I think using one or two mechanical switches defeats the purpose what relay switching is used for. It’s for 2-3x longer life in use compared to a latching one. Swtch on pcb could be led pwr out, but without pcb schematic or docs in hand its hard to make more than a guess. So you want: -relay...

That’s missing pwr gnd reference for pcbs, won’t work as intented. Your first posts picture is an attempt for star grounding method, but misses one thing about shielding. If going for star-G, the shielding should be with one single common gnd reference and all gnd leads should go to one single...

Fix the schematic with white textil painter pen! There’s no other option.

Well this thread really grabs attention and educates, please continue! :)