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⬇️ So yeah, stickchops, 90 degree zig zags etc have been tried. There’s distance and 90 degree crossings which aren’t so obvious from a pic. And yeah, after the pic wiring is tidier and some changes there too. The same hum problem was there with the original PCB before I touched any offboard...

Just build Lead version if you’re planning to use modern speakers. I just built an amp with Bass versions preamp section and ended up changing it to resemble Lead, ’cos bass content was too superwhelming with fuzz through 15” speakers.

🤟

Yeah, it played last yesterday, watched it for 30 mins before heading to train. Wall of bass was so massive it did tingle my peepee… I’m on my way to festival day two and Pelican starts in half an hour. After it Acid King plays Busse Woods album.

It was happening on somewhere between V2 and PI+NFB. NFBs first resistor from speaker feed has a pot wired as variable resistor series onto it. If I turn pot to reduce NFB amount the hum is more aubile. Now the NFB section is valued 20K resistor+50K (or was it 100K pot) from 16 ohm to 10K...

Pcbs would be named ”Model Tea&Biscuits”? Oh and latest build mostly solved hum problem. It was either reducing grid leak values from 200K to 126K or amount of NFB fed to PI. Also ditched shielded input wiring to V1 grid and raised stoppers from 10K to 40-50K. Response for dirt pedals is now...

I just made a long post about last year tinkering with the amp, but accidentaly closed my browser window. Poof, all gone. Shit. So let’s keep this short: 1. ruined vintage value with new caps and resistors 2. Hum and pcb falling apart bothers - rebuild on tag strips with first timers messy...

Guy was just huslin’ sum dope ICs. 🤷‍♂️

I’ve just read 3 hours ampgarage, diyaudio and various application notes/datasheet to land here seeing this. Thank you for making my train trips tube study session worth it. Now Im not gonna worry about Va being same as Vg2.

On saturday gonna see Acid King, Russian Circles, Pelican and Jesu. Looking forward to it. :oops:

Played few months without bigger problems. Accuired 2x15” speakers and they revealed a need to reduce PA coupling cap values. OTX pushes lows efficiently to the point overexcursion was happening with modern speakers. Also grid blocking was occuring. Blocked spkr cab’s reflex ports and reduced PA...

Start of the story. Couple years ago I was on hunt for a new amplifier and found Simms-Watts AP100 sale nearby. Amp was in good shape, played regulary and power side was recapped within 10 years. Majority of the components were original and circuit compared to schematic available. Topology was...

Sidejacks and cheap aluminium knobs (I know ’cos I use these too). Boutique build indeed.

Troubleshooted mates Vox VT30 quickly and changed a new dual pot for ”Power soak” control. Symptom was weird muffled sound with vol drop and OG soak pot resistance reading drifted like Twin turbo Supra. Now it blasts again. Weirdest thing what gave me joy was I found finally use for arced NOS...

It’s not FF or TB where people usually aim for certain gain and leak. IMO everything between 20-90 hfe is mostly fine. Also the feedback circuit from C to B helps clipping stages transistor biasing. And if not, fine tune E or C resistor values.

Yeah, BUT maybe this could work better attentuating AC signal going to IC. So maybe a quickie with alligator clipping 22nf cap between C2 and R3 to ground could do the trick. It would halve input signal strength.

For my taste and needs 100nF between tube stages is just too much and lets too much lows through which only causes problems. And I play with low tuning. 47uF cathode bypass cap is also one I’d change. I’d do it like this: C5 1-4.7uF C9 20-25uF C10 10-22nf Maybe you overload ampsim with low...

Either trace the signal with oscilloscope to see waveform changing or audio probe to see where signal loses it strength? Could you share preamp schematic? Edit. Looked astrosims schematic. 1M/470K divider before IC and some EQd feedback part to make the amp simulation going there too. I’d try...

Uneducated guess would be: Low power strum = less ac mV getting into circuit and circuit clips in a behaved way resulting amplifying signal toward the output High power strum = more signal strength to input, grid/base/(gate?) blocking happening and there’s just too much clipping going on so...