Search results

  1. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    ⬇️ 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...
  2. JohnnyCreepy

    Mojotone British 100w Lead/Bass

    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.
  3. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    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...
  4. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    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...
  5. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    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...
  6. JohnnyCreepy

    Low Gain Silicon Transistors

    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.
  7. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    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...
  8. JohnnyCreepy

    Simms-Watts AP100 mkII 1972

    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...
  9. JohnnyCreepy

    106NU70 Germanium Transistor Equivalent

    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.
  10. JohnnyCreepy

    Analog Tube Power amp simulator: studying possibilities

    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.
  11. JohnnyCreepy

    Analog Tube Power amp simulator: studying possibilities

    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...
  12. JohnnyCreepy

    Analog Tube Power amp simulator: studying possibilities

    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...
  13. JohnnyCreepy

    Analog Tube Power amp simulator: studying possibilities

    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...
  14. JohnnyCreepy

    How Can I Bias a Push-Pull Fuzz?

    How it sounds with neck PU and from 12th fret upwards? Is the octave effect more apparent?
  15. JohnnyCreepy

    Bean LA2A optical limiter

    Conspiracy 2 commit child labour???
  16. JohnnyCreepy

    I built a pedal!

    IS THERE A SCHEMATIC FOR THIS???? 🤡
  17. JohnnyCreepy

    Excessive microphonics in a guitar & PUs

    My surgical tubing is a hose from disposable low volume air mask so yeah, that’s as surgical as it gets. Those masks are used in infarmys and operating rooms. Yeah, tubing is in. Installed new bridge and changed other pickups too, but something’s still off. I’ll try changing tone caps next as...
  18. JohnnyCreepy

    Excessive microphonics in a guitar & PUs

    My problem child is an SG-like Aria CS-250 so no pick guards or other hollow sections apart the switch and pot cavity. Fixed topmount bridge and so on. I’ll look that article up!
  19. JohnnyCreepy

    Excessive microphonics in a guitar & PUs

    Took guitar apart for bridge change and noticed PUs fit too tightly in their cavities. Maybe that is the source of unwanted body resonance pickup?
  20. JohnnyCreepy

    Excessive microphonics in a guitar & PUs

    Yes,,,If it has clean blend. Where do these noise gaters dwell?🤡 Good! At first I thought you’re not helping, but on the other hand you really might have a point there. HB on neck and p90 (hb sized) on bridge, both originally bridge PUs. Selector switch leaves coil start hanging there on air...
Back
Top