Built up a discrete unity gain audio buffer. Really great sounding buffer. I tried to channel a bit of Jim Williams in this build.
Been sick and stuck at home for the past week, so I finally got a chance to get my Farfisa working perfectly. Some of the issues included notes that could not get in tune +/-8 semitones, notes without vibrato, notes with missing frequencies, and notes with a strange beating noise.
Almost all of the issues mentioned above can be fixed with a bunch of 1uF caps and 2N3096 transistors. Each sound card has convenient tabs for attaching a scope probe to view the waveform. Each tab is labeled on the copper layer of the PCB. Generally, if I saw an issue with a waveform, I first swapped out the corresponding 1uF cap. If there was still an issue, I'd trace the corrupt wave back to the transistors. If the corruption traced all the way back, I'd replace the transistors. I noticed a few times that the wire connected to the vibrato tab broke off on a few cards. Check for this first if you are missing vibrato on a few notes, it is an easy fix.
I also had a friend crawl out of the keyboard while I was repairing it. Almost had a heart attack. It was the last thing I was expecting while repairing a keyboard.
First off, ran the MS-20 into a TV's composite video input. What you see is what you hear. Or... What you hear is what you see?
Just to note, this is in no way an oscilloscope.
Also, ran some video through a TC Electronics Ditto Looper. Happened to be a techy scene from Willy Wonka:
Ran the MS-20 mini through a DOD R-870, then an Ibanez AD-120, then a Master Room XL-120, into a tube pre-amp. Zero musical value, but a demo of some of the sounds.
Mods included in this video: 8-step sequencer, PWM modulation, ring modulator.
Started building some custom wooden side panels for my MS-20 Mini. Using mahogany, ebony, mahogany, rosewood, roasted maple, rosewood, and mahogany. So far, we just did the glue up and some planing. Should be ready next weekend or the weekend after that.
Should we sell these? How much would you pay for something like these?