I have a small collection of about 30 AC128’s and some rare NKT275’s too!
I built my very own ‘Fuzz Face’ and ‘Tone Bender’
(nearly same circuit with an extra input pnp germxistor).
Then I tinkered around and invented a one AAA battery version pnp germxistors fuzz.
It plugs right into my Fender Strat Squier Bullet Electric Guitar.
Even though I have a Roland GR-55 Synth w/Ibanez Electric 24-Fret Guitar,
Marshall Amp and all kinds of gadgets I love the simple J.H. Fuzz Face.
Those 'ole Germaniums are so sensitive. I use a reverse 1N4001 diode on the
power input to prevent FRYOUT!
Almost all Fuzz Type PNP Germanium Xistors are Pinout:
(Looking down from top and from left to right order
With the base protruding slight towards the back.)
Collector (C) Base (B) Emitter (E)
This is for any ‘newbies’ that buy a couple to make sure they work right.
Sometimes I fool around with stomp-box design and use Wave files in simulation.
Was never satisfied with NGspice so, I use LTspice but, I setup the circuit in Kicad (here’s a link to doing it)
Perhaps NGspice (as it’s packaged in Kicad, now works… I don’t bother to find out).
Thus, you can Record your Guitar and see effects of electronic’s tweaking…
AC128 ? really ? HaHa ! takes me back years and memories of the OC72 in the black painted glass bullet cases with the red dot, i used to scrape away the paint and marvel how it changed characteristics in light ! Could make light sensors out of them
I also have a mini transistor curve tracer and it is absolutely amazing the variation of ':hfe"
(gain) these prehistoric crittters have. From about 20-120 average.
Ha Ha! I found one that looked defective because it has a gain readout of about 800
but when I popped it into the fuzz transistor socket …
J.H./AC/DC/Led Zeppelin/Metallica Screamer. WOW!
(That ‘Mascot’ out in front in the pix)
I always use transistor sockets for these sweeties … far to delicate to solder IMO.
I keep them stored on that breadboard in a non-conductive styrofoam base
at room temperature in my trailer/lab/workshop.
Brought back to mind the instructions to attach a crocodile clip to the leads while soldering to draw away the heat as Ge is more susceptible to heat damage than Si.
Seriously #^@ Scraping off paint to peak in at the illumination and those vintage looong leads and drawing away the heat so they won’t cook and that Marilyn Monroe red dimple and that voluptuous analog even harmonics sound and a negative power supply and no two of them are remotely alike? I should get out my 1900’s college slide rule and whack!
Average authentic Dallas Arbiter Fuzz Face cost is outrageous.
i have the full ready to manufacture KiCad board with all parts easily available and will post same ASAP,
.You can DIY through JLCPCB (5 pcb boards) for a U.S. $Jackson.
Plus parts and a small enclosure about 2 U.S. $Jackson.
I got my NOS (New-Old–Stock) AC128’s from a U.S. Vietnam Vet Monk in the Himalayans.
Every single one works.
BEWARE the fake clones!
I did once use an OC71 with the paint scratched off as a phototransistor for a slave xenon flash trigger. That was a really sinple circuit involving a SCR and I think one additional transistor.
I think it was something like this. I had only Ge transistors to work with. The SCR was the only Si device in the circuit.
I gave away most of my Ge transistors, and even my valves, years ago. Maybe I should have hung on to the magic eye tubes. There’s no point hanging on to old stuff. Might as well use them up while you’re alive because your inheritors will just toss them into the e-waste bin.
The Ge has an ‘ON’ voltage of about 0.3V
and Energy Gap of 0.67
vs.
The Si ‘ON’ voltage of 0.7V (sqrt2/2)
and Energy Gap of 1.11
The original Ge semiconductor ‘doping’ produced unrivaled transconductance.
On a late 60’s chilly winter day outdoor live show the sound of
the electric guitar fuzz was less intense and much different than a summer gig.
Had to ‘crank’ my Fender Bandmaster volume from 7 to 9.9 …
When I added a preamp pnp xistor (my version of a tone bender)
it was the beginning of the new era of heavy metal rock & roll sound for me.
Now … I play really mellow jazz/rock with my Roland GR-55/Ibanez Electric Guitar.
Yes, a depressing thought. I still have several hundred of these tin-can devices collected many years ago.
The first time any have seen light in probably thirty years was to make the above post.
The 5.25 floppy drive still lives in my desktop computer, along with a 3.5 floppy drive, a CD drive, a couple of DVD read/writes and a row of USB sockets. It is a 25+ year old grey metal box over 700mm high. The internals have been upgraded many times and most of the above listed drives haven’t been connected for many upgrades. I suppose I’m just too lousy to upgrade the box, however it does make an interesting conversation piece for visitors.
