![]() It's not the part number, it's the technology: Ge transistors are slower (as in narrower bandwidth) and their sound is therefore less harsh, warmer than Si ones. It was an ordinary low cost part that later became famous for being used in the original fuzz pedal as a result it is today sold at outrageous prices, while any normal Ge transistor would work with no difference in sound. Speaking from experience as I had to ditch like 25% of a big lot purchased years ago in which many were shorted to death.Ībout the AC128, I stopped using it in pedals years ago. They can also be used for guitars, but as Class D stages distortion sounds like pure junk, everything has to be redesigned so that the final stages are kept clean and distortion happens before entering them.Ī problem with germanium transistors is their tendency to degrade over time until they either start leaking too much current also when unbiased or go directly to short circuit, no matter if they're used or not, so it's advisable to test a small stock before buying bigger lots that could contain many now defective parts. I wouldn't however use tubes for clean HiFi amplifiers as more modern technologies such as Class D today made possible building incredibly good amplifiers at a fraction of the cost, space and energy requirements. Tubes are better than both in this context because they saturate in a really graceful way and produce mostly even harmonics which give tube guitar amps their unique different sound this is something hardly reproducible in solid state, unless DSPs are involved. The difference between germanium and silicon transistors lays in the former having much narrower bandwidth, so that it naturally and more gracefully limits higher audio frequencies, and some the artifacts of distortion become less audible making the sound more warm. I guess I kind of like playing a fuzzy guitar as much as ZZTop :)Ĭrossover distortion is completely inaudible if the amplifier is correctly biased as it amounts to a fraction of a fraction percent of the output power, like attempting to listen to a distorted 100 mW pocket radio put on top of a perfectly linear 500W amplifier set at maximum output. One megohm impedance for guitar input is good, and play it by ear for a wide choice of output impedance into the guitar amplifier. Doesn't matter if it's positive or negative ground since it's floating. If the situation arises the whole thing could then be heat-shrunk right there into the middle of the cable. Without a guitar pedal enclosure you can just cut a long guitar cable in half and solder it to the PCB's input & output with the battery hanging off. Leave one in then audition the germaniums in the other socket, biasing each one accordingly. Put on adjustable bias and find some superb high-performance small-signal BJT silicons for reference. Before they could be sure the transistors were more reliable than the sockets. I like transistor sockets like there were on some of the early solid-state scientific instruments. I think it's good to make musical or audio circuits from just about any tube or transistor whether it was originally intended for audio or not.Ī very simple 2-transistor PCB can have art where it can mirrored and used for NPN or PNP, with positive or negative ground to your battery clip. ![]() One of my best sources of tasty germaniums was from boards about the same vintage as these IBMs. I would say they are like tubes because the distortion is more interesting than the silicon alternatives.įor non-distorted applications if you do overdrive a bit it can be a lot less harsh too.Īlso very difficult to make two the same, so specs were wide and top parts were hand selected from large batches of on-spec parts.
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