Hi, guys. I wears thinking about these transistors I have that are unusable in fuzz circuits and I was wondering if it would be possible to make a small practice amplifier with them. Has it ever been done before? Thanks.
Has anyone ever made an amplifier using germanium transistors? Well, yes, they have. Before silicon came along and took over, ALL transistor amps were made with germanium. I had a germanium transistor radio 50 years ago or more. There were early guitar amps made with germanium transistors.
Cool. So then, it is possible. I wonder how this type of amplifier would sound. I have an old reel to reel that appears to be full of germanium trannies and it has a really good sound. Kind of a warm sound. Thanks.
Look at a few of the transistors, then look up their numbers. Germaniums don't look any different. Like old metal ones could be silicon or germanium. You have to look them up.
If those transistors are unsuitable to make a Fuzz, which is the easiest job on Earth (they must work sloppily) , they are even less suitable for real amplifiers.
Sound is not in the parts but in the circuit/implementation.
You won't have power transistors among them, you don't have a working schematic, even if you did they won't be what it demands.
This is a little like finding a few car parts at some junkyard and wonder about building a working car around them.
Sorry.
Well, that's a good straightforward answer to my question. I had hoped they would work. They're all AC128 with low leakage and low hfe. Thanks.
AC128 might do for a transistor radio type amp, 250mW to 600mW or so, and you'd still need to get driver and output transformers.
And then a humble LM386 will sound as good or better, so ...
So you could use them in a preamp circuit and make a power amp with something else. I can't really think of any particular transistor that could be used for every position in a whole amplifier.
If they are not gainy enough, darlington them up in pairs. Or just string extra stages.
Nothing special about germanium in audio, they get special in our overdrive circuits, but then the Tube Screamer folks have arguments over brands of op amps.
Well, I was only thinking about it because I'd hate to see these transistors go to waste. I figured you guys would probably know of a way they could serve a purpose. I've never built an amp, but I would like to.
(http://www.tonegems.com/wp-content/uploads/ad-k700s-1965c.jpg)
(http://www.tonegems.com/wp-content/uploads/kay_704s_schematic.jpg)
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Thanks, guys. And thank you, Juan for posting that schematic. That one must've been difficult to find. The tremolo circuit looks a bit odd to me, but of co use, I'm no electronics engineer. I'm lucky to do what little I can. So, would this type of amp be of lower output? I assume it would be a good amp for recording if it is. And, could one possibly build that tremolo circuit as a standalone outboard effect?
Well, the main problems here are the hard to find output transistors and the impossible driver transformer, but with what you have you might build just the input section: preamp and tremolo, basically everythingb to the left of Q3.
Problem is that the rightmost Q2 is dual function:part of the preamp, part of the power amp, and receives NFB from the output.
Let me think about it.
If possible, you can build it as a standalone preamp, to be fed either to input or the effects loop in to basically bypass the preamp, or drive a chipamp, a TDA something.
Just remember this needs positive ground supply while 99.999% of modern stuff uses negative ground.
Positive ground is not a problem for me. Later on, I'm gonna try to get one of those solderless breadboard so I can experiment with things like this. I'm always looking for different possibilities for getting cool sounds. So, if I built the preamp and tremolo sections as a standalone pedal, could I then run it through my Kasino amp?
Yes.
A good thing is that Kasinos, like all Kustoms, *can* be set flat, what is not true (or much harder) on Fender and Marshall, so you can use it as a flat reamper and hear the true preamp sound.
Cool. I guess that old amp has a few tricks I still don't know about. Thanks again, Juan. Maybe I should start another topic about my old Kasino amp and see what the possibilities are with it? Because it seems I'm still learning it.
Oh, just use it and you tell us :)
Will do. :tu:
On the subject of the germanium preamp and tremolo, what's the supply voltage supposed to be? Thanks again.
No voltages are mentioned but C10, the preamp supply caps are rated 15V, so preamp/tremolo supply voltage is probably -10/-12V .
That makes sense.