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The other thing with Electrolytics is that their capacitance performance can vary depending on where you are in their voltage rating range I think? I swear I read that somewhere, but now I don't remember where.

Thanks everyone, I'll keep these in mind while designing.

You're unlikely to run into headroom issues with a guitar signal input and the output required going into a poweramp. Look at what the Revv G3 and the Firedman BEOD achieve on 9v. Something to think about with a clean channel is you still want some compression. Spikey transients aren't nice...

As a replacement for the amps in built preamp?

Live spice doesn't like overly complicated circuits, you sometimes have to split things up. Ive found issues in the past with specific opamps if they're not powered with +/- supplies. Im still not sure what your ultimate goal is here. Why do you need high headroom.

Using this schematic from AionFX to build a negative voltage supply for my bread board. I notice they have separate ground for the negative voltage compared to the input filtering. Is this necessary or just to minimise switching noise?

For some reason that only happens once I publish the post. Replaced with an image instead.

Alright, back with another round of Ge transistor testing this time the GT309B. These were quite a bit more expensive per transistor than the previous boxes I purchased. However if you want higher gain but low leakage these definitely seem worth taking a risk on. Out of 20, only 1 device is...

Hey folks. I built my first ever bread board circuit, an LPB-1 and tested the NPN 3BX31C. It biased up nicely, here's the oscope results, 1000khz 0.6v P-P signal input 1000khz 1.2v P-P signal input Haven't measured the biasing resistor values yet, but seems like the low leakage readings...

This quote on an old thread discussing diode Vf and knee made me realise, in a lot of circuit analysis, a lot is mentioned of the voltage but rarely the current. It made me want to do some simulations and examine this topic further. Thing is I've only ever used LiveSpice, does any have a SPICE...

Yeah there's no reason the design needs to be all Germanium, would be fine to use a JFET input buffer for instance, and a Si BJT follower to buffer the output.

Could be fun, any sweet example circuits? I probably have like 100 devices in this range, so I could make quite a few things ha ha. Would really love to do a microphone preamp, and line amp too.

In the above examples though, the clipping would be symmetrical in both typologies though right?

Hey folks, just looking at this "tape simulator" schematic, the original schematic is on the left, what I'm wondering is, would there be any difference compared to the version of the right? I'm vaguely aware of the concept of diode ladders, but usually I think there are some resistors in the...

The other thing of course is, I'm not married to 9v. Using an external supply and an LT1054 means that anything up to 15v is possible, not sure how that affects things but maybe it will help these lower beta devices be more useful.

I think you would treat the composite like this, using the marked point as Bass, Collector, and Emitter for the test.

Yeah, I hate the idea of these devices just rotting away doing nothing. I know we have a tendency match a device to the circuit, and not the other way round, but that seems so wasteful? Surely there are some clever circuit designers around that can make these things useful.

Nice! I wonder if bootstrapping and/or negative feedback can help stabilise low Hfe Ge Transistor circuits. I'm curious eventually to make a cascading preamp design similar to the JFET amp simulators and see how it sounds.

How did vintage Fuzz Faces and Rangemasters handle this problem then? Given they would be connected to an amplifier down range? Once I built something permanent I will definitely use the charge pump inverter.

Nice, been interested in a Vari-Mu type thing.