[sdiy] Which transistors for synth circuits?

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These days, I'd say IF there was a need for a germanium or GaAs 
transistor you'd already know.
Yes, there are a few corner cases where one could use properties of 
III/V devices, say, high power/ high linearity microwave circuits, or 
some ultra low noise RF.
The only reasons to use germanium I could see is their lower forward 
drop of their base-emitter diode. But this hardly matters in practical 
circuit implementations. Or you'd want to use them as photosensitive 
devices in the medium infrared range (roughly 1000-1900nm wavelength).

As I said, if any of these applications play a role in your experiments, 
you'll most likely know already. Otherwise I wouldn't care. It's good to 
know they exist in case they are useful to meet specific needs, but 
apart from that very few electronics experimenters actually could use 
their properties.

HTH,
Florian

On 31.12.21 04:07, cheater cheater via Synth-diy wrote:
> Thanks all, do any of you also every mess around with germanium or
> GaAs based transistors? Is there a reason to get a bunch to play
> around with? Not for production, just for own fun.
> 
> 
> On Fri, Dec 31, 2021 at 12:11 AM Oren Leavitt via Synth-diy
> <synth-diy at synth-diy.org> wrote:
>>
>> Some transistors in my general stock and what scenario I use them in:
>>
>> 2N3904/BC847 (NPN), 2N3906/BC857 (PNP), and 2N3819 (N ch JFET), 1N4148
>> (Si diode) - most general purpose "jelly bean" stuff.
>>
>> BCM847 (dual NPN) and BCM857 (dual PNP) - small SMD matched pairs for
>> discrete OTA/ladder filters, current mirrors, expo converters, etc.
>>
>> SSM2212 (dual NPN) - precision, low rbe expo converter for VCOs.
>>
>> MPSA42 (NPN) and MPSA92 (PNP) - high voltage 300V.
>>
>> 2N5088/5089 (NPN) and 2N5087 (PNP) - high hFE.
>>
>> 2N4402/4403 (PNP) and 2N4857/4391/4393 (N ch JFET) - Discharge switches,
>> choppers.
>>
>> Other small signal and power transistors for occasional hi-fi/power
>> amplifier projects.
>>
>> - Oren
>>
>> On 12/30/21 12:18 PM, cheater cheater via Synth-diy wrote:
>>> Hi all,
>>> I was wondering how you pick out transistors (as well as diodes) for
>>> synth circuits like filters. For example moog filter, 303 filter, etc.
>>> Do you look for anything in specific? I'm talking about a situation
>>> where you don't want to use the exact part in the schematic, but want
>>> to play around with parts and see what comes out of it.
>>>
>>> Best regards
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