Any use for noisy Ge transistors?

[Harry Klippton]

I've got a small handful of RCA germanium pnp transistors with decent gain for fuzz faces. DCA 55 reports no leakage too, but they're very noisy in every circuit I've tried them in. I tried them in some broadcast builds and fuzz face circuits on the breadboard and they were unusable. I haven't tried using them as diodes yet. Is there anything else I could try?

 

[benny_profane]

Are they noisy in all locations of those circuits? I.e., if they’re noisy in an amplification stage, have you tried them as an emitter follower?

 

[Harry Klippton]

Honestly I hadn't paid attention to that but I'll check it out later

 

[Bricksnbeatles]

Create a simple noise synth. The noisiness of the transistors will create extra strong vibes, and the temperature instability will make you the envy of the indeterminacy crew

 

[Harry Klippton]

@benny_profane just tried them in both Q1 and Q2 in a fuzz face on the breadboard. The RCA 2N1301 hissed in Q1 more than a GT308b, but the RCA hissed significantly worse in Q2 than it did in Q1 or than the GT402b I tried

 

[benny_profane]

@benny_profane just tried them in both Q1 and Q2 in a fuzz face on the breadboard. The RCA 2N1301 hissed in Q1 more than a GT308b, but the RCA hissed significantly worse in Q2 than it did in Q1 or than the GT402b I tried

Hmm, okay. When you popped it into the Q2 spot, was the Q1 device already determined to be noisy?

 

[Harry Klippton]

It wasn't a completely empirical test since I didn't use the same transistor in each spot. I guess it could be that the higher gain transistor I used for Q2 is noisier than the one I used in Q1

 

[benny_profane]

It wasn't a completely empirical test since I didn't use the same transistor in each spot. I guess it could be that the higher gain transistor I used for Q2 is noisier than the one I used in Q1

try breadboarding a unity gain stage to see if it’s introducing noise on its own. If so, it’ll be noisy when used as an amplifier or getting hit with a large signal (e.g., FF Q2), and you may want to consider using them as clippers or exploit the noise in something weird.

Basic Buffers

Basic buffer circuits for use with guitar effects pedals.

www.muzique.com

 

[Harry Klippton]

try breadboarding a unity gain stage to see if it’s introducing noise on its own. If so, it’ll be noisy when used as an amplifier or getting hit with a large signal (e.g., FF Q2), and you may want to consider using them as clippers or exploit the noise in something weird.

View attachment 60299

Basic Buffers

Basic buffer circuits for use with guitar effects pedals.

www.muzique.com

I'll try this tonight

 

[Laundryroom David]

I'll try this tonight

You should be okay as long as you’re just doing up a unity gain amplifier. Just don’t venture into elite unity amplifier territory or all hell might break loose.

 

[giovanni]

Worst case can you use them as diodes? Maybe the single junction is less noisy?

 

[jwin615]

Earrings on Etsy.
Or you could try the de-whiskering, though with no leakage, doubt that would help.

 

[Harry Klippton]

try breadboarding a unity gain stage to see if it’s introducing noise on its own. If so, it’ll be noisy when used as an amplifier or getting hit with a large signal (e.g., FF Q2), and you may want to consider using them as clippers or exploit the noise in something weird.

View attachment 60299

Basic Buffers

Basic buffer circuits for use with guitar effects pedals.

www.muzique.com

I just tried this and ran through all of that particular transistor that I have, plus a couple of the Russian types. The RCAs still exhibited a little white noise with the above circuit engaged, but not significantly more than with the Russian type transistors

 

[benny_profane]

Hmm okay. You won’t really be getting an added benefit of a ge part as an emitter follower, so you probably won’t want to use them there. I think the next test would be to try it as an amplifier in isolation. Try breadboarding a treble boost circuit and see how that sounds.

If they’ve been noisy in the FF Q2 spot, though, you may run into issues with them if they ever see a big signal.

It may be best to try them out as diode junctions in a clipping circuit.

 

[Harry Klippton]

@benny_profane yeah kinda noisy in the rangemaster circuit. The higher the hfe on the transistor, the noisier it was

 

[benny_profane]

Yeah, I think you’ll have to go with your tolerance for noise here. If it’s too much, I don’t know of a way to dial that out. You may have to relegate them to clipping diodes.

 

[Harry Klippton]

That's sort of what I was expecting. I'll have to try it out

 

[benny_profane]

That's sort of what I was expecting. I'll have to try it out

Yeah, sorry that I couldn’t be of more help.

 

[Harry Klippton]

Yeah, sorry that I couldn’t be of more help.

No worries, this has been a good exercise

 

[SillyOctpuss]

I've just ran into this problem and was also hoping for a different answer. Annoyingly I've got a set of transistors that sound fantastic but as you turn the volume down to clean up the noise makes them unusable. They're probably the best sounding transistors I've had if they didn't have the background noise.