What are the worst BJTs and/or op-amps you can think of?

Thread Starter

Comrade Pingu

Joined Aug 30, 2018
24
I'm working on a voltage controlled amplifier at the moment, and the goal for it is to, no joke, sound as crappy as possible. In general, it's just a long tailed pair of BJTs followed by an op-amp difference amplifier, with the gain controlled by a single BJT current source. If anyone here—especially anyone that's been in engineering for a while—knows a particularly yucky BJT or op-amp, lemme know.
 

Audioguru again

Joined Oct 21, 2019
3,857
The 741 opamp is 53 years old and has poor performance. It needs a fairly high supply voltage of 10VDC or more, it produces a lot of noise (rumble and hiss) and It has trouble with high level frequencies over 9kHz.

The LM358 dual and LM324 quad opamps produce crossover distortion, produce a lot of noise and have trouble with high level frequencies over 2kHz.

Guitar pedal circuits produce a lot of awful distortion. Some of them use old vacuum tubes, others use old germanium transistors and others use old opamps.

I have heard some compressor circuit that produce very bad sounds because their output levels keep changing.
 

Ian0

Joined Aug 7, 2020
3,768
My vote goes to the LM358/324 for the worst op-amp, but I don't even think crossover distortion appeals to guitarists seeking that ultimate distorted tone!
and probably the glass-cased OC71 for worst transistor, especially if the paint starts to come off.

To take a slightly different approach, I bet you could make something particularly dreadful-sounding with a CD4007. There's a fair bit about the 4007 on page 8 of this magazine:
https://worldradiohistory.com/UK/Electronics-Today-UK/ETI-Electronic-Circuit-Design-No-1.pdf
I thought I remembered there being a VCA, but it was a VCO, but it's food for thought.
The CMOS inverter with a feedback resistor makes an interesting amplifier, because the gain reduces as the output gets closer to the supply rails.
For some reason they still make the CD4007, I can't imagine why!
 

DickCappels

Joined Aug 21, 2008
7,985
General Electric 2N107 small signal PNP. They kind of worked. They were production fall-outs but were sold for hobby use in the late 1950's and early 1960's. At U.S. 55¢ cents each, they ate up more than one week's allowance.
 

Thread Starter

Comrade Pingu

Joined Aug 30, 2018
24
My vote goes to the LM358/324 for the worst op-amp, but I don't even think crossover distortion appeals to guitarists seeking that ultimate distorted tone!
and probably the glass-cased OC71 for worst transistor, especially if the paint starts to come off.

To take a slightly different approach, I bet you could make something particularly dreadful-sounding with a CD4007. There's a fair bit about the 4007 on page 8 of this magazine:
https://worldradiohistory.com/UK/Electronics-Today-UK/ETI-Electronic-Circuit-Design-No-1.pdf
I thought I remembered there being a VCA, but it was a VCO, but it's food for thought.
The CMOS inverter with a feedback resistor makes an interesting amplifier, because the gain reduces as the output gets closer to the supply rails.
For some reason they still make the CD4007, I can't imagine why!
Funnily enough, EDP made their Wasp synthesizer with liberal use of the CD4069, another CMOS inverter (see http://www.synfo.nl/servicemanuals/EDP/WASP_SERVICE_MANUAL.pdf), and that sounded awful in the best way possible. You're definitely on to something with that, so I'll look into that after I finish up the more conventional VCA I'm working on—I'll post the schematics once I get a working prototype up and running.
 
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