Speech Compressor from Popular Electronics.

[mac]

I found this speech compressor while looking for something else.
Might be useful as a guitar compressor.







It's easy tor read PE JPGs by changing the page number of the above links

mac

[R.G.]

I actually built one of these and adapted it for guitar back in 1968.

It worked OK, but was a little too heavy handed in compressing for my tastes now. It over-clamped the signal to a slightly lower level than after the signal decayed a bit.

Still, it's useful, if quite complex.

[Kipper4]

I'm guessing here but by the age of it,the tape application.
I assume it was intended for use with a ribbon or crystal mic right?

[Mark Hammer]

My 1973 Sams Transistor Substitution Handbook lists the ECG102A and SK3004 as subs for the 40395, and BC107B/108 and ECG123A as subs for the 2N2925.  There are other subs listed but those would be the more common and obtainable....in case heavy handed is what you want.

[mac]

Things I'd tweak:
- time constant given by R11 and C9
- R10 and/or R12 to have some control over gain,
  or make R14 a pot, connecting C10 to the wiper.
- R13 to fine tune bias

mac