Jahnke U111 limiter modul - how is it reducing gain?

[L´Andratté]

On my quest to learn as much about compressors as possible, I´m repeatedly looking at this one seemingly simple, but I can´t find even the GR cell or the link between audio (left between in and out transformers) and sidechain.

There´s a lamp there, so that could be it, but I don´t get how (Also makes no sense with fast timing settings)?

Anyway if someone would be inclined to explain and still my curiosity, that would make me sleep better tonight!  ;D

The pdf has been dl from Kubarth´s circuit vault, the schematic is on (last) page 8...
https://www.dropbox.com/s/x9tew6oo4ln8vbr/u111.pdf

 

[PRR]

> I can´t find even the GR cell

Diode bridge (3).

> the link between audio (left between in and out transformers) and sidechain.

Diode bridge (3) shorts-out input transformer (1).

 

[L´Andratté]

NICE!
Thought it was a parallel sidechain for a meter. What a clueless brain comes up with... ;D

 

[Murdock]

Sorry to revive this thread but this compressor seems interesting.
Does anyone know, what the transformer ratios could be?

 

[thomasdf]

Beautiful design, and beautiful documents ! Transformer are BV111 which come up with no result ... Did you contact Kubarth or Jensenman ?

 

[Murdock]

Beautiful design, and beautiful documents ! Transformer are BV111 which come up with no result ... Did you contact Kubarth or Jensenman ?

No, I did not contact them. Although I got the documents from the Kubarth files…
But a member here was kind enough to offer his help as he has an original module. Sadly he can’t unsolder the transformers as the wires are already very brittle.
If anybody has some ideas of how to measure the transformers in circuit please share them.
I thought about applying a 1v 1khz sine and measuring the voltage on the other windings should be close enough?