RCA 86-A Compressor XFMR

[emrr]

Awesome.

Clean-up points:
drawing shows 1800T + 1800T in one spot and 1800T + 3600T in another. Earlier you said 1700T and 3400T.

Puzzling to me how DCR could read 1:1 on all the examples I've seen, yet you are counting a lesser number of secondary turns, all with #38. So what's up? Did they forget to wind all of this one? ahahaha

 

[CJ]

Turns on the inside have less resistance than turns on the outside,

What puzzles me is why they used a fancy innerstage transformer for the side chain rectifier circuit,

It would be nice to know what the average signal layers going into the secondary are.

 

[emrr]

I'd say part of the philosophy was to keep the output stage separate, driven by an interstage gain control, so as to be tweaky about exact levels feeding the transmitter. No use of a balanced output attenuator here....also....the limiter in some cases would replace the program amp, which also did not have an output atten, but an interstage gain pot. The 'limit level' control would be vernier on absolute output once roughed in by the stepped gain pot. This feeding side chain additional single ended gain and rectification, thus the transformer. No additional gain before this, outside of whatever the 6K7's are doing, so more gain needed to drive levels to higher compression ratios. The way the 'limit level' is tapped off to operate within a specific range is also goofy. The 'current sink' voltage divider bias tree also looks goofy, holdout from the previous era of unreliable master voltages.

 

[CJ]

this transformer resembles a UTC commercial grade CG-233 , 1 to 0.9 ,

with these high DCR coils, the voltage ratio differs from the turns ratio due to the voltage drop across the winding that carries the tube plate current.

only no push pull secondary, dB is about the same, they might start a coil with one section, then slide whatever they want over that, and then finish it off with whatever amount of turns they want, thus having a bunch of options for one size core.