Chicago B series transformers

[rackmonkey]

I recently scored a second Chicago BO-2 push-pull output transformer. The “Bx-x” series is their “full fidelity” line aimed at broadcast and studio applications (30-15k, according to the case; 30-20k in the catalog). Never seem to hear much about these guys. I seem to recall that the BO-2 was used in the CCA LA-1 limiter, but I haven’t heard of any other vintage units that used Chicago transformers. I’ve not yet tested these beyond frequency response and primary inductance measurements, so no clue how they sound.

Anyone know what other classic (or even classic in the Edsel sense) units may have used Chi Std?

 

[My3gger]

I have Chicago BIH-1 mic/line input transformer with 150/600-50k impedance, 30Hz-20kHz response, +15dBm and 70dB attenuation shield. This is their "High Fidelty" line very similar to UTC A-10 and other classics. Ratios are very high which cane be problematic, but nothing good pad wouldn't be capable to deal with.
People who are into vintage iron told me this is very high quality iron, so let's hope prices don't skyrocket. If the didn't yet, like UTC A-10, Triad AJ-9/10 and others did...
Catalog will help you compare yours to other models, specifications suggest they are high quality. I haven't use outputs but did BIH-1 input which sounds very nice, we even compared it to some other known old iron and sounded as good.

http://www.junkbox.com/electronics/Chicago%20Transformers%20Catalog%20ctc-58%201958.pdf

You are welcome to pm me about them because we don't want prices go up.

 

[rackmonkey]

thanks for the reply. Let me clarify. My intent wasn't to ask whether Chicago made good iron or not, or who has used it/liked it in projects really. I know the high end stuff is good. It's more about wondering whether anyone knows if it was used in any vintage broadcast/studio products other than the LA-1, or if any specific manufacturers had an affinity for it or tended to use it often. Other than Langevin and Altec/Peerless, most of the major manufacturers sourced at various times from the big guys like UTC, Triad or ADC, with the occasional outliers like NY Transformer, Microtran, Wahlgren etc thrown in here and there. I just haven't seen much Chicago or Stancor (Stancor supplied quite a few power transformers) in the audio path.

So really just curious where it showed up.

Thanks again though. Definitely not looking to get a GS-style rave fest going on here.

BT

 

[emrr]

Chicago made a lot of the pre-war Collins transformers.  Pretty thin on the ground.  They switched to Thordarson directly after WWII, and there's a lot of Thordarson used in GE products in the same era. 

 

[rackmonkey]

Right - forgot to mention Thordarson in the list of biggies.

Didn't know about the Collins connection. But then, I'm not too familiar with anything pre-war from them.

Thanks

 

[emrr]

Gates used Chicago outputs in the mid-50's console PGM and MON amps.