Bauer 920 Limiting Amplifier - a "Heathkit" UA-175

[rackmonkey]

Have searched a few times through the archives and haven't found any mention of Bauer Electronics Corp kits for the broadcast industry. It's an interesting story. Bauer was formed in the late 50s by Fritz Bauer and a former Gates field engineer named Paul Gregg. Their initial claim to fame was a DIY AM Transmitter called the Bauer 707. Later, they started offering various other broadcast gear in kit form. At trade shows, they liked to claim that a "secretary could build their kits" (in a perfect-for-the-period sexist moment; "Even a girl can do it!!"). I read somewhere that they actually had what used to be known as a "Kelly Girl" (temp secretary, back in the day)  build a 707 at the NAB trade show.

One of their kits was the 920 Limiting Amplifier. One look through the manual (attached here) tells you its a copy of the UA 175. Uses a UTC O-1 on the input. But the interstage and output are the same as the 175 (A-19 and PA-6003).

Thought this was interesting. Wondering if I missed a reference to these somewhere in the stacks. Interesting piece of history, either way.

Anyone familiar with these?

BT

 

[gridcurrent]

Anyone familiar with these?

only a photo.

 

[mjrippe]

Yes, I was aware of them.  Used to search ebay in hopes of finding one.  Never did.  Have a manual for another limiter of theirs on it's way to me now.  Will see if it is a clone also!

 

[rackmonkey]

Yes, I was aware of them.  Used to search ebay in hopes of finding one.  Never did.  Have a manual for another limiter of theirs on it's way to me now.  Will see if it is a clone also!

Let us know what you find out. Solid state or tube?

 

[Brian Roth]

I recall Gately who also sold kits:

http://www.preservationsound.com/2013/02/forgotten-70s-pro-audio-maker-gately-electronics/

 

[emrr]

Yes, have seen Bauer and UA side by side in studios many times.  It’s been a long time since they were the cheaper alternative I think, enough people had caught on 20 years ago. 

 

[mjrippe]

I recall Gately who also sold kits:

http://www.preservationsound.com/2013/02/forgotten-70s-pro-audio-maker-gately-electronics/

The Gately kits were for their modular mixer systems.  They also sold a discrete transistor opto limiter.  The model 1800 used a custom opto module that ran off of +300VDC.  Small and large mixers were also available fully constructed.

 

[mjrippe]

Let us know what you find out. Solid state or tube?

Solid state, dual band, opto compressor with peak limiting.  Uses two VTL5C7 optos.  Manual has complete tech details, calibration, and schematics (including large blueprint style).  I may scan it if there is interest and I have the time.

 

[Gold]

That looks like a cool unit. I’d like to see that schematic.

 

[mjrippe]

That looks like a cool unit. I’d like to see that schematic.

Here's the small version.  Does not show the +/- 15VDC PSU.  Also, I missed the two VTL5C7 in the limiter section for a total of four!  Slightly larger image size than my usual posts to allow better readability.  I will definitely be scanning the whole doc in the future.

 

[Gold]

Thanks. Do you  have a unit or have you heard one? I’d like to check one out.

 

[mjrippe]

Thanks. Do you  have a unit or have you heard one? I’d like to check one out.

Hi Paul, I do not have one.  In fact, I have never seen one in person, not for lack of looking! - Mike

 

[radardoug]

The other two are in the meter circuit. Quite a nifty design.

 

[Bill Wilson]

After I had sold my location recording equipment & was Pastoring a church, in upper N.Y. State; I was asked to make a record for a church in New Jersey I had helped start.  Used my Teac 3300S reel to reel & a Gately Prokit 6 mike input mixer.  While I had it, took the liberty to open it up; mike pres used 741 chip. It worked & got the job done & was a good value for the money.

Gately also manufactured the gain makeup amplifier for Lang PEQ, pultec copy. Lang also sold most of the Gately line.
Was called by Ben Speer of the Speer Family, Gospel singers to work on a Moms Wholesome audio 16 input P.A. mixer; it used 748 chips through out.

 

[PRR]

> Gately Prokit 6 ..... 741 chip.

The early ones were uA301 all the way through; and I think with 30pFd which made them essentially '741.             

 

[gridcurrent]

I suspect there was communication between Hafler and Gately.
Both made kits.
Both imported Danish audio equipment (Dyna:  B&O), (Gately: Ortofon).

 

[alishablosser]

Is this what you were looking for? And did you ever find what you needed? I came across this page as I was doing research on this amplifier I found in my basement. We will never use it and if you’re still looking for one, here is one.