Info on some vintage Geo Space corporation preamps I just received.

I just received 2 vintage  preamps (+1 for extra parts) that were supposedly made for Nasa and these thing look insane. I can't find any info on them whatsoever so I was wondering if anyone has ever heard of these? Any info would be great Thank you for your time! Looks like they have a regular 16 pin 500 series style connector on the the back and at least 5 custom gs transformers per unit.

Any info or thoughts would be  much appreciated. Thanks.

The front of the units....

I can't  be of any help but they look very cool!

From the look of the front panel, I'd guess these are hydrophone preamps. Those are mic preamps too, but usually have enough differences to make them unsuitable for audio.

That also explains the number of transformers in these. When you place a hydrophone at a depth of 500 m in a well, you want as much isolation as possible.

Yeah these dont look like audio preamps. The circuit should be simple enough to start drawing out.

cyrano said:

From the look of the front panel, I'd guess these are hydrophone preamps. Those are mic preamps too, but usually have enough differences to make them unsuitable for audio.

That also explains the number of transformers in these. When you place a hydrophone at a depth of 500 m in a well, you want as much isolation as possible.

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Thanks for the response and informed insight!
From what I've heard they may have been made for Nasa so I assume it would be a similar design for space as it would undersea. Even if they are unsuitable, the sound designer in me wants to hear what audio sent through these would be like like Will keep looking for answer or just sell for parts. There was definitely no budget limit on the quality build of these!

mrclunk said:

I can't  be of any help but they look very cool!

Click to expand...

Thanks anyways for looking! Hoping to get to the bottom of this.

iampoor1 said:

Yeah these dont look like audio preamps. The circuit should be simple enough to start drawing out.

Click to expand...

Thanks for the reply. Was told they were audio preamp's but I have no idea whatsoever and I'm sure you would know more than me about them. I really am horrible (trying to get better) at circuitry so its kind of a lost cause for me to try and map them out.

This is the description I got when buying them lol -

"This is for a pair of vintage high quality audio preamps by GS Company
Geo Space Corp  Houston, TX
Very high quality build.
2 mono preamps, 1 cable, no power supply, one extra chassis."

Those are so cool looking that I couldn't resist a little detective work... from archive.org, a 1967 brochure from this same company about something else, but with the following quote:

"Geo Space Corporation is a major producer of both analog and digital seismic exploration field recording and data processing instrumentation."

That's general background on the company, from this brochure, which is just for a CRT display of some kind:
https://archive.org/stream/TNM_DP-203_digital_CRT_plotter_-_Geo_Space_Corp_C_20171025_0107#page/n1/mode/2up

Anyway, looking at the numbers on the filter switches in your photo, they look to be quite low frequencies, which would possibly make sense for some kind of seismograph?  Not that I know anything about that kind of instrumentation, but it seems plausible...

Transformers look like Triad Geoformers (low frequency transformers), or knock-offs.  Usually that style chrome case is a clue.