General Electric BA7A

[heatwalk]

Check out this monster. In to reattach a broken cap can and swapping some questionable tubes. Waiting for that Fairchild to fall from the sky some day

 

[vintagelove]

They are pretty awesome. I had one and it was very impressive. Enjoy!!!

 

[emrr]

Top shelf tech. Amazing how badly GE panel paint seems to have fared under poor conditions. Lots looks variations of bad!

 

[heatwalk]

From a quick google - “A Fairchild 660 was $970 in 1963 and the GE BA7A was $1000 - and both were top of the line units in 1963 ($1000 in 1963 is roughly $8000 today)… The GE BA7A limiters were more rare than the 660, so very few engineers have seen one, let alone used one.”

The BA7A design was truly innovative for it's time and used a very unique method of limiting which was based around the audio modulation of an RF carrier, the imposition of limiting action on this signal and the demodulation of the RF to render a virtually thump free, peak-limited audio signal.”

Sure are a handful of inductors in play inside.

They are pretty awesome. I had one and it was very impressive. Enjoy!!!

Enjoyment through popping it open and marveling at the engineering. Wish there was something wrong beyond a broken multican so i could poke around more but ill take an easy fix too. Lucky enough to see it and work on it but a bit above my pay grade to own and use! Jealous of you!

 

[emrr]

The GE BA7A limiters were more rare than the 660, so very few engineers have seen one, let alone used one.”

This is definitely not true. For example, Rein Narma told CJ only about (45) 670 units were ever sold, the interview is probably still posted here somewhere.

I've definitely seen more BA-7's go by on the market than 660's or 670's, maybe even 45 of them! I've got a pair of BA-7 meters on the shelf here. I've probably had a dozen offered to me in trade over time. 670...that I've seen once, 660, never.

 

[Rob Flinn]

If anyone has the circuit diagram for the Ba7a I would be interested to see it, sounds like an interesting topology.

 

[heatwalk]

This is definitely not true. For example, Rein Narma told CJ only about (45) 670 units were ever sold, the interview is probably still posted here somewhere.

I've definitely seen more BA-7's go by on the market than 660's or 670's, maybe even 45 of them! I've got a pair of BA-7 meters on the shelf here. I've probably had a dozen offered to me in trade over time. 670...that I've seen once, 660, never.

Thanks for clarification. It did seem a little suspect but first time I've seen any of the above. Marketing to make a sale, no surprise I guess

Found this thread here quoting the interview.

Rob - attached is the schematic. Looks like someone just posted it in the tech documents also but here is the full manual

 

[Rob Flinn]

Rob - attached is the schematic. Looks like someone just posted it in the tech documents also but here is the full manual

Thanks Heatwalk