Here is an extremely rare 1957 General Electric BA7A "Audiomatic"
Limiting Amplifier - a peak limiting device which was one of the most
expensive (and complex) tube limiters ever produced. These are every bit as rare as the Fairchil 660 and they sound every bit as good! Some of that rarity is due to the fact that a Fairchild 660 was
$970 in 1963 and the GE BA7A was $1000 (that' would be roughly $8000 today) both of were top of the line
units in 1963 . If you can't afford the $25000 it takes to buy a Fairchild 660 the GE BA7, just running
signal through it adds rich harmonic detail to tracks. For crushing drum
tracks, or subtle limiting on vocals the GE BA7A is every bit as great
sounding as an original Fairchild 660. In total there are 15 tubes and 5
transformers and three large stepped Daven
attenuators. 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. From the manual "The use of this new
design permits an 8db increase in limiting range, a 15db increase in
output level and a reduction in size as compared to the popular GE
BA-5-A Limiting Amplifier." Output level: +27dbm maximum. Frequency
response +/-1 db from 50-15,000 cycles. Gain 57 dbm. Noise -65dbm or
less, signal to noise ratio at verge of gain reduction. Attack time 70
microseconds. Recovery time: .5 seconds to 1.5 minutes. A full copy of
the manual will be included with the sale. This one is in very nice condition and was in regular use in my studio for a number of years but has now been in storage for at least 15 years now. It powers up with no problems the meter is working and all tubes light up but that is all the testing I am able to do on it. All transformers have been tested and are good and the NOS tubes shown in the pictures are included. It has a solid state rectifier installed but I am including a 5U4GT which is what it came with originally. Either the 5U4 or solid state rectifier cane be used with no modifications. It comes with the NOS tubes shown, power cord (very hard to find), an output connector, and as stated a PDF of the original manual. This thing weighs a ton 45 pounds unpacked so shipping is high.
