collins 'minimixer' project finished

kiira · Mar 2, 2006

[quote author="NewYorkDave"]

1952 RCA BC-2B ads. Right click and "save as..."[/quote]

my xpdf thinks they are corrupted Dave

"[/home/kiira]
bullwinkle
root:>Error (0): PDF file is damaged - attempting to reconstruct xref table...
Error (47659): Bad Huffman code in DCT stream
Error (1398301): Bad Huffman code in DCT stream"

root

Larrchild · Mar 2, 2006

I keep laughing at the guy on the left with the can of contact cleaner in the background. Yer gonna need that, buddy!

NewYorkDave · Mar 2, 2006

Hey Kiira... As a test, I downloaded the file just now. Worked fine. Perhaps something went fubar during your download.

If your inbox will accept such a large attachment, let me know. I'll give it to you that way.

emrr · May 15, 2006

Here's an eight-banger I did on some Collins Radio Company 356A modules about 2001 (notice the first pics are film), which also got all new resistors and caps since they'd lived in a barn for many years. The pics show a few different stages of the build, but what's there is -20 pad, 620 ohm output load, 600 ohm T output attenuators, phantom on back. All DC voltages in the PSU which is all Power One units. I machined a new connector bar so the units can be unplugged to the needed number of channels. The audio wiring all comes in the back, goes down and under, and then back up. There's another steel plate under the main case to protect the wiring and form a channel of sorts. Chassis is an RCA BA-31/33/34/41/43/44 era rack shelf, repurposed with new front and back panels.

First pics are old, scroll below for a recent (2017) set of changes.

Recently (2017) removed the 600 ohm output ’T’ (no point to it), and installed a negative feedback gain control mod which can raise gain roughly 20dB over stock. With the gain knob all the way down, gain is stock. If you take the feedback loop out completely the top and bottom response falls apart, so there’s a stop resistor to limit the range. Tonal/harmonic quality varies a good bit across the gain range. Also fixed the dumb gender choice on the PSU umbilical and made the cable longer.