What did EMI/Abbey Road do to modify their Altec 436 compressors back in the
sixties..
I saw some docs on ebay for 250 US dlrs(!)
Wasn't that complicated or what...?

heyhey wrote:
What did EMI/Abbey Road do to modify their Altec 436 compressors back
in the
sixties..
I saw some docs on ebay for 250 US dlrs(!)
Wasn't that complicated or what...?

$250 for some paper sounds extremely complicated to me! I was always
under the impression that Abbey Road pretty much gutted & rebuilt the
Altec's you see in the old pic's (while we watch all these Beatles
crazies still buying those green Altec's in droves, for "that" sound -
which isn't "that" sound at all!) Tee Hee!!!!

On Sun, 20 Feb 2005 11:05:12 +0100, heyhey wrote:

What did EMI/Abbey Road do to modify their Altec 436 compressors back in the
sixties..
I saw some docs on ebay for 250 US dlrs(!)
Wasn't that complicated or what...?

I would imagine they put a trimmer on the bias of one side of both the
vari mu and output valve, so you can get rid of cv breakthrough. And
perhaps a variable attack.
I am no electronic engineer, but I built one and those were useful mods.

Don't know what they did, but I've added a variable attack knob with a
switch ala 1176 so you could shut off the compressor to use it as a
line stage. Also added a variable release knob. Add to that premium
film caps and it's pretty high fi. You can also add a rotary switch
with a few resistors to change ratios. Great box with lots of
potential, it's really a copy of Urei's 175.

Jim Williams
Audio Upgrades

Don't know what they did, but I've added a variable attack knob with a
switch ala 1176 so you could shut off the compressor to use it as a
line stage. Also added a variable release knob. Add to that premium
film caps and it's pretty high fi. You can also add a rotary switch
with a few resistors to change ratios. Great box with lots of
potential, it's really a copy of Urei's 175.

Jim Williams
Audio Upgrades

wrote:
Don't know what they did, but I've added a variable attack knob with a
switch ala 1176 so you could shut off the compressor to use it as a
line stage. Also added a variable release knob. Add to that premium
film caps and it's pretty high fi. You can also add a rotary switch
with a few resistors to change ratios. Great box with lots of
potential, it's really a copy of Urei's 175.

I've seen folks do the variable release and attack controls, and it never
seemed all that useful to me. The knee on these things is so soft that
changing the attack and decay don't produce terribly dramatic effects.
They can be decent sounding boxes, though, for not too much money.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Just curious, Jim. Have you ever done or are you familiar with any mods
for the Urei 175?

Mikey Wozniak
Nova Music Productions
this sig is haiku

Sure, done several. The 176 has the variable attack/release with a
ratio switch. This can be added to the 175 if you can accept drilling
some holes in it. The audio mods consist of premium film signal caps
and some good tubes.

Jim Williams
Audio Upgrades
818-780-1222