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ADM 770 Mic Pre/EQ Modules
Old 20th May 2006
  #1
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ADM 770 Mic Pre/EQ Modules

Anyone have any experience with the ADM 770 mic pre/eq's? I have an opportunity to buy a bunch of these, all racked up. They have 4 band EQ with switchable points and boost or cut in 2db increments. So far I have only been able to hook an SM57 up to them and talk into them. They seem pretty interesting. I am planning on running some pre-recorded tracks through them next week to see how they sound on drums, vocals, etc.

I appreciate and feedback on these, positive as well as negative.

Anyone here work on these modules? A couple of them will need some help to get them up and running and I'm not really adept in electronics. I just use the stuff, I can't troubleshoot it.
Old 21st May 2006
  #2
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While the 770's had a discrete opamp mic preamp stage, the rest of the signal path uses the prehistoric LM-301 op amp chips.

Bri
Old 21st May 2006
  #3
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Thanks for the response Brian. Forgive my ignorance, are you saying they don't really have all that great of a circuit design? Can they be modded to be better?
Old 22nd May 2006
  #4
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The LM-301 chips were basically a "second generation" opamp, and not really great for audio. Yes, the chips can be upgraded, but one problem is the package that ADM used...the round "TO-5" metal package vs. the much more common 8 pin DIP. Not too many opamps are still available in the TO-5 package.

Later ADM modules used the LF-35x family which were in the TO-5 package, and last I checked they were still available from Digikey. The LM-318 is another possibillity, as is cobbling a DIP-8 wirewrap socket into the round PC board positions.

Bri
Old 28th May 2006
  #5
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Can't you just bypass them as what Pat Morford does with his mod probably?
Old 28th May 2006
  #6
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I can't imagine how you can bypass all of the opamps in the EQ section of a 770! <g>

In a 780, you can bypass the LF356 stages *if* you don't want a "fader" to allow level trimming.

Bri
Old 23rd October 2018
  #7
I know I’m ressurecting the dead here but I was just at a studio opening (Electric Garden, check them out!) in Brooklyn and none other than Ricki the old tech from electric lady (pre-2006 when I got there) approached me as I was taking this picture and simply said, “those ADM 770’s are the absolute holy grail inductive EQ’s on the planet when racked properly.” They seem to share the same family of the old electrodyne and spectrasonics yet Ricki claims even bigger and more musical. I don’t know bout you but when one of the greatest techs on the planet uses the words, “ holy grail” I get some terrible g.a.s. They were feet away from an absurd amount of gear too, GML eq’s, masenburgs, etc...

I’ve got a friend at Kizmit Studios in BK with Sinatra’s old electrodyne and a pair of v610 spectrasonics comps and he and we were like, why have we not heard of these?? I’m on a mission to buy a pair myself now of course. Because that’s what slutz do don’t we. We Facepalm and spend some of that rent money.

Anyone else using these in 2018? Is there any other ADM model similar (having a real tpugh time finding 770’s)?Are these that amazing? Is anyone working on an old ADM console these days? Thanks all!
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