ADM Transformer 3-010-5197-0 Take Down

[Whoops]

Nice Thread CJ,  thanks for sharing your work.

I have 2 ADM modules, one mic pre and another is an EQ.

The Mic pre has a small round UTC transformer I think, and the output transformer looks exactly the same as the one you studied.
I will check the reference number next time I go back to the shop.

I have quite a few schematics of ADM circuits, I will search my backup hard drive.  Unfortunately I was never able to get schematics for the modules I own.

there's ADM schematics also in the technical docs section here:

https://groupdiy.com/index.php?topic=45601.msg767879#msg767879

 

[mjrippe]

ADM 2783 Preamp with UTC O-8 input transformer, ADM 202 discrete opamp, VCA card with dbx 2151, and ADM output transformer dated 2984.

 

[mjrippe]

ADM 1540-200 EQ with BH 1-205-0001 and BH 501-0174 inductors (1984 date codes).  The "-200" means no transformers.  Type 1540-100 would have the UTC O-8 and ADM output.  Also note this card does not have the discrete transistor output stage fitted.

I have full docs for the 2783 and 1540 if they are not in the Tech Docs section.

 

[mjrippe]

My four output transformers.  All from the same lot (5081) but no other markings.  They are 1" or 25mm tall.

Primary DCR = 16.5R
Secondary DCR = 55R + 72R total 127R
Interesting that 1/2 of the secondary is lower than the other but consistent across all 4 transformers.

Inductance readings from my Sencore LC75 (60Hz)
Primary ~2H
Secondary 3 to 3.5H each half  (Sencore only goes to 10H and cannot read full winding)

Inductance readings with a Tenma 72-875 (985Hz measured)
Primary ~.5H
Secondary .7 to .8H each half

Inductance readings with Tenma 72-875 (115Hz measured)
Primary ~.7H
Secondary .8 to 1.2H each half, 5.8 to 8.6 whole winding

 

[rackmonkey]

Thanks, Mike. These are the toroid core versions just like the one I posted earlier about. Your measurements align well with the ones I made, including the asymmetrical center tap.

You wouldn’t know which modules these came out of, would you?

Thanks,

BT

 

[mjrippe]

I don't know what modules they were taken from, but I bought them from a GDIY member.  I'll see if I can find out.

 

[Whoops]

My Mic input Channel has a 3-010-5197-0 output transformer

input transformer is this guy
Hi think the stamp reads: 3-010-5944-0  1006  2787

Here is the input module without the switches pcb that mounts on top

Switch PCB

here is the EQ module

I don't have any documents for these modules, if anyone has info or docs even from other modules that could help me out in racking them please let me know

 

[rackmonkey]

I might be missing it but can you find a model number for either module?

 

[Whoops]

I might be missing it but can you find a model number for either module?

not really unfortunately, no model number in any of the 2 modules

 

[Brian Roth]

Interesting!!! 

My hands-on experiences with ADM desks are those built in... say....early 1970's and into the 1980's.

@Whoops....the construction of the innards of the first "guts pic" posted looks quite typical...BUT the PC boards in the rest are from a later era.  As I recall, that EQ module had some sort of remote/"automation" capability.  The small "riser" boards..............

What's up with the crooked mounting of the input transformer??

Bri

 

[Whoops]

My hands-on experiences with ADM desks are those built in... say....early 1970's and into the 1980's.

Hi Brian,  someone told me these modules could be from a Broadcast console of the mid to late 80s.
But personally I don't even know if they are from the same console.
I bought them some years ago from a member around here, he knew as little as I know about the modules

@Whoops....the construction of the innards of the first "guts pic" posted looks quite typical...BUT the PC boards in the rest are from a later era.  As I recall, that EQ module had some sort of remote/"automation" capability.  The small "riser" boards..............

The previous EQ's were inductor based, this one is based on DBX IC's, the small riser boards have the DBX units, those are pretty much the EQ circuit

What's up with the crooked mounting of the input transformer??

it's like that because I removed the 2 screws from the transformer in order to be able to take a picture of the Stamps and codes.
There's nothing wrong with it, if it  was in place with the 2 screws it would look the same as in other units

Thanks

 

[Brian Roth]

I have only a few ADM docs from those later years.  The closest I find is an EQ with three bands and the VCA's..

The earlier mic preamps used (IIRC) a UTC O-8 nested inside of a O-17 mu-metal shield.

Bri

 

[Whoops]

The earlier mic preamps used (IIRC) a UTC O-8 nested inside of a O-17 mu-metal shield.

Hi Brian,
do you have a picture of that transformer?

Thanks

 

[mjrippe]

That EQ may have been from me Whoops!  I had some like that a while back.  Never did anything with them due to lack of info and sold them off.  Looks like it could be stuffed with more parts for a stereo eq? 

P.S.
I got your PM and will email you all the docs I have.

 

[Whoops]

That EQ may have been from me Whoops!  I had some like that a while back.  Never did anything with them due to lack of info and sold them off.  Looks like it could be stuffed with more parts for a stereo eq? 

P.S.
I got your PM and will email you all the docs I have.

Thank you so much

 

[rackmonkey]

Hi Brian,
do you have a picture of that transformer?

Thanks

Pic attached. UTC O-8s were turned backwards and used as inputs on many ADC modules, as Brian stated. Picture is of a 1280 preamp card. O-17 shield is shown too, as Brian mentioned.

Several of the schematics I have (including the 1668) specify the following for T1: "SAW-469 or O8". I couldn't read the numbers on your input, but it's clear that they used a similar transformer to the O-8 from a lesser known manufacturer.

You may get some clues from the 1982 Broadcast Console catalog as to which units these are. Nice pictures of the faceplates of the various units should make it easy to match yours to, if indeed what you have is from that timeframe. The catalog is 15MB, so I had to share it from my Google Drive:

https://drive.google.com/open?id=1X9RgY78tFnSGtjGyCRBqkzHwVAihP345

 

[Whoops]

Can't see your picture Brian, it says 404 - Attachment Not Found

I Think the stamp on my input transformer reads: 3-010-5944-0  1006  2787

 

[rackmonkey]

Changed it to jpg format. Seems to show up now.

 

[Mr797]

I did a few sessions on a brown faced ADM board in the 80s and at the time I'd never heard of ADM. I quickly fell in love with the EQ and the sounds I was getting.  A long time later I found a pair of the EQ modules on eBay and then picked up some grey faced mic pre amps with the DOAs. Then I found some distribution amp cards.  The brown face EQ is inductor style EQ which is my favorite. Still have to rack these up. Oh so many projects.....

 

[Mr797]

Here is one of the mic pre modules and a distribution amp board loaded with the output transformers.