ADM Transformer 3-010-5197-0 Take Down

[CJ]

lots of lams,  varnish dipped,

there is no coupling cap on the P=P circuit so the core has to have room for unbal DC.

 

[CJ]

ready to unwind, looks like a guitar pickup,

 

[CJ]

4 shields were used,

 

[CJ]

secondary wind,  nice to have grn and red wire to sort things out,

random wound, about 30 turns per layer, 

 

[CJ]

and we are done!  last primary,

 

[CJ]

here is the print,  first try so there might be a gaff or two as it is getting late,

the core steel was probably an alloy of some type, as the perm measures out at 17,000

10,000 is usually the number for silicon steel,

and you can see that the saturation levels was down there at about 5 KG which is another clue.

you could probably wind this on a regular steel core and have great results, a few Henries less but no big deal.

Thanks to rackmonkey for snding this out, it was a real pleasure to see something new and exciting!

 

[gyraf]

Thanks, CJ.

I hope you realize just how much I (and probably many many others with me) enjoy these show-and-tell stories.

OTOH having very little to add or contribute with, I often feel that your tear-down-threads are undeservedly empty of interaction. So this really just to let you know that the audience IS listening..

/Jakob E.

 

[mjrippe]

Thanks indeed, CJ, I have a few of these transformers and I knew very little about them.  Now I have more info than I know what to do with!  Coincidentally, I have a cadaver to send you for autopsy, so watch for the postman...

 

[CJ]

Great! The doctor is in!

we got enuff info on these ADM's to start some DIY strips, anybody every rack u one as a mic pre?

 

[Brian Roth]

Great! The doctor is in!

we got enuff info on these ADM's to start some DIY strips, anybody every rack u one as a mic pre?

A few pictured here:

http://www.brianroth.com/custom/custom.html

In addition......maybe 10 years ago, I learned that KWTV, the local CBS affiliate, was junking their ADM desk as they converted everything to digital.  I literally "stood between the door and the dumpster" and dismantled the desk with the assistance of a friend.  Pix (last couple show the desk in one of it's last days doing a newscast):

http://www.brianroth.com/pix/ch9adm/

I saved all of the modules (sold most of those) and tore apart the frame.....made $85.00 of beer money from the copper and aircraft grade aluminum at the recycler.  Sad to tear up such a great piece of machinery, but no one needed a 32 input desk.

Bri

 

[CJ]

Wow! Awesome work on those raks and what a score at the TV station!

How do the ADM preamps sound? Like a cross between a Neve and an API or something like that?

thanks for the pics!

 

[Brian Roth]

Thanks for the kind remarks!

I've never recorded with any ADM gear, but reports say they have a pretty clean sound.  The build quality is excellent since most ADM gear went to broadcasters in a 24/7/365 world.  I have run across some modules with shorted "jelly bean blob" tants on the power rails, which is no surprise for gear made in that era.  The old Auditronics modules were even more likely to have shorted tants....I guess they used a lower quality part.

Bri

 

[mjrippe]

Heck, even Neve had trouble with tants on power rails.  Just a bad idea in general.  I have a couple ADM modules (one pre, one EQ) in the back of my shop that were soaked by hurricane Sandy, washed, and set aside to dry nearly 8 years ago.  Should see if they still work!

 

[MediaWorksOKC]

Hey gents,

There appear to be at minimum 5 different versions of the “mysterious” ADM 1:2 PCB-mount output transformer—in a similar 5-pin footprint—with varying heights (taller/shorter) and core material/design.

I have two variations here, both appear to be nickel alloy, but I’m not sure.

1. CJ’s fat stack “guitar pickup” steel alloy
2. Rackmonkey’s toroidal
3. My nickel? alloy “short” Marked: 431 W 11 1005022
4. My nickel? alloy “tall” Marked: 431 W 15 1005109, a little heavier than no.3
5. A grey version that is much taller than all others, unknown design/core material (the boards pictured are apparently the same module that I believe had possibly 4 revisions, one of which, presumably the final, was transformerless)

3 through 5 were found in a distribution amplifier unit, Model DA-20, Rackmonkey and Brian Roth originally helped identify the module boards and the main unit.

https://groupdiy.com/index.php?topic=73258.msg927228#msg927228

Pictures to follow...

Chris

 

[MediaWorksOKC]

3. nickel, shorter, more lams, 25mm tall
Marked: 431 W 11 1005022

 

[MediaWorksOKC]

4. nickel, taller, less lams, 33mm tall
Marked: 431 W 15 1005109

 

[MediaWorksOKC]

5. unknown, silver, larger than others

 

[rackmonkey]

Thanks, Chris. They are different model numbers, at least. Can you see the model number on the tall one? Looks like they used wax potting instead of epoxy?

I think CJ has done a hack job on that 431-W. Not sure which of the two models. He sent it to me when we were talking about this transformer donation via email. Maybe he can clarify.

Have you done any DCR and/or inductance measurements?

And last question, do you know which units yours came out of?

Thanks for the info!

 

[MediaWorksOKC]

Previous posts clarified.

I will get these measured and update.

There are no other markings or numbers that  I can see anywhere.

I can’t tell what the potting material is, I thought at first it was wax but it doesn’t respond even slightly to the heat gun.

 

[CJ]

the PC pins are mounted to a chunk of fiberglass, underneath that is potting compound that shoud respond to heat.  thanks for the info on the other models!

i do not think the torroid could touch the fat stack as far as freq response as there is huge capacitance from pri to sec in a torroid,  and the torroid is super sensitive to DC imbalance so the 375 EI is the way to go,