Mixer Restoration/ transformer guidance.

[elam]

Hi. I  hope everybody's  doing OK. It's my 1st post here.

I'm starting a mixer renovation/mod project. Being a real noob (my brain have  issues with electronics ) BUT with decent soldering skills, I'm gonna do what I can now, then pass it the a more knowledgeable mind (while I upgrade my knowledge ???)

I'm hunting for suitable transformers for now. This unit is originally designed with Triad A-12J (balanced mic/line to grid/Primary 600-150/secondary 60.000/ 1:10) input and A-67J line trannies.

Right now, I'm reading each and every old tansformer catalog I can find and try to grab some models  with the exact same specs. But for what I understand so far, I can go in a lot of different other ways.

I don't want more A12/A67's sonically, BUT I wanna stick with a pre-1975 "vibe".

So
1- Being a muscician/producer (Definitely not tech-minded, but I'm getting better  :-[) could you push me in the right direction to WHAT specs to look for, for replacement. Can I go for a inferior turns ratios? Different Primary, Secondary matching impedances, DC resistances (don't even get this one)  And to what limitS? The freq. response is not that much of an issue in my case, as I can compensate from the mixer EQ (maybe not with transformers from the 30's but let stay in the 1960's-1985's range or their modern counterparts ).

2- Could you suggest me some replacement (or ideas)... from experience. Old or new productions, my only "demand" is to stick with some old iron sonics. I don't need nor want clean xformer for this project.  And I know I will go through trial an error too anyway.

Thanks in advance.

 

[mjrippe]

What is the mixer you are working on?  Do you have schematics and can you post them?  Are there channels missing transformers or are you looking to replace some for a different sound?  What do you like/dislike about the Triads?

 

[elam]

Thanks mjrippe. The mixer is  homebrew US made from the mid 70's. Absolutely no schematics available. I "think" I found the creator in the Whitepage and sent him a letter (not a email) to see what he still have.

Out of 12 channels, 4 are working and equipped with the Triads. That's how I found out about the transformers. The rest is missing.

Last, I like the Triads (that's one of the main reason  I wanna restore/mod it ). But I wanna try other flavor of xformer and see if they can go well with my taste and the mixer electronics. I wanna buy pairs, and through trial and errors find what works well with my material. I'm working in an hybrid configuration. So I'd like different options going in and out of the computer.

I don't wanna restore it to specs at all, just create a more versatile and suitable tool for me. Starting with what I can do now, trying different transformers. And I ask you guys to give me some suggestions.

 

[mjrippe]

Ok, sounds like you have a good grip on things and you've been reading lots of old iron catalogs.  Personally I have always liked UTC transformers and there should be at least one of each type that would meet your needs (O series, A, HA, LS, etc.).  For example, A-10 or A-11 for mic input and A-20 or A-21 for line.  I'm sure there are Stancor, Thordarson, Hammond, and others that would work as well.

 

[elam]

Thanks mjrippe.

UTCs was were I started to look 1st. the A-10 and A-21 are already on my list. I've found some match with Beyer and Thordarson and Tamura. I'm reading about Peerless and some other less common american iron too. What's your thoughts on Japanese/Asian or German/European made transformers or less known companies like Dynaco or Acrosound?

Any other idea, where to look at?
Thanks.

 

[mjrippe]

Besides Tamura I don't know much about Asian transformers.  Vintage European stuff can be great - Haufe, Jorgen Schou, and others made amazing iron but it is harder to get over here.  And of course the British stuff from BBC, Carnhill, St. Ives, etc. but again harder to get and very $$$.  I don't think that Dynaco or Acrosound made anything for pro audio input/line use - mainly power and power amp output iron.

 

[elam]

I won't go expensive British  with this mixer. For what I understand the rest of the design can't come up to this level + my budget won't permit it. I'll still check on the old European stuff as I like old German EQ sonics and try to dig deeper in American made stuff. Thing that I have more chance to find around here and  less expensive to "try".
Thanks mjrippe, I really appreciate your input.
Thread's not close yet  Anybody feel free to participate 

 

[elam]

What is the consequence if I use an inferior turns ratio on the input ? That could help  broader my choice.