Last minute build

Hello friends,

I have a large recording session coming up and I have a need to build probably 4-8 channels of something to make sure I'm covered. I saw a number of AM16 PCBs become available and I've been wanting to build some of them anyway, but the problem will be getting transformers from Cinemag in a timely manner. Any suggestions on transformer substitutions or other circuits to consider? Worse case I'll do a couple more 500 series kits, but my plan is to just get some boards and crudely slap them in a case and make it work to try to keep costs reasonably low. Something with character would be preferred as its for a hard rock band, but not necessary.

Thanks!

Paul

Crudely slapping things in a box can give you a lot f headache.

For transformer coupled I strongly recommend Jeff's (CAPI) 500 modules. A single opamp, a few resistors and capacitors and you can't go wrong.

But if you consider a transformerless design and economy you can check out my MICPRE THREE, now that GBP is all over the floor.

https://groupdiy.com/index.php?topic=52462.0

Rochey's Eden can also be a good choice.

However, for more like a 1U arrangement I also have these new in box LA Audio micpre modules which can save you a lot of time. The input tx is Sowter and the output is OEP. The opamp is 5532. One half forms the mic-amp stage the other half line. The good side is that the mic and line stages ar separate, so you can also inject line level straight into the line stage. The XLRs already fitted.  Replace the trimpot with a pot and you are done. Full schematic will also be included. Picture is attached. PM me if interested.

Sahib,

Thanks for getting back to me. I have a number of Jeff's products and they are great. I am indeed looking for something to mount in a case. The constraint I'm working within is the time frame of getting them as I would need to everything built by the 8th. At some point I would like to try out your Mic Pre Three's.

Thanks!

Paul

HI Sahib,

I am curious about the OEP output transformer. Is this a custom version?

Cheers

Ian

Hi Ian,

The OEP output must indeed be custom as it is not in their standard product range. Actually I am going to discuss it with them for the project that we have been discussing (over e-mail).

Potato Cakes said:

Hello friends,

I have a large recording session coming up and I have a need to build probably 4-8 channels of something to make sure I'm covered. I saw a number of AM16 PCBs become available and I've been wanting to build some of them anyway, but the problem will be getting transformers from Cinemag in a timely manner. Any suggestions on transformer substitutions or other circuits to consider? Worse case I'll do a couple more 500 series kits, but my plan is to just get some boards and crudely slap them in a case and make it work to try to keep costs reasonably low. Something with character would be preferred as its for a hard rock band, but not necessary.

Thanks!

Paul

Click to expand...

I guess the easiest circuit to build would be some API 312 type Mic Pres.
in transformer, opamp , output transformer
Easy enough
You can easily self each the boards yourself
a lot of transformers available for a 312 type mic pre

As for the AM16 you really need the custom transformers, as far as I know only Sowter and Cinemag make replacement transformers for the AM16 mic preamps.
I see that Audio maintenance has an inspired AM16 mic preamp, it's called the ezAM16 and it uses the Carnhill mic transformers,  you can check the schematic in AML website to see how they've done it so they could use the carnhills, but anyway as you are not located in Europe don't know how much that would help.

if you don't have the time to build something and want to be sure you are covered you can quickly buy one of this, it will also serve as a good backup in the future. I have one and although I have great mic preamps this unit always served me well:

https://www.thomann.de/pt/behringer_ada_8200_ultragain.htm?ref=search_rslt_behringer+ADA8000_317776_0

I think I'm good to go now.  I have an 8 channel baby animal unit built, but if I run into something else I'll keep these in mind.

Thanks!

Paul