Turtlerock Forum

So, I got a 1589B, two channel mixer amplifier.

It came with one 1588a module, I'm getting two 1588c modules.

There are several things I hope to achieve and will outline what I can see needs to be done to this end.

It's got a 110v power supply, I want to change it to 240v and add phantom capability. I also want to give it direct outs for each channel.

Here's what I'm thinking.... Correct me if I'm barking up the wrong tree!

Remove power supply/mixer board (I don't need the mixer functionality).
Add power supply capable of supplying 12v and 48v (JLM kit seems ideal - T-rex and universal 48v supply)
Add JLM Go-between to each channel.
Adding VUs would be cool, just 'coz VUs are cool....

The unit has an output transformer, I guess I need another one to give me two outputs. Can I find, or even use, one the same as it has already? If not what can I substitute?

The mixer board has a 20db amplifier, will I need extra gain or is this used as makeup gain after the mixer?


Hopefully, with guidance, I can do most of this stuff myself (I'll be getting someone else to do any panel work required, I'd make it ugly for sure)

Hi Kurt,

I've pretty much done what you're talking about with my altec 1588c 4 channel preamp I listed here. 4 1588c, with a jlm power supply, switched pads and phantom, direct outs with transformer option and variable gain. The only thing I didn't do was use the 20db extra gain board (I didn't have one). So absolutely its possible. The T-rex fits the bill perfectly, will allow you to provide phantom power and 20vdc rather than the onboard 12v for greater headroom/gain. The 15xx series will drive a 600ohm load as they are so you can add a line out transformer or a step up transformer without needing the 20db gain board. The 20db gain would probably be useful but without it I used my altecs for all sorts of recordings and the gain was never an issue. check out five fish diy site...

Myles

The plan is to hook it up to a D/A to let me use the s/pdif inputs on my soundcard.

The fivefish guy doesn't use output transformers. Do I need them? Is there a benefit to using them?

Hi Kurt,
You don't 'need' output transformers, you can use a quasi balanced output stage which is how I've used two of my pre outs. But you can use transformers and they add a flavour as well as full balancing and 3db gain increase so I've got two of my pre outs balanced by transformers. Then you can select the color you want for the application. In fact you could even add a switch to select tx out or not. Seeing as you'll have a two channel pre why not make one tx out and 1 switchable?

Either way you wont have a problem with driving your sound card inputs.


myles