32 Channel Microphone Preamp

[Volpe42]

A friend of mine as asked me to look into building him a Balanced Tube Microphone Preamp for his Digital Recording Studio (if I remember correctly he uses a DAC), and I am wondering how much of an undertaking this would be?

[CSlee]

There are quite a few mic preamp threads out there already, some are really informative, there will certainly be enough there to give you a good idea.

Antonio and Ruffrecords have been working on a 10 channel mixer for a while, and that seems like a big task.

http://www.diyaudio.com/forums/tubes...ube-mixer.html

32 channels would be a mammoth undertaking.

Charlie

[ruffrecords]

Yes, a bit more information would be helpful. Is this just 32 individual mic pres or is there some mixing to do as well?

A 32 channel tube mixer would indeed be a challenge!

Cheers

ian

[Volpe42]

My understanding is that he just wants the preamps.

[artosalo]

My understanding is that he just wants the preamps.

Don't you have any specification ?

[kevinkr]

Originally Posted by artosalo

Don't you have any specification ?

Yeah you need that.. Here are some questions that I would ask, and I expect ruffrecords probably has many additional useful suggestions, but at a minimum I would ask:

• Do you need (switchable) 48V phantom power?
• Do you want input transformers, and if so what part of the budget can you allocate to their purchase?
• What features are on the mixing board that you don't need to duplicate? (EQ, polarity inversion, etc?)
• How much gain is required, and how do you want to control it?
• What is the noise floor, typical and peak output levels of the microphones being used? (Gain requirement, noise floor and overload margins, any special supply or load impedance considerations?)
• Do you need balanced output? (Since this is a tube pre, that probably means another transformer.)
• Stick to commonly available tubes like the 12AX7, 12AT7 or go for something more exotic and hence expensive?
• What sort of packaging/chassis format do you envision as being ideal? (4 ITU rack chassis with 8 independent channels sharing a supply for example or ?)

This sounds like a really, really big project to me..