Looking to build a mic preamp

[TimWaldvogel]

I want build a semi simple mic preamp. Balanced xlr in and out. Something with a simple power supply
I can buy from radioshack or use a guitar power supply up to 24v.
Preferably a transformerleas design but I wanna see those too.
Something that will pass or potentially produce phantom power.

I am also curious if there are any mic preamp kits where I can only buy the PCB and parts list. Then I can purchase my own parts.
Please help, thank you.

[Cliff Schecht]

Paia sells a cool tube mic pre kit .

[mth5044]

Check this out

http://www.audiomasterclass.com/?p=archive&a=giant-killing-$5-mic-preamp-its-secrets-revealed


..or you could just buy this

http://pro-audio.musiciansfriend.com/product/ART-Tube-MP-Studio-Mic-Preamp?sku=180581

[Top Top]

The funny thing about the "$5" preamp is that if you add it up, he is suggesting you use NINE 9v batteries (four for the +/-18v and five for the phantom power).

That brings the total up to considerably more than $5 

[malrock75]

I've built 3 of these and they are an easy build.

http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=6

They are like a neve on steroids. Down the bottom of the page you have options. I went with the jlm14 and 99v op. You don't need a transformer they have a load of gain.
Mal

[mth5044]

The funny thing about the "$5" preamp is that if you add it up, he is suggesting you use NINE 9v batteries (four for the +/-18v and five for the phantom power).

That brings the total up to considerably more than $5 

Ehhh don't ya know everyone has a battery drawer? 

Just kidding.. at the price ya might as well get the $30 one from MF, even if the tube might be a gimmick.

[TimWaldvogel]

I like the idea of the cheap 5 dollar mic preamp. But it doesn't have a balanced output it seems. Any schematic where people have changed this?
Another thing is I would prefer not to build a power supply. I don't understand it very well as far as a power supply

[andymac1962]

http://fileshare.eshop.bg/equipment_mfg/Amek_41.html
http://fileshare.eshop.bg/equipment_mfg/Allen+%7C+Heath_41.html
http://fileshare.eshop.bg/equipment_mfg/Soundcraft_41.html
http://fileshare.eshop.bg/equipment_mfg/yamaha_41.html
http://fileshare.eshop.bg/equipment_mfg/StudioMaster_5.html
http://fileshare.eshop.bg/equipment_mfg/Neotek_5.html
http://fileshare.eshop.bg/equipment_mfg/Mackie_5.html
http://fileshare.eshop.bg/equipment_mfg/KlarkTeknik_41.html
http://fileshare.eshop.bg/equipment_mfg/Crest_5.html
http://fileshare.eshop.bg/equipment_mfg/Benringer_5.html

lots of good mic pre schematics here

Also do a web search for focusrite & neve,   lots of info on their mic preamps on the net

[.Mike]

There's a DIY Green Pre page here that I have thought about building.

It has a single-sided transfer (archive) so you could make your own board. It does, however, require a +/- 15V supply.



Mike

[therecordingart]

Hard to beat the JLM Audio Baby Animal pres or anything from Seventh Circle Audio. I've spent many hours building some snobby mic preamps, and I can't say enough good things about JLM Audio.

If you are on a budget you probably won't be able to build anything for less than you can buy the ART Tube MP (like $29). Like it has been pointed out, the "$5 mic preamp" costs much more than $5. You can build preamps similar to those that cost $500-$1000 per channel retail for about $200-$250 per channel (think Neve 1272 using Carnhill transformers).

[Salvatore]

24 Volts ?

This is an interesting one, good quality and can be configured in many ways.

http://home.comcast.net/~markfuksman/hamptone.jpg

[Mark Hammer]

Check out the manuals at the Rolls site.  A lot of their boxes include simple mic preamps and the manual includes the schematic.

[TimWaldvogel]

lets say i DO decide to go with something i can operate on lower voltages using transformers. can someone recommend a way of getting some dirt cheap mic input and output transformers that sound pretty good?

cause a mic input and output transformer basically turns a balanced signal into a unbalanced and then the output transformers job is to put it back to balanced correct?

other than that its a fairly simple quiet opamp based gain circuit? maybe some cascaded opamps for  quieter gain.

but the transformers usually are passive correct? meaning i can simply run the opamps at close to their max voltage for high headroom and thats the key behind the whole thing?

maybe i should look into it more and someone could recommend me to an article where i could better understand the science behind it all

and PLEASE post some URLs for afforadable transformers


maybe this i found would work???

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=242-905

[TimWaldvogel]

would something like this work?

http://www.provideosound.com/tx-lm2.html

or this
http://www.radiodesignlabs.com/product.php?page=160

[Salvatore]

As there are countless choices of different output/input transformers in all values, I would first choose a good schematic to build, and then buy a transformer with the exact specs the design needs.
A manufacturer of transformers who has a pretty good reputation for making ok transformers for not to much money is this one..

http://www.edcorusa.com/Products.aspx