DIY mic pre

  • Thread starter Thread starter MarkW
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MarkW

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MISTERQCUE,

The Jensen one I am interested in is:
http://www.jensen-transformers.com/as/as083.pdf

There are lots of other circuits there, including phantom powering, making a condenser tube mic using one of their transformers, etc.

John Hardy (no web page, but does have E-mail) makes the 990 op-amp, the finished amp, and sells some of the other components. In his info pack, he sends the original AES paper that Deane Jensen wrote about it (990=discrete component op-amp module). Other people make 990 compatible discrete op-amps (Millenia Media and Fred Forsell).

The INA103-based one is in the applications booklet for this chip at the Burr-Brown site (www.burr-brown.com). This is the easiest circuit--the instrumentation amp and a servo. No expensive transformer. The Grace preamps use the 103 as the front-end.

Both of these can have a lot of gain (60 dB), so these are not beginner projects (oscillation, hum, etc.), but what the hell?
 
Thank's. Me thinks I'm going to give a crack at it as most of the parts on the schematic
can be obtained from Radio Whack and other electronic-outlet supply stores.
The only part that I might have difficulty in obtaining is the conductive plastic dual pot for the reverse log taper.
I'll probably give it a go next weekend.
Let you know how it turns out.
 
Anyone out there build their own mic pres? Thoughts?

I am considering building the Jensen dual servo circuit found on their web page or the one Burr-Brown has in the INA103 chip datasheet.
 
If you really want near-total RS parts availability see:
<A HREF="http://laplaza.org/~fvuotto/ssmicpre.html
 
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