« Reply #4 on: May 24, 2006, 02:18:34 PM »
Any suggestion?
AD-20 is the inbox? Or am I mixing things up?
In general: if it uses opamps and uses resistors to set the gain you can vary that gain by changing resistors.
AD-20 Zefiro Inbox.
I should have to reopen the AD.20 and check if the resistors ara "normal" resistors or SMD...
Definately not surface mount. That box has been around for quite a while.
Maybe while you are in there swap out the crappy op-amp with something a little better sounding and call it the lordbelial mod!
Actually the opamp in there is fine. It is cheap, but fine, since it is after the discrete transistor stage, where the gain is being achieved.
What needs work is the transistor front end. And that is a lot of work, unfortunately. And I don't know how to design with discrete stuff.
Hmm. If I was really going to modify that thing I would replace the transistor front end *plus* the opamp, with something good like an AD8620. But that is a lot of work too.
As far as reducing gain, it *might* be possible to just reduce gain at the opamp. But I have not tried this.
Have fun!
Richard
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Mics: Sennheiser MKE2002 (dummy head), Studio Projects C4, AT825 (unmodded), AT822 franken mic (x2), AT853(hc,c,sc,o), Senn. MKE2, Senn MKE40, Shure MX183/5, CA Cards, homebrew Panasonic and Transsound capsules.
Pre/ADC: Presonus Firepod & Firebox, DMIC20(x2), UA5(poorly-modded, AD8620+AD8512opamps), VX440
Recorders: Edirol R4, R09, IBM X24 laptop, NJB3(x2), HiMD(x2), MD(1).
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