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General Discussions => Drawing Board => Topic started by: ChrioN on June 01, 2008, 07:49:47 AM

Title: Changing tone of a mic preamp
Post by: ChrioN on June 01, 2008, 07:49:47 AM
What can one do to change the sound of a transformer balanced in/out mic preamp?
By changing the tone I mean "add" distortion or change frequency response.
Variable impedance? Change loading of transformers?
 :?:
Title: Changing tone of a mic preamp
Post by: SSLtech on June 01, 2008, 09:34:12 AM
"Distortion" is a simple word, meaning many things, few of which are simple. -You haven't really given anyone enough to go on.

Variable impedance? --Sure. Try it.

Loading of transformers? -Sure, try it.

If you're looking for a blanket answer, you probably won't get one that's very accurate, the only answer is... -guess what... "Try it".

Keith
Title: Changing tone of a mic preamp
Post by: JohnRoberts on June 01, 2008, 10:56:32 AM
While some purists (like me) might not approve, you can change the sound character of passive microphones by altering the termination impedance either higher or lower than expected nominal terminations. Active microphones will often have flat resistive source impedance so be less affected by termination impedance, but in the extremes some differences there may be audible too.

Transformers prefer to be driven from low source impedance and properly terminated to deliver target bandpass. Output transformers offer more flexibility in this regard but some again may not embrace increasing  transformer distortion.

Have fun... perhaps add a switch so you can easily compare before and after.


JR
Title: Changing tone of a mic preamp
Post by: EmRR on June 01, 2008, 11:17:44 AM
you basically just asked to become a preamp designer.   get crackin'!
Title: Changing tone of a mic preamp
Post by: ChrioN on June 01, 2008, 02:00:41 PM
Quote from: "emrr"
you basically just asked to become a preamp designer.   get crackin'!


Haha. Thats so newbieish of me, I'm sorry...
I just had to ask though :green: Thanks for the replies.
Title: Changing tone of a mic preamp
Post by: tv on June 01, 2008, 03:11:08 PM
Quote from: "JohnRoberts"
.... While some purists (like me) might not approve, you can change the sound character of passive microphones by altering the termination impedance either higher or lower than expected nominal terminations ....

Even more useful when loading passive guitar/bass pickups.