diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Analogue Source (http://www.diyaudio.com/forums/analogue-source/)
-   -   Ultrasimple MM/MC RIAA Preamp mkIII (http://www.diyaudio.com/forums/analogue-source/125745-ultrasimple-mm-mc-riaa-preamp-mkiii.html)

GlidingDutchman 2nd July 2008 02:17 PM

Ultrasimple MM/MC RIAA Preamp mkIII
 
2 Attachment(s)
A friend of mine (Ludo) tweaked the circuit by Mads K.

I a having trouble getting it to work so I thought I post it here for some discussion.

peranders 2nd July 2008 02:23 PM

Have you checked the working points for all three JFET's? Are the JFET's capable of 12 mA Id?

GlidingDutchman 2nd July 2008 02:29 PM

Quote:

Originally posted by peranders
Have you checked the working points for all three JFET's? Are the JFET's capable of 12 mA Id?
20mA max...

D

Conrad Hoffman 2nd July 2008 03:36 PM

You're at the mercy of whatever current flows with the gates grounded (Idss?, I forget), and this can vary. You might have to adjust the upper three resistors to get the voltage drop you want. Other than that, it looks like it should work fine. I assume the gain is rather low and another gain stage has to follow this.

GlidingDutchman 2nd July 2008 04:08 PM

Quote:

Originally posted by Conrad Hoffman
You're at the mercy of whatever current flows with the gates grounded (Idss?, I forget), and this can vary. You might have to adjust the upper three resistors to get the voltage drop you want. Other than that, it looks like it should work fine. I assume the gain is rather low and another gain stage has to follow this.
I guess so...

Conrad - this design stems from here: http://www.diyaudio.com/forums/showt...postid=1550522

and the unit, as designed by Mads K works just fine as it stands with my Kiseiki Purpleheart Sapphire low output MC cartridge...!

D

tschrama 2nd July 2008 08:42 PM

If you really want to optimize the circuit, read the optimum Voltage supply idea of Nelson in:

http://www.diyaudio.com/forums/showt...88#post1552988


and posts before there...


All times are GMT. The time now is 02:59 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2