[sdiy] Ringmod output level problem

[Fredrik Carlqvist]

I don't think the 12/15 volts is essential. I don't know this particular
chip, but I'm sure someone here does... I assume you DO use both inputs
when the output is very low ;-) 

Do both ring modulators have the same problem? Or have you built just
one?

There could be a calibration problem. There are two trimmers in there...
Have you followed the calibration procedure? 
 
You can set the amplification of IC2 with the R17/R19 resistors. Higher
value => louder output. They should have equal resistance. If you put
two 1M resistors in there, you should have 10 times the output. R16 thru
R19 should probably be of 1% tolerance.

If you do need to adjust the 1496 bias, you can try different values for
R13. It sets the internal bias current, perhaps it is getting to little
juice? 
 
 
Fredrik C
 
 

________________________________

From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of mikael at mikmo.dk
Sent: den 12 oktober 2005 23:36
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Ringmod output level problem 



Hi list

I have build the Digisound dual ring mod, link to PDF here :

http://www.digisound80.co.uk/digisound/modules/80-11/construction/80-11A
.pdf

It works ok, but the output level is rather low. The problem probably
comes from the fact that it's meant to be run at 15V, but my system is
12V.

Can anyone please tell me what changes i should try to make to the
design to make the output level higher when run at 12V. I would really
apreciate an explanation so i could learn something here.

My guess is that it is just a few resistors that need to be changed
(around the  081 opamp maybe ?) since the circuit is so simple ??

Thanks 

Mikael