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<P>Hej Fredrik</P>
<P>Thanks for your suggestions. Yves Usson also suggested the two resistors around the output OpAmp, i thnik i will try them first. I dd build both ringmods, and both have the same problem. I did follow the calibration procedure. The output level is not VERY low, just somewhat lower than my other modules.</P>
<P>I'll try R17/R19 first, if that's not it, i'll try R13 as you suggest.</P>
<P>Thanks again</P>
<P>Mikael<BR>
<BR>
<BR>
<BR>
<B>On Thu Oct 13 10:43 , 'Fredrik Carlqvist' <Fredrik.Carlqvist@iar.se> sent:<BR>
<BR>
</P></B>
<BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #5167c6 2px solid; MARGIN-RIGHT: 0px"><BR>
I don't think the 12/15 volts is essential. I don't know this particular<BR>
chip, but I'm sure someone here does... I assume you DO use both inputs<BR>
when the output is very low ;-) <BR>
<BR>
Do both ring modulators have the same problem? Or have you built just<BR>
one?<BR>
<BR>
There could be a calibration problem. There are two trimmers in there...<BR>
Have you followed the calibration procedure? <BR>
<BR>
You can set the amplification of IC2 with the R17/R19 resistors. Higher<BR>
value => louder output. They should have equal resistance. If you put<BR>
two 1M resistors in there, you should have 10 times the output. R16 thru<BR>
R19 should probably be of 1% tolerance.<BR>
<BR>
If you do need to adjust the 1496 bias, you can try different values for<BR>
R13. It sets the internal bias current, perhaps it is getting to little<BR>
juice? <BR>
<BR>
<BR>
Fredrik C<BR>
<BR>
<BR>
<BR>
________________________________<BR>
<BR>
From: <A href="javascript:top.opencompose('owner-synth-diy@dropmix.xs4all.nl','','','')">owner-synth-diy@dropmix.xs4all.nl</A><BR>
[<A href="javascript:top.opencompose('<a href=" javascript:top.opencompose(?owner-synth-diy@dropmix.xs4all.nl?,??,??,??)?>owner-synth-diy@dropmix.xs4all.nl</A>','','','')"><A href="javascript:top.opencompose('owner-synth-diy@dropmix.xs4all.nl','','','')">owner-synth-diy@dropmix.xs4all.nl</A></A>] On Behalf Of <A href="javascript:top.opencompose('mikael@mikmo.dk','','','')">mikael@mikmo.dk</A><BR>
Sent: den 12 oktober 2005 23:36<BR>
To: <A href="javascript:top.opencompose('synth-diy@dropmix.xs4all.nl','','','')">synth-diy@dropmix.xs4all.nl</A><BR>
Subject: [sdiy] Ringmod output level problem <BR>
<BR>
<BR>
<BR>
Hi list<BR>
<BR>
I have build the Digisound dual ring mod, link to PDF here :<BR>
<BR>
<A href="parse.pl?redirect=http%3A%2F%2Fwww.digisound80.co.uk%2Fdigisound%2Fmodules%2F80-11%2Fconstruction%2F80-11A" target=_blank><FONT color=red>http://www.digisound80.co.uk/digisound/modules/80-11/construction/80-11A</FONT></A><BR>
.pdf<BR>
<BR>
It works ok, but the output level is rather low. The problem probably<BR>
comes from the fact that it's meant to be run at 15V, but my system is<BR>
12V.<BR>
<BR>
Can anyone please tell me what changes i should try to make to the<BR>
design to make the output level higher when run at 12V. I would really<BR>
apreciate an explanation so i could learn something here.<BR>
<BR>
My guess is that it is just a few resistors that need to be changed<BR>
(around the 081 opamp maybe ?) since the circuit is so simple ??<BR>
<BR>
Thanks <BR>
<BR>
Mikael<BR>
<BR>
<BR>
<BR>
<BR>
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