[sdiy] The TL072

[David G. Dixon]

Do all of these opamps have the same pinout pattern?  If so, one could use
sockets and try a bunch of different ones (presuming the sockets themselves
don't add to the noise).

David G. Dixon
Professor
Department of Materials Engineering
University of British Columbia
309-6350 Stores Road
Vancouver, B.C. V6T 1Z4
Canada
 
Tel 1-604-822-3679
Fax 1-604-822-3619
 
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> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Ingo Debus
> Sent: Friday, February 20, 2009 9:51 AM
> To: Synth DIY
> Subject: Re: [sdiy] The TL072
> 
> 
> Am 20.02.2009 um 17:54 schrieb Altitude:
> 
> > The reason I am focusing in on the mix amp is when I tap the
> > individual
> > outs, the SNR is quite good but the mixed outs have a substantial
> > amount of
> > noise.  Should I be looking elsewhere for the source?  There really
> > is not
> > too much in the signal path
> 
> It depends on how many inputs the summing amplifier has. Even if the
> gain for each input is low, the noise gain can be pretty high if
> there are many inputs.
> 
> I once replaced the opamp in the summing amp in my DIY 12 input mixer
> (5534 vs TL072) and got noticably less noise. The summing amp has a
> gain of only 1 for each input, but with 12 inputs the noise gain is 13.
> 
> Ingo
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