Vintage Synth Repair

Here's a tutorial I found on how the LM3900 is different from a "regular" opamp:
http://mysite.du.edu/~etuttle/electron/elect21.htm

--- On Sun, 8/19/12, Doug Slocum <dougslocum@...> wrote:

From: Doug Slocum <dougslocum@...>
Subject: [vintagesynthrepair] Re: ARP 2601 (2600) 4072 VCF problem...
To: vintagesynthrepair@yahoogroups.com
Date: Sunday, August 19, 2012, 11:49 AM
















 



  


    
      
      
      Argh!  Nooooo!    The 3900 is a completely different type of “opamp”.  It’s VERY likely that it could NOT be replaced with a standard opamp.  It is good that the 3900 (LM3900) is still available because there are so many legacy designs that rely on them.  They are a very useful, yet “white elephant” opamp.  If you think it’s bad, order the real thing.  Substitution will not work.