[sdiy] OTA replacement

[Mark Smith]

The 3080 works fine as a replacement for the BA662. I have built 303 clones with both the BA662 and 3080. I have even made a small pcb which converts an SMD 3080 into a 9 pin SIL and is a drop in replacement for the BA662. The only issue is offset, but this can be trimmed out externally.

I have tried this in my JX-3P and could tell no difference - it sounded rubbish before and rubbish after - (only kidding).

...the 3080 doesn't have the second buffer stage, but you can use a transistor or op-amp to do this.

mark

> -----Original Message-----
> From:	Byron G. Jacquot [SMTP:thescum at surfree.com]
> Sent:	Monday, March 29, 2004 7:52 AM
> To:	synth-diy at dropmix.xs4all.nl
> Subject:	Re: [sdiy] OTA replacement
> 
> > I've just read on a couple of webpages that the
> > obsolete BA662A (OTA) could be replaced by
> > the CA3080.
> > Could anyone confirm this ?
> 
> I seem to recall people using 3080's in some TB303 clones, and they 
> seemed to work OK.  Not that I ever sat the curcuit  in question 
> alongside a real 303 for sonic comparison, but it wasn't 
> unacceptable.
> 
> IIRC, The BA662 is in a SIP package, and also has an onboard output 
> buffer, something like a 13600.  The 3080 is usually in a DIP 
> package, and lacks the buffer.
> 
> Byron Jacquot