There is no op amp in the 490. It is a Moog 904A emulator, all
transistors, with a dual OTA output buffer. In the theory of operation,
Paul Schreiber wrote, "A passive mixer is used to mimic the loading
effects of the 904A filter...". Is the lower output level of the 490
really a problem? It's still much higher, I believe, than the output of
a real 904A. It works fine for me, as is.
Richard Brewster
http://www.pugix.comJohn Mahoney wrote:
>> Yes, that seems like it would work too. While I'm sure it's a fine
>> product, I wouldn't even need a MUUB board for that. Building a
>> summing amp would only require one dual op-amp. Although I would
>> still have to run power, mount it somehow, etc. Which is much more
>> work. Ideally, the 490 should have had an input amp with a gain knob.
>>
>
> Surely there's an input amp in the 490, no? Presumably it's set up for unity gain, but changing that would be trivial, as would adding inputs. However, I'm miles away from my 490 schematic, so I may be totally wrong (and I'm not even a dancing fool!).
>
> John
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