On 2008-02-04 20:00 +0100, JH. wrote: > >Thanks for the update. On board 1, Q2 and Q3 are either 2 x 2SA733 > >or 1 x 2SA1349. Neither seem easy to find. > > You don't have to take that 2SA733 verbally. And decent pnp > transistor with the right pinout will do. > No matched pair required. There is a trimpot to adjust the > balance between the two expo outputs, because some of the OTA > chips I tried had terrible matching. That trimpot will even out > any transistor mismatch, too. Thanks. Something else : I was wondering how hard it would be to put N sets of boards behind the same panel for an N-voice frequency shifter module. The mic stuff could be left out. The RANGE, TUNE, MANUAL and FINE pots are just voltage sources so they could be shared. The LIN FM pot would have to go or be replaced by N VCAs. Replace the EXP FM pot and NORMAL/INVERT switch by a +/- voltage source controlling N four-quadrant multipliers. Make the NORMAL/DEEP PHASE switch an NPDT. Replace the whole output dry/wet and feedback part by some combination of VCAs and NPDT switches. Or, since it's for a modular, provide just one N-way input (AUX), two N-way outputs (SUM and DIFF) and do everything else with external mixers and VCAs. Did I miss something ? (Other than the fact that it's an utterly crazy idea.) -- Andr\ufffd Majorel <URL:http://www.teaser.fr/~amajorel/> Do not use this account for regular correspondence. See the URL above for contact information.
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Re: [motm] Re: [sdiy] Frequency Shifter FS-1A update
2008-02-24 by Andre Majorel
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