The .01 should give a lower cutoff on the high pass (more bass) than the .0047.
There may be other variables including the opamp.[/quote]
Sorry, I'm unclear as to whether you're suggesting that I try using the .0047 to reduce the "brighter sound"? I'm not sure if I'm interpreting your post the right way.
Regarding the opamp(s):
The opamp in the OD1 (serial number 10200) which I really like the most of the OD1s I have is an NEC 4558C. I haven't gotten around to replacing the power adapter jack on this one for A-B purposes.
The opamp in the OD1 (serial number 0200) which I used for A-B purposes has a JRC4558D.
The opamp in the SD1 which I did the mod on is 4558DD. Is there *really* that much difference in the C, D, and DD suffixes? I guess that could be the case, since I don't know much about the subtleties of these things... Any suggestions or recommendations would be appreciated.[/b][/quote]
The "DD" op-amps are apparently the later re-issue version and sound a bit "crap"
They were the ones in my Park G10r amp, which i replaced with Panansonic NE5532's - IMO that made a HUGE difference to the tone and drive of that little amp.
My OD-1 is from 1979 ( 6800 ) and has a 14 pin op-amp RC3403ADB
The board is thick cream coloured, almost looks like "perf" and the traces are all solid "solder" traces, like a vintage Phase 90 board !!
I would suggest the NE5532 or a Ti- RC4559p for a nice "quality" op-amp but for "original" tone maybe the JRC4558D would be best ?