I forgot about the tone control in the organ.
That'd be a good adjustment for Myth to look into for the Lee Michaels sound since it has a fuller bass with less treble.
Myth, have you got a copy of the Service manual?
I've only had one experience with a lowboy leslie, but the tone of it might not have been typical.
My DIY leslie when on full volume has a similar bass to the PR40 which I guess is pretty atypical.
Kon remembered a few more things which I'll post up here too:
I forgot to mention that if Bill Beer had installed the BC manuals into Lee
Michaels's BV organ, then if the donor BC organ's serial number was below
5075 this means that it would have the non tapered manuals. The manual
tapering scheme was introduced sometime in 1937 and it was included in the
BC organs with serial numbers above 5075 as well as the Model A, C and D
organs still in production after the manual tapering schem was introduced in
1937. The manual tapering scheme was used in the various console organ
models built until the end of tonewheel organ production in 1975 and thus
including the BA, E, BV, CV, G, K, RT, B2, C2, RT2, A100 series, B3, C3,
D150-series, RT3 and the E-100 series console organs.
The H-100 series, the R-100 series and the X77 console organs from the
1960's and 70's as well as all the L-100 series, M, M3, M3 , M-100 series,
Porta B and the T-series spinet organs have the non tapered manuals so
therefore the H-100, R-100 series and the X-77 organs would sound closer to
the earlier era Model A and BC organs with the non tapered manuals if a
similar preamplifier was installed in these organs.
The non tapered manuals have both a deeper bass response as well as a
brighter treble response compared to the manuals with the manual tapering
scheme which tend to be more dominantly midrangey. I have played a wax
capped 1937 BC with the non tapered manuals and an AO28 preamp installed in
it and this BC was hooked up together with a wax capped 1957 C3 with the
AO28 preamplifier in it and the signal from the BC and the C3 went into the
same Leslie 760.
With the same drawbar settings and volume levels the 1937 BC sounded
clearer and deeper whilst the C3 sounded somewhat dull and muddy.
The pre 1937 Model A and BC organs with the non tapered manuals and the
'bass all the way down" and the resulting deep bass response are considered
to sound really good for Funky and Rock music.
All the best.