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capacitors  so therefore it would  be very interesting to compare the
output levels readings if a brand new wax cap with high ESR and a new
modern  capacitor with low ESR but that both capacitors have an EXACT
identical mfd value  were tested on  TG note filters throughout the
various frequencies in the TG notes 49 to 91 range.

Has anyone done this or can anyone explain how the ESR factor affects
the output levels or the resonance factor of the filters ?

William Mark Bristow wrote:
>The Factory Sound - sounds like any red-mylar-cap B3 or C3

Yes , because the red mylar capacitors did not drift up in mfd value
with age like the wax capacitors did ,  the post 1964 red mylar capped
organs  would be the most reliable  guide as to what the  factory TG
output curve for the TG notes 49 to 91  looks and sounds like as long as
the  TG was calibrated properly at the factory  with a smooth output
curve  without peaks and dips. I have the TG output curves of many red
mylar capped organs in my TG spreadsheet and I used the similarities  of
the output curves of  the red mylar capped organs that had a smooth
output curve  as the  basis of my own understanding about  the
theoretically possible  factory TG output curve levels for the TG notes
49 to 91. The output levels of the TG notes 1 to 49  tend to be more
consistent in most of the organs in my TG spreadsheet with the
noticeable factor that the pre 1956 organs had somewhat higher output
levels in the TG notes 1 to 43 range compared to that of the post 1956
organs and sometime in the mid to late 60's the levels of the  bass
pedal TG notes 1 to 12 were lowered even more. This means that the pre
1956 organs would have a warmer bass and lower midrange than the post
1956 organs.


> Listen to the recordings made in the 1960's & 1970's - the Hammonds
sound
>pretty much the same as now. 

The organs on my 1960's / 70's  recordings do sound similar to the
organs on several contemporary recordings , especially with contemporary
Jazz / Blues recordings with the typical Jimmy Smith type drawbar and
percussion settings and the Jimmy Smith influenced playing style.


> There were Hammonds then that were thick and muddy - and some that
were thin and nasal and some that sounded >wonderful.

This helps to confirm that even when they were new , each organ sounded
somewhat different from each other  and there were some great fat
sounding organs and some not so great thin or muddy sounding organs .
The authorised  factory TG output curve specs chart would have been used
as the calibration  guide  however because each TG was calibrated  by
hand whilst observing the factory voltage meter and due to the extremely
delicate and sensitive nature of the pickup positions and the fact that
the output levels can often change when the set screw was tightened ,
each organ would have had a somewhat different TG output  curve and a
somewhat different timbre. This is a major reason why I like seeing the
measured TG output levels of organs and especially the TG output curves
of  great sounding organs. Of course the manual tapering and the preamp
and Leslie component tolerance  factors  would play some part here as
well.  


Brad Baker wrote:
>All this stuff about cap matching and tolerances and procedures in the
factory is almost meaningless if in the Hammond >factory the Tone
Generators were calibrated after the caps were installed... The tonal
balance is done primarily by >the TG calibration. Having a proper filter
center frequency will perhaps make the calibration procedure easier, or
>more consistent from unit to unit.  A mistuned filter might affect
harmonic content or noise level associated from a >tone, but not the
tone level in a calibrated TG.

Yes , regardless of how exact the capacitors were matched to the
transformer coil filters at the factory, the TG was calibrated to
produce  the overall TG curve  with the capacitors that were already in
place. I do not think that the harmonic content from a slightly mistuned
filter would be very noticeable especially considering  that the
waveform from a filter with an aged wax capacitor can still sound
acceptable even though the noise level and the extra harmonic content is
a little more noticeable along with the very noticeable decreased
output level.    The problem that can happen  with recapping is that if
the new capacitor is  more exactly matched to the transformer coil
filter  than what the original wax capacitor was, then that TG note will
end up a little louder than what it should be but this can be rectified
by recalibrating the TG as you mentioned. I understand however that
other people will not be willing or able to recalibrate  their TG. 

>(It doesn't make much sense for them to be calibrated *before* the caps
were installed).

If this was done then the TG output levels would have ended up all over
the place and they would have  needed to be readjusted  in order to
produce a smooth output curve.

>One approach to fixing a dull organ might be a TG recalibration.  If
such an organ were one with badly mistuned >filters with wax caps whose
values were 200% of the stock values then it may not be possible to
calibrate that TG >without installing new caps.  The new caps would
approximately center the filter response on each associated tone, and
>would provide an increase in the adjustable tone level thereby.

If the wax caps are not too far gone , the weak TG notes can be
recalibrated but a problem with doing this is that the pickup might need
to be set too close to the tone wheel thus resulting in a dirtier
sounding waveform with more noise and possibly a warbling tone as well.
If the TG is recapped properly  then you can get a slightly louder than
stock TG output curve  but still with pure sounding waveforms. The
louder  than stock TG output curve  but still with pure sounding sine
waves  is  especially  possible if the organ is a late 60's or early
70's red mylar capped organ with the R/C filters and the bright red
enamelled wire on the transformer coil filter bobbins because these
transformer coils produce louder output levels than the early 1960's
transformer coils with the dark brown enamelled  wire. I have verified
this with my own 1962 C3 after I transplanted  the red mylar caps and
transformer coil filters  brass tray from a 1970 T-300 into my C3 and I
transplanted the recapped transformer  coil filters  brass tray into the
T-300. \

The reason why I transplanted  the red mylar caps tray from the  T-300
into my C3 was because the red mylar caps are still more or less
properly matched  to the transformer coils  thus ending any issues with
mismatched capacitors. I had originally replaced the wax caps  from my
1962 C3  with new capacitors , many of which  produced the peak filter
outputs  so therefore I expected that the red mylar caps tray originally
from the T-300 would  produce a slightly mellower TG output curve in my
C3 but on the contrary  the TG output  levels of the TG notes 49 to 91
were now noticeably louder and conversely the output levels of the  TG
notes 49 to 91 in the T-300 become noticeably lower  with the recapped
brass tray originally from my 1962 C3. The T-300 originally had very
high treble levels  with a resulting nasal thin sound but I had
recalibrated the whole TG to produce a typical B3 / C3 etc output curve
but with a warmer bass and lower midrange whilst the red mylar caps tray
was still in the T-300.

After I transplanted  the recapped tray from my C3 into the T-300 , the
output curve of the TG notes 49 to 91 became almost a straight line
instead of the typical upward rising curve  of the B3 / C3 etc , and
this made the  T-300 sound quite nice and fat  so therefore I decided to
leave the TG curve it as it is without  recalibrating it a second time
in order to bring back the typical B3 / C3  upward rising curve.

All the best.
Kon