[HAM] Question about a Rola treble driver on a 1969 ? Leslie 122

[Keith H Clark]

Kon,
   Two helpful items.
1/ The Rola treble drivers I have are Alnico,they made both.
2/ I have customers running 8 ohm Altec woofs in a 122 type situation, for
decades, with no problems,even though I recommended the 16 ohm version.

-----Original Message-----
From: hammond-bounces at zeni.net [mailto:hammond-bounces at zeni.net] On Behalf
Of Kon Zissis
Sent: Saturday, June 21, 2008 7:11 PM
To: hammond at zeni.net
Subject: [HAM] Question about a Rola treble driver on a 1969 ? Leslie 122

Hi Goffmac
I have found that the treble driver used in the Leslie is very crucial
for getting a good sound.
I have heard some unpleasant  sounding treble drivers that add a very
unnatural and sterile and brittle quality to the sound. 
 
Many treble drivers are very efficient thus being too loud compared to
the bass speaker  and they have a stronger upper midrange response thus
making the treble horn sound too honky or shrill.
The worst sounding treble drivers that I have in my small collection are
the TOA-650 and two Kustom brand treble drivers. 
 
The bad sounding treble drivers can make an otherwise good sounding
Hammond organ sound fake or like a toy organ. 
The unpleasant sound quality is especially  noticeable  with the tremolo
setting which just does not sound right with a bad sounding  treble
driver.
 
I think that most people consider the Jensen V21 to be the best sounding
treble driver. The V21 has a hollow midrange response compared to most
other treble drivers and the V21 also has a particular a resonance which
just works very well with the Hammond sound.
The Rola  version of the Jensen V21 which has a round ceramic magnet
instead of  the alnico magnet of the older V21's  has a fuller midrange
response but the treble  response is similar to that of the older V21's
.
 
I also like the JBL 2482  which I have in my Leslie 122 at the moment.
The JBL 2482 has a nice fat sound although it is very efficient so
therefore I have wired an L-pad before the JBL 2482 as a volume control
to bring the volume level down so that the JBL  2482 is properly
balanced with the bass speaker . 
 
 I have also tried out the L-pad volume control with some other treble
drivers in order to properly match their volume control with the bass
speaker but  the other treble drivers frequency response still did not
sound right in the Leslie.
 
I have an Atlas PD-60  which I tried out in my Leslie but I could not
get it to sound as good as the JBL 2482 or the Jensen V21.  I have heard
a Hammond Suzuki 100 watt ferro fluid driver in other people's Leslies
and this was too loud and honky sounding . I would like to one day have
a ferro fluid driver so that I can  experiment with it in my Leslie 122
and find out how to filter it properly so that it sounds better. 
 
I have experimented with a few different bass speakers including the
stock Utah black  bass speaker with the square magnet, a Lorantz
C386TPA16, a JBL E140 and  the 8 ohms / 60 watt 15 inch bass speaker
with an alnico magnet that was in the Leslie 102 cabinet that I bought
from my friend. I did an A/B test  with the bass  speakers and the JBL
E-140 and the speaker from the Leslie 102 had the best sound and they
were louder than the 16 ohms Lorantz speaker . 
 
The speaker from the Leslie 102 with the alnico magnet  had a noticeably
stronger response in the bass pedals than the JBL E-140 so therefore I
currently have this in my Leslie at the moment.
 
The 16 ohms Lorantz C386TPA16 speaker sounds similar to the old stock
Utah bass speaker but when I did the A/B listening test it sounded less
efficient  and thinner  compared to the JBL E-140 and the alnico magnet
speaker from the Leslie 102.
 
I usually use a flat response solid state amplifier with my modified
Leslie 122 so therefore the 8 ohms speaker  is safe to use in my Leslie.
I use the external solid state amplifier so that I can easily use what
ever effects units I want after the organ. 
 
Some people say that 8 ohms is in fact OK even with the stock Leslie 122
/ 147 valve amplifier but I don't know how long the output transformer
which requires a 16 ohms speaker will be able to withstand the 8 ohms
load.
All the best.
Kon
 
 
Goffmac wrote:
To add to this, I found that using other speakers other than the ones
that came original with the leslie as in the instance of the 15 in my
222, that changing out the 15 to another brand, created an un-leslie
like character as the bass rotor would ramp. For some reason only the
original 15 and I'm wanting to say it's a Jensen, having a square
magnet? retained the traditional leslie ramp sound. I went through the
same search some months ago, trying to find out who made the 15 in my
222 which was there in the 222 for the last 40-50 years and since it did
not have the usual number codes as it was painted over when I was
younger and ignorant-er, by a reconer 20 years ago, It was a guess
whether it was a Jensen, a Utah, or what have you. Might have been a
Rola...Although JBL's have been used with good results as far as the
traditional bass rotor ramp sound,? I myself have wondered about Altec
15's in a Leslie and know someone who has some old Altec 15's sitting
around...
 
There is a certain sound that the bass rotor gets when it's at mid speed
ramp. When i put in a Goodman Audiom 81, thinking it might have a sound,
I was wrong. It produced this unnatural honking "whooh-whooh" overtone
as the rotor ramped up and down. And it didn't get as low as the
original. Needless to say, it was back to the tried and true. I might
get in touch with the guy i know who has those Altecs as this thread Kon
has started has got me curious...
 
But back to the idea that Don L determined what HE wanted, sounds to be
most likely the truth.. It seems to be a calculated mix of parts that go
into a Leslie. How he arrived at it, only he knows... Wish his kids were
able to shed some light. 
 
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