Leslie Hot Rod

[Trevor]

To whom it may concern,
I'm trying to biamp my new Leslie Speaker model 122A. My master plan
is to use the stock 40-watt amp to drive only the horn and a Mackie
SR1530 for the low-end duties. The Mackie is a solid-state tri-amped
system. In this scheme, I won't need the services of either the Mackie
mid or upper drivers. In other words I'll be using the Mackie amp to
power only its woofer, which now resides in the Leslie cabinet.

Here is the cut and paste spec sheet for the Mackie SR1530:

SR1530 Specifications
System:
Freq. Range (-10 dB)
40Hz - 20kHz
Freq. Response (-3dB)
45Hz - 18kHz
Horz. Coverage Angle (-6dB)
90°
Vert. Coverage Angle (-6dB)
40°
Directivity Factor; DI(Q)
10.77 (11.95) averaged 2kHz to 10kHz
Rated Maximum SPL (peak)
126dB @ 1m
Crossover Points
700Hz, 3,000Hz

Transducer:
Low-Frequency:
Diameter
15-inch (381mm)
Power Handling
300 watts Dynamic Program Power

Mid-Frequency:
Diameter
6-inch (152mm) diameter
Power Handling
100 watts Dynamic Program Power

High Frequency:
Exit Throat
1-inch (25.4mm)
Power handling
100 watts Dynamic Program Power

Amplifiers:
Low-Frequency Power Amplifier:
Rated Power
300 watts @ Low-Frequency Driver Impedance
Rated THD
< 0.05%
Cooling
Class AB Convection Extrusion

Mid-frequency amplifier:
Rated Power
100 watts @ Mid-Frequency Driver Impedance
Rated THD
<0.01%
Cooling
Class AB Convection Extrusion

High-frequency amplifier:
Rated Power
100 watts @ High-Frequency Driver Impedance
Rated THD
<0.01%
Cooling
Class AB Convection Extrusion





Being more musician than electrician results in the following
Shortcomings of knowledge;

Do I need a load of any kind where the mid and upper drivers were so
the Mackie amp doesn't suffer any ill effects from only being
connected to the woofer? (e.g. make amp run to hot, not at peak
efficiency, shorten its life, etc…)

If I need to have a dummy load where the mid and upper drivers were,
what is the best way to go about this. Just wire in the appropriate
resistor? If so what is the appropriate resistor?

The Leslie 122A is a 40 watt tube amp. I plan to put a load (16 ohm
10 watt resistor) on it where the original woofer was after the
crossover. Is that the best way to do it? The way I understand it
the woofer, driver and crossover all are 16ohm in the Leslie 122.

I would like to optimize the power going to the driver w/o alteration
of the driver's sound. Will running the amp into the crossover then
into the upper driver with a dummy load where the woofer was complete
the task? Or am I missing something here?
The driver is the new Leslie Ferro-fluid 100 watt driver.

I would be much obliged for any help I can get on this project.
Thanks.
Sincerely,
Trevor

 

[Myron Samila]

"Trevor" <trevor.reynolds@insightbb.com> wrote in message
news:f17a987b.0401270819.5007e507@posting.google.com...

To whom it may concern,
I'm trying to biamp my new Leslie Speaker model 122A. My master plan
is to use the stock 40-watt amp to drive only the horn and a Mackie
SR1530 for the low-end duties. The Mackie is a solid-state tri-amped
system. In this scheme, I won't need the services of either the Mackie
mid or upper drivers. In other words I'll be using the Mackie amp to
power only its woofer, which now resides in the Leslie cabinet.

You can disconnect the mid and high, nothing will happen. These amps
in the Mackie self powered cabinet can run in the "open" position without any
problem. ie: if you blow the high frequency driver, it is open, the amp won't be
harmed unless there was a short.

The Mackie is all solid state, why would you want to drive it with that? Isn't the
Leslie a tube box? Oh well, if you must, I guess you can, although you could have
saved yourself a lot of trouble and bought a cube amp especially for this purpose.
They are available as a rear mounting amp to most cabinets and are UL approved.
Once the amp is out of the Mackie cabinet, it is NO longer UL approved, since the
cabinet itself provides any kind of fire/shock protection, putting it in wood isn't
recognized
by UL unless all components are tested for dielectric strength and proven that it won't
cause a fire if there is any kind of failure.

Being more musician than electrician results in the following
Shortcomings of knowledge;

Dangerous combination , usually, the outcome is less than what you expect, seriously.
The
Mackie box sounds quite good to begin with!!!

Do I need a load of any kind where the mid and upper drivers were so
the Mackie amp doesn't suffer any ill effects from only being
connected to the woofer? (e.g. make amp run to hot, not at peak
efficiency, shorten its life, etc.)

No, putting a load, especially a resistor load will make the amp super hot. The
resistor cannot change impedance with frequency, I use resistors to load amps while
I'm testing them, but impedance changes with frequency (on a speaker/transducer).
Leave it open, or disconnect the preamp driver to the output stage, usually an
op amp somewhere on the board, or cut the signal path trace to the op amp.

If I need to have a dummy load where the mid and upper drivers were,
what is the best way to go about this. Just wire in the appropriate
resistor? If so what is the appropriate resistor?

naw... I test 2500W amplifiers (Crown, Crest), /ch, and find it hard to get a big
enough resistor network that doesn't get hot, you'd need quite a few to handle the high
and mid frequency. A JBL EON G2 box produces 150W at 8 ohms for the HF!!!
You'd need a resistor that is capable of dissapating a lot of heat! ouch, it would be a
good heater in a cold room.

The Leslie 122A is a 40 watt tube amp. I plan to put a load (16 ohm
10 watt resistor) on it where the original woofer was after the
crossover. Is that the best way to do it? The way I understand it
the woofer, driver and crossover all are 16ohm in the Leslie 122.

ouch, that may wreak havoc on the tube section, pull out the tubes. A resistive load
on a tube amp may not be a good idea, I'm not overly familiar with tubes, but I can
tell you, a solid state amp like the one found in the Mackie can drive all kinds of
BAD loads, including resistor loads. However, a tube amp may have difficulty.
I'd remove the tubes!?!? on the output, or somehow de-energize that part of the
amplifier

I would like to optimize the power going to the driver w/o alteration
of the driver's sound. Will running the amp into the crossover then
into the upper driver with a dummy load where the woofer was complete
the task? Or am I missing something here?
The driver is the new Leslie Ferro-fluid 100 watt driver.

A solid state amp alone is gonna make the whole box sound totally different.
Especially since the Mackie amp was designed to drive a 8ohm woofer, not a
16ohm. The Mackie has a built in crossover, you won't be able to change the
characteristics of the preset crossover points. You can't optimize much other
than dial in the gain on the back of the amplifier panel. Does your Mackie have
an EQ section? If so, you may be able to enhance the bass a bit.

The whole point of tube vs transistor is sound. People who love audio swear by
tube, I swear at tubes! I have a Bryston 3B for my home amplifier, at only 100W/ch
it will certainly sound better than the Mackie. The Mackie is a portable self powered
box, if it had a large enough power supply to run the amp properly, the box would weigh
in over 100lbs. My little Bryston weighs 60lbs, all transformer(s x2).

Stick with the tube, see what that sounds like. You can actually alter the sound by even
using
different tube manufacturers!! (from what audophiles tell me, or so they say, these are
the
same people who say burning audio (wave) onto a cd at 32x sounds worse than at 1x!! ummm,
no
its digital!).


I don't think you'll totally be happy, the sound will certainly be bass heavy, as the 40
watt tube amp
is probably all higher than lower frequency capable, the Mackie will be able to produce
lower
frequencies with the same given woofer. Try it out either way, and let us know.

But again, leaving a tube "open" may not be a good idea. Hooking it up to a cap may not
be any
better, (cap will be always storing a charge, could pose havoc on the tube).

Anyone else got suggestions?

I would be much obliged for any help I can get on this project.
Thanks.
Sincerely,
Trevor

Leslie hot rod, well......... hehehe, just gut the whole thing, put in amazing components
and drive it
with one serious power amp in a secret remote location, then it would be like sticking a
Ferrari H-12 into
a Fiat 500!!!! (A Fiat 500 was a 2cylinder half litre displacement car!!!)


--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19

 

[Myron Samila]

"Trevor" <trevor.reynolds@insightbb.com> wrote in message
news:f17a987b.0401270819.5007e507@posting.google.com...

The driver is the new Leslie Ferro-fluid 100 watt driver.

Ummm, I bet it doesn't have Ferro-fluid where it needs to be!! Usually, Ferro-
Fluid is placed in the magnet gap, and it transfers heat from the coil to the
magnet (which is the other purpose of having a magnet, it dissapates heat to
overcome power compression, as heat builds, impedance goes up). This would be
hard to do in a speaker with so much travel, a typical high frequency diaphragm doesn't
move much, not enough to make the ferro-fluid raise the mechanical Q.

This woofer looks a lot like a driver made by Eminence:

Quoted from some Leslie website
"The upper driver, woofer and tube amplifier's 16 ohm output transformer were specially
designed to be used as an integral group in conjunction with the original 16 ohm, 12 dB
per octave, 800 Hz crossover. This overall design philosophy is the heart of the classic
tube amp Hammond / Leslie sound, and cannot be altered without changing the original
sound! Before you spend money on high-power alternative speakers / drivers, consider that
the vast majority of touring professionals use these same components in their equipment."



--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19


The above line came from a Leslie website, umm, lookin' at the pic provided tells me
it is an Eminence, which is a decent general purpose speaker.

I think using the original tube amp isn't a bad way to go, ORRRRRRRR making that tube
amp have more grunt, you'll still get that "warmth" as people call it (its cuz its missing
so much
dynamic range!!! hehehe).

A class A amplifier would sound great on the HF, and a class AB or H amp on the low would
do
you fine.

 

[Bob Stephens]

On Tue, 27 Jan 2004 21:03:40 -0500, Myron Samila wrote:

"Trevor" <trevor.reynolds@insightbb.com> wrote in message
news:f17a987b.0401270819.5007e507@posting.google.com...

The driver is the new Leslie Ferro-fluid 100 watt driver.

Ummm, I bet it doesn't have Ferro-fluid where it needs to be!! Usually, Ferro-
Fluid is placed in the magnet gap, and it transfers heat from the coil to the
magnet (which is the other purpose of having a magnet, it dissapates heat to
overcome power compression, as heat builds, impedance goes up). This would be
hard to do in a speaker with so much travel, a typical high frequency diaphragm doesn't
move much, not enough to make the ferro-fluid raise the mechanical Q.

This woofer looks a lot like a driver made by Eminence:

Quoted from some Leslie website
"The upper driver, woofer and tube amplifier's 16 ohm output transformer were specially
designed to be used as an integral group in conjunction with the original 16 ohm, 12 dB
per octave, 800 Hz crossover. This overall design philosophy is the heart of the classic
tube amp Hammond / Leslie sound, and cannot be altered without changing the original
sound! Before you spend money on high-power alternative speakers / drivers, consider that
the vast majority of touring professionals use these same components in their equipment."

I concur. I spent 10 years "Slammin' the Hammond" B3 with two 145 Leslies,
and nothing beats the warmth and depth of those 6L6 finals. There was a
maina during the 1980's with chop shops "portablizing" B3's and Leslies.
The results, while portable were unplayable mainly due to the original tube
amplifiers being replaced by solid state. Don't do it! If you want a cheesy
sound, buy a synthesizer with one of the rotary speaker simulators.

Bob

 

[Trevor]

Hi Myron thanks for the info it was very helpful. I ended up aborting
the whole project. Put the Leslie back together like it was as well as
the Mackie. Now I back to where I started. Some guy suggested that I
get another Leslie here is my cut and paste response to him.

Hi Jeff,
I guess I want to biamp it because it's never loud enough on stage
once the drummer begins to play. I don't want the drummer to have to
play like a sissy because I can't come up to his level. Also, with
both a chopped Hammond A102 and a Leslie 122 cabinet to drag around
from gig to gig life is hard enough w/o adding a second Leslie to my
burden, not to mention the expense, $2000+ for the new ones. I'm not
like I was when I was 22 when I could just put a Leslie under each arm
and head up a flight of stairs (kidding.) Also, adding a second Leslie
doesn't give you that much more and certainly not enough to warrant
the trouble of adding it to the arsenal. Check out Clifford
Henricksen's page at
http://theatreorgans.com/hammond/faq/mystery/mystery.html for the 411
on that one.

I'm not playing with Neil Young and Crazy Horse, just small time
blues clubs. I though if I kept the tube amp driving the horns then
most of my crunch i.e. characteristic Leslie sound, would be
maintained. I've seen several Internet sites where this is the exact
approach they use as well: Drive the horn with the stock amp and the
lows with some solid-state amp with appropriate crossover. I thought
if I could rig my Leslie 122A up like this with what I already have
then I could reach my goal w/o to much compromise in sound and w/o a
huge cash outlay. I'm trying to make money as a musician not spend
it. Considering that I've already forked out $4500 for the Hammond
and Leslie it's kind of a shame that once the band starts playing I'm
lost in the mix with no headroom for solo's and it's not even a metal
band just classic rock and blues.
Yes, I've tried miking it but what a royal pain in the ass not to
mention the feedback problems that causes. When I mike it I can get it
loud enough through the mains but pulling it back up through the
monitors always causes problem and on stage is exactly where I need
the added dB's not out front.
I realize that some compromise would be made simply from the fact
that I'm introducing a solid-state amp into the mix. But overall I
think I would still have a better sounding Leslie than the new ones
simply from the fact that I was driving the horns with the tube amp.
If money were no object then I would just go out and buy the new
Motion Soun Pro-145 to the tune of $1800. But such is not the case.
You should know that the new Leslie 122's have a 100watt driver.
Anyway, thanks for the referral to the relevant groups.
Trevor

Do you think you have any suggestions to help me? I don't mind
comprimising a little sound quality for added volume but I don't want
to comprimise to much. Whether you can supply additional help or not,
I really appriciate what information you did provide. Probably
prevented me from burning something up.
All the best,
Trevor















"Myron Samila" <myronx19@no.spam.sympatico.ca> wrote in message news:<XEERb.4774$qU3.304014@news20.bellglobal.com>...

"Trevor" <trevor.reynolds@insightbb.com> wrote in message
news:f17a987b.0401270819.5007e507@posting.google.com...
To whom it may concern,
I'm trying to biamp my new Leslie Speaker model 122A. My master plan
is to use the stock 40-watt amp to drive only the horn and a Mackie
SR1530 for the low-end duties. The Mackie is a solid-state tri-amped
system. In this scheme, I won't need the services of either the Mackie
mid or upper drivers. In other words I'll be using the Mackie amp to
power only its woofer, which now resides in the Leslie cabinet.

You can disconnect the mid and high, nothing will happen. These amps
in the Mackie self powered cabinet can run in the "open" position without any
problem. ie: if you blow the high frequency driver, it is open, the amp won't be
harmed unless there was a short.

The Mackie is all solid state, why would you want to drive it with that? Isn't the
Leslie a tube box? Oh well, if you must, I guess you can, although you could have
saved yourself a lot of trouble and bought a cube amp especially for this purpose.
They are available as a rear mounting amp to most cabinets and are UL approved.
Once the amp is out of the Mackie cabinet, it is NO longer UL approved, since the
cabinet itself provides any kind of fire/shock protection, putting it in wood isn't
recognized
by UL unless all components are tested for dielectric strength and proven that it won't
cause a fire if there is any kind of failure.


Being more musician than electrician results in the following
Shortcomings of knowledge;


Dangerous combination , usually, the outcome is less than what you expect, seriously.
The
Mackie box sounds quite good to begin with!!!


Do I need a load of any kind where the mid and upper drivers were so
the Mackie amp doesn't suffer any ill effects from only being
connected to the woofer? (e.g. make amp run to hot, not at peak
efficiency, shorten its life, etc.)

No, putting a load, especially a resistor load will make the amp super hot. The
resistor cannot change impedance with frequency, I use resistors to load amps while
I'm testing them, but impedance changes with frequency (on a speaker/transducer).
Leave it open, or disconnect the preamp driver to the output stage, usually an
op amp somewhere on the board, or cut the signal path trace to the op amp.


If I need to have a dummy load where the mid and upper drivers were,
what is the best way to go about this. Just wire in the appropriate
resistor? If so what is the appropriate resistor?

naw... I test 2500W amplifiers (Crown, Crest), /ch, and find it hard to get a big
enough resistor network that doesn't get hot, you'd need quite a few to handle the high
and mid frequency. A JBL EON G2 box produces 150W at 8 ohms for the HF!!!
You'd need a resistor that is capable of dissapating a lot of heat! ouch, it would be a
good heater in a cold room.


The Leslie 122A is a 40 watt tube amp. I plan to put a load (16 ohm
10 watt resistor) on it where the original woofer was after the
crossover. Is that the best way to do it? The way I understand it
the woofer, driver and crossover all are 16ohm in the Leslie 122.

ouch, that may wreak havoc on the tube section, pull out the tubes. A resistive load
on a tube amp may not be a good idea, I'm not overly familiar with tubes, but I can
tell you, a solid state amp like the one found in the Mackie can drive all kinds of
BAD loads, including resistor loads. However, a tube amp may have difficulty.
I'd remove the tubes!?!? on the output, or somehow de-energize that part of the
amplifier


I would like to optimize the power going to the driver w/o alteration
of the driver's sound. Will running the amp into the crossover then
into the upper driver with a dummy load where the woofer was complete
the task? Or am I missing something here?
The driver is the new Leslie Ferro-fluid 100 watt driver.

A solid state amp alone is gonna make the whole box sound totally different.
Especially since the Mackie amp was designed to drive a 8ohm woofer, not a
16ohm. The Mackie has a built in crossover, you won't be able to change the
characteristics of the preset crossover points. You can't optimize much other
than dial in the gain on the back of the amplifier panel. Does your Mackie have
an EQ section? If so, you may be able to enhance the bass a bit.

The whole point of tube vs transistor is sound. People who love audio swear by
tube, I swear at tubes! I have a Bryston 3B for my home amplifier, at only 100W/ch
it will certainly sound better than the Mackie. The Mackie is a portable self powered
box, if it had a large enough power supply to run the amp properly, the box would weigh
in over 100lbs. My little Bryston weighs 60lbs, all transformer(s x2).

Stick with the tube, see what that sounds like. You can actually alter the sound by even
using
different tube manufacturers!! (from what audophiles tell me, or so they say, these are
the
same people who say burning audio (wave) onto a cd at 32x sounds worse than at 1x!! ummm,
no
its digital!).


I don't think you'll totally be happy, the sound will certainly be bass heavy, as the 40
watt tube amp
is probably all higher than lower frequency capable, the Mackie will be able to produce
lower
frequencies with the same given woofer. Try it out either way, and let us know.

But again, leaving a tube "open" may not be a good idea. Hooking it up to a cap may not
be any
better, (cap will be always storing a charge, could pose havoc on the tube).

Anyone else got suggestions?




I would be much obliged for any help I can get on this project.
Thanks.
Sincerely,
Trevor

Leslie hot rod, well......... hehehe, just gut the whole thing, put in amazing components
and drive it
with one serious power amp in a secret remote location, then it would be like sticking a
Ferrari H-12 into
a Fiat 500!!!! (A Fiat 500 was a 2cylinder half litre displacement car!!!)

 

[Bob Stephens]

On 28 Jan 2004 09:04:56 -0800, Trevor wrote:

Hi Myron thanks for the info it was very helpful. I ended up aborting
the whole project. Put the Leslie back together like it was as well as
the Mackie. Now I back to where I started. Some guy suggested that I
get another Leslie here is my cut and paste response to him.

Hi Jeff,
I guess I want to biamp it because it's never loud enough on stage
once the drummer begins to play. I don't want the drummer to have to
play like a sissy because I can't come up to his level. Also, with
both a chopped Hammond A102 and a Leslie 122 cabinet to drag around
from gig to gig life is hard enough w/o adding a second Leslie to my
burden, not to mention the expense, $2000+ for the new ones. I'm not
like I was when I was 22 when I could just put a Leslie under each arm
and head up a flight of stairs (kidding.) Also, adding a second Leslie
doesn't give you that much more and certainly not enough to warrant
the trouble of adding it to the arsenal. Check out Clifford
Henricksen's page at
http://theatreorgans.com/hammond/faq/mystery/mystery.html for the 411
on that one.

I'm not playing with Neil Young and Crazy Horse, just small time
blues clubs. I though if I kept the tube amp driving the horns then
most of my crunch i.e. characteristic Leslie sound, would be
maintained. I've seen several Internet sites where this is the exact
approach they use as well: Drive the horn with the stock amp and the
lows with some solid-state amp with appropriate crossover. I thought
if I could rig my Leslie 122A up like this with what I already have
then I could reach my goal w/o to much compromise in sound and w/o a
huge cash outlay. I'm trying to make money as a musician not spend
it. Considering that I've already forked out $4500 for the Hammond
and Leslie it's kind of a shame that once the band starts playing I'm
lost in the mix with no headroom for solo's and it's not even a metal
band just classic rock and blues.
Yes, I've tried miking it but what a royal pain in the ass not to
mention the feedback problems that causes. When I mike it I can get it
loud enough through the mains but pulling it back up through the
monitors always causes problem and on stage is exactly where I need
the added dB's not out front.
I realize that some compromise would be made simply from the fact
that I'm introducing a solid-state amp into the mix. But overall I
think I would still have a better sounding Leslie than the new ones
simply from the fact that I was driving the horns with the tube amp.
If money were no object then I would just go out and buy the new
Motion Soun Pro-145 to the tune of $1800. But such is not the case.
You should know that the new Leslie 122's have a 100watt driver.
Anyway, thanks for the referral to the relevant groups.
Trevor

Do you think you have any suggestions to help me? I don't mind
comprimising a little sound quality for added volume but I don't want
to comprimise to much. Whether you can supply additional help or not,
I really appriciate what information you did provide. Probably
prevented me from burning something up.
All the best,
Trevor


SNIPSKI

I don't see why Mikeing the Leslie is such a PITA. I did it for years, and
I played with drummers from Hell. I ended up permanently mounting two
SM58's on goosenecks inside the cabinet and brought the cables out to XLR
connectors on the back of the cabinet - Then just plugged it in to the
board with microphone cables - easy. I used to put the Leslie up on milk
crates right behind my head and had no problem hearing myself. Even if the
band's onstage volume was horrific, I could at least tell how loud I was
playing by watching the purple glow of those beautiful 6L6 tubes


Bob

 

[Trevor]

Hi Bob,
The more I think about it the more I have to agree with you. Thanks
for throwing some water in my face and waking me up. What was I
thinking?
Sincerely,
Trevor




Stephens <stephensyomamadigital@earthlink.net> wrote in message news:<13ug2t36dr7v6$.win450brqzyn.dlg@40tude.net>...

On Tue, 27 Jan 2004 21:03:40 -0500, Myron Samila wrote:

"Trevor" <trevor.reynolds@insightbb.com> wrote in message
news:f17a987b.0401270819.5007e507@posting.google.com...

The driver is the new Leslie Ferro-fluid 100 watt driver.

Ummm, I bet it doesn't have Ferro-fluid where it needs to be!! Usually, Ferro-
Fluid is placed in the magnet gap, and it transfers heat from the coil to the
magnet (which is the other purpose of having a magnet, it dissapates heat to
overcome power compression, as heat builds, impedance goes up). This would be
hard to do in a speaker with so much travel, a typical high frequency diaphragm doesn't
move much, not enough to make the ferro-fluid raise the mechanical Q.

This woofer looks a lot like a driver made by Eminence:

Quoted from some Leslie website
"The upper driver, woofer and tube amplifier's 16 ohm output transformer were specially
designed to be used as an integral group in conjunction with the original 16 ohm, 12 dB
per octave, 800 Hz crossover. This overall design philosophy is the heart of the classic
tube amp Hammond / Leslie sound, and cannot be altered without changing the original
sound! Before you spend money on high-power alternative speakers / drivers, consider that
the vast majority of touring professionals use these same components in their equipment."

I concur. I spent 10 years "Slammin' the Hammond" B3 with two 145 Leslies,
and nothing beats the warmth and depth of those 6L6 finals. There was a
maina during the 1980's with chop shops "portablizing" B3's and Leslies.
The results, while portable were unplayable mainly due to the original tube
amplifiers being replaced by solid state. Don't do it! If you want a cheesy
sound, buy a synthesizer with one of the rotary speaker simulators.

Bob