Leslie Hot Rod

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.

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

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.

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.

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

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?

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

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.

diaphragm doesn't

specially

ohm, 12 dB

the classic

original

consider that

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

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

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" wrote in message news:...

be

Isn't the

have

purpose.

the

isn't

it won't

seriously.

The

while

speaker/transducer).

big

the high

would be a

resistive load

I can

kinds of

have

100W/ch

powered

would weigh

sound by even

these are

1x!! ummm,

as the 40

to produce

know.

cap may not

amazing components

sticking a

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

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

Ferro-

be

diaphragm doesn't

were specially

ohm, 12 dB

the classic

original

consider that

their equipment."