Stevieb
07-03-2011, 08:23 PM
Okay, I am starting with two Leslie-type units from Dolphin-class Hammonds. The organs themselves are transistor and SS, and they do play- but intermittently, which is driving me mad- probably not worth repairing or keeping, so I am planning on cannibalizing the organs for parts.
I have gleaned some info from this thread, and I thank those who have gone before me. I still have questions, though...
One of the L-units is 2-speed, other is 1-speed.
The speaker signal and the current to drive the leslies' motors come via a small circuit board that mounts to the front speaker baffle board. They look similar, both having a relay(?) housed in a small clear box, a capacitor, and several connections. Are they interchangeable? Do I need them if I am building this leslie unit for use with a L-102?
Should (Can?) I use the rocker switches on one of these Dolphins to switch my leslie, or should I build a switch unit from other parts?
Which unit should be used for which frequencies- i.e. should the 2-speed unit be used for the highs, or the lows?
When I connect the 1-speed leslie unit to the organ that has the 2-speed unit, the motor turns, but no sound comes from the speaker. Turns out the 8" speaker is not functioning.
The rotating, stryo-foam baffle is about 14" in diameter, the center baffle section is about 8" wide. I have heard of folks replacing the 8" speaker with a 15" one- but wouldn't that cause reversion problems, or too much of the sound NOT be routed through the baffle, thus greatly reducing the leslie effect? Wouldn't a 10" speaker that is built for bass response be a better choice? Eminence, for instance, makes a 10" speaker that goes down to 40hz- (Legend BP102.) The 15's they make go down to 47hz, at the lowest. Installing a 10 would be much easier than shoe-horning a 15 in there. That Eminence speaker is an 8-ohm speaker, not a 4- but I think it will work.
I intend to put a 6" speaker that is treble-heavy in the other baffle, so I don't have to figure out how to make a horn fit on the pulley.
I read that leslie treble horn rotates at 48 RPM on slow speed and 400 on fast, and the lower drum rotates at about 342 RPM on tremolo and 40 RPM on chorale. I understand this speed difference contributes considerably to the leslie effect. (It seems to me I read somewhere that the horn turned at TWICE the speed of the woofer, but I can not confirm that.) If I put a larger pulley on the motor, that would increase the speed of the baffle, I am thinking a 1.5 or 2" pulley, in place of the 1" pulley, should do the trick. Agreed? HEY, WAIT! the 2-speed unit already HAS a bigger pulley on it! Maybe it will turn at a different speed than the other one.
I also read, on page 2 of this thread, that the upper and lower horns rotate in the opposite direction. No problem- I can just mount one of the units with the baffle on top, the other with it on the bottom- and they rotate in the opposite directions! I read somewhere that these units would only operate with the shaft of the motor horizontal, not vertical, but one of 'em worked fine for me in all directions.
What is a cheap source for a crossover? I am hoping some stereo speaker I can pick up from a thrift store has a crossover that will work just fine. What should I look for?
These Dolphins have SS power amps, of about 15 watts, I am guessing. Can I use one for each Leslie speaker? How to wire them into the L-102's circuitry?
That's all for now- I will return to this thread and read more of the 99 pages (got as far as 5, today!) and will no doubt have more questions.
Thanks.
I have gleaned some info from this thread, and I thank those who have gone before me. I still have questions, though...
One of the L-units is 2-speed, other is 1-speed.
The speaker signal and the current to drive the leslies' motors come via a small circuit board that mounts to the front speaker baffle board. They look similar, both having a relay(?) housed in a small clear box, a capacitor, and several connections. Are they interchangeable? Do I need them if I am building this leslie unit for use with a L-102?
Should (Can?) I use the rocker switches on one of these Dolphins to switch my leslie, or should I build a switch unit from other parts?
Which unit should be used for which frequencies- i.e. should the 2-speed unit be used for the highs, or the lows?
When I connect the 1-speed leslie unit to the organ that has the 2-speed unit, the motor turns, but no sound comes from the speaker. Turns out the 8" speaker is not functioning.
The rotating, stryo-foam baffle is about 14" in diameter, the center baffle section is about 8" wide. I have heard of folks replacing the 8" speaker with a 15" one- but wouldn't that cause reversion problems, or too much of the sound NOT be routed through the baffle, thus greatly reducing the leslie effect? Wouldn't a 10" speaker that is built for bass response be a better choice? Eminence, for instance, makes a 10" speaker that goes down to 40hz- (Legend BP102.) The 15's they make go down to 47hz, at the lowest. Installing a 10 would be much easier than shoe-horning a 15 in there. That Eminence speaker is an 8-ohm speaker, not a 4- but I think it will work.
I intend to put a 6" speaker that is treble-heavy in the other baffle, so I don't have to figure out how to make a horn fit on the pulley.
I read that leslie treble horn rotates at 48 RPM on slow speed and 400 on fast, and the lower drum rotates at about 342 RPM on tremolo and 40 RPM on chorale. I understand this speed difference contributes considerably to the leslie effect. (It seems to me I read somewhere that the horn turned at TWICE the speed of the woofer, but I can not confirm that.) If I put a larger pulley on the motor, that would increase the speed of the baffle, I am thinking a 1.5 or 2" pulley, in place of the 1" pulley, should do the trick. Agreed? HEY, WAIT! the 2-speed unit already HAS a bigger pulley on it! Maybe it will turn at a different speed than the other one.
I also read, on page 2 of this thread, that the upper and lower horns rotate in the opposite direction. No problem- I can just mount one of the units with the baffle on top, the other with it on the bottom- and they rotate in the opposite directions! I read somewhere that these units would only operate with the shaft of the motor horizontal, not vertical, but one of 'em worked fine for me in all directions.
What is a cheap source for a crossover? I am hoping some stereo speaker I can pick up from a thrift store has a crossover that will work just fine. What should I look for?
These Dolphins have SS power amps, of about 15 watts, I am guessing. Can I use one for each Leslie speaker? How to wire them into the L-102's circuitry?
That's all for now- I will return to this thread and read more of the 99 pages (got as far as 5, today!) and will no doubt have more questions.
Thanks.