Leslie Amp question

crowsmith8 · 06-02-2007, 12:33 AM

Hey all, I have a Leslie amp 825 that out of the blue the slow speed doesn't work anymore. The fast speed works like a charm and sounds great, but when I switch over to the slow speed it clicks on for a second and then goes right back to the fast speed. I checked the motors and both the slow motor and the fast motors work fine. But I don't know where to go from here. Is it something with the switches in the preamp or is it something in the power amp? Does anyone have any knowledge in leslie amps that might be able to help? I would greatly appreciate any help anyone can give. Thanks.

Enzo · 06-02-2007, 05:38 AM

Obviously a faulty switch could send unwanted control signals to the Leslie, check it out. Also the 9-pin cable, and the connectors it plugs into at each end could be bad. Check those.

But if the circuit is dropping from slow back into hugh, then explore the switching circuit. Neither motor will run unless its relay is energized, and one motor has no idea what the other is doing. Not that you would want it, but both could conceivably run at once - if the switching was screwed.

The entire circuit comprises 3 transistors, 5 diodes, 9 resistors, and a cap. Just check them all. the circuit latches on one speed or the other. SO perhaps yours is not latching.

Schemo:
http://www.captain-foldback.com/Lesl...matics/825.gif

crowsmith8 · 06-04-2007, 04:43 PM

Thanks for the reply. I'll look into this. I'm sure you'll be hearing from me if I get stuck or have more questions.

flagrace · 03-05-2009, 10:07 PM

Quote:

Originally Posted by Enzo

Obviously a faulty switch could send unwanted control signals to the Leslie, check it out. Also the 9-pin cable, and the connectors it plugs into at each end could be bad. Check those.

But if the circuit is dropping from slow back into hugh, then explore the switching circuit. Neither motor will run unless its relay is energized, and one motor has no idea what the other is doing. Not that you would want it, but both could conceivably run at once - if the switching was screwed.

The entire circuit comprises 3 transistors, 5 diodes, 9 resistors, and a cap. Just check them all. the circuit latches on one speed or the other. SO perhaps yours is not latching.

Schemo:
http://www.captain-foldback.com/Lesl...matics/825.gif

Hello! I have an leslie 16 with active tube amp in cabinet. Where I can find Schematic?many thanks

06-02-2007, 12:33 AM	#1
crowsmith8 Junior Member Join Date: Jun 2007 Posts: 2	Leslie Amp question Hey all, I have a Leslie amp 825 that out of the blue the slow speed doesn't work anymore. The fast speed works like a charm and sounds great, but when I switch over to the slow speed it clicks on for a second and then goes right back to the fast speed. I checked the motors and both the slow motor and the fast motors work fine. But I don't know where to go from here. Is it something with the switches in the preamp or is it something in the power amp? Does anyone have any knowledge in leslie amps that might be able to help? I would greatly appreciate any help anyone can give. Thanks.

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06-02-2007, 05:38 AM	#2
Enzo Senior Member Join Date: May 2006 Location: Lansing, Michigan, USA Posts: 10,301	Obviously a faulty switch could send unwanted control signals to the Leslie, check it out. Also the 9-pin cable, and the connectors it plugs into at each end could be bad. Check those. But if the circuit is dropping from slow back into hugh, then explore the switching circuit. Neither motor will run unless its relay is energized, and one motor has no idea what the other is doing. Not that you would want it, but both could conceivably run at once - if the switching was screwed. The entire circuit comprises 3 transistors, 5 diodes, 9 resistors, and a cap. Just check them all. the circuit latches on one speed or the other. SO perhaps yours is not latching. Schemo: http://www.captain-foldback.com/Lesl...matics/825.gif

06-04-2007, 04:43 PM	#3
crowsmith8 Junior Member Join Date: Jun 2007 Posts: 2	Thanks for the reply. I'll look into this. I'm sure you'll be hearing from me if I get stuck or have more questions.

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