Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Cabinets-Speakers => Topic started by: TIMBO on September 13, 2014, 05:38:51 pm

Title: ROTOSONIC II
Post by: TIMBO on September 13, 2014, 05:38:51 pm

Hi guys, I've got an even poorermans Leslie, as this one is only a single speed.

I did some searches to see if it could have a speed control added, but nothing that I could under stand

Title: Re: ROTOSONIC II
Post by: bigsbybender on September 17, 2014, 10:05:05 pm

Original 2 speed Leslies have actually 2 motors, fast and slow. The modern Leslies use just the "Fast" motor but use a "Pulse" circuit that provides AC in pulses so the motor cannot achieve full speed, the kits to convert Leslies to do that are rather expensive. https://bborgan.com/hamptone-mk1c-motor-control.html (https://bborgan.com/hamptone-mk1c-motor-control.html)

Title: Re: ROTOSONIC II
Post by: Willabe on September 17, 2014, 10:25:27 pm

Quote from: bigsbybender on September 17, 2014, 10:05:05 pm

The modern Leslies use just the "Fast" motor but use a "Pulse" circuit that provides AC in pulses so the motor cannot achieve full speed......

Ahhhhh........    interesting.


                  Brad     :think1:

Title: Re: ROTOSONIC II
Post by: TIMBO on October 04, 2014, 11:49:40 pm

Hi guys, The SS amp side of this build http://el34world.com/Forum/index.php?topic=17531.0 (http://el34world.com/Forum/index.php?topic=17531.0) has past the sound check.
The use of the 50w module is so much quieter than the old stuff.

Just need to sort out a power supply for the 12v relays. I was hoping to use the +15v for the EQ and add a dropping resistor to get around 12v. Can this be done. Thanks

Title: Re: ROTOSONIC II
Post by: TIMBO on October 10, 2014, 06:22:54 pm

Hi guys, I been having a few problems sorting out the electrics for the switching and power supplies. So things are a bit slow on the construction side.

Title: Re: ROTOSONIC II
Post by: TIMBO on January 10, 2015, 09:23:03 pm

Hi guys, How time flies.
With some distractions out of the way and the wait for parts, the end is here for the "ROLASONIC VIBRATO"

I'll get some sound clips ASAP. :icon_biggrin:

Title: Re: ROTOSONIC II
Post by: stingray_65 on January 10, 2015, 11:17:29 pm

WOW!


I've always knew something like this was possible, but never got around to searching out how one would use one of those leslie units.


I think I have 3  maybe 4 of those leslie units in storage


I have a larger one with a wooden rotor that used to be a 2 speed that i put a PWM controller and motor on it to make it a fully variable speed.


I harvested them from old organs and I used the swell pedal to vary the speed.


never mounted it in a cab or anything.


I think I know what my next project is going to look like!


This is so cool!


Ray

Title: Re: ROTOSONIC II
Post by: TIMBO on January 11, 2015, 12:43:24 am

Hey stingray, I look at those variable speed controls but the cost is a killer and I didn't find much in a DIY unit. Can you elaborate on the PWM. Thanks

Title: Re: ROTOSONIC II
Post by: SILVERGUN on January 15, 2015, 11:34:14 am

Nice work TIMBO!!   :occasion14:

Here's a little reading on PWM, as it applies to DC motors:
http://www.electronics-tutorials.ws/blog/pulse-width-modulation.html (http://www.electronics-tutorials.ws/blog/pulse-width-modulation.html)

Here's an example of a schematic that we use for a wire feeder to control wire speed in a welding machine, just to give you an idea of how the circuit looks.

If I was gonna try it I'd just cheat and steal the control board and motor out of an old feeder.  :icon_biggrin:

Title: Re: ROTOSONIC II
Post by: TIMBO on January 15, 2015, 11:44:31 pm

 :huh:

Title: Re: ROTOSONIC II
Post by: TIMBO on March 11, 2015, 02:17:57 am

Hi guys, Sound clip here.http://el34world.com/Forum/index.php?topic=18409.new#new (http://el34world.com/Forum/index.php?topic=18409.new#new)  :icon_biggrin: