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From the Motion Sound KBR-3D to the Leslie 3300

3 posts in this topic

Hi guys and gals.

Thought I'd share my experiences with these two amps.

Also I have a few questions for the techies out there.

In the last year I've had an increase of demand for organ from my various bands/gigs so I thought I'd take the plunge into a rotary horn amp.

(I also got a Nord Stage 88 so as to have a decent B3 simulation).

I'm basically a piano player and I've traditionally used synth organ settings and fake Leslie sounds with Kurzweil, Roland etc. etc. keyboards.

I started with the Motion Sound KBR-3D.

I would describe this a fun and interesting unit but hardly adequate for a serious player.

Not enough power or high end, it's screechy, the built in mics suck, the "low rotor" out carries the entire frequency range (!!), the craftsmanship is shoddy.

The 2nd channel (which directs the output to a stationary speaker instead of the rotor) sounds brittle and is really weak and unusable even in the lowest volume performance environment.

The foot pedal is the worst thing I've ever seen, with a battery holder that is held in place with velcro. It's just not road worthy. I have to carry it around on a pillow!

I haven't yet been able to jury rig another pedal to work (the pedal thing is an entire saga unto itself).

I just bought the 3300 which costs a bit more but is obviously light years above the KBR-3D.

It's bigger and heavier, but is a much more serious device and my initial impressions are really positive.

It's clear, loud, expressive, has all the right gain and tube distortion adjustments, and pretty much sounds like a classic Leslie (at least to my untrained ear).

And, joy oh joy, a Boss foot switch magically works with it! (the Leslie foot switch is back ordered).

So, now for the techies:

Any suggestions for improvements, tube upgrades or other tweaks for either of these units?

I'll keep the KBR-3D for low volume situations (e.g. rehearsals and piano bars!) (plus I hate selling useful gear anyway).

Also, my deepest thanks to Jim for all he has done to promote and educate us about playing and configuring the Hammond organ.

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I have the predecessor to the MS-KBR3D, the KBR-M which is a wedge-shaped monitor version as well as a newly-acquired Leslie 3300. I love the little MS amp for light duty gigs and the beauty is having a mic'd small amp (w balanced output) that projects fine through a larger sound system. There is a fair bit of adjustment in the MS amp though nothing like the Leslie 3300. I assume your MS amp has adjustments internally on the PC board for rotation speeds like mine and you can tweak the mic volume as well as gain controls for different effects. The sound by itself is a bit lame beside the real leslie (duh) but would fool most of the people all of the time. A fairer comparison with the Leslie 3300 would be with the MS-Pro145 though still a less expensive and lower-powered (200w vs 300w) option. I agree about flimsiness of my MS unit and my rubber feet ripped out of the particle board almost immediately. Pound for pound though it is brilliant since I also run an electric piano through it - taking the 110 lb 3300 also means carting a keyboard amp.

As an upgrade to the Leslie 3300 I had a traditional half moon type switch made for me by Jim Trimper of Half Moon Electronics and a use it together with a foot switch using a Y-jack (since I find it is handy to have both foot and hand switch). My dealer also did not inform me the foot switch did not come with the unit so I had to make one with a doorbell switch. Because the Leslie is a momentary type, the half moon switch for the leslie is spring-loaded to the centre position (on-off-on)...I am going to get him to make another 3 position one for the Motion Sound unit (Off-Chorale-Fast) which works more like the original Leslie switch. I will use a stereo Y-jack with this setup.

I understand those 12AX7xx tubes are interchangeable but at the moment find I can get more than enough distortion from the stock tube with the circuit cranked up...which also cranks the volume. I would be interested in the results if you experiment with swapping the tube .

I am just adding a subwoofer to the 3300 to see what that sounds like...I made the mistake of getting a passive subwoofer so have ordered a rack mount Behringer bass amp to power it....that should give it some serious bottom end.

Edited by William Steward

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So sorry I missed this.

I've never cared for the Motion Sound stuff, but I appreciate them being there when there really was no other option for quite some time.

The 3300 is a true beast. With the right tube, you can get awfully close to the tone of a classic Leslie 122, but with about 3x the headroom! It's a glorious thing!

I suggest scrapping the 12AX7 and putting in a lower gain tube like a 12AT7. Why? Because the tube circuit goes from nice and smooth to downright ugly and there's no reason to go to that extreme. With the lower gain of the 12AT7, you have a much wider range of smooth before it gets into ugliness and it sounds to my ears much closer to a 122. I've never really cared for 12AX7s in anything but a guitar amp anyway (and then only in the right circumstance).

I had a NOS RCA in mine up until last April when it started developing microphonics. I replaced it with a NOS Jan/Philips, but the low end wasn't as clear. So I put in a brand new Electro-Harmonix and while it isn't quite as pleasing in the midrange as the RCA or Philips, the bass is much tighter and more defined. I'm digging it. I need to get another RCA or Tung Sol in there, though.

William, nice to hear you're going the sub route. It makes a world of difference, especially playing pedals.

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