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Boss RT-20 Rotary Ensemble Sound Processor

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From the Beatles to Jeff Beck, Santana to Stevie Ray, many guitar greats have incorporated the rotary speaker into their rigs. With this in mind BOSS proudly presents the RT-20 Rotary Sound Processor.... Read More

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From the Beatles to Jeff Beck, Santana to Stevie Ray, many guitar greats have incorporated the rotary speaker into their rigs. With this in mind BOSS proudly presents the RT-20 Rotary Sound Processor. Employing COSM-modeling technology, the RT-20 authentically reproduces classic rotary-speaker sounds. It offers adjustable Rise Time, Horn and Bass speed, Overdrive, and more. And not just for classic twirl, the RT-20 can be used to create unique overdrive and pulsating effects as well. This pedal sounds amazing, and offers a stunning graphical view of the virtual rotors on its built-in display.

  • Authentic rotary speaker sounds via COSM technology
  • Slow/Fast transition time is adjustable from gradual to rapid change; optional Expression pedal can control speed in real time
  • Onboard Overdrive effects
  • Adjustable mix balance between Treble Rotor and Bass Rotor
  • 4 types of sounds, from standard rotary speaker effects to rock-oriented tones, UNI-V, and more
  • Guitar/Keyboard switch
  • Nominal Input Level: -20 dBu
  • Input Impedance: 1 M ohms
  • Output Impedance: 1 k ohms
  • Recommended Load Impedance: 10 k ohms
  • Display: VIRTUAL ROTOR
  • Controls: EFFECT ON/OFF pedal, SLOW/FAST pedal, MODE knob, RISE TIME knob, EFFECT LEVEL knob, DIRECT LEVEL knob, BALANCE knob, OVERDRIVE knob, SLOW SPEED knob, FAST SPEED knob, DRIVE TYPE switch
  • Indicators: POWER(serves also as battery check indicator), EFFECT ON/OFF, SLOW/FAST
  • Connectors: INPUT A (MONO) jack (1/4 inch phone type), INPUT B jack (1/4 inch phone type), SPEED (EXP PEDAL) jack (1/4 inch phone type), PHONES jack (stereo 1/4 inch phone type), OUTPUT A (MONO) jack (1/4 inch phone, type), OUTPUT B jack (1/4 inch phone type), AC Adaptor jack
  • Power: DC 9 V=Dry battery (R6/LR6 (AA) type) x 6, AC Adaptor (PSA-series)
  • Accessories: Owner's Manual, Dry battery x
  • Dimensions: W 6-13/16" x D 6-1/4" x H 2-1/4"
  • Weight: 2 lb. 7 oz.
Boss pedals - 5 year parts warranty
90 day labor warranty.
1 year warranty - Multitracks, Jamstations, etc.
Check with manufacturer for specific product warranty.

  • Customer Reviews


by PowerReviews

(based on 10 reviews)

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Reviewed by 10 customers

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By marvin

from Richmond, VA

Love this pedal! the speed options and the distortion work well... I use this in a small church where it's not much room for a leslie, and leslie's are costly AS WELL AS HEAVY. with a 1/4 out added to a C2 Hammond organ this pedal has experienced organist looking for a leslie. my only issue that the exp pedal option does not gradually increase/decrease speed, otherwise it would get 5 stars

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Gives you the Hammond thing pretty well...

By Valter

from Santo Andr���, Brazil

Hi guys, I have played with a couple of Leslie cabs in the 90s and this thing, when well used thru a good Tube stack, will do its job. With the right amp it will give you the heart shake of the real thing. Thumbs up, will take you to early Deep Purple type of sound.

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(1 of 1 customers found this review helpful)


Leslie in a box.

By Ron Hill

from Portland OR

I have had this pedal for a week 1/2 and it is the best unit out there. I would recomend this to anyone who plays keys or guitar, it,s a lot lighter than a full size leslie. the only downside is the dist. Its a bit harsh. I still give it a 5 and would recomend the RT-20 to anyone,its the lighter version and sounds just as good.

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(3 of 3 customers found this review helpful)


Kudos from a former Leslie owner!

By Nick Tambakis

from Washington, NJ

I've been using the RT-20 for a couple of weeks now. The quality is extremely good. Boss has come a long way in stepping up their game with these dual pedals. I probably would have given the RT-20 5 stars if I didn't cut my teeth on a Hammond M3/Leslie combo in the '70's. This pedal does come close....very close to the response and feel of my old 122, with a lot more flexibility and control. After trying several of the "rotary" stompboxes currently being marketed, I assure you that if you want the Leslie sound without breaking your back (and bank account), you need to give the RT-20 a shot.

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(6 of 6 customers found this review helpful)


Great effect, couple issues

By Paul

from Hubbard, OH

Instead of giving a glowing review of the RT-20, I'd like to inject a bit of reality. First off, the rotary effect itself is nothing short of amazing, effectively reproducing the Doppler swirl of the two different rotors inside a Leslie cab. Not sure how they did it, but they did it. Several options available in the RT, so it's versatile. As some others have noted, the distortion in the RT is almost unusable, coloring the tone too much. But alas, the bad news here is that there is a noise gate built into the unit which cannot be adjusted or switched off. The badder news is that it is set so that it mutes the very tails of the notes, instead of being set to a less-invasive point. And with all its knobs, you'd think if Boss HAD to put a noise gate in the thing, they'd have included something to control it. Grrr.

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(4 of 4 customers found this review helpful)


Boss RT20

By Ouijam

from Here, Now

The RT-20 does not disappoint me. It produces a classic rotary speaker sound and captures that Pink Floyd spacey-fill guitar sound. I can an almost exact sound as in Nazareth's "Love Hurts" and some Frampton Comes Alive guitar solo sound. Our band covers Badfinger's "No Matter" and the RT20 puts the grind on the lead part very well! The RT20 is definitely part of my permanent rig.

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(4 of 4 customers found this review helpful)



By Ethan F.

from Potomac, MD

This is everything you want from a pedal. Easy to use, and it delivers great results, and it is built like a tank. The addition of the expression peal is great, even though i don't have one. Overall, it is great, and for the price nothing can beat it

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(9 of 9 customers found this review helpful)


Boss's BEST Pedal!!

By Richard

from Northern Illinois

I have been using Boss pedals since 1985, and they are fantastic. I've tried lots of other rotary speaker sim. pedals, and this one is the best. The RT-20 has more user definable parameters than most of the others, and it has almost no noise. It is the most authentic sounding Leslie tone I've heard--Jimi would have trouble telling this thing from the real article. It sounds even better with a little reverb after it.

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(14 of 28 customers found this review helpful)


Join Rotary

By the81charge

from Columbus, OH

I do not own this pedal but had the chance to experiment with it at the store. Alone I'm not sure this pedal would be a tongue wagger. But when mixed with a distortion/overdrive, delay and a little fuzz this pedal really shines. The next purchase I make will be this pedal.

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(26 of 29 customers found this review helpful)


Leslie in a Box

By brlrs

from Kent, OH

Did you ever imagine a Leslie rotating speaker that would fit on your pedal board and cost under $1500. The rt-20 is it. This box has four equally awesome, fully adjustable modes. 1.Leslie 122 with natural overdrive. 2.Leslie 122 with on-mic setting, giving a tremolo-like effect. 3.Leslie backed by a distorted 59' Marshall. 4. UNI-V, which is a very accurate model of a Univibe. A stunning visual display gives you the actual speed and rotation of the speaker and is very helpful. My favorite feature is the brake, which allows guitarists to stop the rotation of the speaker, while leaving the effect on. The brake, with practice will allow you to have some Hendrix-esque feedback sounds that will definately impress a crowd or will sound great on a recording. When combined with a Vox-wah, the rt-20 is capable of stunning tones. This pedal has far too many other features to speak of, but, suffice to say, the Boss RT-20 is a vital addition to any guitarists pedal collection. P.S. Dont forget to try out the "Wild Spin" setting in the owners manual, it will blow you away.

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