Boss RT-20 Rotary Speaker Simulator

As with most digital doo-dads, the tweakability is enormous. Plenty of tonal variations---read the manual!

I'm using this for guitar, on a pedalboard, after the wah and before the OD/distortion and delay pedals. No effects looping, just straight into the input of a Fender or Marshall amp. I tried moving it (the RT-20) down the effects chain, but I found it tended to compress the OD/distortion in an uncomplementary way. It's very quiet, but be careful with the built-in distortion. It wicks up the volume considerably (this can be compensated for with the blend control). The Leslie tones are delightful (even in non-stereo mode) and the Univibe is nice, too---although it's difficult to balance the intensity and speed effectively.

Jeez, it's built like the proverbial brick **** house.

No need . . . yet.

What a great pedal! It does exactly what I'd hoped for . . . it gets that big, fat Leslie sound without having to carry a 120-pound piece of furniture. The Univibe sounds right on the money, too. Just add a shade of the built-in distortion and channel Jimi or Robin. Bear in mind, this thing will not physically throw the sound around the room like a real Leslie, but logistically, it'll spare your back and get that tone---and EVERYBODY will comment on the super-groovy spinning lightshow it puts on (but don't use it drunk, it'll make you barf).

Just an update to my review of the RT-20 below

I moved the RT-20 from the stereo configuration into the front end of my amps to the parallel effects loop of one amp in my rig. I liked the stereo effect, but found it difficult to control my overall sound. With the effct in the paralell loop I found the rotary effect was not pronounced enough. I added an EQ in front of the RT-20. After some experimenting with the EQ frequencies, I found that a boost at 400 and 1600 HZ (the rest flat) brought the RT-20 to life in the parallel loop. These 2 frequencies sit on either side of the horn / rotor crossover which better matches the guitar to the leslie effect IMO. It has taken some time to integrate this effect into my rig however I now have my original sound, plus an excellent Leslie effect enhanced for guitar. What I mean by this is you can voice your notes to sit on the horn (treble) side or the rotor(bass) or in the middle. (Magic Carpet ride organ solo) Playing the effect by timing the fast and slow speeds relative to the tune you are playing adds, a lively color that accentuates your music as only a leslie can.
This review is not meant to say the RT-20 is difficult to work with. It is another tool in the arsenal, just took some moving around to dovetail it into the sound I am looking for.I hope the EQ discovery might help out someone else, might work in front of the amp as well however I have not tried this.

Simple controls, detented midpoints give good starting points for dialing in the correct sound. Display shows mode and rotating speed.

I'm running a Hammond Porta-B into the RT-20. The stereo output then runs to my stereo keyboard mixer/amp, and also to the main board for house sound. The key to getting a great sound is to have a really good ear and then tweak each of the settings to find it's sweet spot. I've got it set to mimic my leslie 145. If you listen closely in a quiet room, you can tell it's a simulator. In a band situation, it sounds exactly like a miked leslie. I've been playing Hammonds since the 1970's, and worked for a Hammond Dealer setting up new B-3's, so I've got a pretty good idea of what the proper sound is.

Built like the proverbial Mack Truck

Haven't had to use it.

If you are a Hammond player and looking to downsize your rig for practice, or open mic nights, etc. I'd strongly suggest you take a look. On a Hammond console you'll need to add a 1/4 inch output or make an adapter cable. On the Porta-B and all clones you'll already have the 1/4 line out. The only thing that keeps me from giving it a 10 is the overdrive. Try as I might, I just can't find a setting that really sounds like an overdriven 122 or 147.

The unit is relatively easy to get operational. Plug and play. Out of the box all the knobs set to 12:00 position, distortion off. plugged into amp input, First reaction was this sweet 3D chorus like sound, then hit the switch for the higher speed and it ramped up like a leslie. Sound is useful at the 12:00 tremolo speed, ramped back down and you could here the inertial lag of the rotor. Perfect. The manual is terse, explains the function of all controls and connections with supporting graphics. The manual explains the difference between the guitar and keyboard settings. I would have liked some additional verbage regarding the stereo operation.

85 strat, 85 Lado solo 2, 71 ES330 ---> A ---> FL9 ---- DC30
B ---> Chieftain --- RT-20(parallel FX loop)

All of the following was performed with RT-20 into the front end of the amps
First thing I did was set the brake on the RT-20 and adjusted the effect and direct levels by alternating between dry and effect , to balance the dry / effect level ( Mode 1). There is definitely some tone coloration, which I expected from the effect. BTW You can adjust the tone of the pedal by adjusting the horn balance knob even while braked. (an observation) When you switch between the various modes the RT-20 begins to spin at chorale speed even though you were in brake mode.I eventually settled in (around 9 - 10 o'clock for both the effect and direct pots). Then verified unity volume by alternating between effect bypass, chorale and Tremolo speeds tweaking till the bypass and effect were closely matched. (another observation) I noticed a brief signal aberation when switching from bypass to effect on which is annoying. Effect to bypass is clean though. I plan to AB switch the effect out of the signal chain anyhow so I'll deal with it. The pedal is not noisy however with the pedal engaged and with a very low input signal, there is some digital artifacts audible as the signal decays. This is not apparent if you strum a chord and let it decay, more apparent with just a low input signal, like it's below the threhold of a compressor or expander. I can live with that :-)

Now for the fun, I personally like the sound of the bass rotor acceleration and deceleration. To me this is the heart of a leslie, I listen to Bryan Lee's keyboard player, Mark, Lucky Peterson, John Lord the iconic Zep "since i've been loving you" etc. The way these guys toggle the leslie, select the draw bar voicings and chords to use the crossover 'hole' to select the rotor and horn is the nuance I am looking for, and is how I plan to operate the pedal. The Boss engineers have done a fabulous job of modeling the inertial effects of the bass rotor and horn. To a lesser degree the phasing relationship is in there as well. I have adjusted the horn / rotor balance to around 10 O'clock to give more emphasis to the rotor. I adjusted the ramp speed to around the 10 O'clock, high speed at 12. Flexibility of speed and ramp adjustments is a deciding factor for me. The slower ramp time gives more wump wump during acceleration and deceleration. Think "magic carpet ride". The horn / rotor speed relationships are truly random whem toggling the speed footswitch, exactly like a real leslie. This effect is NOT a slow /fast speed syrupy chorus pedal.

After playing for a few hours, I have actually adjusted my playing style and chord voicings to enable me to play the effect. This means constantly tapping between Chorale (slow) and tremolo (fast) as I play. Not going to find constant speed, vibratone "Cold Shot" here, this pedal does much more. The boss style footswitch is perfect for this repetetive switching.It's not a 147 or 122 with the combo preamp, which I have played through, but it is damn close.

Moving forward I tried a couple of pedals in front of the RT-20. It's a little touchy due to the crossover but you can dial in some decent sounds, An Ibanez CP9 made the horn to bright, The TS9 is on the edge but much better than the onboard distortion for guitar, the Boss CE-5 caused a volume drop when engaged. I connected it in stereo as the manual eludes to. Not sure if there is some kind of a phase relationship issue here, but it didn't work very well. I don't like this pedal anyhow. I connected an old DOD fx65 Chorus pedal which I normally don't like either but it actually complemented the RT-20 swirl. Turned it into a monster chorus but that's something I won't use. Would have been great back in the 80's, LOL. I tried a Ibanez FL9 in front which sounded very good.
Distorion is pure mush for guitar. Not useable

Don't forsee any reliability issues from this device. Boss has been around for years, they have a reliable switching system and robust mechanical pedal design. I would gig this pedal without a backup.

I did email to ask about the stereo operation. Received same day appropriate response, BTW Rt-20 is not 2 channel stereo but a blend.

I did significant research on the currently available rotary pedals. I found the youtube demos to be marginal at best. Some are just plain atrocious. Most of these videos contain too much talk and then the individuals demoing the pedals don't demonstrate the nuances that these effects are about. Are you listening proguitarshop?

I started to focus on the RT-20 and Rotosim. Even the rotosim MP3 downloads, and Boss vids are marginal. We're all so subjective creatures so you have to try any pedal before you buy. I played an RT-20 at Motor City Guitars prior to this purchase, unfortunately they did not have a Rotosim. I read a couple of blogs and finally found comments from an individual that made sense at Gilmourish.com. I managed to find an RT near my home for a reasonable price, so I purchased it.

I play mostly blues /blues rock. I started playing a week after the Beatles were on Ed Sullivan :) the late 60's and early 70's keyboard bands are my favourites and of course the great Government Mule. My main sound is straight into the amps, the RT is for fun & color. I'll be using this pedal for the rythm parts of slow blues tunes. I think it is a perfect match for my playing style and music genre.

I wish the pedal had seperate horn and rotor outputs, separate ramp up and down speeds, and the ability to EQ (emphasize) the horn on acceleration and the rotor on deceleration. Most leslies you hear on a recording and live for that matter have at least 2 mics. This gives the opportunity to fade the mix to emphasize the doppler on acceleration and the amplitude modulation on deceleration.

Over the years I've owned A 67 ash bodied tele, a 50's Les Paul junior, a70's Les Paul Deluxe, a blonde 65 Fender Bassman, played through a Fender Showman and Traynor Bassmasters, ART sgx2000 Xpress with a stereo power amp etc. found my sound 8 years ago with the Chieftain, then 5 years ago with the DC-30 clone & the Chieftain. The Lado is my favorite playing guitar(a gift from my wife).I love the sound of the strat as well. It is a very expressive instrument.

The unit definitely helps make music. I have moved from in front of the amp, into the tube buffered parallel effect loop on the chieftain(addition) It can add very nice controlled color to a tune by appropriately timing and hitting the speed switch, I sometimes get goosebumps when I play with this . Nuff said!

Very easy to use. Keep it on the first choice(122)

Im using this now with a Hammond M3(Baby B) through a Fender Princeton.

Let me say that I was looking/struggling to find the "Leslie" sound without purchasing a 122. Let me just tell you right now. You cant get a 122 sound from ANYTHING other than a 122 or a "Leslie" type speaker of the same physical and mech. specs. So stop looking.

I have owned MS Pro3x and currently* own the Motion Sound Pro 3t/Low Pro. It sounds great but these units are old and moving parts will eventual fail. Plus...its heavy and my back hurts.

So I like the Lonnie Smith, MMW ,Robert Walter sound on the Hammond. The Choral/Trem of a leslie is important but I really wanted the tone(Tube Drive).

My Pro 3t/Low Pro comes close.

This Pedal NAILS IT. Just a Little Dirt on the dial and a mix with Dry(Direct) and "Effect". Bang!

So far so good.

Playing JaZZ Funk for 10 years...If you need the Third/Perc setting and you want a nice clean sound you can get it. If it was stolen I would def. get another one. I love that it doesnt break my back and sounds "Bossy".

I havent played it though a keyboard amp just through guitar(not stereo) and it just sounds great.

The Boss RT-20 is a Leslie speaker emulator based upon the Leslie 122. Its four modes offer two choices of mic position, a Leslie emulation fronted by a Marshall 1959 emulation (John Lord fans take note), and a Univibe emulation. A variable drive control is supposed to emulate an overdriven Leslie power amp, but falls short of the real thing by being dark and muffled-sounding. Fast and slow speeds as well as ramp time are all adjustable. A bicolored rotating display which indicates rotor and drum speeds is not as distracting at it appears it might be. One foot pedal turns the effect on and off while the other toggles speed. Pressing both pedals simultaneously sets or releases the brake.

Aside from the issues with the drive sound (which can be disabled) the RT-20's Leslie emulation can be fairly convincing. The trick (counter-intuitively) is to mix the direct and effect sound using the individual controls on the panel.

It took me a long time to warm up to the RT-20. If you're looking for an authentic Leslie sound it's going to take a bit of tweaking to get it right. (I have a real Leslie 147 for comparison.)

I play a pair of Koll DL Thinline guitars into various clean amps or a DI into a venue's PA.

The RE-20 can do a fairly accurate impresssion of a real Lesiie, but it takes patience and a good ear to find the right settings. If all you want is a some kind of mutant swirly sound then the RE-20 can deliver.

I've had the RT-20 for seven months. I don't expect to have problems.

I don't expect to have to contact Boss for support.

I play improvised fingerstyle guitar in a style that I call "psychedelic folk jazz." The RE-20 contributes nicely to the "psychedelic" aspect of my sound.

I started playing in the mid 1960s and have been playing seriously for eight years.

I've played a lot of other Leslie emulators. Although the RE-20 is far from being "plug and play" (the Leslie mode of the Digitech EX-7 walks away with that award) it has a pretty good sound and a good interface (on/off, fast/slow, brake).

I could do without the spinning display. Although it's less distracting than one might expect, that's faint praise. The display really doesn't add anything to the functionality of the RE-20. I'd like to see the panel space used for an additional control to independently adjust the ramp time of the rotor and drum.

While all the knobs are self explanatory in my opinion this pedal does take a while to get the sweet spots in. If your impatient then this pedal is going to be a very daunting task to work with. Whats great about it is the jack in the back for an expression pedal.
If you dont plan on using a power supply with this thing then you are a fool.

Getting one thing out of the way... strictly for guitar the distortion is absolutely worthless in any way. It just sounds muddy and digital.

Now on to the effect. I have had this box for about 5 months now. When I first got it the thing I noticed was the VOLUME BOOST. Kick this thing on and your gonna hear a distinctive boost. To get around this I have turned my effect and direct settings to around 9 o'clock to avoid a sharp volume increase, this does take away from the intensity of the effect though. The second thing I noticed is that when left off

The rotary sound is very nice. Setting one is a classic Leslie sound which is awesome with a clean guitar. Distorted it seems to get a little to harsh for me. On the higher speed it is easy as hell to get into "Any Colour You Like" tones.

Setting two is the one I use most. It is kind of like setting one and a subtle univibe thrown together. This tone is where it's. It has a more drastic spin on it.
Setting three I have found no use for other that weird keyboard stuff (which I forgot to mention, keyboards and thing box are tops)
The univibe sutting (setting four), is kind of subpar when compared to even the Dunlop reissues so I choose not to use it much. It does give a nice Trower's Hannah tone though if the intensity is turned up.

All in all Settings one and two are going to be your money makers. They are a true sound and easier to carry around than a real leslie. When you kick this thing on and sit next to your cab you can almost hear the horns spinning around inside... It's a pretty cool 3D effect.

This thing is tough. With all my pedals I take advantage of the warranty and throw them down my stairs (im serious) first plan. If they survive then I can use them. If they break then I take em back and tell the guy that I opened it up and it was not working. The reason I do this is because when I play live I have a habit of stomping the crap out of my pedals.
This is a Boss and all Boss pedal I have used have passed the test.

I take this on gigs and it hasn't failed me but if it does then I have a Phase 90 in my board that I would use instead.

Overall this thing is ballin. It gives you awesome rock tones from Trower to some AWESOME vocal tones (I recorded some vocal with this thing and it was perfect for that "Planet Caravan" feel).
I play in a psychedelic/fuck/rock Mars Volta/Hendrix kinda outfit and this suits our styles perfectly.

I run it through my chain as such.
Fender modded strat > Vox V847 > Ibanez Analog Man TS808DX > Fulltone Fulldrive 2 > Seymour Duncan Tweak Fuzz > MXR Phase 90 (modded for true bypass) > Boss RT-020 > Marshall DSL50

I have been playing for 10 year and gigging for 8. If it was lost or stolen I would drop some bills for another one simply because it is the easiest way to get the Leslie sound I want.

I have two gripes about it though.
ONE: The damn horn display is extremely distracting to me... I have an affinity for spinning lights and I often find myself looking down and my board cause this thing is so psychedelic.
TWO: when turned off (like with all digital effects) I can feel a slight digital tinge is my sound rather than if I were to take it out completely. Although this is not as bad as it sounds. I find my tone a bit darker with this thing is chain.

Overall, go try one out for a good hour and get over the volume boost... i mean come on use your volume knob for christ's sake.

This is an easy peice to operate. There is one footswitch to turn the effect on and off and another to change the speed of the rotary effect. The knobs that effect the sound are easy to figure out with minimal fuss. The manual is pretty simple to follow plus it gives a couple starter settings.

I have been using this in my pedal board with the following signal chain. 51 RI Tele>Peterson SS2 Tuner>Fulltone Fulldrive 2>RT20>MXR Carbon Copy>Fender Deluxe Reverb RI. I also tried it with a mid 70's Silver Face Twin Reverb.

When I first tried the pedal I set the eceffect knob at unity gain and nearly blew my eardrums. The pedal has a lot of gain so I turned the output to 3 o'clock and the direct signal at about 12 o'clock. This made it pretty transparant and when switched on not as jarring. Since I already have the Fulldrive so I do not use the OD that is built in the unit. I did try it, but found it really altered the tone of my guitar. If you already have a decent OD you can just leave this off. You can also tweak how much of the "rotar" and "bass" you want.

You can get most of the stock "guitar through leslie" sounds straight out of the box. It nails the Joe Walsh sound down as well as the George Harrison sound on the solo from "Let It Be". The Uni-Vibe effect however is a little to bright and in your face. It's hard to get a subtle sound from this mode. the other two modes I found not much variant in sound. I would give it a 9 overall were it not for the jarring Uni-Vibe.

Well I have e not useed at a gig and I am running it through a Visual Sound One Spot on my board so with constant power it is very reliable. I wouldn't use the AA batteries since this thing looks like it has a hefty appetite for batteries. I tend to run modulation effects through dc anyway.

Haven't had it long enough and I never had a problem with Boss effects through the decades I have been playing.

Keep in mind that this is part of Boss's line of "Twin Pedals" so it has a larger than normal footprint. If your short on real estate on your pedalboard you may want to take this into consideration. With other Leslie simulators on the market this is one of the best sounding units available at a decent price. I have seen others that cost twice as much and if your going to pay that much for a leslie simulator you may as well just get a Motion Sound cabinet.

I play mostly 60's style rock as well as country and blues. This is a pretty flexible great peice of gear. If you want that tone from "Badge" it's here. It is a very musical effect.

I find the 4 position mode switch is lkind of unnecessary since the 1 st postion gives me everything I want. It seemed to me a little bit of overkill but that is what makes it flexible.

The controls are simple and it's very easy to adjust the settings to recreate classic Leslie effects. The brake control can be a little difficult to engage if the pedal isn't sitting perfectly flat or firmly anchored in a pedal board, but that is a minor complaint. It's also a major current drain so an AC adapter is a must.

My main instruments are a 1975 Gibson Les Paul Deluxe and a custom Strat with active EMG's played through a 50W 1981 Mesa Boogie Mark II. The rotary effect works very well with my rig and I am easily able to recreate every nuance of the classics - everything from Badfinger and George Harrison (Badge) to early Zep (Good Times Bad Times), Joe Walsh and SRV.

It's Boss, built like a tank. I've never had any problems with anything from these guys in more than 25 years of professional gigging.

Don't know... never had any occassion to need customer support for anything from these guys.

The effect isn't for everyone, but more than fits the bill if you're looking for a decent Leslie sound for you guitar rig and don't want to spend a fortune or deal with the space/weight of the real thing. I am extremely pleased with it - my only regret is that I didn't get one sooner.

It's a little more complicated than your typical effects pedal but it's not rocket science either. The controls are pretty intuitive and it's not difficult to get a decent sound from the RT-20. In fact, there are a few good sounds to be found here. The most difficult part is setting the levels (effect and direct) which is where most users probably start complaining. I've found for most curcumstances to keep the levels between 9 and 12 o'clock in order to keep the thing from boosting the volume too much. Other than that, it's pretty easy. Just fiddle around until you find what you like.

The RT-20 has awesome sound to my ears. I've had the Hughes & Kettner rotary pedal, an old Digitech RPM-1 rack (both had tubes), a Lexicon Vortex, plus I have the Damage control Glass Nexus (which is an amazing multi-effects pedal worth checking out) and the RT-20 has that swirling, gritty rotary tone. It's not a clean effect, it isn't s'posed to be. It can be fairly clean but it's a rotary unit, if it is emulating a real Leslie is going to be a little dirty. I do agree that the overdrive gets unusable anywhere past 9-10 o'clock (at least for my tastes) and I usually only turn it on a little, but that's not why I got it. The speeds are good and usable and it does have a brake to stop the swirl; it does everything a rotary should. It's not a Leslie so stop expecting it to be, but it does do the job very well. By the way, put the Boss RE-20 Space Echo after it and whoa ...

I've never had an issue with a Boss pedal in 15 years.

See reliability.

The RT-20 is a great value considering other pedals that do the same thing cost more and don't sound that much or any better depending on what you buy. I've been at this for 30 years and go through trading gear a lot, so I know what's available and what sounds good. Right now I'm using Damage Control pedals and a few Boss twin pedals and an AdrenaLinn III and a Boomerang, but I've had Lexicon, TC Electronic and Rocktron racks plus E-H, MXR, Line 6, Boss, Pigtronix ... pedals. For some reason Boss pedals always seem to grace my pedalboard.