• Boss RT-20 review

    Since the early 70’s David Gilmour’s been using rotating speakers to make his sounds fatter and more three dimensional. Recently I got my hands on a Boss RT-20 Rotary Ensemble. It’s difficult to capture the natural sound of something as unique as a rotating speaker but the RT-20 sounds remarkably close. Here’s a little review.

    The RT-20 was introduced in 2005 housed in the new dual pedals from Boss. Featured controls are:
    – Mode: allows you to switch between 4 different modes. 1 is the normal Leslie type. 2 and 3 is a combo of a Leslie and a Marshall amp with a bit more gain on mode 3. Mode 4 is a very bad sounding Uni-Vibe clone…
    – Rise Time: controls how fast you want the right pedal to switch between slow and fast rotary.
    – Effect: controls the level of the rotary effect.
    – Direct: controls the blend of the effect and your guitar. By turning the Effect all the way to the left and the Direct all the way to the right you’ll get a clean tone equivalent to switching off the pedal.
    – Balance: placement of the microphone on the Leslie cab. More amp or more horn.
    – Overdrive: thin and fuzzy… don’t use it!
    – Slow: rate for slow mode.
    – Fast: rate for fast mode.

    The left pedal switches on/off the effect and the right pedal switches between slow and fast settings. A cool display – the “virtual rotor” – indicates the rate setting of the horn.

    The pedal works equally well on keyboards with a mode setting for impedance on the back. Sounds great for Hammonds and that Wrightish Echoes piano.

    So by now I guess you’re wondering “didn’t Bjorn ditch all his Boss pedals?”. “Didn’t he say that they messed up everything?”. Well, kind of… I never threw away my Boss pedals but I didn’t want too many of them on my stage board because their buffers didn’t go well with especially the Colorsound PB and the Sun Face. I once had a DD-20 digital delay, which sounded quite nice but the pedal was noisy and it totally ruined my signal. I was very sceptic to the RT-20 and I’ve tried all sorts of combinations with my pedals. The result is that it sounds very nice indeed and it doesn’t seem to colour my tone as much as the DD-20 and some of the other Boss pedals (especially CE-2, CS-2, GE-7). It’s very quiet and clean.

    The RT-20 is in essence an amp simulator and you’ll get a distinct volume boost when the effect is switched on. I took some time to figure how to avoid increasing the volume too much especially since all my sounds are either based on the Colorsound PB or the BK Tube Driver but it works very well for chorus sections and solos where you normally would want a little boost. On the more quiet parts you just have to use the volume pedal.

    Keep in mind that a real rotating speaker acts just like a tube amp, – it’s almost alive and very “organic”… if that term can be used on electronics. Also, the Doppler effect that the horn creates needs something to bounce off on. The closer you place a rotating speaker to a wall, the more dramatic the effect will be and that’s near impossible to simulate. What you’ll get is something very similar. This isn’t a distortion effect but a simulator.

    I haven’t been able to a/b test the pedal against a real rotating speaker but I’ve played through them enough to say that the RT-20 is extremely close. It adds a wide 3D effect to your tone and with some delay or echo it sounds just incredibly rich and fat. You can hear the horn swirl around adding that tyical almost scratching or swoshing tone (listen to the effect loop on On the Run). I would like this to be a little more audioable but with a mild overdrive in front it sounds very nice. I strongly recommend using an additional overdrive. The one featured in the RT-20 doesn’t sound any good.

    I keep all the controls at 12:00, except: slow 1:30 (o’clock) and the overdrive is off. I mostly use the slow setting and always mode 1.

    Soundclip: Raise My Rent
    On this song David used a Yamaha rotating speaker on both the rhythms and solo. The RT-20 captures that swirling, slightly unpredictable tone and works very well on the solo too.
    – Custom 69 pickups > Sovtek (green) Big Muff > Boss RT-20 > GarageBand with a clean British type amp sim and a hint of delay and reverb.

    Soundclip: Us & Them
    On Dark Side of the Moon David played this song through a Leslie 900 (also seen on the DSotM documentary). With additional overdrive the RT-20 sounds very similar to the tone David had on the 1973-75 tours.
    – Custom 69 pickups > Boss CS-2 > Maxon OD808 > Boss RT-20 > GarageBand with a clean British type amp sim and a hint of delay and reverb.

    I’m very pleased with pedal. Surprised actually. I’m a huge fan of both Steven Wilson and John Wesley from Porcupine Tree and they both use this pedal frequently (see John Wesley’s presentation here – select “video” in the menu). I will mostly use the RT-20 with my band Airbag but certainly for Floyd stuff too. Recommended!

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72 Responsesso far.

  1. Rookie says:

    Hi Björn, how is a stereo setting supported by the RT-20 (and other devices with stereo option, like Boss CH1). Is the signal sent out to the two channels left/right identical and the stereo effect is created by the physical distance between the two speakers only, or is the stereo signal designed in a way the rotating sound is created with two different, corresponding signals, comparable to a Ping-Pong delay? I did not figure out when using the device yet.

    • Bjorn says:

      I’m afraid I’m no good at explaining the technical stuff. I’m sure there are videos out there explaining what stereo pedals does.

  2. Alex Walker says:

    Hi, just a slight correction, mode 2 is also an attempt at a normal Leslie, but with a close mic placement, producing a rotary with a deeper tremolo. I actually really like mode 2 set just a bit below 9 with the balance knob slightly favoring the bass for a very subtle shimmer and throb for songs like Us And Them. Modes 3 and 4 are the ones with the Marshall, neither of which I really care for.

  3. Cédric says:

    Hi Bjorn,

    I just want to share my experience with rotary sims.
    A few years ago, i wanted to experiment that.
    First, I’ve tried the Strymon Lex. It’s really a great Leslie sim. I loved it, but like you’ve said many times, it don’t work for Gilmour rotary. even in a parallele fx loop, it’s to dominate and colour to much the sound.
    So, i sold and bought a used RT20. I played it in mono and i immediately hated it. It sounded Nothing like i hope.
    I get no swirl with it. It ad nothing to my tone. In fact, it loose my tone. I wondered “Why does Bjorn like this piece of shit?”
    So, I endly sold it.
    But i missed this 3D effect in my tone.
    Yesterday, i’ve bought an other RT20 to experiment again. I immediately remember why i hated it the first time. No swirl and i loose all the dynamic i have in my tone.
    Then, i ‘ve tried it in stereo with an old little shitty bass amp for second amp i immediately get this 3D effect i hope. and it sound great.
    Now, i love it but i think it really need a stereo set up to work.

    Thanks to share your experience with us, and keep on.


    • Bjorn says:

      Thanks for sharing, Cédric! It’s always hard to describe how a rotary set up should sound like and especially David’s, which is quite unconventional. The Lex is, in my opinion, the best Leslie sim out there but it doesn’t work for David’s tones, unless you want his 1972-75 tones when he actually used Leslie cabs on stage. Set the Lex up with a blender or master volume mix like the Lehle and you’re there. The RT20 is a pretty shitty attempt at recreating the extremely complexe doppler effect or rotary sound. It sounds too much like a chorus and far from that lush rotary or tremolo sound. BUT, David’s old Yamaha cabinets that he used on Animals and Wall, did sound different than the Leslie. So did his custom Doppola speakers in the 90s. They had much more of that liquidy chorus tone. Any sim will sound better when you set them up in stereo. That would be a much more accutare simulation of the doppler effect. However, the RT20 can sound great in mono with the right settings and right placement. Just don’t expect it to sound like a lush Leslie cabinet :)

  4. Ben says:

    Hi Bjorn.

    Sorry to bring up this very old thread. I just picked up an RT-20 and it has a noticeable amount of “white” noise / hiss when the “Direct” level is set greater than about 9:00 (nothing being played or guitar volume at 0). It’s not horribly loud, but it is there. Just a faint hiss that gets progressively louder as you increase the level to becoming very noticeable at full level. Oddly enough, the “Effect” level has no audible noise or hiss no matter how high I set the level. I am curious to see if this is normal for the RT-20 or if I picked up a “noisy” one. Most reviews of the RT-20 comment on how quiet it is. Mine is quiet compared to some of the Boss pedals I have from the 80’s and 90’s, but not compared to their current line. Does your RT-20 exhibit similar background noise?

    Also, do you still use the RT-20 much or have you replaced it with something else?

    Many thanks!

    • Bjorn says:

      I don’t really use mine that much other for recording, whenever I want some of that rotary/chorus to blend with certain tones. For true rotary tones I use the Strymon Lex. It’s two very different sounding pedals serving different purposes. Anyway, I’ve never had any issues with mine but how’s your powering? These things draw a lot so be sure to either use a dedicated power or make sure that your power unit/station has enough ampere. Do not chain it with other pedals.

      • Ben says:

        Hi Bjorn,
        I’m powering my RT-20 with a Fulltone regulated power supply (non-switching). I’ve had problems with other power supplies, especially the switching ones, causing all kinds of strange noises and interference with pedals. However, the Fulltone ones are dead quiet. The RT-20 manual states the max current draw is 85 mA and the Fulltone FPS-1 power supply I’m using is rated for 200 mA. My RT-20 is not chained with other pedals with this power supply, so I should be covered. However, I will try some other power supplies and battery power just to make sure.

        It’s entirely possible I got a “noisy one”. My suspicion though, is that may just be how the newer RT-20’s are made (cheaper components, different manufacturing, etc). Mine is brand new. I received it as a Christmas present, so I can exchange it for another unit, which is what I’ll probably do and keep the “quietest” one.

        As a side note to the shitty overdrive in the RT-20: as you suggested, I keep the overdrive off on the RT-20. I happened to have a BOSS Wazacraft Super Overdrive that I picked up a few years ago (like you, I’m not a fan of most BOSS pedals in general, although I have a few in my collection). When pairing the Waza Super Overdrive with the RT-20, setting the super overdrive very low gives a good idea of what the RT-20’s built-in overdrive SHOULD have sounded like. Maybe not the greatest overdrive pairing, but it’s fairly good, infinitely better than the built in crap, and since they’re both BOSS pedals, you would think they could have done this!

  5. Bjorn
    I know this is a very old thread , but now I have the RT-20 on my pedalboard and I’m trying to figure out how to integrate it tonally. Do you run your RT-20 with stereo-out to two amps? Or do you split signal before and send the wet signal to one amp and a separate un-modulated (RT-20’d) signal to the other? My dilemma is that the RT sounds like crap with my Tube Driver and Musket, coloring the tone and making the highs sound brittle and …just bad. Any recommendations on how to organize the RT’s place in the chain, especially in terms of Stereo/mono and how to mix it? My amps are a Laney L20-H through a Hi-Tone 2×12 with their own Fane copy speakers and the other amp is a Quilter 101 Miniblock through a custom-made 212 cab loaded with a WGS ET-90 + Avatar H75 (Fane F70).

    • Bjorn says:

      I usually have mine placed in front of the delays much like a chorus. My opinion about the RT20 is that it’s a crappy rotary simulator but it creates some really lush chorus sounds and very similar to what David gets from his Yamaha and Doppola rotating speakers, which sounds very different from a Leslie. I usually keep the effect level quite low, around 8:30 and the direct around noon. That creates a nice balance.

  6. Thanks, Bjorn! I bought a RT-20 after read your texts. Congrats!

  7. Hey Bjorn, sorry to comment on such an old post, but I have been having trouble getting a good slow swirl. The fast swirl is fine for the Any Colour You Like stuff, but I just can’t get a good sound on really anything clean to Muff’d on the slow setting. It just sounds “fake” and sort of “metallic”. Someone told me they like it better in the effects loop but I use a Tweed Blues Jr. now. Any suggestions?

    • Bjorn says:

      Depends on what tones you want, I guess. As I’ve said before, the RT20 is a really shitty Leslie simulator but a great sounding chorus. If you want authentic Leslie rotary, then check out the Strymon Lex or Neo Ventilator. I find the RT20 to be a perfect match for David’s rotary tones, especially the Doppolas he used during PULSE but also the Yamaha cabs he used between 1977-83, because you can mix wet and dry and, the fact that David did mix his amps with rotary, made them sound a bit different. My favourite slow setting would be: Mode 1, effect 8:30, direct 11:00, balance 11:00, overdrive either off or just a hint to roll off the high end, slow 12:00. Hope this helped :)

  8. Fritz says:

    Hi Bjorn!

    Think I’ll buy an owened RT20.

    One question:
    In which parts of SOYCD do you use it?

    Greetings from Austria,


    • Bjorn says:

      I leave it on for pretty much everything. Keep in mind that David’s using rotary cabinets as a part of his main tone so you would want to set it very mild and leave it on for most stuff. It’s not like a phaser or UniVibe, which you’d use for specific applications.

      • Fritz says:

        Thanks a lot, Bjorn!

        Today I found another Pedal:
        Digitech Ventura Vibe
        Seems to bring Univibe, Rotary and Leslie-Sound in one small pedal.
        Do you have experience with it?


        • Bjorn says:

          I haven’t tried it yet but the reviews seems promising :)

          • Fritz says:

            Hi Bjorn!
            I tested today both pedals.
            And I took the Digitech Ventura!
            I love it!
            Noiseless, versatility, super sound, and enough space for it on my pedalboard.

            Settings “Vintage” or “Rotary” – both worth for David’s Sound.

            If you also test this pedal, would be nice to hear your experiences!

            Greetings from Austria,

            Every day I find new ideas for me in your website. thank you!

  9. Allen says:

    Hi Bjorn

    How about a tech21 Roto Choir ?
    Do i get a better sound than BOSS RT20?
    please comment
    thanks so much

  10. David Gow says:

    Hi Bjorn, I recently got myself a second hand RT 20 and I really like it. Could I have your opinion on a couple of points? If playing clean or with some mild overdrive I find it sounds nice with the effect more dominant (for example as in your Us and Them clip) – I have the effect and direct controls both somewhere around 10 o’ clock. I find this makes the effect pronounced but without a large volume boost. However, with heavier distortion I find I need to turn the effect level way down and balance the volume by turning the direct up, otherwise it becomes way to dominant. Are you doing something similar? For example, how are you using it in your ‘Louder than Words’ jamming video? Lastly, are you putting it at the very end of the chain, after the delay? Thanks as ever, the new site looks great. Best Wishes.

    • Bjorn says:

      Thanks David! I often use different settings for different tones. As you’ve discovered, cleans and overdrives often require more of the effect, while heavy gains needs a more subtle setting. It’s obviously down to taste but heavier gains will drive the sound more and also create more pronounced transients, which can make some modulation effects sound pretty harsh. On Louder Than Words I think I used a fairly moderate setup although I used an overdrive tone.

  11. Alan says:

    I found a univox univibe” on ebay if your interested

  12. alan says:

    ive tried the BBE soulvibe and i wouldnt reccomend it because it doesn’t go fast enough and it sounds flat . I hope this helps .

  13. Jeremy W says:

    I am also wondering about the Behringer VT999. I have the Behringer CS100 compressor sustainer and it works great.

    If anybody has any info on comparing the Behringer VT999 to the tube Works Tube Driver please comment.

  14. Gestaltito says:

    Hi, it was nice reading this article cause I got the RT-20 a month ago.
    The moment I saw Dave Kilminster had it and heard some demos, I said: this is the one.
    I agree that univibe mode is lousy. For that kind of stuff I use a modified Small Stone, I’m in love with that sound, wouldn’t change for an Univibe for the moment.
    About the Electric Mistress… I definitely prefer RT-20.
    Digital, ok, but sounds more “warm” to me, I couldn’t explain. I had a new Deluxe one, and a week after RT-20 came into the pedal board, the Mistress went out, sorry. As a flanger, much better than a Boss of course, and maybe neccesary for The Wall and solo Gilmour tones, but for playing DSOTM, wich I enjoy the most, not neccesary at all, I think. Anyway, congratulations and thanks for this website,

    [Well, I wouldn’t really compare the Mistress and RT-20. To me they’re two completely different effects for different purposes. Both are great tho but if I had to choose only one for David’s tones I’d go for the Mistress… my opinion :) – Bjorn]

  15. Luciano says:

    Hi, Bjorn,

    I haven’t got the time to post recently, but I read the site everyday.
    Quoting the Fab Four, I must say “it’s getting better all the time”. :-))
    Congratulations, man.

    But one thing got me puzzled.

    I’ve heard the Small Stone, MJM Sixties Vibe and RT-20 (superb!!!) clips thousands of times (and read the review and comments over and over), and I can hear some differences, but I still can’t quite get it properly.

    You see, as you say on the buyers guide, the Uni-Vibe was designed to capture the effect of a Leslie, then, here, you say the MJM is a Univibe clone, while the RT20 is a rotating speaker simulator, and that they’re quite different.

    Well, wasn’t the original univibe intended to be a rotating speaker simulator too?

    I assume that the intentions and the final sound must have taken different paths…

    Still, despite the fact that I have loved your RT-20 clips, I can’t make up my mind about getting a univibe clone or a rotating sim (I must say that I already have the small stone, the mistress and the CE-5).

    Talking of budget effects, can you (or any of the guys), PLEASE, tell me anything about the Rocktron Vertigo Vibe ??? Is it any good??? And what about the Behringer VT999 Tube Monster??? Can it come even close to a Tube Driver, or should I stay with my Boss BD-2 until I manage to get a real BK (that will be the day, hehe, i mean, they are impossible to find and incredibly expensive here) ??

    Sorry for all the questions, but, at least to me, you are much more reliable than any guitar player magazine or harmony central reviewers.



    [Hi Luciano. Sorry for my late reply. First of all, the Buyer’s Gear Guides are ridiculously outdated and in need of a serious overhaul. The UniVibe was designed to capture that Leslie or rotating speaker tone. I think the idea was to get a Leslie in a box but to make it more pshycedelic… if that makes sence. However, it should not be mistaken for a rotary simulator. The effect is perhaps closer to a phaser but it’s uniquely designed circuit makes it different. The tone is thick, smokey and kind of wobbly, while the phaser uses basic phase shifting for a slightly smoother, dirtier tone. It’s not easy to describe the differences but once you compare the two, you’ll hear how distinctly different they are. A rotary sim, like the RT-20 is indeed a Leslie in a box and it’s not meant to be anything else. I think a UniVibe or phaser would be a better choice all together regarding a Gilmour setup. A rotary sim is a cool effect but you can’t really use it to replicate the effect of David’s Yamahas and Doppolas and how he’s using them. That’s another discussion :)
    I can’t help you with the budget requests… Anyone? I did however try the Soul Vibe from BBE and it sounded quite nice. – Bjorn]

  16. Alan says:

    If your willing to spend about $2000 for a leslie you can get one on musiciansfriend.com and you can buy another $2000 leslie head if you want.

    I know very expensive.


  17. T C Russell says:

    Great information here Bjorn. I was considering a RT. I have 7 Boss pedals simply because they have never failed on me. (30yrs of playing). My current effect string is Guitar-CarlMartin Comp/Limt-CryBaby-TU2-GE7-SD1-OC3 to face of MesaBoogieLonestar. Mesa Effects Loop= CE5-PS5-DD20. I was told to put “Timed” effects thru the loop. Im considering a RT20 since the price has come down abit. I considered going to the rack mount effects, but that was way out of price range. I found that all of the prior posts on the RT20 was very helpful.
    Im also considering a unit that will allow me to create different loops with my existing effects pedals.
    Gilmour is one of my top5 favorite guitarists of all time. I could listen to him all day long and not be exhausted at all.

    [Well, Boss will last a lifetime :) I think it’s recommended to use the effect loop if you’re using the distortion channel on your amp. That way, the modulations and delays be lined up after the distortion as one would normally do. If you’re only using the clean channel, which I assume you do since you’re using the SD-1, I would simply place the modulations and delays in the effect chain for a better signal and tone. Read more in this article. Cheers! – Bjorn]

  18. Howard says:

    Your RT-20 review and sound clips are superb… YOU make it sound real sweet.. not sure if I could do it justice.. hmmm… it sounds a bit like a weak phaser.. but its somehow more “airy”.. I cant describe it… like it colours the tone less… Like I say your sound clips are awesome. Maybe I need to try one.. :-) ON Shine On, WYWH albumn, what effects are on when he hits those 4 big notes? Is that a leslie or a slow univibe? he never plays it live with the same sound… I love the albumn tone.

    [Thanks Howard! I think the tone is closer to a flanger or chorus than a phaser, which is more smokey and dirty. David used an MXR Phase 90 on the album… You’ll find the setup here. Cheers! – Bjorn]

  19. fede says:

    hi Bjorn hope you are fine!

    3 things:
    1) my DD 20 is not noisy at all – maybe you have a fulty one? : )
    2) I own a prescription electronics univibe – what do you think of it? I love it for Breathe type of sounds..spot on!
    3) to emulate the Dogs solos (i think was tele + big muff?) sound would you use a univibe or the rotary emulator?

    finally..I always have problem in mixing overdrive and univibe..they don’t blur right in my rig (I have tried both combinations of pedals).. is it better with combining overdrive and the RT-20?

    [Hi! Well, my DD-20 wasn’t extremely noisy but it could have been more quiet. The biggest problem was that it didn’t go that well with some of my pedals, like the Colorsound and SunFace, which both sounded distinctly thinner. I haven’t tried the Prescription UniVibe… sorry. For Dogs I’d use the RT20 or better, an Electric Mistress. Hmm… I don’t like using the UniVibe with neither overdrives nor distortions myself. Sounds a bit too dominating… The RT20 goes very well with both. – Bjorn]

  20. peter endes says:

    Happy Birthday David! ! !

  21. Adrian says:

    This for Nate

    you should also check Line 6 toneport

  22. Nate says:

    Is there any pre-amp or interface in particular that you would recommend? It’s really driving me nuts as I don’t have my amp and pedalboard available so Garageband is my only option…besides buying another amp :-p

    [Check out M-Audio. – Bjorn]

  23. Adrian says:

    Yeah I really like the sound of the Celestion speakers my Line 6 tube amp has. They sound great for the hiwatt sim on my PODxt live. What kind of speakers does david use????

    [His WEM cabs have original Fane Crescendos. – Bjorn]

  24. Nate says:

    Hey Bjorn, I know this question is completely off topic but some other people might be interested in the info as well. I’ve been trying to use garageband lately and I have a very noticeable lag that makes it almost impossible to play. I’ve turn the latency settings down, closed all other programs and all that stuff but I still can’t use it without a delay creeping in. Have you experienced these problems and how did you work around it? By the way it’s a brand new macbook pro so it ought to be more responsive than my old ibook was (which it isn’t)!

    [Hi. You can plug your guitar straight into Garageband without a soundcard/pre-amp. However, it’s always recommended that you do use an interface to eliminate noise (from having to boost the amp sims) and to avoid latency. I recently bought a new iMac with Leopard and I noticed that there’s some latency in Garageband and it seems that the soundcards in new Mac’s aren’t as powerful as the older ones (there are many debates on this on the net). Also, Leopard is much more memory consuming than OS 10.4 so I do recommend using a pre-amp. – Bjorn]

  25. Paul-Mark says:

    Do you use the Ceramic or Alnico version of the Weber Thames? For the Fane sound, what is the difference in tone? I’ve never tried Fane speakers

    [Ceramic. They’re dead on the old Fanes I had. – Bjorn]

  26. Jason says:

    yeh speakers is an interesting topic. i had to read into a little bit as i had to choose a speaker for my tweed deluxe. didnt realise they played such a large role. FYI i got the celestion vintage 30 which is a nice speaker, crisp, bright and articulate. BUT. far toooo mid range focused. i read that they take a while to settle in tho so lets hope so. the amp its in is also a very middy amp tho so obviously factor that in. my lead licks cut but rhythm stuff is just too honky!

    my cab maker recomended these speakers called scumbags which are modelled on early celestion models. thought id throw that into the mix as your all dropping brand names!

    [It takes some time for speakers to break in. It depends on how much you’re playing and how hard you’re driving the speakers really but with a normal couple of hours a day playing at home kind of routine I think that they should better in two months and reached their full potential in three months. – Bjorn]

  27. Deck says:

    Hi Bjorn,

    your last message concerning the amps speaker made me want to know a bit more about this, as I am totally unaware of the differences of all these speakers.
    Could it be a good idea for a review ?
    Comparing Fanes, Celestion, Weber…
    I do have Celestion in my amp, though I have never looked at the precise model, but maybe a Weber could be better, if I read correctly your previous message.

    [I don’t really have that much experience with different speakers although I’ve played through tons of stuff. My general opinion is that Celestions have a bit too much mid range… at least for my taste. Some of the older models or vintage reissues is great but perhaps not ideal for Gilmour’s tones. Newer Celestions frequently used by Marshall etc are only good for Metallica… Old Fanes are near impossible to find and the new ones fail to live up to the legend. Weber Thames is dead on and IMO even better, although compared to my old tired Fanes. I also like old Eminence and Jensen. I’ll try to do some research on this… Cheers! – Bjorn]

  28. Frails says:

    Hey thanks for the curveball! LOL Ok, I’ll check them out. My head is 135W so I need speakers that can handle that power. But those Thames look more than capable. I’m pretty set on the Jensen but I am willing to change the Celestion for something else. Its weird, so many reviews say the G12T-75 is great in a support role, but not so great as a main speaker. But I guess when you consider Gilmour uses those WEM cabs as the main set and adds in the Celestions or Doppolas, it makes sense.

    [Yeah the Thames are 80w so with four of them it should be more than enough. – Bjorn]

  29. Franck Machu says:

    Hi Bjorn,
    One question out of topic. You write in “Buyer’s Guide that among the huge choice of Fuzz there is on the market you personaly like the Boss Hyper Fuzz, probably one of the least sought after fuzz units, and you advise to listen to your Echoes soundclip.
    This soundclip is the best Echoes “clone record” I have ever heard. Do you mean you were using this Boss Hyper Fuzz during recording of this soundclip ? Whaaaooouuu. What version is it ? the FZ2, FZ3 or FZ5 ? The FZ2 can be found much cheaper on eBay than the Analogman and seams to be a good alternative. Does the Analogman really worth the higher price ? Thanks in advance.

    [Thanks Franck! At the time this version of Echoes was recorded I used a Boss GT-3 board in addition to my pedal board. The GT-3 had a FZ-3 I think. I haven’t tried the actual pedal but the one in the GT board sounded very thin alone but with some bass and mid range boost (GE-7) it sounded very nice indeed. It’s what you hear on the clip. Now that I’ve replaced it with an AnalogMan SunFace I must admit that the SunFace is in a league of it’s own. The FZ-3 sounds raw and edgy but a bit flat, while the SunFace has tons of character and dynamics. Check out this clip for the SunFace. – Bjorn]

  30. Frails says:

    I mis-spoke. I have Oxford’s not Utah’s. I did read in the Analogman review of the Gilmour NYC concert that he’s using Celestion 75’s. I’ve decided to go with a Jensen C12K and Celestion G12T-75. I’ll let you know how they sound. I’m using a Eminence Legend in my Leslie and may try these others to see what sounds best.

    [Yes, I think David’s using Celestion 75. My Sound City cab had original Fanes Cresendos in them but I had to replace them about a year ago. I got recommended Weber speakers and decided on Weber Thames Ceramic, which is “clones” of the old Fanes. I have to say that I couldn’t be more satisfied. I was really afraid that I was going lose my tone but the Webers are dead on and even better IMO. A bit warmer and a bit more character… Definitely recommended. Personally I like Celestions but I think they have a bit too much mid range for the typical Gilmour tone… especially the 70’s era and OAI/RTN. Keep me posted! – Bjorn]

  31. Rick Cash says:

    Hi Bjorn! Great review, i have been looking for a rotary speaker sim and this has give me another one to consider. I had my mind set on the DLS rotosim after hearing a few bad reports about the H&K Rotosphere (mainly that it was noisy and too big.)

    Have you tried any of these models? I would love to know how the RT-20 compared to the DLS Rotosim.


    [Thanks Rick! I considered the DLS. It’s about the same price range as the RT-20 and the tone is very similar. The DLS is perhaps a bit warmer than the RT-20 but I think the RT-20 has a bit more liquidy tone, which was closer to what I wanted. I didn’t try it enough to experience any noise issues. – Bjorn]

  32. Adrian says:

    what is the next article???

    [Stay tuned my friend :) – Bjorn]

  33. Frails says:

    Bjorn- Not sure where to post this question so thought I’d post it here since it’s where your focus is. Do you know what kind of Celestions David uses? I’m looking to replace my Utah speakers with something else. I thought I’d start with some Celestions since his Fane’s seem impossible to find. I need 8 Ohm and at least 50W per speaker. Have you always use Fanes? Any suggestions? Thanks in advance.

    [Please see my response in your latest post. – Bjorn]

  34. Rob k says:

    The Us And Them soundclip was AMAZING i loved it!!! Makes me want one terriblyy, just gonna have to add it to my list of must haves.

    [Thanks Rob! I think you’d be very pleased with the pedal. Cheers! – Bjorn]

  35. Daniel Krause says:

    Ahh, yes…ok. I guess you’re right. And it would indeed be a bit weird if it would only be a dry signal. I think I’m gonna give it a go with seperate amp for the RT20. I’ll let you know how it worked out ;-)



    [Please do! – Bjorn]

  36. Adrian says:


  37. Collin says:

    Sounds pretty cool. I had seen this pedal around, but figured it was probably crap. Guess not.

  38. Adrian says:

    what kind of P.A. system do they use???

    [Floyd used WEM in the late 60’s and early 70’s, then Martin and Altec during Wall. On PULSE they used TurboSound Flashlight. On David’s latest tour he used Turbosound Aspect. – Bjorn]

  39. bernhard says:

    only able to take a very quick listen at your clips; sounds like a remarkable job, very close indeed. I’ve bee struggling through all sorts of rotary sims myself, and where they all fail is exactly the setitngs you are spotlighting here. great job! cheerio, bernhard

    [Thanks Bernhard! – Bjorn]

  40. Daniel Krause says:

    Hi Bjorn,

    A little question. Did David use his leslie’s/doppola’s wet or dry? So with or without delay’s and stuff like that?
    I’m asking because I’m thinking of putting the RT20 on a seperate(third) amp. As you know, I am now using it only on my left channel, but it does get a bit dominating in some occasions and I can’t really turn the volume down on it, which would be nice.



    [His main signal is split into right and left channel and the Doppolas on a third or split from the right mix. So yes, all his effects are runned through the Doppolas. I don’t have any documentation on how he did it in the 70’s with the Leslies and Yamahas but I’m pretty sure everything just got split equally. Wouldn’t really be any point with just a clean signal… Cheers! – Bjorn]

  41. Adrian says:

    How does david use his leslies ext…. in the studio and on stage do u mic them or turn em up really loud???

    [I’ve answered this already in some previous comments on this post. David doesn’t use rotating speakers that much in studio. Most notably it’s used on Animals (Dogs) and it’s also on a couple of songs on David’s first solo album, The Wall and Final Cut, although not that audioable. In the studio the Leslie or Yamaha is both on a separate line and lead… for different purposes and sounds. On stage the Leslies, Yamahas and Doppolas are on a split signal mixed slightly lower from the main rig. Please read more here . Hope that answered your question :) Cheers! – Bjorn]

  42. Micha says:

    Hi Björn

    What I am interested in as the “David G.” in a rising Tribute band here in Germany, and to bring it back to music. What are all the particular Songs/Soli, the RG-20 would cover? Hearing about all those Dopplers, Leslies, Univibes, ect. I only think of “Any color you like”. But what are really all the things, such effect is to be used, to meet it most authentically? If such effect is only neccessary for 1 song, I would not spend the money; but if it could cover a whole range of songs, then I would go for it. All the same I am not sure how the unit reacts only to be placed in a Loop-In of a BOSS GT-Pro.


    [During the 70’s and in ’94 David would use his rotating speakers on basically all the songs. You really don’t hear it but you’d notice if it wasn’t there. They’re on a separate line mixed slightly lower than his main rig. This is a bit tricky to achieve with the RT-20 unless you’re splitting your signal. However, it’s cool for a number of things as sort of a substitute for a Mistress or a UniVibe. The obvious songs would be Us and Them, Any Colour You Like, Brain Damage and Eclipse and sounds very nice on stuff like Comf Numb for that typical Wall live tone where David used both Yamaha rotating speakers and the Mistress. Ultimately I think a phaser and a flanger is more important if you don’t have them already. – Bjorn]

  43. ruud says:

    Hi Bjorn,

    You’ve made me very curious again. I have a question about it. I want to give my solo’s that typical Gilmour flow as on The wall livetracks. He’d created that sound with the Mistress but when I use that effect it sounds very dominant.
    Do you think that the RT 20 can be used as some kind of surrogate effect for the Mistress?? Did he use the RT 20 like effect on the Pulse Numb solo, the part with the glitterbal effect??

    [David had two Yamaha rotating speakers in his Wall live rig that were on pretty much throughout the concerts. The swirly tone you hear on stuff like This Ice and Comf Numb on the Wall live album is the Yamahas and the Electric Mistress. Mind that the original 1976 Mistress is a bit less dominating than the new Deluxe version. The RT-20 sounds quite nice with a Big Muff and you can get a similar tone but I think the Mistress suits the tone better. As I’ve written in an earlier comment David’s Yamahas were mixed lower than the Hiwatts so that you get a sense that they’re there but they’re not his main amps. I’m not sure what you mean by “glitterball effect” but what you hear on PULSE is pretty much just the Big Muff and Tube Driver with a hint of chorus. There’s also the Doppolas but you don’t really hear them that much. When he starts waving the guitar with the long sustained notes and heavy whammy, he just adds more delay. – Bjorn]

  44. matt says:

    I was thinking about getting one of these even though I have a leslie. It takes up so much room and I need to get a better amp to run it. It probably will save my back :)

  45. Adrian says:

    hi bjorn

    i’m currently working on a backing track for the site. Shine on 6-9.

    It should be done my monday or tuesday so i hope you will like it!!

    Question what do u think of the leslie clone in the POD xt live

    [I think the Roto Machine sounds quite nice but a bit too digital in my ears… Please send the track! Thanks! – Bjorn]

  46. Hugo says:

    Hi Bjorn. Interesting article. I must confess that I can’t really tell the diference between the univibe and a rotary speaker simulator, but that’s maybe because I haven’t tried many pedals or the originals, only the ones in my GT8 and some web sound samples. Maybe that’s another idea for some sort of “theme or line of articles”: getting to know different effects and diferences betwen them.. just a thought.

    In the other hand…. about Porcupine Tree, they absolutely RULES!!! what an awesome band, I went to see them las october in Mexico City.. fantastic, great, incredible band!!! like some online magazine wrote abouth them, they are “making the music interesting again”.. just wanted to share that jejej sorry.


    [Check out my UniVibe clips and compare. As you can hear, the UniVibe is darker, smokey and not as liquidy as the RT20. Porcupine Tree is my fav band next to Floyd. Although I think their present sound is awesome I do prefer them around Stupid Dream. – Bjorn]

  47. Frails says:

    You know, I can’t remember. It’s a tube model, 2-speed type I bought used back in 1992 for $125 from some guy who said it stopped working. I disconnected the tube amp and wired up an old Ross pedal to it with one switch for On/Off and the other for Slow/Fast speeds. I removed the tone circuit from the pedal. You can see the pedal (the tan one) sitting on top of the pedalboard, upper left. I wired in one of those heavy duty orange electrical cords so the cab can be placed up to 30 feet away from me for playing out.

    I have to run it through my Fender PA135 head but that’s not a problem with multiple outputs and it sounds fantastic. I replaced the original speaker with an Eminence Legend. As you can see in the picture, my Leslie has three louvers on the bottom sides and front, and none on the top. It’s 29 1/2″ tall which is a few inches shorter than the most popular Leslie’s like the 122 and 147.

    I just want to point out that Leslie cabs are not that expensive. You may have to piece one together but if you bypass the power section like I did and use your main amp to power it, it can be done for under $250. I run mine mainly on the left channel with one of the speakers from my main guitar cabinet taking up the right channel.

    As you can also see in the picture, I have a BYOC Analog Chorus and Uni-Vibe. Now of course I can dial in more sounds with these but I still prefer the sound of the Leslie on slow coupled with my main cab. It’s a very nice and smooth effect that makes the overall sound wet with some depth. Sorry about the long-winded post, Bjorn.

    [Thanks for the info! I’ll check out your mail too. Cheers! – Bjorn]

  48. Whalen says:

    Thanks for the review! Now you’ve got to update your pedal board pic, it never ends!

    – Whalen

    [It’s gonna drive me mad one day! LOL! – Bjorn]

  49. charaf says:

    Thanks for this nice review Bjorn, very informative as usual. I own Korg G4 and it souds quite good.
    I’m also using the small stone phase from EHX, and I’m wondering if still a univibe is needed?
    Now I start to think about a crazy idea about how to build the perfect beast sory the perfect effects board?


    [I think that phasers and UniVibes are more similar than a rotary sim and a UniVibe and whether you need all three or not is up to you but I have them all on my board and I use them for different purposes and I think they sound quite different from each other. Check out my UniVibe clips here and some Small Stone clips here. Cheers! – Bjorn]

  50. Frails says:

    Hey Bjorn, nicely done!! The clips sound really nice I think for a sim. I use a Leslie and it really is one of a kind sound. But I liked the sound of the clips; they work. I agree the UniVibe is totally different. I have the Dunlop version also and I can’t come close to my Leslie in matching the sound.

    If you are posting other clips, how about Any Colour You Like? That is THE Leslie tune for me.

    [Thanks Frails! What kind of Leslie do you have? – Bjorn]

  51. Adrian says:

    hey great review I might buy one!!!!

    I got your email about the us and them backing track so I hope to see it on the site soon.



    [Cheers Adrian! – Bjorn]

  52. matt says:

    Do you still use the Sixties Vibe?

    [Yeah. Like I said in a previous comment, – I think the UniVibe is very different from a Leslie or Leslie sim. I use them for quite different purposes. – Bjorn]

  53. Ernest Peske says:

    Nice review, again!
    Isn’t the MJM Sixties Vibe perhaps a better (analog) option for this kind of modulation / rotary sim.?

    [Thanks! I think they’re two completely different pedals. The RT20 is a rotating speaker simulator while the Sixties Vibe is an Uni-Vibe clone. A UniVibe sounds much darker, smokey and thick while a rotating speaker sounds brighter, swirly, liquidy. Kind of like the difference between a flanger and a phaser. – Bjorn]

  54. Daniel Krause says:

    Hi Bjorn,

    I’m really happy that you like this pedal! I’ve been telling you about it for quite some time now ;-) Did it get annoying? lol
    Really nice clips you did there too…sounds great on “Raise my rent”.



    [Not annoying but inspiring! Cheers! – Bjorn]

  55. Juan says:

    Hi Bjorn, nice Site!, nice Review!
    How much did it cost you? u$s 200?
    Do you plan to use it with another amp?


    [Thanks! I think I’ll mainly be using the RT20 with my main stage board and the Sound City. (I deleted the links… sorry but let’s keep this site Gilmour related.) – Bjorn]

  56. I didn’t like it! Too digital! But not bad at all!

    My band have an leslie (yamaha) and is very different! The digital have no noise, but also no soul!

    I tested my DLS rotosim (I’m selling it) with the real leslie: EQUAL!

    Boss are trying to get vintage with SPACE ECHO digital pedal… another pedal you must not buy! But is just my opinion!

    [Well as I was mentioning in the review, this is not a Leslie… it’s a simulator. It sound very close but it is digital and as explained there are many factors to why a Leslie sounds better, – like how you mic the cabinet. How the horn bounces off the walls etc. To my ears the RT20 is the best rotating amp simulator I’ve tried (including the legendary Korg G4). I also enjoy the RT20 because it’s a very cool effect on its own, regardless whether its close to a Leslie or not. Cheers! – Bjorn]

  57. Alex says:

    Yet another great article Bjorn, just another reason to contribute a little bit to your site. How do you feel the RT20 performs when it’s used like DG’s Doppolas or Yamaha (set lower in the mix)?

    [Thanks for your support Alex! I haven’t had the time to experiment with using the RT20 as David uses the Doppolas or Leslies. As an effect in the chain the RT20 is a bit too dominating I think to compare but you could split the signal before the RT20 into two amps and set one of the amps slightly lower than the main amp. Or you can tweak the “effect” and “direct” knobs for a similar result. – Bjorn]

  58. Leandro says:

    Great article Bjorn!! cool sounding pedal…the soundclips are great…you really nailed David’s tone….too much GAS for me !!


    [Thanks Leandro! – Bjorn]

  59. Erol says:

    Ah Yes!

    Very nice Bjorn, good review. As an RT-20 owner, i agree with most of your comments, the rotaries are good the univibe blows (hence my BBE soul vibe) but the simulations are pretty convincing. Where are you putting this in your chain – before or after distortions/Overdrives? Also if you can, pick up a EV-5 expression pedal to control in real time, its loads of fun!

    Also one quick question – Regarding your DD-20 and being noisy; how did you have it powered? The Twin pedals have very specific requirements and should be powered on there own by a boss PSA and not daisy chained (as i found out the hard way). My DD-20 had really bad noise issues till I isolated the power to it, then viola no noise at all.

    till the next time,

    [Thanks Erol! The RT20 is placed last in the chain in front of the delays. I’ll try it with an expression pedal. I had the DD20 powered with one Boss 9V adapter… as does the RT20. Cheers! – Bjorn]

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