DIY Stompboxes => Digital & DSP => Topic started by: Doug_H on December 31, 2005, 03:15:29 PM

Title: Line 6 Roto Machine
Post by: Doug_H on December 31, 2005, 03:15:29 PM
I purchased a Roto Machine earlier this week and I really love it. :) So much so that I completely "retooled" my rig and am running my SS amp as a "satellite" for full stereo. I can't wait until I show up to rehearsal with 2 amps. The other bandmembers will think I've gone nuts... ;)

According to the HC review, some of the guitarists don't like the heavy EQ, while it seems like keyboardists love it. I can vouch for that, as it sounds just about "perfect" with my Korg CX-3, while with the guitar it seems to affect the EQ more dramatically. But that's what speaker cabinets do, and leads me to believe that this is a true spkr cab simulation, rather than just a fancy chorus with some special features to "leslie-fy" it. ;) It will be interesting to see how it works with the band, but I'm not anticipating any problems, I think it will sound great. As Mark Hammer mentioned, ya gotta go stereo with this guy. It sounds great mono, but once you go stereo you won't want to go back.

As for my rig, I dumped the boosters and am running both amps completely clean, David Gilmour style (heh-heh). I'm just using pedals for the distortion sounds (pentode driver and hwy89). In addition to my delay, I'm using a compressor every once in a while and my EB volume pedal for swells. Sounds pretty cool to me. ;) Next, I'm targetting an Echo Park... Then I can toss the delay *and* the volume pedal... Haha! This is too much fun. ;D

Hope everyone had a good Christmas.

Title: Re: Line 6 Roto Machine
Post by: MartyMart on December 31, 2005, 03:19:19 PM
Very cool Doug, that ones on my "new year's gift" list  :icon_wink:
How is the leslie "ramp up/down" sound ... ?

Title: Re: Line 6 Roto Machine
Post by: Mark Hammer on December 31, 2005, 08:11:41 PM
The ramp thing...

There are three ramp up/down speed presets, all of which have a nice feel to both directions.  While I have a small Leslie at home, I imagine the deceleration and acceleration for cabs with different mass to move is also a little different; you know, all that "things in motion..." stuff.  Whether Angelo and the gang decided to model the "physics" of the 3 different Leslies and alter the ramping depending on model selected, I honestly couldn't say.  Still, I doubt that many folks would be disappointed if it wasn't or disappointed with the absence of a continuously variable ramp-time control.

Note that while the other modulation effects in that pedal series (Tone Core) use a soft-touch foot press to do tap tempo (a firm press and tactile click are needed for bypass, using the same treadle), the RM uses standard pots for the speed settings, and allows the soft-touch function to do the go-faster/go-slower thing.  Each soft press reverses speed direction.  Get yourself a talkbox and you could start your very own Peter Frampton Live tribute band!

The stereo thing...

It's like the difference between fresh salsa and stuff from a jar.  No comparison.  Once you have fresh you'll never go back to jar, unless it's an emergency.  Same thing with hearing the full swirl of a Leslie (which the stereo use of a RM captures nicely).  Ironically, one of the real advantages of the pedal is that it is a damn sight lighter (and cheaper) than lugging around a real Leslie.  On the other hand, if you find yourself always wanting/needing a stereo setup to use it.....  Kind of three steps forward, two steps back, isn't it?  :icon_lol:

The EQ thing...

Pretty hard for speakers which don't face out from a vertical baffle board to deliver the same tone as speakers which face outward like a "normal" amp.  If you can get a real Leslie to sound as bright and crisp as a Twin or other similarly clean amp, you have my deepest respect.  Leslies will decisively round all edges on your tone because of that, which Line 6 appears to have modelled.  Keep in mind that Leslies are a kind of "live post-production" effect in that they are mapped onto the final product at the very end of the signal chain (well, up to the point where you stick a mic up to the speaker) in a way that pedals are not.  The speakers break up differently, the amp has its own grind, as does the output transformer, and all of that seems to have been reasonably well approximated in the case of this pedal.  Not having heard all that many analog or other emulators, I can't say whether this one captures the vibe better than others do.  I only know that you find yourself willing to put your chorus pedal aside for a lot of things you would normally want to use it for because the swirl is so seductive.

The only real downside to the pedal is that output level varies with the Drive setting.  Like a distortion pedal, the more grind you set it for, the louder it gets.  Its a luscious grind, to be sure, but there is no way to adjust volume level and get the effect/bypass volume you want.  On the other hand, once you turn it on you find it hard to turn off, so maybe a level balance is moot.
Title: Re: Line 6 Roto Machine
Post by: Peter Snowberg on January 01, 2006, 02:53:38 AM
I get a really good chuckle out of seeing an analog designer whom I respect so much, talking about loving the output of DSP.

I think it just goes to show that digital has lo-fi and hi-fi too. :)

Line 6 seems to be the first outfit to toss the right ingredients into the DSP pedal realm. DSP is quite capable of being superior to analog in just about every way if you have enough horsepower to work with. There are aspects of distortion which I think analog will ALWAYS dominate, but when it comes to filters, DSP is the E-ticket!

We'll be seeing lots of neat stuff from that product line I'm quite sure.  :icon_biggrin:
Title: Re: Line 6 Roto Machine
Post by: chrishopkins on January 01, 2006, 05:56:38 AM
I got a Roto Machine just before Christmas - fantastic pedal...Haven't had a chance to try it in stereo yet though.

I haven't noticed any problems with the EQ but I haven't tried it with my full rig (I'm tempted to do a Harmony-Central Review style listing but I'm not that sad).

If I find the EQ is a problem I'll knock up a DPDT Looper and run it in conjunction with my Boss BassEq which is sitting on my shelf starting at me.

And I might finally have a pedal that works  :icon_biggrin:
Title: Re: Line 6 Roto Machine
Post by: MartyMart on January 01, 2006, 06:01:55 AM
Probably not in the same league, but the Dano "RockyRoad" will give
you a nice "Leslie Chorale" tone for about 30 bucks.
There's a mod at "Stinkfoot" for correcting the "drive" boost
problem too ....

Title: Re: Line 6 Roto Machine
Post by: aron on January 01, 2006, 06:39:44 AM
The Roto-Machine is very, very cool. The ramp up/down is great and the tone - well, I love it.

I have the small univibe Dano but the roto is a totally different beast.
Title: Re: Line 6 Roto Machine
Post by: chrishopkins on January 01, 2006, 12:05:04 PM
I've got the Rocky Rhoad as well.  It sounds like a cheap chorus to me but that might be a problem with my pedal itself.

I think I'll go home from work today (yup stuck in work!) and plug my Strat into the Roto & a DD6 in stereo....then wig out

Title: Re: Line 6 Roto Machine
Post by: Doug_H on January 01, 2006, 05:40:22 PM
Hi Marty, yes the ramp up/down works *great*. With the 3 speed adjustments as well as the adjustment for the fast/slow speed it is very flexible. It's not hard to dial it up for whatever mood you are in. The volume change with the drive control is the only minor nit I have with it. Then again, that's what a "real" leslie does- turn up the volume and you get distortion, so it is "accurate" from that standpoint. However, organists compensate with the expression pedal when they are using a real leslie too. In fact I found my volume pedal useful in that way and you could use the guitar volume control for that too. Turn up the roto for the maximum grind you want and then dial it down with your guitar for clean. It seems to have a lot of headroom and responds well to that kind of operation. It responds well to outboard overdrives too, so that may be the ticket for consistent volume. I haven't really figured out yet what I'm going to do with the drive control. FWIW, it's fun to run a heavily overdriven signal into it and get the tone Trower *really* intended to get with his univibe on Bridge of Sighs (haha!! ;D).

Incidentally, as much as I love the stereo sound, there are some sounds where mono is more applicable. After getting this thing I couldn't resist getting out my old vinyl copy of Joe Walsh's "Barnstorm". That grindy rhythm guitar in "Mother Says" definitely sounds better in mono. In stereo it is too spacious & lush. It's good to know there are so many different sounds at your disposal with this thing.

I also believe that for good time-based effects at a reasonable price, DSP is the future.

Title: Re: Line 6 Roto Machine
Post by: barret77 on January 03, 2006, 03:55:36 PM

I'm about to get the poor cousin of the Roto Machine - the Dano Rocky Road, and wondered "which songs can I cover with this?..."

by the way, the rest of that site is great.
Title: Re: Line 6 Roto Machine
Post by: Mark Hammer on January 03, 2006, 04:03:59 PM
That IS a great little site.  Here I had always described what I had as a Leslie, when in fact it is the same as a Vibratone, complete with the ever-popular styrofoam "cheese wheel" (as I like to call it).  The separate woofer and horn rotors of a true Leslie likely do make a big difference in terms of "throb", though less so in terms of the doppler thing.

BTW, that's a cute list of songs.  Wouldn't you love to have a list like that for other pedals?
Title: Re: Line 6 Roto Machine
Post by: Peter Snowberg on January 03, 2006, 05:02:38 PM
I've got a 122 and it's nothing short of amazing. Lately I've found that I like the bass rotor spinning at maybe 1/2 speed while the horn spins a bit slower- at roughly 1/4 to 1/3 speed. Full speed is just way to fast. A static horn and slow bass rotor is also very good.

I've seen Hammond players quickly flick the rotate control on and off while playing the bass parts to modulate the speed for their Leslie(s). That isn't as practical with a guitar. ;)

I think part of the ability to deliver "throb" is that the larger ones at least have 15 inch woofers. With the rotor pointed in any random direction you still get bass just fine but when the baffle is pointing at YOU, you can start to really feel it. :D
Title: Re: Line 6 Roto Machine
Post by: SeanCostello on January 03, 2006, 06:07:32 PM
I also believe that for good time-based effects at a reasonable price, DSP is the future.

My guess is that it depends on the application. For simple time-based effects such as standard choruses (one delay line or a dual delay line), and short-to-medium delays, the cost of a BBD/clock combo or a Princeton delay chip will be less than using a DSP, SRAM, crystal, codec, and ROM. Also, spring reverb emulation is still complex enough that using a spring will be cheaper. I know that the Cirrus Logic reverb chip in the Holy-ish Grails has a spring mode, but to me it doesn't do a very good job at spring emulation.

For more complicated multitap applications, like chorus, Leslie, and reverb, digital definitely rocks. Plus, if you want a multimode pedal, it is easy to do this with a DSP.

I know that people here have experimented with various DSP configurations, but does anyone have a good handle on the minimum cost needed to implement a DSP-based pedal at reasonable volumes? Do people know what chips are used in other pedals? What platforms incorporate other peripherals in addition to the DSP - i.e. on-chip RAM, codec, flash memory? What DSPs are good for low power apps?

We know that the Line 6 Tone Core platform uses the Motorola 56364 DSP. It is pretty cheap for the amount of CPU power ($4.95 in quantity for a 100 MHz DSP), and has good bit resolution for pedals. On the other hand, it has fairly high power consumption, with a battery life measured in minutes in the Verbzilla I have. It also needs a separate codec, ROM, and an SRAM chip for delay applications.

I work on SHARCs at my job, which are nice chips, but are higher cost and higher power consumption - for commercial pedals, $20 can be too expensive. I also work with Blackfin DSPs, which are cheaper, hella fast, and can apparently work in lower power modes. The Blackfin is only 16 bit, but it is fast enough to program in 32 bit double precision. Still, both of these DSPs require SRAM, ROM and/or FLASH memory, a crystal, and a codec to be a complete design. The upcoming SigmaDSP ADAU1702 from seems like a good candidate for pedals, as it has a lower pin count, on board A/D and D/A (plus lower quality A/D convertors for knobs), boots from ROM. It remains to be seen if it has an SRAM interface, which would be needed for most delay-based applications, although I know that SigmaDSP has a nice low-memory reverb and chorus for some of their other chips that work with onchip memory.

The Wavefront chips seem like good options, especially the AL3201BG with built in delay RAM. However, the chips require a separate A/D and D/A.

The Crystal Semiconductor CS4811 and CS4812 are single-chip solutions, which is nice. However, they are not user programmable (you can change parameters on the CS4812, but not algorithms), and I think that they might be discontinued according to the Cirrus site.

What other chips are used in pedals? Do Boss and Yamaha make their own DSPs? Are there companies that license DSP cores?

Sean Costello
Title: Re: Line 6 Roto Machine
Post by: barret77 on January 06, 2006, 11:39:04 PM
I just scored a Dano Rocky Road, for $ 20. It's great! No roto machine, but for 20 bucks the leslie ramp is sweet. The non-ramp settings sound similar to the univibed phase 45. Ok, time to play "Across the Universe"...