A-B Switch for Guitar Amps

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#1

Hi All,

Just picking brains here …

I was disappointed to find that among all the pedal plugins that AmpliTube 5 provides, there doesn’t seem to be a classic A/B switch. I use them a lot: create a great rhythm setup (amp+cab(s)+mics+room), and a great lead setup, and switch between them on the fly. Some amps have channel switching built in, but not too many of them. Plus, there’s something magic about playing rhythm through a Super Reverb or AC30, then jumping to a Soldano or a Marshall for the solo! :star_struck:

So far, I’ve found three ways to simulate the switch, none of which is ‘1-click easy.’

  • Create pair of bindings in Cantabile to enable/suspend the two VSTs, controlled by a MIDI CC, with one amp responding inverted. This works great, but there is a brief (500mSec?) silence when switching a VST on.

  • Adjust the gain of the two amps with similar bindings. This, of course, requires freezing the output levels of the two VSTs at some predetermined level, making later edits difficult.

  • Add a volume pedal in front of each amp in AmpliTube, and use AT’s control matrix to turn one all the way up, and the other all the way down. Works fine, but kind of clunky to set up.

Am I missing something easy? Does anyone know of a simple VST that just turns one audio input into two outputs, and can switch between them quickly?

Regards,
-BW

#2

I generally use bindings to enable / disable routes in Cantabile between VSTs or Linked Racks.

It does require that the route be named (with the route selected Edit => Rename or [F2] shortcut) so that you can select the route as a target of a binding. Then it is simply Enabled On or Off.

In cases where multiple parallel items need to be controlled together, I sometimes use a small embedded racks as a junction point, which lets me control signal flow to all of the items.

Hope this helps!

#3

+1 what Clint said, enabling/disabling routes is way faster. It does mean you keep the VSTs running though.

#4

@ClintGoss @mmichaelc Thanks, I’ll try that trick with routes. I don’t know if it’s any easier with AmpliTube (than the pair of volume pedals), but it’s a trick I can use in songs where I use two different VST synths at different points.

And yeah, embedded racks are great for lots of things that don’t scream ‘rack’ in the real world. I use a very realistic (and free) Farfisa organ VST called Combo F that has worlds of tone, quite a few tweaks, and decent reverb and amp/cab sims, but no way to store patches. But turned into its own little rack, it works as well as any other VST in my arsenal!

I might just make a rack that is nothing but an audio input to two outputs, with the routing controlled by bindings. Let’s see, I think I’ll call it … um … “A-B Switch” … :laughing:

Regards,
-BW

#5

I do use 4 instances of my go-to reverb, SIR3, in my main “Rig” rack that serves most songs. They serve four independent signal channels.

SIR3 is a convolution reverb that is fast as far as convolutions reverbs, but still takes noticeable CPU. In that one case, I do take care to disable the appropriate instances of SIR3 depending on which signal channels are active (in addition to en/disabling the appropriate Cantabile routes).

#6

Couldn’t you use one instance of Amplitube and have different patches for each “sound”? Then send a program change to Amplitube—that’s what I do in my rig.

Note: DON’T use the VST3 version of Amplitube, as it doesn’t handle PCs. I have a bug in with IK Multimedia about that very issue.

#7

@mavriq I could do that, in most circumstances. In fact, I already use the PG approach. But in my most complicated settings, I need virtually instantaneous change between two complete ‘guitar’ + amp + effects setups. (I use guitar in quotes because I’m actually using RealLPC and RealStrat, two guitar synths/samplers to do the playing.) I like to keep the LP and Strat paths self-contained, so it would mean sending PGs to each Real{Guitar} and AmpliTube at the same time. Most of the time this works OK, but once in a while I get a momentary glitch during the change, which throws off my playing. Bear in mind that I’m a) playing live; and b) trying to do things like simulate two guitars trading fours, so seamless changes are absolutely necessary. I’ve become pretty proficient with the Mod Wheel, so tying it to a crossfade (or cross-switch) for the two guitars just feels natural to me. They are both running in the background, so I never have to worry about loading delays.

This whole quest started because I went looking for an A-B box in the AmpliTube arsenal, and was surprised not to find one, given that I have 5-6 wah pedals, more overdrive boxes than I could throw across the room, and 20-30 speakers whose tone I don’t really care for. But no A-B switch – even though one shows up on many guitar pedalboards.

It turns out that the Binding enable/disable method will help in most cases, and a pair of volume pedals works in a few others. I was simply curious if I was overlooking something really obvious.

Interesting about the program issue with AmpliTube VST3. I haven’t seen it, because I use Switch Presets for most of my VSTs. I got out of the habit of using the built-in program capabilities of VSTs because every manufacturer rolls their own solution for saving/accessing programs, and I don’t want to learn one method for IK, another for GEforce, Cherry Audio, etc. It’s an area where I wish the Steinberg spec was less flexible, rather than more so. YMMV.

Regards,
-BW

#8

Ah makes sense. It sounded like you knew what you were doing, but just wanted to be sure. As for program change, I just found another bug with Arturia plug ins… It also is not functioning correctly and have to report a bug to them…

#9

not sure if Amplitude has a “scenes” or “snapshot” feature? TH-U has it - it allows you to turn certain effects on/off for four different “scenes”; when you select such a scene, TH-U will automatically do all the switching for you. I use that all the time for seamless switching: simply put multiple amps in your configuration and just turn on the one you need for a config.

If AmpliTube doesn’t have this, I’d simply use as many instances of Amplitube as I need different sounds in a song and simply change the routing from the guitar signal based on song states. Actually no need to name routes or have multiple routes - you can simply activate the “target” state behavior for that specific route from guitar signal to the amp and then create different song states which send the guitar signal to the correct amp.

I would make sure to change the input routing going from the guitar to your Amplitube racks (or plugins), so that any reverb or delay tails still playing in one instance keep ringing out while you are already feeding the other Amplitube instance.

This is pretty much what the “target” state behavior does - as long as you use song states to control your config (which I very much recommend). OTOH if you have dozens of changes between your guitar sounds (trading fours), using song states might be a bit of overkill - in that case, a simple embedded rack that uses its internal rack states (“A” and “B”) to route audio to one of its outputs and uses a simple Rack MIDI input binding to switch between its states would also work nicely. Just need to make sure it is initialized to the correct state when starting the song…

Cheers,

Torsten

#10

@mavriq Unfortunately, that seems to be the current state of VSTs in general: they make amazing noises, and manage to break the simple tasks in the process! I created my A-B Switch and tested it – and found a bug in MusicLab’s RealStrat Elite where it seems to obey MIDI even when the receive channel is disabled! It only happens with that VST: RealLPC and RealRick both work as expected. But if I select RealStrat as Device A, it plays solo. If I select RealLPC as Device B, both VSTs play – even though the MIDI monitor and indicators in Cantabile show the path to be disabled! I haven’t heard back from MusicLab yet.

Regards,
-BW

#11

@Torsten Thanks for the tips. It turns out that I don’t really need a classic A-B switch as much as I need an A-B MIDI switch. That eliminates the audio tail issues. Now, if MusicLab has a fix for the MIDI bug I just found (see other post) …

Regards,
-BW

#12

Nevertheless: here is a simple audio A/B switch rack:

grafik
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two audio output ports; two routes inside the rack with “Enabled” state-dependent. Here’s state B

grafik
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Use one changing binding to toggle between states: a NoEdge Button binding on CC64 (sustain) will switch from State 1 to state 2:

grafik
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Since state behavior “Target” is active for the binding, it will change its destination when in state 2 so that pressing sustain will then go back to state 1.

grafik
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Simple as that!

You can use exactly the same mechanism to create a MIDI A/B rack (embedded or linked) - just use MIDI routes instead of audio routes. You may need TWO MIDI input ports for this - one to control switching, one for the data to be routed (if you plan to route CC 64 to your A/B ports).

Cheers,

Torsten

1 Like
#13

That’s what I love about Cantabile, so many creative ways to achieve a certain goal. Torsten’s method certainly works. Usually I just use song states and enable/disable routes and I get a very short “glitch”, maybe 100 ms or so. I’m a guitar player and I’ve done something similar when needing a seamless change, sometimes between 2 different amp vst’s…both vst’s running, both getting independent guitar signal, then a binding to change rack volumes. You can do smooth crossfades between them too by adding a few more bindings…first reduces volume by 3 db, next by another 3 db, etc. Use delays to adjust timing and it can be an extremely fast switch.
But here’s the real trick…Even back in the days of my huge pedalboard and tube amp, I had to learn to mute the strings for an instant while making a change. I still do that now instinctively with song states and most guitar players I know do the same. Tough on a keyboard I know, but with some practice maybe it will help a bit?

I also toggle between rhythm and lead with 1 button, binding with song state by index. Not at my PC so can’t show it but if you want it let me know!
Tom

#14

Thanks to all for their ideas. I’ve created a couple of A-B routings that I’ll use for synths. I’m sticking with the two-volume-pedals method with AmpliTube for now, because I’ve got a big gig coming up next Saturday, and this is probably not the time to be experimenting! In most cases, I use the Mod Wheel to cross-fade between the two guitar sounds – I prefer aftertouch for vibrato – which has no glitches, and I can always bind a switch to CC1 to make a switch. But who knows what approach I’ll eventually stay with?

Regards,
-BW

#15

Hi
May be this will help.
A/B Audio Switch - pongasoft


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2 Likes
#16

Thanks! It’s kind of backwards to what I need (1 In and 2 Outs), but I think I might have a use for it, anyway.

Regards,
-BW