Glue the Giant's Rack Modules Release Announcement

Glue the Giant has released its modular bus mixers for VCV Rack. Including the Mini Bus Mixer, School Bus Mixer, Bus Route, and Bus Depot, these modules make it easy to mix your patches to stereo output. More importantly, you can improve your sound with the ability to quickly create simple or complex effect sends and returns.

The Glue the Giant modular bus mixers include support for polyphonic cables, constant power panning, accurate peak metering, and plenty of CV inputs. More information can be found at

Available now in the VCV Plugin Library.



They look interesting and I am always on the lookout for mixers with sends that take up minimal real estate, but I can’t figure out how to use some of these modules. I’m dumber than most.

Hi Jon,

Well, the documentation is sparse right now and people are just starting to use them, but let me see if I can help. Someone (maybe me) will probably make a video soon.

A 10,000 Foot View
The modules use red, orange, and blue stereo bus routes for your audio. The red bus is usually considered your master audio bus (although you can use the buses however you want). All your sounds travel on this master red bus and you adjust the levels with the red knobs in the mixers.

The orange and blue buses are usually meant for effect sends. For example, the orange bus could be connected to a single reverb effect. You can then adjust the amount of reverb on each sound with the orange knobs on the mixers.

A 10 Foot View

  1. Route a kick sound to the input on a Mini Bus Mixer.
  2. Route a snare sound to the input on a Mini Bus Mixer.
  3. Add a Bus Route module and a Bus Depot module.
  4. Connect everything up. (This step is easier than it sounds. It’s a modular environment and everything has to be connected.) Connect one Mini Bus BUS OUT to the other Mini Bus BUS IN. Connect the next Mini Bus BUS OUT to the Bus Route BUS IN. Connect the Bus Route BUS OUT to the Bus Depot BUS IN. Connect the LEFT RIGHT outputs of the Bus Depot to your left and right audio outputs.
  5. Connect up your master bus (with no effects) by connecting both red outputs to both red inputs on the Bus Route module (you could add EQ, a limiter, or other master effects on this bus later).
  6. Connect the orange outputs of the Bus Route module to a reverb effect. Connect the reverb effect outputs back to the orange inputs on the Bus Route module. Adjust your reverb effect to a fully wet signal. (If it’s not a stereo reverb effect, you can create two outputs with the CTRL key and connect them back up to left and right orange inputs of the Bus Route module.)
  7. Mix down your patch. Now when you adjust your red knobs for each instrument, you adjust their master levels. When you adjust the orange knob for each instrument, you adjust the amount of reverb. The kick should probably have very little to no reverb, but you might want a lot of reverb on the snare.

With these modules you can do quite a lot more. For example, you can route everything in your blue bus to an effect and then route it back into the orange bus to go through the reverb. You can mix down drum sounds along three buses, with a drum room reverb, mix down your bass and other instruments along buses with another reverb, and route your drums to an empty bus or to the AUX inputs on a Bus Depot module. And obviously, to really take advantage of the stereo space, you would use the pan controls on the School Bus Mixer instead of using the simple Mini Bus Mixer. And an upcoming module will give everyone some powerfully fun stereo control over polyphonic instruments.

Anyway, I was just wanting a modular way of adjusting effect sends. Whatever I came up with using existing modules was overly complicated or didn’t make sense when I looked at it the next day. After a few different designs, I came up with these modules that use the red, orange, and blue bus concept. It makes everything simple for me.

If you’re really new, know that effect sends make your patches more efficient. With sends, for example, you can reuse a single reverb effect for all your instruments, even though some instruments need much more or much less reverb. Using common delays and reverbs on multiple instruments also helps give glue to your mix (instead of having different effect chains, with different sounds, for each instrument). I can’t live without effect sends.

I hope this helps. I think if you see these modules in use one day in a video, you will also see that it’s really quite easier than it sounds in writing. But the above text should be useful to move you in the right direction. Let me know if it helps.




Thanks for the info!

but I’m dumber than you :stuck_out_tongue_winking_eye:

I really would like a video explaining all the features of these modules
I tried them yesterday and couldn’t make any sense of it

@gluethegiant thank you for the more in depth explanation :+1:

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Thanks for posting! I added my attempt to respond to the GitHub wiki as “A Letter to a Troubled Forum Member.” :slight_smile:

Until we get a video, the text might help someone else enjoy the modules. Anyway, I don’t think I’ll have time to make a video until after I finish coding the next module. Then the bus mixer suite will feel more complete (for now).

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Interesting concept and I think the design looks really nice! I’m looking forward to trying these out

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It’s very neat! I was hoping for a less monolithic solution than the available mixers, it’s probably gonna be my go-to mixing system now.
It’s much easier to understand how it works as a complete system than trying to figure out what the individual devices do in isolation.

By daisy chaining left to right the Bus Out to the Bus In of devices, you create a single mixer comprised or three pairs of color-coded stereo channels. The red channel is the main one, the yellow and blue are for sends. School Bus is your main mixer channel, add as many as you need. Mini is a smaller School Bus when you just need a mono input panned center. The Bus Route is the breakout box for the sends, and if there are no effects on a bus, you have to manually wire the send to its respective return. The Bus Depot mixes it down to a pair of monophonic channels, ready to patch to an audio output. Enter and Exit devices allow you to tap into the buses at any point of the chain.


It looks interesting but when CF tried a similar thing it really didn’t work for me (and other people I know complained about latency issues). Omri makes a lot of use of the CF modules though.
It’s good that they work for you but if I wanted something modular like that I’d use the Squinky labs system.

The Squinky Labs mixers are light and, with easier stereo modules, full featured. But they are more expandable than modular. For example, you mentioned latency. if you need major or minor latency compensation for an effect send, where would you add that to the Squinky Labs master bus on an expandable mixer? Speaking of latency, if you wanted to add latency to a bus for a musical effect somewhere along the chain, could that be accomplished with a monolithic mixer or with an expandable mixer?

We usually ignore the single sample latency between rack modules, even with complex effect sends that use more than one module. However, if you don’t want to ignore that latency, or if you can’t ignore that latency because it becomes audible with particular sound, a truly modular mixing system gives you logical places to insert latency compensation.

By the way, using the best modules for the job isn’t a bad idea. If you have a single mono instrument made of multiple oscillators, you should probably use another light mixer (VCV’s VC Mixer, Lindenberg’s VCMA, etc.) before sending that instrument to any mixing strip, including a modular bus mixer. If you have a few sounds with no sends, on one effect route, then CF’s mixers work. And if you have dozens of sounds with simple routing needs, a monolithic or expandable mixer is probably the right tool.

But if you want a quick, truly modular setup with a handful of sounds and a send effect or two, the modular bus mixers from Glue the Giant might be your choice.

If you want to have a truly modular mixing setup with complex multiple effect sends on different buses, a good pan law, nice options for CV inputs, the ability to put your mixing wherever you want on your rack (and even the ability to add latency to compensate for a heavy send effect or to add delay somewhere on a bus for a musical effect), these modular bus mixers can do all that, and perhaps do it more logically than other current methods. And they will do more and some of the above even better as they get improvements in the near future.

Some people will probably find the modular bus mixers fun and useful. :slight_smile:


@gluethegiant Just wired these up as an 8 channel drum mixer in a patch. Dig them. Here’s a mini review:

  1. Love the look - 70s awesomeness in a good way

  2. Great taper on the knobs - having a good taper on a knob or fader is the difference between a great mixer and a functional one. You got this right.

  3. I know there’s no space, but pans on Mini Bus would’ve been nice. For instance, panning hi-hat, clap, toms in a larger drum-mixer configuration School Bus for any channels you plan on panning even if they’re otherwise mono. Not a big deal, but sometimes I’m going to wish there was a pan instead of two Auxes.

  4. U-he does this think where you can label effect instances where they make it look like someone added a masking tape label to the GUI. Something like that would be cool too just so I know what channel is what. Would also fit in with design aesthetic. But again…space!!!

  5. Thanks for the ability to quickly configure Pre/Post Fader on Auxes on School Bus!

  6. Thanks for summing polyphonic inputs. Saves a module otherwise.

Great stuff. Thanks a lot. These will definitely get some use.

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Okay, i am streaming with these right now. Seems to work okay (if you plug things into the correct port, i have been awake for 30 hours at this point).

Right, so I’m pretty much finished with the stream now (you can still watch the VOD for a couple of weeks) and I’ve come to the conclusion that the Glue modules work pretty well. I need to get into some of the details a little be more and I’m not sure what purpose the exit and enter modules serve (bus route seems to do what they do) but other than that my fears seem to have been unreasonable.
Also thanks to SpatialFree for the kind words.

I finally got around to trying these out, and yes, I like them. I was confused about the lack of pan on the MINIs, but taking into account that this mimics the (often) mono Eurorack world, I understand why its not there. Personally, I’ll keep two sends over losing one to a pan knob. I always add both reverb and delay, so I need two send busses.

I guess the SCHOOL BUS is then a super deluxe MINI, yes?

Overall, yes, I like 'em! :+1:

Two more questions:

  1. When you chose the signal levels at which to fire the different level LEDs, are they commonly referenced signal levels? It more or less seems like the Red one is clipping (obviously, I guess). Are the next three more or less -3dB, -6db and -12dB?

  2. I’m not extremely knowledgeable about mixing. What is a use case for the AUX input on the BUS DEPOT?

Thanks for the detailed feedback.

As for 3., there will probably be a modular bus mixer that is somewhere between Mini Bus Mixer and School Bus Mixer, probably with all the features of School Bus, but without CVs to save space. I just haven’t liked my designs yet and was worried that four bus mixers would be too many (there will for sure be a new bigger bus mixer with new features).

And with 4, the tape idea has crossed my mind too. Great minds must think alike. And it’s something that can be done on a real rack.

Thanks again for the input!

Thanks for the stream. That was cool! I hope you’re finally asleep right now!

Hi Jon,

  1. Funny you would ask. There are a couple of upcoming UI enhancements, and one of them adds a little db info to the vu meters on Bus Depot. The top red light is an indicator that your mix went above 0db. I’ll try to add something about the vu meter in the documentation, too. I think each light represents 6db.

  2. The AUX on the Bus Depot is a way to easily chain multiple Bus Depots, or even use another mixer or external mix. For example, you could mix drums separately and then chain them in through AUX.

Thanks for the great questions!

Maybe one tiny feature request: Add POST FADER contextual menu options to the MINI. (I don’t know how “tiny” that really is, coding-wise …)

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That would be really handy, I’m not sure that prefader is a sensible default.