Small Knob Panel Group

I populated a section of one of my cabinets with all of the modules I’ve built using the small knob format.  From left to right:

  • Mattson EG/VCA (2 modules)
  • Mattson EG/VCA (2 modules)
  • Dual Plague Bearer (2 modules)
  • CGS Twin Wasp (2 modules)
  • Mattson Distributor (4 modules)
  • Mattson VC Mixer (1 module)
  • CGS Super Psycho LFO (1 module)
  • Dual CGS Slope Detector (2 modules)

That’s 16 separate modules in 8U of space!

The 1U panel dimensions are 8.75″ high by 1.725″ wide.  I leave it a little shy of 1 3/4″ wide to assure fit with other modules. I use this size for all 1U panels, not just this format.

The MOTM jack grid of 8 x 2 locations is ubiquitous. Vertical spacing is 1.0″ and horizontal is 0.85″.  I locate the lowest row 0.90″ above the bottom of the panel, which leaves clearance for parts both top and bottom.  Any standard panel component fits: a jack, a pot, an LED, a toggle switch, and even a miniature rotary switch.  Just make the hole the correct size for the part you’re fitting.

The main difference from the standard MOTM format is the small knob.  Although I happen to have used 16mm round Alpha pots for all of these, there is room to fit 12mm square Spectrol pots.

I generally put jacks to the right or below other components.  One reason for this is the use of Bridechamber 3-jack brackets to mount PC boards behind.  I like to use jacks to mount this bracket, but in the case of the Psycho LFO the bracket is mounted behind three pots.  Most of these modules are dual, with one module physically located above the other.  I try to co-locate a knob with its corresponding jack.  A CV attenuator will have its input jack just to the right.

A vertical column of eight small knobs has the downside that you have to look closely when grabbing one, to make sure it’s the intended one.  Naturally, a small knob doesn’t offer the same amount of control as a larger does.  (These are 3/4″ in diameter vs. the 1″ MOTM standard. )  I was willing to give this a try, as a trade-off for the module density, especially for use in the 20U portable cabinets.  I’ve proven the concept now, at least to myself.  Currently my DIY module queue is empty, but no doubt I’ll be considering the use of this format again for future modules.


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