Knobs and O-Rings

Our Mackie DL1608 Mixer has a frustrating flaw. And I have an inexpensive low-tech solution that works.

See that row of 16 gain knobs along the DL1608 back panel?  They are super-low torque and easy to turn, which means that every time we transport the mixer between gigs and rehearsals, something gets bumped. 

This defeats the entire purpose of a digital mixer’s ability to reliably reproduce a mixer setup from one gig and rehearsal to the next. I had to resort to taking pictures of the mixer knobs before moving the mixer!

This problem isn’t confined to the mixer of course. Any guitar player with a bunch pedals strapped to a pedal board knows how frustrating it can be when all the pedal knobs get bumped in transport.

So here’s what I did to solve the problem:

I bought a pack of these soft rubber o-ring grommets on ebay for around $6 . They are actually listed as “mechanical gaming keyboard o-ring switch dampers”. Their dimensions are 3/16” inner diameter and 5/16” outer diameter. The 3/16” diameter is just right to fit snugly over a 1/4” knob shaft.

For the DL1608, I gently pulled off the friction-fit knobs from the DL1608 and inserted a one of these o-rings over each knob shaft. You can use two if you want an even tighter fit. After pushing the knobs back on, they are now much higher torque, and not easy to turn.

 
I did the same thing with some of my pedal knobs.  Here you can see my boost pedal with the knob lifted up, exposing the o-ring on the shaft. When the knob is pressed down, it’s nice and tight.

So that’s my low-tech solution for retaining knob settings during transport!