I've got a few Marshall effects pedals (e.g. the Vibratrem VT-1) and I love them, except for the terrible design of the knobs. They've got a shiny chrome, dome-shaped top with a small black mark which wears off after time, meaning it becomes impossible to read them especially in any dark room. I've searched in vain for replacement knobs with a different design. My understanding is that the shaft is a different size/shape to Boss pedals so Boss knobs wouldn't be compatible.

Is there a third-party knob out there which will fit my Marshall pedals and be easier to read?

  • I've had a couple of these pedals! Have you considered just sellotaping a marked bit of paper over the knob? Are the knobs easily removable so that you can measure the shaft diameter? (I don't recall if Marshall pedal knobs have a little screw you can loosen, or of they're just held on by friction; if the latter, a good trick is to wrap a thin cord or bit of polythene bag around under the knob so that the increasing thickness gradually pushes the knob off). – topo Reinstate Monica Nov 19 '17 at 9:39
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    I'd take off a knob, saw a shallow slot , use a black marker pen to highlight it. I have a Marshall pedal, and the pots seem to have a standard 1/4" striated shaft, rather than the D shape. Tried a couple of knobs from other amps and they seem to fit. Googling 'knobs' , as I've done before trying to match mixer knobs, reveals loads. – Tim Nov 19 '17 at 10:15
  • I prefer the Paul Gilbert method of using bright tape oriented such that when the knob is in the desired position, the tape is straight vertical. – Sarkreth Nov 21 '17 at 0:19

AFAIK there are only two standards for potentiometer shafts. This means the diameter can be metric or imperial. (6 mm metric if i recall) most pot shafts are both slotted and ribbed(?) to fit many different knobs. Some knobs have a screw that you can tighten to forcefully hold them on to the shaft. Electronics suppliers will carry a selection of knobs, as will some musical instrument dealers.

Of course the simple answer is to take a sharpie to it or glue on some dots that stand out against the chrome.

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  • Good answer. A couple sites you can check out for knobs are Stewmac and Digikey. They both have a pretty good selection. – Tama Feb 21 '18 at 18:23

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