Removing Volume Controls
Greg,
I have two crystal mics with volume controls installed by a well known harp mic builder. They work well but I've decided I prefer either playing without a volume control, or using the inline volume control I got from you. So I've rewired them to bypass the volume control. How can I remove the volume controls and seal up the hole?
Of course they don't hurt anything but they add just a bit of weight, and aesthetically I like to keep my gear as minimal as possible, without any unused parts.
Thanks,
Steve
Great advice Greg. Steve... because you have crystal elements there's no need to plug the hole left over from the volume control... the crystal elements are not vented on the back. If you were to use Shure CM/CR though, they do have vented backs and an open hole is an invitation for feedback. Greg's generally correct to recommend to close the hole, but in your case it's not needed. Greg, please correct me if your experience tells you otherwise.
Dave, I agree - crystals are not vented to the rear and therefore a hole shouldn't make nearly as much difference as it would with a CR/CM. On the other hand, the element can absorb the vibrations through the case, not just the diaphragm - that's where handling noise comes from, for example. Plugging a hole big enough for a volume pot to pass through might make some difference, even with crystal elements. I haven't tested that - but plugging the hole is easy and the mic will look better besides - so I do it anyway.
/Greg
Great!, thanks.
Thanks Greg and David. Removing the VCs turned out to be pretty quick and easy following your instructions, and the mics are lighter now. For now I just covered the holes with some duct tape to prevent dirt and stuff from getting in.
Steve
Hi, Steve
Given that you've already bypassed the volume control (you took it completely out of the circuit, right?) then I'll assume you know how to get the grill off and the element out of the way.
Generally a volume control is removed by removing the knob, which provides access to the nut that retains the volume pot in the shell. However there are many times when fitting a volume control to a shell requires some heroics - and without seeing your mic I can't say for sure - only that a visual inspection should allow you to see how it comes apart.
You are right to be concerned about plugging the hole - a large hole in a shell can create a big feedback problem. I turn a nice press-fit plug for the hole out of delrin (black acetal plastic) or aluminum - but you can make a plug that is functional out of just about anything. A piece of tape along may not be as effective as a solid plug of some sort, wood, cork, plastic, ball of glue, etc.