'no load' pop noise

[seacon]

Does anybody have a wiring technique to help reduce the pop noise that can occur when 'no load' pots switch in and out of circuit bypass? Or is the pop something we have to live with just like those true bypass pedals...

Thanks

[newey]

Seacon-

Hello and Welcome!

I don't have an answer for your question, but someone will be along soon.

[seacon]

Thanks for the welcome! I've been a reader of this forum for a while - but now I have a question!..

[JohnH]

It would depend on the cause of the pop.

It might help to add a high value resistor across the switch, something significantly higher than the pot value (so you still get the no-load effect), but enough to keep the cap from having a floating end and so building up static charges. Id say 3.3M should do it.

John

[ChrisK]

While a parallel resistor can be added, since there is no connectivity to the isolated terminal, it would have to be added across the pot from the CCW end terminal to the wiper.

That being said, I'd go along with JohnH's suggestion to use a large value, but I might start with 1 Meg Ohm and work my way up.


Most of the no-load pots that I've seen are 250K, so I might just replace it with a 500K "loaded" pot. A 500K audio pot is down to 250K at about "7 1/2" to "8" on a Strat knob, so in essence it goes to "12" when at "10", but still has an effect similar to a 250K pot.

I never had much appreciation for the no-load concept anyway since it functions like a 250K tone control until it functions like a switch.

500K


You could also try the TBX approach. It's a 250K pot up to "5". Then it's a 1 M Ohm pot up to "10" (or so depending on the external components used).

[seacon]

Hey thanks for the replies.

I'm using two TBX pots in my Strat.

TBX 1:

250K - no load treble cut (normal tone control)
1M - bass cut

TBX 2:

250K - no load blend middle p'up with bridge p'up (for fine-tuning 'quack' position, or taking edge off bridge p'up)
1M - blend bridge p'up with neck p'up

The 250K section of the TBX pot goes into 'no load' from the centre detent position (up to 10), that's where the pop occurs. I want the no load 'feature' but not the pop!

I'll try the resisitor across the centre and edge lugs of the 250K pots. I think I'll go higher than 1M resistor because I think there will still be some signal bleed with 1M (It seems to me that the 1M section of the TBX bleeds some signal at the centre detent)

A follow up question: with a resistor across the centre and edge lugs of the 250K pot, will that change the inherent sweep range (250 to 0) of the pot?

Thanks

[ChrisK]

Ooooh, so you're not actually using a no-load (as in Delta tone) pot, but TBX pots.

Which TBX pot is causing the pop? Are they both causing this?

TBX 1:

250K - no load treble cut (normal tone control)
1M - bass cut

TBX 2:

250K - no load blend middle p'up with bridge p'up (for fine-tuning 'quack' position, or taking edge off bridge p'up)
1M - blend bridge p'up with neck p'up

[JohnH]

Ive been using 3.3M to ground floating input and output caps on my stompboxes, which works quite well and I think the 'pop-potential' in your case is not worse.

For the tone control, I think 3.3M is high enough that it will not cause any other noticeable effects. Lower is probably OK too. Assuming we are right about the cause of the pops.

John