Hotcake / Awful Waffle Bright Switch

[debrad]

Hi folks,

I'm currently working on a HotCake build using a vero layout and wanted to implement a suggested mod to create a "bright switch" based on the stock 470pf cap (C4 on PedalPCB's Awful Waffle).

The suggestions I've read say to put the 470pf cap on one side of a DPDT and a jumper on the other for the brighter tone; however, looking at AionFx's "Anomaly Overdrive" schematic (see attached), it looks like it would make more sense to put the 470pf cap on one side and leave the other side open.

With the jumper in place and selected, the signal completely disappears and, when I toggle BACK to the 470pf, it seems to take a couple seconds for the signal to return. Alternatively, I tried a 20pf instead of the jumper and noticed a SLIGHTLY brighter tone than the 470pf but when I wired the DPDT with 470pf on one side and an open connecting on the other, the two sides sounded identical to me.

Do these behaviors make sense? Should I try different capacitor options? Do I need more "level" before I notice a difference between the "stock" and "open" settings (or maybe more (or less...) presence)? Any other suggestions?

 

[Feral Feline]

You've mentioned which cap you're referring to in PPCB's Awful Waffle schematic, but then posted the Anomaly schematic and not mentioned which is the equivalent cap — there are missing cap values from that Anomaly schematic. Makes it difficult to help.

C5 in the Anomaly = C4 in the Awful Waffle.

I suspect what you've done is put a jumper where a cap-to-ground goes, which means you're letting ALL the signal go to ground when you select the jumper.
When you switch back to the 470p, the signal doesn't come back right away because it takes time for the cap to charge back up and do its job.


Which schematic are you following for your vero layout? The two (Anomaly & AW) are quite different, I think.




What I would do is install a SPDT on/on switch that simply interrupts the 470p's path to ground. Then you'll have stock (with 470p) and bright (470p effectively out of circuit 'cause it goes nowhere).

If you want to get fancier and have levels of brightness, a SPDT on-off-on wired so the cap's output feeds the middle lug of the SPDT, and then have two different cap values on the outer lugs (470p and ... 1n, 2n2 or whatever fits your fancy), the output of those two outer caps go to ground. Middle you have bright, one side stock with the 470p, the other side whatever you want — you could even go the other way with the second cap and have it 220p instead of 1n.

Make sense? If not, I'll draw up a diagram/schematic if you like.

 

[debrad]

Apologies...you are right @Feral Feline, C5 on the Anomaly is C4 on the Awful Waffle. I believe the vero layout is a closer match to the PedalPCB circuit (see below). I have simply replaced the 470p cap with a DPDT switch wired like this:

• input to middle right,
• output to middle left
• 470p across bottom lugs
• nothing between top lugs

Not sure why folks were recommending a "jumper" on the toggle since I figured that it just took all the signal to ground.

Sounds like I should be noticing more of a difference between the 470p side of my DPDT toggle and the open? Perhaps I need to try it again with more volume coming through the circuit?

 

[Feral Feline]

No apologies necessry! It is I who should apologise. I re-read my post and it does start off as "GET OFF MY LAWN". Sorry. I just meant to point it out.

You've got it wired correctly if output middle left then goes to ground; as you surmised, the signal got dumped completely with the jumper.

You could put a much larger cap (ex 2n2) temporarily across the outside lugs opposite the 470p just to see if you hear a difference between the two.

While a bit more volume would help you hear the difference, I don't think it'll make much of a "physics" difference — ie you should be able to discern a difference whatever volume you've set it at — but, it may still be a subtle difference.

Where is the PRESENCE set when you've tried it, maybe it needs being cranked when switching between the two? To overcome the subtle nature of the control.


Maybe it's more noticeable when the pedal is stacked with other dirt...

Ahh MichaelW noticed gain levels made a difference.

So maybe you're right about pushing the gain-level a bit.