Foxx Tone Machines - Why No Bias or Starve?

[Feral Feline]

Hello @Ginsley, you might be interested in this thread:

Switching between multiple resistors

I'm playing around with the Six String Stinger circuit at the moment, planning out a few potential mods. Having learned this week that this OD/boost pedal has absolutely nothing to do with a very clean high headroom boutique tube amplifier - which is obvious on reflection🤦‍♂️ - and is instead...

forum.pedalpcb.com

Have you got any SPDT on-off-on?
Or have you come by some DPDT on-on-on since last posting in this thread?

 

[Ginsly]

Hello @Ginsley, you might be interested in this thread:

Switching between multiple resistors

I'm playing around with the Six String Stinger circuit at the moment, planning out a few potential mods. Having learned this week that this OD/boost pedal has absolutely nothing to do with a very clean high headroom boutique tube amplifier - which is obvious on reflection🤦‍♂️ - and is instead...

forum.pedalpcb.com

Have you got any SPDT on-off-on?
Or have you come by some DPDT on-on-on since last posting in this thread?

I haven’t quite crossed this bridge yet, but I will soon! I still figure I can just use a DPDT on/off/on toggle, which seems pretty straightforward- put the board wires and lowest cap across lugs 2 & 5 (which will always be in the mix), and a couple higher caps across 1 & 4 and 3 & 6. Sounded like that would work, right? I might have some SPDT on/off/on switches, and I’ll certainly take a look at that possibility again- is there any advantage to doing it that way?

EDIT: I originally started this thread about resistors on toggles, but ALSO plan on putting caps on a toggle switch, which this post references. Sorry for the confusion, my bad!

 

[Fama]

I haven’t quite crossed this bridge yet, but I will soon! I still figure I can just use a DPDT on/off/on toggle, which seems pretty straightforward- put the board wires and lowest cap across lugs 2 & 5 (which will always be in the mix), and a couple higher caps across 1 & 4 and 3 & 6. Sounded like that would work, right? I might have some SPDT on/off/on switches, and I’ll certainly take a look at that possibility again- is there any advantage to doing it that way?

Tbh I would argue that using a DPDT is simpler because you could wire it so that you always just have one resistor, which makes it a little bit simpler - you pick three resistors and get those values in each position.

To elaborate, using the type 1 diagram I would put one resistor between lugs 1 and 4 (so straight across the top, active in the Switch DOWN), second one between lugs 3 and 6 (active on Switch UP) and the third one across lugs 1 and 6. And in/out wires on lugs 2 and 5. But that's just how it would be the simplest for my brain, YMMV. And I assume you still mean resistors and not caps, with caps it would be different (since with caps, parallel ones are easier to just add up).


As far as I understand, with a SPDT on/off/on you always would have one resistor always in the path, and on the sides you add in another parallel resistor, in which case you would need to calculate the three resistors based on what end values you want. So it's a little harder, but not very much harder.

 

[Ginsly]

And I assume you still mean resistors and not caps, with caps it would be different (since with caps, parallel ones are easier to just add up).

Well, that would be safe to assume if I wasn't a dumdum and pivoted to suddenly talking about putting caps on a switch! Ha... Too many mods going on at once, my apologies! Until my last response, yes, I was looking at putting different resistors on a switch. I'm also going to put caps on a DPDT on/off/on, but like you said, that's pretty straightforward and not the original issue.

When it comes to a three-resistor approach, you mention the Type 1 on/on/on diagram; it sounds like Type 2 is the more common one though - correct? In that case, would I just connect resistor 3 across lugs 3 & 4 instead of 1 & 6?

 

[Fama]

Well, that would be safe to assume if I wasn't a dumdum and pivoted to suddenly talking about putting caps on a switch! Ha... Too many mods going on at once, my apologies! Until my last response, yes, I was looking at putting different resistors on a switch. I'm also going to put caps on a DPDT on/off/on, but like you said, that's pretty straightforward and not the original issue.

For a cap I'd go with a SPDT on/off/on tbh since like I said, parallel is easier in that case, but a DPDT would also work.

When it comes to a three-resistor approach, you mention the Type 1 on/on/on diagram; it sounds like Type 2 is the more common one though - correct? In that case, would I just connect resistor 3 across lugs 3 & 4 instead of 1 & 6?

Yep, I forget which one is more common but it could very well be Type 2, and yeah I would go lug 3 & 4 in that case.

 

[Ginsly]

For a cap I'd go with a SPDT on/off/on tbh since like I said, parallel is easier in that case, but a DPDT would also work.

Huh. I guess I'm trying to visualize the difference between the two. In my head it seems cleaner to just use a DPDT and attach all cap legs to the lugs (and board wires to 2&5)... Same with resistors, but the calculations would be different. Otherwise, you'd have resistors or caps kinda floating between the board and the switch, like in this parallel diagram (below). I might be way off on this, so please correct me! Ha... Still putting all the pieces together...

 

[Fama]

Huh. I guess I'm trying to visualize the difference between the two. In my head it seems cleaner to just use a DPDT and attach all cap legs to the lugs (and board wires to 2&5)... Same with resistors, but the calculations would be different. Otherwise, you'd have resistors or caps kinda floating between the board and the switch, like in this parallel diagram (below). I might be way off on this, so please correct me! Ha... Still putting all the pieces together...
View attachment 76196

No, that's how it works, but I just meant that it's a little simpler if you do resistors in series and caps in parallel because you don't need to calculate anything more than A + B. But it's not really an issue at all, just use what you have and do the calculations for parallel resistors.

 

[Ginsly]

No, that's how it works, but I just meant that it's a little simpler if you do resistors in series and caps in parallel because you don't need to calculate anything more than A + B. But it's not really an issue at all, just use what you have and do the calculations for parallel resistors.

Gotcha! Thanks for chiming in, it helps to know what options I have.

Speaking of options... Since I don't have a Fuzzy Fox yet I might just stripboard a FTM, and this one actually has a Tone switch baked in already:

Outside of fiddling with voltage/bias, I'd really like to see if I can change the normal Octave on/off switch to Aion's three-position control - Octave On, Standard Octave Off, and Modified Octave Off , which takes out the series diode completely (D2 in Aion's schematic, D4 in PPCB's apparently?). I'll need an SPDT rather than SPST, but I'm not sure if/how I can alter that vero layout. I'd LOVE some help with this! Below left is the standard off/on setup, and right is Aion's on/off/off (mod):