Function f(x) Clusterfuzz

culturejam · Post by **culturejam** » 06 Feb 2017, 18:46

That's about the most precise, detailed copying of art I've ever seen.

johnk · Post by **johnk** » 06 Feb 2017, 22:19

thanks. yeah etching that one was a real PITA.

culturejam · Post by **culturejam** » 07 Feb 2017, 01:37

johnk wrote:thanks. yeah etching that one was a real PITA.

Nicely done. But in the future, I'd appreciate it you didn't copy the art exactly. When this one shows up on Reverb and gets sold to some yahoo who plugs it into an 18V AC power supply, I'll be he one getting a call to fix it. Hell, I'll probably get somebody asking me to take it back for a refund.

People are dirty cheap bastards.

I realize you left the brand name off, and I appreciate that. At least that's one way to tell it's not one of ours. Well, that and the inside is obviously going to not at all look like a Function f(x) build.

I suppose I should be flattered. And I guess I am.

johnk · Post by **johnk** » 07 Feb 2017, 03:13

well, it'll never end up for sale since i built it for myself and i dig it a lot. i'm also not going to build any more of them (just one for me).
i really liked your graphics so i just went with that since it's my own personal pedal build.

culturejam · Post by **culturejam** » 07 Feb 2017, 04:04

It's cool, man.

Chuck D. Bones · Post by **Chuck D. Bones** » 04 Oct 2018, 18:31

Hi,
A quick intro and a couple of questions / comments on the ClusterFuzz for the group.

My name's Dave, nickname Chuck, I live in L. A. I'm a retired EE who has been building & modding pedals (mostly for myself) for longer than I'd care to admit. This group has been a great resource to me.

1st question/comment: the Filter switch connects the base of Q1 to the emitter of Q4 via C2 and C6. At first this looked like negative feedback, except Q4's emitter is essentially grounded by C5. So why not just ground C2 & C6? Sure, C5 has some ESR, but it's small and not well controlled. Anyone know why it's wired this way?

2nd question/comment: as we have seen in so many distortion pedals using MOSFETs as limiters, the two 1N4001 diodes appear to be installed backwards. As shown on the schematic, the only parts of Q2 and Q3 that will conduct are the body diodes. In that case, Q2 & Q3 might as well be 1N4001's. Has anyone tried reversing the diodes to get the MOSFETs to conduct in the forward direction?

Regards,

- Chuck

culturejam · Post by **culturejam** » 04 Oct 2018, 23:56

Chuck D. Bones wrote:Hi,
Anyone know why it's wired this way?

It's been a few years, but as I recall, we were getting some pop on that switch *sometimes* and on *some* units. I think we used the emitter resistor as a bleeder. But honestly, my memory on that is hazy.

As for the MosFETs, I was under the impression that having external diodes in series with the body diode would make the forward voltage greater than that of the MosFET's internal PN junction and cause it to conduct (instead of the body diode). I do believe our production units have them in series correctly, as they have a significantly higher voltage drop than the silicon diodes that are also available in the circuit.

However, I'm not an EE. I'm an English major. So maybe you are right. If so, that's hilarious and also awesome because however it ended the way it is, the sound is bad-ass.

FeVeR2112 · Post by **FeVeR2112** » 06 Dec 2020, 07:27

There is a 10R resistor off the power supply - what function does this serve?

Also, is the schematic correct with the 2N7000/1N4001 (per chuck's comment) just doing up a layout for a 125B enclosure and want to be sure.

FeVeR2112 · Post by **FeVeR2112** » 06 Dec 2020, 07:31

... and here is my layout so far - please note the polarity resistor is off board on the foot switch PCB.

UPDATED: now includes 10R resistor R11 and POT/SW placement now at 28mm vertical distance from top row

deltafred · Post by **deltafred** » 06 Dec 2020, 09:27

FeVeR2112 wrote: ↑06 Dec 2020, 07:31 ... and here is my layout so far - please note the polarity resistor is off board on the foot switch PCB. The 10R resistor is not here (yet) as I don't see whether it serves a purpose (yet).

It is part of the power supply smoothing/decoupling along with C11.

FeVeR2112 · Post by **FeVeR2112** » 06 Dec 2020, 17:17

deltafred wrote: ↑06 Dec 2020, 09:27 It is part of the power supply smoothing/decoupling along with C11.

Thank you. I have updated the PCB layout above.

FeVeR2112 · Post by **FeVeR2112** » 07 Dec 2020, 04:29

Here is a variation with the selector switch connections on the bottom which can be perhaps easier to read the labeling
.

deltafred · Post by **deltafred** » 07 Dec 2020, 09:06

The 10R resistor needs to go between +9v input and the 220uF capacitor - C11.

Where you have it on your PCB it does not form a low pass filter, to block any high frequencies which might be on the incoming 9V, with C11.

I would also include the reverse polarity protection diode D2 on the PCB.

plush · Post by **plush** » 07 Dec 2020, 15:40

FeVeR2112 wrote: ↑07 Dec 2020, 04:29 Here is a variation with the selector switch connections on the bottom which can be perhaps easier to read the labeling
.

10R put from V+ to ground is a no-no, dude.
Otherwise you need to rename your brand to "funny smoke effects".

FeVeR2112 · Post by **FeVeR2112** » 08 Dec 2020, 02:51

plush wrote: ↑07 Dec 2020, 15:40 10R put from V+ to ground is a no-no, dude.
Otherwise you need to rename your brand to "funny smoke effects".

I was obviously D.U.I. (Designing Under the Influence) on that last revision. I have put it right for both versions.

deltafred wrote: ↑07 Dec 2020, 09:06 I would also include the reverse polarity protection diode D2 on the PCB.

The reverse polarity diode is already on the footswitch board where the power input goes to and provides power to the LED. The V+ pad is the contact after the protection diode.

Thank you both for pointing out my D.U.I.

orangetones · Post by **orangetones** » 02 Jan 2021, 19:15

Hello all!

I just boarded this up on my breadboard and it sounds pretty fantastic.

One thing that happens to me is that there is a significant volume drop when selecting the BAT41s and 1N914s, as compares to the LEDs and FETs. It is also significantly louder without clipping, but that makes sense to me. In the demos I have seen of this pedal there doesn't usually seem to be a huge volume drop when they switch to the 2 Si options. Any thoughts on what the cause is here?

Also, I have seen mention in other places of the value of the resistor on the collector of the 2n5089. It is 20K on the schem, but I have seen others put a trimmer in there and mention anywhere from 10k to 22k. Thoughts on this?

Thanks folks!

Steve

culturejam · Post by **culturejam** » 02 Jan 2021, 20:11

orangetones wrote: ↑02 Jan 2021, 19:15 In the demos I have seen of this pedal there doesn't usually seem to be a huge volume drop when they switch to the 2 Si options. Any thoughts on what the cause is here?

Either they adjusted the volume in editing, or they have some kind of automatic level control going on. There is a MASSIVE volume difference between the schottky diodes and LED/FET or no clippers.

orangetones wrote:Also, I have seen mention in other places of the value of the resistor on the collector of the 2n5089. It is 20K on the schem, but I have seen others put a trimmer in there and mention anywhere from 10k to 22k. Thoughts on this?

The production schematic and the placement sheet both say 10K for the collector resistor. I'll double check with my business partner to see if he has made changes that I'm not aware of, but I highly doubt it.

plush · Post by **plush** » 02 Jan 2021, 20:31

culturejam wrote: ↑02 Jan 2021, 20:11 Either they adjusted the volume in editing, or they have some kind of automatic level control going on. There is a MASSIVE volume difference between the schottky diodes and LED/FET or no clippers.

Should anyone have troubles with volume levels in this one, it's quite easy to fix this by adding resistor attenuator using the 2nd half of the rotary switch

orangetones · Post by **orangetones** » 03 Jan 2021, 02:08

culturejam wrote: ↑02 Jan 2021, 20:11
orangetones wrote: ↑02 Jan 2021, 19:15 In the demos I have seen of this pedal there doesn't usually seem to be a huge volume drop when they switch to the 2 Si options. Any thoughts on what the cause is here?
Either they adjusted the volume in editing, or they have some kind of automatic level control going on. There is a MASSIVE volume difference between the schottky diodes and LED/FET or no clippers.

Thanks for the note on this. This is the video I was referencing.

Must something in post?

Also, I love the sounds from this pedal. Thanks for being so open about it.

orangetones · Post by **orangetones** » 22 Jan 2021, 22:14

Hey there! Thanks for the info so far. I just played around with this on my breadboard again. Sounds great. One thing I notice is that it sounds a little dark with my Strat, of all things...

To get a little more treble response from this pedal, would I just change the input capacitor? output cap? What capacitor in the tone area would I play around with to change the effect of the tone control? Any advice?

Function f(x) Clusterfuzz [traced]