Fuzz Face Board Grounds Question

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CircuitBendah
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Post by CircuitBendah »

Ok. I've done a ton of searching and I can't find an exact answer to my question. I'm working on my own FF layout. I fired it up the other day and it works beautifully, but I have a couple questions about board grounds.

I remember reading something where somebody said that you shouldn't "piggyback" the grounds together. He said that each ground wire should run to the board, rather than using a ground wire that goes from the board to both jacks, and a ground wire that connects fuzz lug 1 and vol lug 1 to the board ground.

Most FF layouts on the internet do not observe this logic. I see plenty of jacks and pots grounded together.

Can someone explain to me the benefits of wiring each ground wire to the board vs running a single board ground to the rest of the grounds?

I'd appreciate it immensely!

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DrNomis
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Post by DrNomis »

CircuitBendah wrote:Ok. I've done a ton of searching and I can't find an exact answer to my question. I'm working on my own FF layout. I fired it up the other day and it works beautifully, but I have a couple questions about board grounds.

I remember reading something where somebody said that you shouldn't "piggyback" the grounds together. He said that each ground connection should run to the board, rather than using a ground wire that goes from the board to both jacks, and a ground wire that connects fuzz lug 1 and vol lug 1 to the board ground.

Most FF layouts on the internet do not observe this logic. I see plenty of jacks and pots grounded together.

Can someone explain to me the benefits of wiring each ground wire to the board vs running a single board ground to the rest of the grounds?

I'd appreciate it immensely!

In some cases running each ground wire to the board can reduce hum levels if each of the separate grounds connect to the circuit board at one ground point, in a commercially manufactured Fuzz Face, each of the grounds on the in/out sockets and the two pots are wired together with a single wire then connecting to the ground point on the circuit board, each approach will work but one reduces hum and noise..... :thumbsup
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CircuitBendah
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Post by CircuitBendah »

Thank you DrNomis! To sum it up, connecting the grounds together with individual wires and running one to the single board ground will work, but from a design standpoint, running the 2 jack and 2 pot grounds to 4 pads on the board(that connect to each other as ground) would be best for noise potential?

Here's another question...

On FF layouts that I have looked at, some people have 1 ground point like we said, and some run all grounds individually to the board too. Some people have a long ground trace running around the outside edges of the board(and let the grounds connect to that trace wherever their layout allows). But also, I have read to keep traces as short as possible. Does this not apply to the ground trace? Is a longer or shorter ground trace better or worse and why?

If I were to run the 4 ground wires to 4 ground pads on the board, would it be better to have the 4 ground pads close together on a shorter ground trace, or does it matter if the ground wires connect to the 4 ground pads, with each pad placed at different spots on a longer ground trace?

I hope my question makes sense. Thank you for your time!


DrNomis wrote:
CircuitBendah wrote:Ok. I've done a ton of searching and I can't find an exact answer to my question. I'm working on my own FF layout. I fired it up the other day and it works beautifully, but I have a couple questions about board grounds.

I remember reading something where somebody said that you shouldn't "piggyback" the grounds together. He said that each ground connection should run to the board, rather than using a ground wire that goes from the board to both jacks, and a ground wire that connects fuzz lug 1 and vol lug 1 to the board ground.

Most FF layouts on the internet do not observe this logic. I see plenty of jacks and pots grounded together.

Can someone explain to me the benefits of wiring each ground wire to the board vs running a single board ground to the rest of the grounds?

I'd appreciate it immensely!

In some cases running each ground wire to the board can reduce hum levels if each of the separate grounds connect to the circuit board at one ground point, in a commercially manufactured Fuzz Face, each of the grounds on the in/out sockets and the two pots are wired together with a single wire then connecting to the ground point on the circuit board, each approach will work but one reduces hum and noise..... :thumbsup

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Nocentelli
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Post by Nocentelli »

From experience, separate ground wires in fuzz pedals are not so critical. By their very nature, high gain pedals are noisy anyway and "star grounding" may well make little or no discernible difference to the noise floor level. On the other hand, modulation effects that have an oscillator with a ground connection often noticeably benefit from using a separate ground wire to the LFO portion of the circuit. If the LFO is regularly dumping current into a ground trace, and that same path to ground also grounds the amplifying/audio section, the audio section may well pick up that regular pulse and your tremelo will tick quite loudly. Some cruder designs like the Vox Repeat Percussion can be rendered almost useless unless the grounding is carefully routed.

When I've had a problem with noise in a fuzz type circuit, it has usually been helped or cured by keeping the input and output wires well away from each other. Also, your fuzzface might well be quite noisy until it's boxed and therefore fully RF shielded.
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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