Deflector Reverb - noise

[owlexifry]

first dabble at FV-1. first time using the 'basic relay bypass' board.
finished this a few weeks ago (pcb came with FV-1 presoldered)
was super excited.
sounds really cool.
just wish i could get rid of this noise

https://soundcloud.com/alexshriffs%2Fdeflectornoise

in this demo everything is at noon, except mix, which i turn up to noon to bring in the effect (and the noise) at the start.

- noise disappears when mix is turned all the way down.
- noise repeats with the echo repeats.
- noise isn’t really affected by altering positions of any controls (except mix)



i thought it might be coming from the relay switch circuit, so i snuck in a 1N5817 between the relay circuit +9v supply, and that did nothing.

volts:
supply - 8.98v
after 1N5817 - 8.68v

tl072 pin8 - 8.68v

ic3
pin 8 - 3.34v
pin 6 - 3.33v

FV-1
pin6 - 3.33v
pin13 - 3.33v
pin14 - 3.33v
pin26 - 3.33v

https://docs.pedalpcb.com/project/Deflector.pdf

is there something i’ve done wrong?
where do i start looking?

 

[music6000]

Pretty sure bet it was from holding it, you need to bend the end of the legs at right angles so just enough is sticking out to clip under each Leg of the FV-1 with no human contact, a hard ask for sure or rubber gloves.

 

[Cybercow]

Because the FV-1's clock is driven by the CD4049, the cap will do nothing but interfere the CD4049's actions. The CD4049 IS the clock and the "Deflect" controls its frequency.

At this point, I suggest you carefully examine every component for the correct value compared to the BOM. There's a chance an incorrect resistor or cap value is at play.

 

[music6000]

We may need to look at the Back of the PCB to look for any stray solder or artefacts that may be causing the issue???
I took a look and the Resistors all appear to be correct.

 

[jwin615]

Because the FV-1's clock is driven by the CD4049, the cap will do nothing but interfere the CD4049's actions. The CD4049 IS the clock and the "Deflect" controls its frequency.

the differentiator cap basically morphs the square clock signal into a single shot signal. I doubt it fixes it but it's no destructive and seemed easy enough to try.

Maybe the 555 in the relay bypass is making noise on the ground, messing with the fv-1? 555s can be very noisy due to their current spikes. Could try a lmc555(CMOS version, lower current) or just try bypassing the bypass board.

 

[owlexifry]

Maybe the 555 in the relay bypass is making noise on the ground, messing with the fv-1? 555s can be very noisy due to their current spikes. Could try a lmc555(CMOS version, lower current) or just try bypassing the bypass board.

fuck, i didn’t think about the ground.
(i did slip in an additional 5817 specifically for the +9v relay bypass supply)

i guess i should at least try it with a 3pdt or something.

doesn’t seem right though because i’ve definitely seen these boards used with soft switch circuits before without issue.

 

[jwin615]

fuck, i didn’t think about the ground.
(i did slip in an additional 5817 specifically for the +9v relay bypass supply)

i guess i should at least try it with a 3pdt or something.

doesn’t seem right though because i’ve definitely seen these boards used with soft switch circuits before without issue.

Just starting to think outside the box some. Idk if a CMOS 555 can provide enough current for the relay, or is it just switching a transistor(haven't looked at schem)? But, I try to use those in any audio circuit when able.
I'm assuming it's just doing a flip flop and isn't a vibrator. If that's the case, I doubt it's the issue.
Again, just thinking out loud.

 

[Harry Klippton]

Have you tried blaming Robert??

 

[music6000]

Hmm, If he didn't have the PCB for sale, none of this stress would be put on us to get this to work correctly!!
Looks like his relay bypass too!!!!???

 

[Robert]

Have you tried blaming Robert??

This is what happens when the build docs are available....

 

[Bio77]

i don't have a signal generator, yes i could just use a 200Hz sine sample or whatever off youtube and send it with my iphone to the pedal, but i'm too dumb to gather anything useful from that process anyway.
so audio probe it is.

- guitar direct into pedal
- audio probe into audio interface:

Pin 2 (INPUT) - clean as a whistle

https://soundcloud.com/alexshriffs%2Fdeflectornoise-pin2-audio

Pin 27 (FEEDBACK) - obvious cyclical repeating artefact noise. (pin 1 is very similar)

https://soundcloud.com/alexshriffs%2Fdeflectornoise-pin27

Pin 28 (WET OUTPUT) - same noise as in previously posted clips

https://soundcloud.com/alexshriffs%2Fdeflectornoise-pin28-audioprobe

so the input signal into the FV-1 (pin 2) is clean and crisp.
the feedback loop output (straight from the FV-1 pin 27) indicates a distinct cyclical repeating clicking noise, also ending up in the wet signal.
and yep the wet signal straight from pin 28 is fucked, despite a perfectly clean input signal.

how does this make any sense.

You can get a function generator app. Mine is called "f generator PRO", think it was like $3.

You should test all the components through the signal path using the schematic. It will tell you exactly where the noise starts. I've had weird things like a bad cap or a cold joint on a resister. My latest problem was forgetting to solder one side of a cap In my experience it is rarely a bad chip, but if the noise starts after the FV-1, that's the culprit.

Lastly, I've some pedals that didn't like certain power supplies. I'm not sure what the current draw of the FV-1 is but if you have a different power supply, might be worth trying.

 

[jwin615]

@owlexifry ever have any luck with this? Or did it fall into the box of forgotten circuits?

 

[owlexifry]

@owlexifry ever have any luck with this? Or did it fall into the box of forgotten circuits?

not yet. this really pissed me off.
for the sake of mental health, i moved on to other builds.
it's still sitting on the shelf next to the scope and audio probe rig.

- as seen above - audio probing was fruitless. clean signal enters FV-1, signal with noise leaves FV-1. not sure how im supposed to break that down any further.
- EEPROM isn't the issue, and we've seen above that the clock signal isn't the issue either. per the scope - it appears to be functioning just fine.

last thing i need to do is try it with a 3PDT (eliminate soft switching circuit to see if the 555 is causing any issues (highly doubt considering the pristine dry signal with effect engaged, and the number of other builders that have built these with soft switching and no issues)

 

[jwin615]

not yet. this really pissed me off.
for the sake of mental health, i moved on to other builds.
it's still sitting on the shelf next to the scope and audio probe rig.

- as seen above - audio probing was fruitless. clean signal enters FV-1, signal with noise leaves FV-1. not sure how im supposed to break that down any further.
- EEPROM isn't the issue, and we've seen above that the clock signal isn't the issue either. per the scope - it appears to be functioning just fine.

last thing i need to do is try it with a 3PDT (eliminate soft switching circuit to see if the 555 is causing any issues (highly doubt considering the pristine dry signal with effect engaged, and the number of other builders that have built these with soft switching and no issues)

Bummer.
I'm inclined to think it's the fv-1 at this point. The 555 was kind of a hail mary recommend,, though not totally unwarranted. Ne555s can cause ground noise... The CMOS 555s (icl555?) are better about that but lower current. I haven't looked at that board but imagine it's just a flip flop so it's probably fine.
You could probably just pull the 9v to the switch board and jumper the pads without fooling with desoldering the whole thing.
Excellent looking job though, none the less. You get the merrit badge for that anyway.

 

[owlexifry]

Bummer.
I'm inclined to think it's the fv-1 at this point. The 555 was kind of a hail mary recommend,, though not totally unwarranted. Ne555s can cause ground noise... The CMOS 555s (icl555?) are better about that but lower current. I haven't looked at that board but imagine it's just a flip flop so it's probably fine.
You could probably just pull the 9v to the switch board and jumper the pads without fooling with desoldering the whole thing.
Excellent looking job though, none the less. You get the merrit badge for that anyway.

thanks @jwin615

i was gonna try and pull the whole thing, but i like your suggestion better... im assuming you mean like this:


soft switch circuit (https://www.pedalpcb.com/product/pcb393/)

 

[Cybercow]

Considering the 555 chip is soldered directly to the switching PCB, I suggest removing the ground from between the switching PCB and the main PCB and running a ground wire directly from the DC jack to the switching PCB.

 

[p_wats]

@owlexifry this won't make you feel any better, but I've also got a Deflector with huge noise issues (sounds fine for the first few minutes of playing, then gets all intermittent and full of static). I've had to leave in the "fail pile" for a few years now, as it frustrated me too much (this was also in a period where I seemed to be frying FV-1s just by looking at them, but was also soldering them myself---haven't built another FV-1 circuit since out of fear)

 

[Bio77]

I would cut the extra ground wire you have running from somewhere near the jacks to the switching board (the one next to the output wire). The ground from the main PCB will be enough.