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2-1 pedal problem

Started by rangermaster, December 29, 2021, 02:23:00 PM

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rangermaster

Hi

I have build 2 circuits in one pedal and i want to control them with 1 3pdt switch 

It's a fuzz face circuit and a rangemaster circuit that goes to the same in and output on the switch so you can blend the 2 circuits together.

But i have a problem.. all the component values are right and the bias is set correct. When i engage the switch the rangemaster circuit gets a lot of crackle sounds when playinh and when the fuzz pot is on max there a weird electronic static noise..(not really loud)

Transistors are all BC547B and both are NPN wired.

Any idea? I attached a photo of my layout.

Thanks.


GGBB

How do the circuits sound independently (not connected to each other)?

Also - your diagram shows each transistor having a different pinout. Is it possible that you have a wiring error?
  • SUPPORTER

sekim

Quote from: GGBB on December 29, 2021, 02:55:03 PM
How do the circuits sound independently (not connected to each other)?

Definitely the first thing to check. I hate unwiring, but sometimes its the best/quickest way to isolate cause.

rangermaster

When using both separately i get the same resulta

I checked the pinouts and they're ok

idy

So the problem has nothing to do with putting them together, since the problem happens either way, you get the "same resulta."

A Rangemaster that has a crackly sound...

and the fuzz face has a fuzz knob, that at max, has a "noise."
a noise like hiss or crackle, or a tone, a hum, a buzz or a whistle?

The rangemaster sounds like bad bias... sound cuts in and out? distorts? Voltages for that transistor?



rangermaster

#5
Bias/voltages are ok. I checked all of them

The sound i am talking about is hard to explain. But sounds like when searching for a radio frequency.

I thought i could have something to with grounding but everything seems to look fine. It's wired like the photo i attached before.

I've build a lot of rangemasters and fuzzes but never had this problem before. I also tried another switch but no luck. I'm using metalfilm resistors with this build for a more stable and less noise circuit... has to be.. :icon_rolleyes:

GGBB

Do you have this boxed up? Some noise and/or interference should be expected if the boards and wiring are out in the open unshielded.
  • SUPPORTER

rangermaster

No. It's all in the enclosure

I think i'll try some new transistors first

rangermaster

Ok i swapped transistors and the fuzz seems fine for now

But the rangemaster is still not ok. When playing there is still this crackling noise

Bias voltages are good

antonis

Try to delete 1M pull-down resistor.. :icon_wink:
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

rangermaster

I changed a few parts and now when testing independently they work fine

But when attached together the noise is back...

rangermaster

Quote from: antonis on December 30, 2021, 04:40:23 AM
Try to delete 1M pull-down resistor.. :icon_wink:

Did that but didn't work

rangermaster

Quote from: GGBB on December 29, 2021, 02:55:03 PM
How do the circuits sound independently (not connected to each other)?

so now both seperatly they work fine.. together the rangemaster circuit sounds crap. Crackles a lot when playing.

GGBB

I'm not qualified to say whether or not the two should sound fine when piggybacked together. It may be that the two circuits won't play nicely likely that. Also - how can you be sure it's the Rangemaster that's the problem when you have no control over the mix (so you can hear just one effect) and the fuzz volume effectively works like a master volume?
  • SUPPORTER

ElectricDruid

Quote from: rangermaster on December 30, 2021, 04:20:16 AM
But the rangemaster is still not ok. When playing there is still this crackling noise

I seem to remember that the Rangemaster's pot has significant DC across it, so crackling noises when moving the pot is pretty much inevitable - a side-effect of the basic design. However, mine was fine as long as you didn't move the pot. Could it be that the pot is a bit wobbly and that's where the noise is coming from?

+1 agree with GGBB - this splitting/mixing is probably going to need to be done carefully to work correctly.

rangermaster

The crackling is there while playing. I know the pot can crackle a bit because of the voltage but that's not the problem.

I'll try to make a audio sample.

The fuzz circuit is fine.

idy

Splitting these two particular circuits is...particularly problematic. Because they both have awfully low input impedance. Electrosmash gives 12k for the RM and 5.2 to 8.4k for the FF. Changing to Si should bump those numbers up, but still....So your overall goal might be "crazy." Or super genius and over everyone's head...

You might try something as simple as adding a series resistor to the RM... and maybe the FF, to raise the impedance. You will lose some volume. Could be a pot for testing, like 100k, called a "smooth" control on a FF. This will change freq. response too....



There is a way to avoid the crackling pot on a RM. BYOC does it for their tribooster; they replace the pot with a fixed 10k R, take the output from the Collector and put it through the output cap first (cutting off the DC) and then through the pot. But that is only good for crackle when turning the pot.

rangermaster


idy

That sure sounds like a mis-biased RM, but you have told us that it is certainly biased correctly, so I guess that's not it.

rangermaster

Yes your right it sounds like a bad biased transistor.  But their all 100%  :icon_confused: