Aquaboy oscilattion bleeding in bypass

[atodovax]

Hello everyone i just finished an aquaboy with the mod board and when the pedal is bypassed y can hearva clock whine and also if i max the feedback i can hear oscilattion bleeding through. Any ideas to how i can stop the effect bleeding through when its bypassed? Has anyone manage to getvthe aquaboy to work without this problems? I saw that many people where complaining about the same things. Im using shielded cables from both jacks directly to the 3pdt instead of the pads in the board but that trick didnt solve the problem

[thomasha]

Was the delay at max. delay time (fully cw)? Or is the whine audible at every setting.

Try adjusting the cancel trimmer for min. whine. Another possibility is to adjust the clock trimmer, so that when this pot is maxed the longest time is still at a higher frequency.

[atodovax]

 

Was the delay at max. delay time (fully cw)? Or is the whine audible at every setting.

Try adjusting the cancel trimmer for min. whine. Another possibility is to adjust the clock trimmer, so that when this pot is maxed the longest time is still at a higher frequency.

Thank you for replying. I managed to get rid of the whine but im still getting delay signal bleeding in bypass. If i max the feedback pot and mix y hear oscilation when the pedal is bypassed. Any suggestion to get rid of this proboem? Lowering the clock trimmer and the bias trimmer got rid of this but i ended up with very short and distorted delays when pedal is on. Is this the whine bleeding into feedback? I dont understand. If i move the IN jack close to the elecrrolitic capacitor just under the MIX pot pads the oscilation and whine are noisier. Im curious if that capacitor is producing noise. Its a Nichicon 50volt capacitor. It just be very good quality

[atodovax]

Please help

[thomasha]

Just to clarify, you're hearing the clock whine, not the crazy oscillations when feedback is maxed? 
Are you using a 3PDT? Which wiring? Grounding the input or output when bypassed?

[atodovax]

Just to clarify, you're hearing the clock whine, not the crazy oscillations when feedback is maxed? 
Are you using a 3PDT? Which wiring? Grounding the input or output when bypassed?

Thabk you for replying i solved the whine provlem. What i hear is crazy oscilation if i max the feedback pot qhen the pedal is bypassed. Its bleeding through the input or output wire somehow. Wiring is the one that the pdf provides which grounds the input when bypassed. I noticed that if a ground the input wire from the jack with an aligatot clip, the oscilations stop so my guess is that they are bleeding into the input wire. I tried puting far away the input and output jack but that didnt solve it. The oscilations are faintly at the back but is not acceptable. Im wondering if is there anything wrong with the design or if its something with me because i read a lot of complaints similar

[madbean]

What i hear is crazy oscilation if i max the feedback pot qhen the pedal is bypassed.

When the delay is in self-oscialltion mode the amplitude of the feedback continues to multiply with each repeat and becomes much greater than the natural volume decay out of the BBD. This creates runaway volume gain which is going to bleed into bypass no matter how you wire it. IOW, self-oscillation is more of an effect you can achieve when you play with the feedback control but it's not a setting you want to keep in bypass.

There are a few ways you could get around this, though:
- Use a 4PDT that disconnects the feedback path on bypass. This is a bad idea since you will quickly find any mechanical pop from the switch is going to create a very unpleasant sound when you turn the effect on.
- Use some kind of FET based switching that disconnects the Feedback pat instead. This is a much better solution most likely but complicates the circuit a lot if you are doing the entire bypass as some kind of flip-flop.
- Use diodes to clamp the oscillation. Put two 1N4001 diodes back to back between pins 3 and 1 of the Feedback pot to clip the repeats once they get above the threshold of their forward voltage (and keeps the repeat amplitude from running away). This can sound cool but it will clip the delay some.
- Use a momentary switch for generating self-oscillation instead. Here you connect an normally open SPST between pins 3 and 2 of the Feedback pot. When you press it the repeats instantly go into self-oscillation.

[atodovax]

What i hear is crazy oscilation if i max the feedback pot qhen the pedal is bypassed.

When the delay is in self-oscialltion mode the amplitude of the feedback continues to multiply with each repeat and becomes much greater than the natural volume decay out of the BBD. This creates runaway volume gain which is going to bleed into bypass no matter how you wire it. IOW, self-oscillation is more of an effect you can achieve when you play with the feedback control but it's not a setting you want to keep in bypass.

There are a few ways you could get around this, though:
- Use a 4PDT that disconnects the feedback path on bypass. This is a bad idea since you will quickly find any mechanical pop from the switch is going to create a very unpleasant sound when you turn the effect on.
- Use some kind of FET based switching that disconnects the Feedback pat instead. This is a much better solution most likely but complicates the circuit a lot if you are doing the entire bypass as some kind of flip-flop.
- Use diodes to clamp the oscillation. Put two 1N4001 diodes back to back between pins 3 and 1 of the Feedback pot to clip the repeats once they get above the threshold of their forward voltage (and keeps the repeat amplitude from running away). This can sound cool but it will clip the delay some.
- Use a momentary switch for generating self-oscillation instead. Here you connect an normally open SPST between pins 3 and 2 of the Feedback pot. When you press it the repeats instantly go into self-oscillation.

Thank you very much for replying! Do you know if this also happened on the original DM2? As i was building this for a friend who wanted an exact copy of the DM2

[madbean]

Well, I've never owned an original DM-2 so I can't say for sure. It's possible the stock flip-flop circuit/fet switching prevented this from happening but AFAIK no one has ever cloned the DM-2 with that bypass circuitry.

BTW - this issue with the oscillation being present in bypass won't be unique to the Aquaboy. It can happen in any analog or PT2399 delay if the oscillation isn't controlled in some way like I mentioned in my previous post. It's just the nature of the beast.

[atodovax]

Well, I've never owned an original DM-2 so I can't say for sure. It's possible the stock flip-flop circuit/fet switching prevented this from happening but AFAIK no one has ever cloned the DM-2 with that bypass circuitry.

BTW - this issue with the oscillation being present in bypass won't be unique to the Aquaboy. It can happen in any analog or PT2399 delay if the oscillation isn't controlled in some way like I mentioned in my previous post. It's just the nature of the beast.

Thabk you very much foe taking the time to reply. The pedal sounds awsome and i built it with the mod board. I think im going to try to lessen the feedback amount rising the resistor to the left of the ne570 to 36k but im afraid i will lose the self oscilation option which is very nice to play with

[gtr2]

Input jack and output jack wiring is also very important.
If both jacks are grounded to the enclosure, I would use a fiber washer or some other method to remove one of the jacks, input or output, from grounding to the enclosure.  Ground the jack you isolated to the PCB ground.  This can help reduce oscillations through a ground loop created through the enclosure itself.  It's amazing how many noise issues this solves.  Many times grounding both jacks to the enclosure is fine, but it can cause an issue in some circumstances.  By grounding the enclosure at only one point (to create an EMI shield) you eliminate a possible unwanted ground return current.

[atodovax]

Input jack and output jack wiring is also very important.
If both jacks are grounded to the enclosure, I would use a fiber washer or some other method to remove one of the jacks, input or output, from grounding to the enclosure.  Ground the jack you isolated to the PCB ground.  This can help reduce oscillations through a ground loop created through the enclosure itself.  It's amazing how many noise issues this solves.  Many times grounding both jacks to the enclosure is fine, but it can cause an issue in some circumstances.  By grounding the enclosure at only one point (to create an EMI shield) you eliminate a possible unwanted ground return current.

Thank you very much i didnt know that. But i also tried with both jacks floating outside of the enclosure and i still have the oscilattion