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Hello all. Some time ago I posted a few issues I was having with my Echo Royal build (see link at bottom if needed). Some were resolved and I decided to give it some play time before pursuing things further. I'm having an issue with the Delay Time knob producing it's own sounds and misbehaving. Here's a video that demonstrates the problems:

https://youtu.be/mCdRXK6ZHwE

I'll sum up the issues verbally here, although the video is much better. All of this happens with the guitar volume rolled off completely.

1 - At the fastest delay time, a noticeable HUM is produced by the pedal. As you turn the knob up from there, it pops at a certain point (~ 8 o'clock), and the hum goes away.

2 - There's a noticeable delay time increase between the "hum" position (shortest delay time) and the point at which the pop occurs and the hum stops. So effectively, I can't get any useful delay times between the maximum speed and the pop point speed.

3 - As I turn the knob up, there are various sound artifacts and at times a very painfully loud POP that delays out.

I'm fond of putting the pedal into self-oscillation and then playing with the delay time knob, but the noise it produces makes it a dangerous (to the ears) proposition. I would say that everything else now works fine except for this knob. Any help would be appreciated.

AND....Since we're on the subject of the delay time knob. Is it possible to narrow the range of delay times and spread the "faster" times out along the pots range? Not sure if that makes sense. Basically, the maximum delay time that I can get is 1.88 seconds. I have absolutely no need for a delay of more than a second, but would like to be able to have more control between the fastest speed and say...1 second. Can something be tweaked to make the MAX delay time about 1 second and the times below that spread out evenly across the pots travel?

Thanks so much for everyones help!

Original Echo Royal issue post: viewtopic.php?f=20&t=56167

If you have the delay set all the way counterclockwise, then tap out like a 1-1.5 sec time with the tap switch, do you get the same weird noises?

Does lowering the mix knob make the pops quieter?

Have you tried the pedal on its own, with no other pedals plugged in to the power supply?

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

Hey Morgan. See answers below:

If you have the delay set all the way counterclockwise, then tap out like a 1-1.5 sec Tim with the two switch, do you get the same weird noises? - YES. I set it counterclockwise, tapped out about 1 second per beat tempo, and then when I turn the delay time knob up again, same deal. Pop. In fact, I hadn't noticed before, but the tap tempo switch actually creates some noise and popping itself. But not consistently. However, the HUM fully counterclockwise goes away when I tap out a new tempo.

Does lowering the mix knob make the pops quieter? - YES. I can control the volume of the noise and popping with the mix knob. However, even at full couterclockwise, I can hear a faint pop coming through.

Have you tried the pedal on its own, with no other pedals plugged in to the power supply? - YES. I tried it without any others pedals in the chain, with its own isolated power supply, and it has no effect on the issue. Also tried a different amp....just because. Nothing external affects the issue.

The tinkering did lead me to an observation. The POP seems to come exclusively from the ~8 o'clock position (#1 in my above list). In other words, if I turn the delay time knob from full counterclockwise to 9 o'clock, where it switches to a slower tempo suddenly and pops, then I wait till the delays pass and THEN turn it suddenly clockwise, I don't get the loud pop anymore. I do get swishy noises, but no deafening pop. That transition point around 8 seems to be the source of the loud pops.

Thanks. I'm trying to determine if the hardware (delay time pot) or software (MCU) is causing the issues. To that effect, can you do some further testing to see if you can determine if the pedal makes that same pop while only using the tap tempo switch, without using the delay time knob?

Also, is your delay time pot mounted to the PCB or is it wired to the PCB? Please forgive my confusion but I have an early beta version of this kit and there was one version where the delay time pot was mounted with wires and I believe another version where it is board-mounted. Either way, if your testing seems to indicate that the delay time pot itself is causing the noise, you should look at how the pot is installed. I've run across issues where when there are a lot ofboard-mounted pots, like with this pedal, one or more of the pots can be installed a little caddywhompus, where one or more pots doesn't quite sit perfectly flush in the enclosure. When they get torqued down to the enclosure, things can get a little bent and the potentiometer wafer sometimes breaks contact during rotation, causing issues such as these. A lot of time, just reheating the solder joints on the pot, while the pcb is installed in the enclosure and everything is still bolted down, can relieve that tension and straighten things out.

If that pot is not board-mounted, check that it didn't rotate out of position during installation, and check the solder lugs are not shorting to the adjacent pot.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker

I'm not completely sure what you mean, but yes, I can get the tap tempo switch to pop....sometimes. However, it's not that deafening loud pop that I get from turning the delay time pot. I played around with the tap tempo switch and sometimes it pops, usually on the first tap after not touching it for some time. It also sometimes creates some of the "swishy" sounds I get when turning the delay time pot. However, it's just not consistent like the POP from turning the pot is. I can get the pot to pop every time passing from full counterclockwise past ~8 o'clock-ish.

Also, the pot is wired to the board, not directly mounted. If you look at my original post linked above, there are pics. HUGE pics since I don't know how to make them smaller!

Oh, and one more thought. I once had the board out of the enclosure, and got all the same popping from the pot, even if I moved it around to make sure it wasn't touching anything (since it's on wires). It is pretty tight in there when getting it into the enclosure.

It really seems like a pot issue to me. I recommend replacing the delay pot and existing wire. I believe that is one of BYOC's small 12mm pots (you need to get the correct size). I would replace that pot, replace the wiring, and make sure the wiring is very neat with no stray wire strands poking out of the solder connections, and as little bare wire protruding from each solder joint on the PCB and pot solder lugs as possible.

I would also look at testing or repalcing the PT2399s. You can remove one of the PTs and jumper pins 14 and 16 together with a small bit of wire to pass audio. Then audition both of the PT chips one at a time in the other position to see if one of them acts any differently.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

OK. I'll give that all a try. It's fun to tinker. I'm still confused about why the tap tempo switch creates noise though. Wouldn't that indicate a different issue?

That's why we're also looking at the PT2399s.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

OK. Got it. Before I order supplies, is the 12mm pot an A or B taper?

Also, is it possible to narrow the range of delay times and spread the "faster" times out along the pots range? Not sure if that makes sense. Basically, the maximum delay time that I can get is 1.88 seconds and fastest is about 110ms. I recorded delays and then zoomed in to get exact times. I have no need for a delay of more than a second, but would like to be able to have more control between the fastest speed and say...1 second. Can something be tweaked to make the MAX delay time about 1 second and the times below that spread out evenly across the pots travel?

Has it always done this, or is this something that just started happening? The symptoms strongly suggest you have one or more of the electrolytic capacitors in backwards. Having an electrolytic cap in backwards usually won't cause a pedal to not work, but it will often times cause strange noise(s) while turning a pot or when the pot is full turn in one direction.

Turn the delay time all the way up. Then disconnect the power. Then plug the power back in. Does it make the gurgling sound still or is that an artifact that is caused by turning the knob and then getting repeated?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

It has always done this since I finished the build.

I checked all the electrolytic caps. They're all oriented correctly.

I turned it all the way up (delay time), unplugged, and re-powered. Nothing happened. The sound is only caused by turning the knob clockwise. No issues turning it counterclockwise. Also, I can replicate most of the noises and pops by playing with the tap tempo switch. There just doesn't seem to be any predictible pattern to when it happens.

I can occasionally get the tap tempo LED to stop blinking completely when I'm trying all different tap patterns/speeds. Not sure if that's normal. When it's off, turning the knob or tapping some more will turn it back on. I can post another video of the sounds with the tap tempo switch if there is any value to doing that. lmk.

I wouldn't bother replacing the pot as Morgan suggested. The pot doesn't directly control anything in the signal path. Although, the digital pot chip may be a problem. You should try pulling the PT2399 chips and jumpering pins 14 and 16 as Morgan suggested. If turning the delay time pot still makes noise then, we should probably look at the digital pot chip. If not, I think one of the PT2399 chips are suspect.

You can limit the range of the delay time pot. It is nothing more than a voltage divide. The wiper connects to the MCU. The MCU reads the voltage. 0V ~ 5V gets interpreted into 0 ~ 255. 0V = 0 = full turn counter clockwise. 5v = 255 = full turn clockwise. 2.5v = 127 = noon.

Does that make sense so far? the delay time pot is 50k. So if you use a 50k resistor to connect lug 3 to the PCB instead of a plain wire, you now make the total resistance 100k. So now, if you have the pot full turn clockwise, the MCU no longer reads that as full turn clockwise. It thinks the pot is at noon because 50k on one side of the pot and 50k on the other will produce 2.5v on the wiper. So now, max delay time with the delay time pot is about 1 second. You can still tap out longer delay times, though.

Understand, that if you do this, you are going to be making the pot seem more sensitive to you. Because the digital potentiometer moves in steps, those steps will become more obvious, and you will make it have more of an auto-tune effect when you turn the knob. So this may be a bad thing when you play with the self-oscillation, or it may be a good thing.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Awesome. I will try the resistor and see how I like the reduced range. Thanks for the suggestion.

I’ll pull the delay chips as you suggest and report back.

OK. I tested the PT2399 chips. Here's are the results:

1 - with both chips pulled and jumpers between each socket's pins 14 & 16, I get absolutely no sound from the delay time knob or the tap tempo switch when I fiddle with them. Audio still passes as expected with the pedal engaged, but no noises or popping.

2 - I tested each chip in each socket position. Both chips behave the same in either position. In the socket on the far left, near the copyright text, both produce some minor gurgling sounds, but no popping. Also, the tap tempo produces some very minor swishy sounds occasionally, but not dramatic. In the other socket, they produce MUCH louder gurgling sounds and loud pops, consistent with the behavior when both chips are in! The tap tempo switch also produces louder swishes and gurgles when the chips are in this position.

So, it seems it has something to do with the IC socket that's closer to the middle of the board. Ideas?

Did you test the PT2399 just one at a time, i.e., one socket still has the jumper and the other has the PT2399?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Yes. I jumpered one socket at a time and tested both chips in the other socket. The leftmost socket (near copyright) produced a little gurgling with both chips, but no pops. The more centrally located socket produced loud gurgling and popping sounds equally with BOTH chips.

The chips behaved identically. The sockets produced very different results.

Please contact sales@buildyourownclone.com and ask for a replacement PT2399 set

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

So you think it’s the chips? I’m certainly not an expert at this, but since they both behaved similarly and OK in one socket, but not the other, wouldn’t that suggest another cause? Is there anything that would cause loud popping and noise in one socket, but not the other? If there’s anything else I can test, I’m open to it. Just throwing it out there before I contact sales.

Thanks!

The gurgling noise with a PT2399 is normal, but it happens when you force it to produce too much delay time. Check the components around the PT2399 chips to make sure you don't have a value out of place. Maybe something is off with the one socket.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

First I'd like to thank BYOC for sending me a new set of PT2399 chips and a digital Pot chip. You guys have been very kind and responsive.

Unfortunately, the new chips have not solved the popping and noise issue. Here are the tests I've run:

-tried both new PT2399 chips in the "bad" socket. No difference.
-tried the new digital pot chip. No difference.
-replaced the delay time pot with a new one...just to try. No difference.

Just for the sake of clarity I'll summarize what I've learned thus far about the "issue":

1) When I turn the delay time pot from full counter-clockwise to clockwise, I get a POP around roughly 8-9 o'clock that reverberates out. It seems that the faster I turn the pot, the louder and more extreme the POP is. I also notice that the delay time LED flashes at a consistent rate (and delays are consistent) from full counter-clockwise until the "POP" point. Right at the point where the POP occurs, the delay time rate drops noticeably and the LED flash rate drops as well. It's only at that 8-9 o'clock point where the problem occurs, and ONLY when turning the pot clockwise.

2) The POP only occurs with a PT2399 chip in one socket (the one closer to the center of the board). If I jumper the problem socket and leave the other chip in place....no POP/noise. If I jumper the left-most socket and test a chip in the problem socket....loud POP/noise.

3) I can recreate much of the noise and popping by playing with the tap tempo switch. It's not consistent when the problem happens, but I can get similar issues by tapping the switch.

I don't want to beat a dead horse here. The pedal is useable if I just set a delay time and stick with it. I can also tap a tempo when the pedal is bypassed to avoid the noise while playing. It would just be such a powerhouse if I could get rid of that pop, get some more delay times between full counterclockwise and 8-9 o'clock with the pot, and trust the tap tempo switch. I'll keep trying any suggestions....

Oh...and I'd like to thank byoc for the suggestion on getting a better range with the delay time pot. I tried a 47K resistor in series with lug 3 on the pot and it was perfect! the max delay time shortened nicely and the range is more gentle when searching for a delay time. The digital pot gradations don't seem to be more noticeable than before.