[yelemusic]

Ah well, technology…
Yes, I’ve already installed the pedal on my pedal board! Can’t wait to present it to the public 😉

[yelemusic]

Hi Brach, don’t know if you received my last EMail. Maybe the spam filter caught it gain.
Anyway, flashing of the microcontroller did work a treat, and now my Quaverato is wobbling away as intended!
So, thanks once again for your great help!
And for those who might be following this thread: I can only say the best about zeppelindesignlabs and Brach, who did an exceptional job guiding ne through the process of troubleshooting my pedal!
I am one happy customer 🙂

[yelemusic]

Hi Brach, I tried again. Let’s hope my Emails don’t get filtered out by your Spam filter. Hm… Please let me know, if it arrived this time.
Thanks, Eiko

[yelemusic]

Hi Brach,
I just sent you an Email as you suggested. It took me a while, been pretty busy the last few days.
Just so you know, that you’ve got mail 🙂
Thanks, Eiko

[yelemusic]

Ok, thanks. Not so good news 🙁
But I won’t touch the ICs now 🙂

I did take care not to hurt the uC with any sort of static charge during assembly, regularly touched “earth”, and only put it in once everything else was done. But hey, Sh!t happens I suppose 🙁

How much would a new uC be? And could it be ordered from France, or only from the US?

Will have to check if a friend happens to have a PC handy.

I’ll contact you via mail in the next few days. Thanks for your help!

[yelemusic]

Hi Brach,
so I reversed the resistors as you said (BTW they both measure a solid 10k), and now the low signal doesn’t shut off, just like the high signal before the change. So it seems that the problem has swapped sides. The mix knob still behaves the same way though, as in no effect in the fully high position.
In fully low position the high frequ band pulsates nicely, while the low portion rings through steadily.
Mix middle gives the greatest effect, while the low signal still bleeds through, albeit less than in full low.
Full high position no effect, however it sounds like the low frequencies get filtered out.
Concluding: The problem seems to be with the low frequency band after the swap.

Hard to describe, even harder to compare between before and after, as it’s been a few days. Good thing I have made these videos 🙂
What I’m gonna do, is swapping the transistors anyway, just to make sure those are Ok. And I’ll be using sockets, so I won’t risk frying them. Also I’m going to undo the capacitor swap and put in fresh ones.
I’ll report back once I’ve done this.
But if I understand you correctly, all of this points towards a problem with the microcontroller. Not happy about this, cos I don’t really know how all that flashing business works, plus I don’t use a Windows PC…

So if that’s the case, shouldn’t that fall under warranty, and thus warrant a replacement uC?
I bought the kit from floating point audio in France. Should we talk to them?

[yelemusic]

Hi Brach,
let’s see:
So I checked the LEDs, they appear to be fine with the diode tester.
R14 is also fine.
I did reflow some of the solder joints, especially those of the micro controller, pin 15 looks good, all legs are properly seated.

Transistors:

Depth all the way down, mix 50/50
Q1 pin1 no voltage, Q2 no voltage
pin2 ca 700mV, both sides
Q1 pin3 no voltage, Q2 022mV

Depth up, Mix 50/50
Q1 pin1 no voltage, Q2 pin1 no voltage
Q1 pin2 fluctuating between ca 150 and 700mV, Q2 pin2 between 0 and ca 700mV
Q1 pin3 two random numbers followed by OL, Q2 same.

second measurement, because I got suspicious:
Depth @ zero, mix 50/50
pin1 no voltage on both sides
pin2 again 700mV on both sides
Q1 pin3 041mV, Q2 022mV

Depth full, mix 50/50
Q1 pin1 zero mV, Q2 pin1 zero mV
Q1 pin2 250-700mV, Q2 pin2 0-700mV
Q1 pin3 as before two random numbers followed by OL, Q2 pin3 same.

My multimeter is a fairly inexpensive one, so it’s certainly not the most accurate, but it seems to me, that Q1 and 2 do indeed behave differently.
As the mix dial isn’t exactly precise either, I do consider the possibility that the difference in voltage between Q1 and 2 might also have to do with mix knob not exact in the middle, but I tried to set it so both LEDs flash the same.

The random numbers on pin 3 seem funny to me, but since they occur on both Q1 and 2 I assume that’s probably fine. With depth all the way down the apparent difference between Q1 and 2 seems to be the voltage on pin 3, which is in fact absent on Q1 (second measurement was different. God knows why).
With Depth up both Q1 and 2 also behave differently, both go up to 700mV, while only Q2 goes all the way down to zero.

So, without knowing much about anything, looking at these measurements I get the feeling that Q1 is funky. I might get a new set of those, and replace them. This time I’ll be using sockets though, as it makes things a lot easier.
Do you agree with my conclusion?

Maybe I’m just trying to ignoring the uncomfortable third option, which might indeed be a faulty microcontroller. I’ve seen that your software is PC only, but I’m on Mac. So I’d have to find a PC for this purpose first. Well, let’s hope it doesn’t come to this.

But I have to say, as annoying as all of this is, it’s also great fun. I feel a bit like Sherlock Holmes 🙂

Thanks a LOT for your help 🙂

[yelemusic]

Oh, sorry. Here it is again. Let’s hope it works now:

http://www.falckenberg.com/downloads/Quaverato/IMG_8775.mov

[yelemusic]

Hi Brach, sorry for the late reply, I was out of town for a few days.
I just checked the pots, they all seem to be fine, going from 0 to 5V, except for th Volume pot, which doesn’t show any voltage. Still working though, so that’s probably fine.
Both LDRs show a resistance of 1,8M in complete darkness. I taped black tape across it, and even shining a light directly onto them didn’t affect it. So I can safely say that they are not leaky.
I attached a video that shows how the LEDs behave depending on the position of the mix dial. It seems inconsistent. One would assume that both LEDs would work in the same but opposite way. But while the low LED flashes on the “low” side of the dial, and goes steady towards “hi”, the high LED only flashes in the middle position, goes steady in the dark position, and goes completely dark when the dial is all the way at “hi”. Sometimes it’s on though, when on “hi”, sometimes it’s not, so that’s another weirdness. So either it’s (from lo to hi) stead-flashing-off, or sometimes it’s steady-flashing-steady.
I tested for bad solder joints but so far I couldn’t determine what makes it go steady or of when the dial is on “hi” position.
http://www.falckenberg.com/downloads/Quaverato/IMG_8773.MOV
http://www.falckenberg.com/downloads/Quaverato/IMG_8775.MOV

Also, in one of the previous videos I showed the erratic behaviour of two pots. Could this be caused by some other fault somewhere else in the circuit? Measuring their voltage seemed fine, no erratic jumps, but as shown in the video they don’t behave that way.
This is getting frustrating 🙁
I could redo the optocoupler, or use a readymade one (I happen to have a silonex nsl-32 and a VTL5C2 lying around somewhere. Could any of these work instead?), but I have a feeling that won’t help, as they seem to be fine by the looks of it. The fault has to be elsewhere…
Could the TL074 be the culprit? Just asking, because it’s soldered in without a socket, so maybe it got too hot. I did take great care not to overheat it, but one never knows… Or the microcontroller? If this thing controls the optocouplers, maybe it’s faulty.

[yelemusic]

It gets even weirder.
Here I turn both the depth and the Mix knob. Note how the depth know does rather weird things, while interacting with the Mix knob:
http://www.falckenberg.com/downloads/Quaverato/Depth+Mix.mov

Could the pots be defective I wonder?

[yelemusic]

Here’s a short video to illustrate how my mix control reacts from LO to HI, coming from the same settings I used for the comparison with your video. On the LO position the effect is fairly subtle, the middle position is actually somewhere around 11 o’clock, and if I turn towards the HI position the effect gets less and less until it’s completely gone in the HI position. That can’t be right, can it?
http://www.falckenberg.com/downloads/Quaverato/Harmonic-Mix.MOV

[yelemusic]

Ok, did some comparison with your very own video.
First off the settings I copied on my box:
http://www.falckenberg.com/downloads/Quaverato/Quaverato-Settings.png

Secondly, the waveform as recorded, both from your video and my Quaverato:
http://www.falckenberg.com/downloads/Quaverato/Quaverato-Waveform.png

Here’s the audio off your video:
http://www.falckenberg.com/downloads/Quaverato/Quaverato-Video.mp3

And finally from my box:
http://www.falckenberg.com/downloads/Quaverato/My-Quaverato.mp3

On my recording there’s always an underlying constant tone, it never shuts off completely. And that’s with wave shape set to square wave, full depth, spacing in the middle, harmonic mix where the effect is the strongest (my pot ends up in the 11 o’clock position when the separation is strongest).

Should I replace the transistors in question?

[yelemusic]

The recording was made with the mix knob in the middle. I will check again. My mix knob is at its most effective setting, that is with the most extreme pulsating a little to the left of the middle position, so that’s what I chose. My idea of recording the signal came from my observation, that it’s kids difficult to hear if the signal really shuts off during the down phase of the cycle, as the natural sound of the guitar tends to confuse the ear (unless I turn up the volume to neighbour-unfriendly levels) The recording gives me an visual representation as well as the option to listening back in isolation.
I watched some example videos on youtube, and there the effect indeed goes from full to silent, so I assume, that’s how the pedal is meant to work.

Also the high portion of the effect not pulsing is consistent throughout my tests. It never goes down to 0, like the direct signal is constantly leaking through.

Let me do some more tests and get back to you.

[yelemusic]

This is getting weird now. So the LEDs are both pulsating, when the pot is in the middle position, if I slowly turn it to one side, one of the two will stop pulsating and go steady, depending on which way I turned. But both LEDs behave in the same way.
As for the pot, it does exactly what you say, it goes from 0 to 5 volts measured from the middle lug to ground.
Q1 is soldered in the correct orientation, which was to be expected thanks to those nifty little drawings on the board, that indicate the direction 🙂 I will however resolder those 3 legs anyway, to make sure they make good contact.
I’m aware that the transistor probably doesn’t like heat that much, but I believe was taking great care to use only moderate heat and make sure to solder it quickly. It might still be fried, who knows. Maybe I should order a few more of these and check if that’s the problem. What do you think?
The three legs are not shorted as in “they don’t produce a beeping sound on the continuity tester”. Also there seems to be a resistance of roughly 600Ω between the middle leg and one side leg. I don’t know if that’s the way it’s supposed to be. Q2 is the same BTW.

I’m also considering the possibility that I’m just too stupid to use the pedal correctly, and that’s actually how it’s supposed to sound! But I don’t seem to be able to create that choppy sound that goes from on to off.

Hey man, I appreciate your help!!

[yelemusic]

Resistance across TP1 and 2 is roughly at 1700k. If I shine a light onto the heat shrink, it goes down significantly (to ±70k) Quite amazing, given that the hole is really really small 🙂

[Author]

Posts