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Correct, the microcontroller should be connected to ground on pins 8 and 22 (not 11, unless the mode switch is flipped). What I was asking in question 1 above is if pin 4 is actually connected to ground even though it’s not supposed to be (use your continuity tester on your meter to find out…when the pedal is powered on). If pin 4 isn’t at ground potential, then tell me what DC voltage is on pin 4 when the pedal is on.
By engaging the routine in the code to flash the software number, it’s acting like pin 4 is being held low upon power on. We just have to figure out what’s holding it low….either there is some sort of external short on pin 4 or the microcontroller is internally damaged.
Let me know.
-BrachThat’s bizarre. 2 more questions:
1) Is the microcontroller pin 4 is connected to ground?
2) Upon power up, does the green LED wait about 2 seconds until it starts blinking?
Let me know.
-BrachYummyFuzz,
The ratio of R3 to R2 will set the gain of the first stage. If you keep them the same this stage will have no gain (unity).
R2 contributes to the input impedance of the pedal, so raising this to 220k (or something relatively high) will help it work better with other pedals and guitars. As you noticed, version 8.2 has some changes that uses a different topology to raise the input impedance very high, as well as a quiet switching circuit that keeps the relay click from being heard when the bypass switch is pressed. If you want to play with the first stage’s gain, I would suggest replacing R3 with a 500k trim pot. This would give you maximum gain of over 2, which is probably too much…the later stages in the circuit might start clipping, but you can always dial it down. There’s no need to use a trim pot in place of R2…it’s best to just keep this as a set resistor.
Hopefully this answers your questions and gives you something to work with.
Good luck.
-BrachWhat are you lifting to cause the symptoms you described to go away? It seems something may be shorting to the board. Make sure the paper under the pots doesn’t have any holes in it from the leads poking through. Make sure none of the pot backs are touching anything they shouldn’t be touching.
Make sure chassis is grounded to the board (use a continuity test).
Also use a continuity test to see if the tap switch wires are connected…they shouldn’t be unless the switch is pressed down.
Let me know what you find.
-BrachRobin,
It was good to meet you yesterday. I’m glad we were able to help you flash your Quaverato.
It seems that now your Quaverato thinks the tap switch is being held down when you power it on. Make sure the tap foot switch wires aren’t twisted or connected somehow. We put this function on the this pedal so customers can see what software version they have on their microcontroller.
Check those wires and let me know if you still can’t get it going.
Good luck!
-BrachThe main thing is we need to figure out what caused R15 to explode. It could be dangerous to use the amp until we figure out what happened. If you are not 100% confident in your solder joints then please take out the board and re-solder them…it’s much better to be safe than dead…or have more components blow up. Also, try tightening your tube socket pins just to make sure everything is making good contact.
All the current the amp uses goes through R15, so something in your amp must have been drawing a lot more current than it’s supposed to. It makes me think that something is shorted….like a bad solder joint or something.
Are you sure that TP6 and TP9 are correct? The bias voltages on those parts of the circuit seem solid, so those test points should be higher. It concerns me that TP5 isn’t giving you a voltage…that’s pretty important to know what that voltage is. Like I said, try tightening your tube sockets, especially pins 8,4, and 9, and re-measure these voltages. Make sure you have the amp plugged into an 8 ohm load (speaker) at all times, even when you take these measurements.
Let me know what you find.
Good luck.
-BrachJake,
If you are getting that voltage range on those pins as you adjust the pots it means that the pots are working correctly and giving the microcontroller the proper voltage. So by deduction, we can say that the microcontroller is damaged and not working correctly.
Your microcontroller may be re-flashable, but it may have been damaged enough by static electricity that I can’t guarantee it will work. If you’d like to get a new microcontroller then contact us via email and let us know your serial number: info “at” zeppelindesignlabs “dot” com …we’ll let you know how to get one if that’s what you want to do.
To prevent static electricity damage you need to make sure that you are grounded, and not at a different potential (voltage) difference than the thing you’re handling. In our lab we have ESD conductive wrist bands that keep us “electrically” connected to the AC mains ground. If you don’t have a ESD wrist band then just make sure you are touching something big and conductive (that is grounded) as you touch static sensitive parts to make sure that no voltage difference can build up on either you or the thing you are working on.
Anyway, sorry about the trouble.
Take care,
-BrachJake,
Yes, it does sound like that may be a microcontroller issue. Just to make sure, what voltages are you getting on pin 25 of the microcontroller as you turn the multiplier knob? It should scroll between 0 and 5V if it is working properly. Let me know what you find out.
-BrachKevin,
Yes, 104 should be .1uF…but you’re good either way.
I’m glad you’re enjoying your Quaverato!
Take care.
-BrachKevin,
Yes, putting a buffer before the Quaverato is something that we’ve discovered does often help. This is because of it’s lower input impedance. One option, if you didn’t want to keep a buffer before it, would be to replace R2 and R3 with larger value resistors such as 220K or so. I’m sorry about the trouble this caused you…but i’m glad you figured out how to correct it with the buffer pedal. I have started telling other customers about this, but usually customers who have this issue have low frequency loss instead of high frequency loss, so it didn’t register with me that this could be your issue too. But anyway, i’m glad it’s sorted out.
C16 is actually a .1uF cap (not 1uf), but a 1uF will work just as well for it’s application as a filter to keep the power rails clean.
I hope your Quaverato gives you years of good service. Let me know if you have any more questions/issues.
-BrachOnly adjust the dip switches if you want to change where the crossover frequency is. Use the high and low trim pots to adjust the relative volume of each frequency band. In your case, you’ll need to adjust the trim pots until you like the sound. The original settings in the manual are just starting points…you’ll have to adjust them by ear once the solder jumpers are connected. Since your high frequency content is lower in volume then try turning the high trim pot up (clockwise) 2 or 3 turns. If you need more highs then, thy turning down (counter clockwise) the low trim pot 1.5 or 2 turns. Keep playing around with it until you like what you hear. It’s helpful to keep track of how many turns you adjust each trim pot so you can come back to the original setting for reference.
Good luck.
-BrachJared,
I’m sorry to leave you hanging…I got caught up in the renovation project in our warehouse for the past few days.
I’ll contact you via email about what to do with your chip.
-Brachtlp,
The point of calibration mode is to individually adjust each filter side (high and low). In this mode only one or the other filter side is working at at time depending on how the harmonic mix knob is set. It sounds like the low side is working properly…being that you get a woolly tone when the harmonic mix knob is set to the “low” side. Is the high side of the filter working when the harmonic mix knob is set to the “high” side? If the high side isn’t letting signal through then that would explain the woolly tone.
If both sides are working then adjust the trim pots until the brightness comes back and the woollyness is diminished.
What did you mean when you said “the issue persists when engaging the tremolo”? Are you getting a woolly tone when the pedal is bypassed as well as engaged…or do you mean just when the depth knob is up?
-BrachTed,
Thanks so much for your kind words. I’m really glad you had a fun time building the Quaverato.
We do have several more product ideas in the works…and all of our products are offered as kits, as well as pre-built. Thanks for the ideas. I am actually playing around with the feasibility of a couple of those ideas. Our design requirements are a little different than most boutique builders because all of our products not only have to sound great, meet a budget, and have a desirable feature set; they also have to be simple enough to be built as a kit by our customers. The first part, and a big part, of every design is just devising a way to meet all those requirements. So the design process can be kind of tedious and it can take a while. A lot of the ideas we have for products don’t end up making it past the first step because we find out it’s not possible to meet one or more of the design requirements. That’s why we try to keep the products we are developing under the radar until we release them.
But anyway, thanks again for the kind words…it’s very encouraging.
Take care and keep in touch (sign up on our mailing list)…we’ll be releasing new products soon.
-Brach
