Home › Forums › Quaverato Forum › Quaverato FAQ & Support › High Pitch Noise/Bypass On has no audio
- This topic has 9 replies, 2 voices, and was last updated 1 year ago by brach.
I’m at wit’s end.
The first time I fired it up, it worked great.
The second time, I got a terrible hum when I used the tap tempo. I’ve done ALL the troubleshooting and all checks out. All solder joints are good.
Fired it up again, and now I have a terrible clocking whine that renders pedal useless. And then, suddenly, the bypass switch, when on, cuts out all the audio.
The power supply used is the same. I don’t know how it could cause the whine since it worked fine the first time I used it.
Any help is appreciated. When it was working correctly, it was awesome!
Fired it up again.
Got signal when bypass on. Still got clock whine (changes with rate and volume of whine changes with depth.)
THEN, I used the phase switch – and lost the audio when bypass on! First time that has happened!
I can send photos or sound examples if needed.
Thank you Brach.
This is almost certainly related to bad connections (ie solder joints) within the circuit. The fact that it is behaving differently even though nothing external has changed indicates to me that something internal has changed…like some connections are intermittent. Please make sure the paper insulation has not been punctured and nothing is shorting to the back of the pots. I suggest reflowing the solder joints (all of them) to ensure that they are all working properly. If you haven’t soldered many projects yet, make sure your iron is getting hot enough and you are using the proper amount of solder on each joint…it’s easy for joints to be bad if there isn’t enough solder on them.
Ok. I will re-solder all the joints and check the paper.
BTW – I’ve been making pedals for 12 years now and soldering for 30. I’m feeling pretty good about the soldering.
I will let you know how it turns out.
tx for your prompt reply,
It has been a while since my last post.
Again, I’m having trouble with the pedal working. It is fine in BYPASS. However, whether the pedal will work when turned on is always a crap shoot. The LEDs light up. I’ve checked all solder joints, made sure that pots are not touching the pcb (I’ve put rubber between them.) Some times it starts to work if I unplug the power and power back up. Sometimes it doesn’t.
One time I turned it on, the bypass and On were backward. Tremelo when bypassed; no trem when “on.” Only once, however; couldn’t replicate.
Very frustrating. When it works, it is wonderful, but I’ve been fighting this pedal since March.
Any help is appreciated.
I understand. That is very frustrating.
I was assuming since I didn’t hear from you for a while that re-flowing the solder joints worked…at least until now. Is that correct?
I know you’ve been putting pedals together for many years now, so I’m sure you know that these types of intermittent issues are always related to bad connections somewhere…that’s pretty much the only thing that can cause them. If you’ve already re-flowed all the solder joints and re-seat the microcontroller, the only thing I think that I could do is to look at your board…there may be something that I happen to notice. If you want me to do that, you can send me some detailed, in focus photos of both sides of your circuit board to info “at” zeppelindesignlabs “dot” com. I want to look at the solder joints, so try to focus on those. You should bend up the pots as much as possible so I can see under them. Hopefully, I can see something in the details of the photos that was easy to miss in real-life.
Once again, I’m really sorry for this annoyance. I know it is frustrating.
Since our last correspondence, I’ve resoldered the entire pedal. Suddenly, it started working!……and stopped.
The most recent problem is this – while the pedal is on, there will be a suddenly eq shift, where all the higher frequencies go away. Sounds like someone put a blanket over the sound. Then, without reason, it will go back to normal. This happens without me touching the pedal.
If you start taking in pedals that need fixing, I am more than glad to send it to you and pay you to fix this. It’s been over a year and I am still unable to use it live. It has been that unreliable. (But boy does it sound good when it’s working!)
Thank you for your help.
I know this has to be really frustrating…to get it working and then it stops again. I’m sorry has been such a long battle.
When you hear the high frequencies muffled…this particular symptom is caused because the signal is not making it through the “high” side circuitry. Please check the high side trim pot by working through appendix A, step a, v and vi (don’t bother with the previous steps). I would even start with the “wiggle test.” It’s an intermittent issue and I’ve experienced the trim pots can sometimes be intermittent. While the high side isn’t working, you can also check to see if there is around 1.8V on the optocoupler pin, as in the voltage chart. This will tell us if the trim pot is actually the issue.
Let me know what you find.
Ps…I’ll let you know if and when I’m able to accept service work again.
Hold on to your seat!..
IT IS WORKING!! (knocking on wood as I type that.)
The last piece, after resoldering, wiggling, resoldering, etc., was getting rid of the sockets. Despite the sockets being secure, and (I thought) the trannies being tight, I finally whittled it down to the “highs” trannie not sitting right. Soldered it, and, voila! All is well. It’s been 24 hours and numerous plays.
Thank you so much for all your support.
IDEA – you had mentioned in an earlier post to me that y’all do not recommend using sockets (which IS a very DIY thing. :). My suggestion is to put that recommendation in your instruction manual.
BTW – I have the volume pedal insert also from y’all and LOVE IT. By far my favorite volume pedal.
Thank you again!
Oh, that’s great!
I forgot that you had installed sockets. I’m glad that you remembered that I said that earlier. Sockets are good for some applications, but they don’t do well with components that deal with sensitive and small signals. I guess it’s a good lesson to take with you in your future projects. You’re right, I probably should mention that in our assembly manual. Thanks for the suggestion.
I’m really glad that you are also enjoying the VPM-1.