January 22, 2022 at 11:13 am #33278
With bypass led off, signal passes normally to the amp. With the red bypass led on, I get no guitar signal output from the unit. However, there is some sound (or noise) going to the amp that responds to volume pot adjustments. This sound is not affected by any of the tremolo controls. There is no audible sign that the tremolo is working, but the green led responds normally when making adjustments to the rate pot and tap switch. I’ve gone through the troubleshooting guide. I’ve checked all voltages – they are normal. I’ve rechecked all the components for proper placement – all are correct. I’ve reflowed all the solder connections and checked for shorts – there are none. I’ve pulled the board from the chassis and bent up all the pots to make sure they are not shorting. Nothing I’ve done has made any difference. Is it a bad microcontroller? Please give me some clues. I really want this thing to work!
PeterJanuary 22, 2022 at 9:35 pm #33347
At which step did you get stuck on the troubleshooting guide?
-BrachJanuary 23, 2022 at 9:01 am #33390
Brach. Thanks for replying. I’ll be honest. I don’t know why, but sometime during the troubleshooting I must have turned down the volume knob on my guitar. This morning, with a clear head and plenty of coffee, that was the first thing I checked. The unit works! And it sounds great. Thanks!June 27, 2022 at 8:04 am #36742
So, I thought I had this fixed, but it’s still not working right. I put it away for a few months as I had other things to do, but now I’ve got the time to try to get it working right.
I do get sound, but the tremolo output is just a fraction of the volume I get when the tremolo is bypassed. It’s like the tremolo volume isn’t being amplified enough. I have to turn my amp all the way up to get any decent tremolo output. I’ve checked all the voltages and they are all normal. All the tremolo controls work normally. Aside from the lack of volume the pedal sounds great. But with the level of output I’m getting, it’s pretty useless.
Please help!June 28, 2022 at 12:26 am #36746
So, I’ve adjusted the gain pot to its maximum. The sound is improved, but still no where near unity gain. The sound, though better, is still pretty useless at this level. Should I look into increasing the value of the trim pot? Maybe a 250K or higher? Or, I was thinking I might wire a guitar pot in temporarily, adjust it to where I get the sound level I like, and then hard wire a resistor of the corresponding value – kind of like biasing an amp, I guess. Unless anyone has a better solution, I think this might actually work. But, hey, I’m no expert at this stuff.June 28, 2022 at 9:31 am #36747
I’m sorry to hear that your pedal isn’t working correctly.
I’ll need to get some more information from you…
Did it ever work correctly? From your post in January it seems like it started working….is that correct? It’s important for me to know if it ever was working right in order for me to troubleshoot it quickly through the forum without seeing it.
If raising the gain trim pot all the way up didn’t solve the problem then replacing it with a higher value is not a good solution.
How confident are you in your soldering work? My first guess of why this is happening is that something isn’t making a good connection somewhere…especially if the pedal once worked. This type of issue is common when there isn’t enough solder on the joints or if the solder joints weren’t heated up enough to get the solder to flow properly into the joint. So that’s the first thing to check. If you have any questions about your solder joints you can take some (detailed, in-focus) photos of your board and let me look at them.
The next thing to do is to turn up the tone trim pots (both high and low). Turn them up the same number of turns each as to retain the relative levels of each. Turn them up nearly all the way (around 20 turns) to see if that makes a difference. Remember the suggested values in the assembly manual were only starting points.
-BrachJune 28, 2022 at 10:39 pm #36749
Thanks for the reply! It was never actually working correctly. The sound I was getting when I replied in January was low and muted, but I was just happy that it was working. I set it aside after noticing the volume discrepancy planning to tackle the problem later. Later is now!
So, you were right that gain wasn’t the issue. I pulled the trim pot and wired in a guitar pot. I got volume all right! And way too much gain. So, I put the gain pot back in and focussed on the hi/lo filter pots. Turing them both up is now giving me the correct volume level – equal to the bypass volume – but when I A/B the tone of the tremolo against the bypass tone, the tremolo is very muffled. I’ve adjusted the filter pots every which way – and the DIP switches – but the tremolo tone is always muffled compared with the bypass tone. Is there any way to get the same level of clarity from both channels?
Oh, and I also checked and reflowed all the solder joints. They all look good to me.
Thanks for your help!June 29, 2022 at 2:02 pm #36751
Thanks for the response. That tells me a lot.
So if adjusting the tone trim pots fixed the volume issue then that tells me we are on the right track. When the sound is muffled like that, it usually means that the high side isn’t working, or is just way lower than the low side. So first of all put the pedal in “calibration mode” to ensure both the high and low signal paths are working. If the high side isn’t working then follow the troubleshooting guide about what to do in that case. If both sides are working then you’ll need to adjust the balance of the tone until you like it and then use the gain trim pot to make up for any volume lost. Start by turning down the lows and adjusting the highs up most of the way. Then move up the lows until you like the way it mixes with the highs.
PS: Remember, that in order to turn up the highs and lows you’ll need to turn the tone trim pots in the opposite direction that you turn the gain trim pot to increase the gain.
-BrachJune 29, 2022 at 10:06 pm #36753
In calibration mode, I was able to even out the response of the hi/lo filters. When I first engaged calibration mode, the lo side was almost inaudible. After about 20 half turns of the lo adjuster, it was about equal level with the hi side. With the gain trim pot was set at 40K, the volume was good, but the muffled tone was still an issue. I tried adjusting the tone pots and the gain pot up and down to varying degrees to get a good balance, but there was no setting where the muffled tone totally disappeared.
The tone isn’t bad, it’s just not the tone I was expecting. I’d really like the tone to have clarity similar to that of the bypassed tone, but with tremolo. Is that what I should be expecting from this pedal? Are my expectations unobtainable?
BTW, my test rig is 2 P90s into a tweed Champ. I get the most muffled and compressed tone when I play through the neck pickup by itself. Not sure if that helps.
PeterJune 30, 2022 at 12:06 am #36754
Do you have a gun? Shoot me! Please, shoot me! I went through my board again checking everything and noticed some resistors that didn’t look right. It turns out I switched up R1/R3 with R17/R21! No wonder it sounded like shit. Anyway, I’ve fixed it now and it sounds glorious. Thank you for putting up with my stupidity and I’m sorry for wasting your time.
PeterJune 30, 2022 at 2:05 pm #36758
Oh! Good job finding that! Those resistors are quite different in value (14k ohms vs. 1 million ohms)! Yes, 14k as R1 in the input would have rolled off quite a bit of high frequencies.
I’m really glad to hear it’s working properly now.
Once again, good job finding those resistors, I probably wouldn’t have thought to look in that direction.
Enjoy your Quaverato!
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