Hello:
This is driving me nuts, cause the pedal sounds great and functions properly, but there is a loud high pitched or whistling sound when the on/on/on switch is in the center position. When switched to either side position, the sounds is still there, but to a way lesser degree. I can still hear it, but those modes are almost usable. I used the Xvive and not the macrons as suggested. I used the exact dpdt switches from small bear suggested in the build document. My build seems pretty clean and I don't believe there are any bridges in the solder causing issues. I'm wondering if I have a bad TL072, but they're new and probably fine. Anyone out there familiar with this problem?
What charge pump did you use? The exact part number on the chip.)
I didn't think to mention before that I had it being powered by a 9v battery, cause I just sold my power supply. I noticed that it's not run on a battery in the build plans. Kind of doubt that's it though.
From the specs read out below of my charge pump, it would seem you may be right? I would think it needs to have a max input of 9v or higher, and put out what for voltage?
Charge Pump:
In smaller characters at the top, LT1503 with a 03 running perpendicular at the the end of the 1503.
Then, in the middle, LT 1504.
And, at the bottom, CN8.
http://www.ebay.com/itm/401303887652?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
LT1054 DIP-8 Switched-Capacitor Voltage Converter With Regulator
DC / DC Converter IC Case: DIP
Input Voltage Max: 7V
Input Voltage Min: 3.5V
No. of Outputs: 1
No. of Pins: 8
Operating Temperature Max: 100°C
Operating Temperature Min: 0°C
Output Current: 125mA
Output Voltage: -5V
Lets see a list of your voltage points so we can better help you.
It wasn't the battery power. I got a new power supply and hooked it up right, but the same whistling is still there. I swapped out all of the TL072 chips and that did nothing also. I'm stumped. I have a 2nd LT1054 charge pump IC I can try, but it's the exact same chip from the same supplier. Doubt thats the problem, and I think I have the right charge pumps. I'm wondering if any other charge pump could work in it's place. I used all the DPDT switches suggested in the plans, but I'm also wondering if the 3 way one is the reverse laid out style.
Also, I think the output or input wire slipped out of my testing rig while messing around and the whistling was still there.
Ohh, sorry, I didn't see that someone had replied about the voltage points. I've never done that before but I'll try and get those on here asap.
Thanks!
Here's my voltage readings along with correct numbers from the build plans. Correct voltages followed by mine.
IC1:
1. 3mV .2mV
2. 3mV .2mV
3. .8mV .2mV
4. -8.59V -7.89V
5. 2.9mV .2mV
6 1.80mV -1.2mV
7 2.3mV -1.1mV
8 9.16V 8.76V
IC2(L): I figured L and R meant the trimpot turned all the way to the left and right. Both sets of readings were almost the same for me, so I only bothered listing my right.
1. .56V .47V
2. 1.2mV 1.7mV
3. 1.1mV .3mV
4. -8.6V -7.9V
5. .7V .46V
6. .73V .46V
7. 2.5V 2.18V
8. 9.15 8.7V
IC3:
1. 0 -1.4V
2. 2.2mV -1.1mV
3. .8mV .3mV
4. -8.61V -7.9V
5. .7mV .2mV
6. .5mV -1.4mV
7. .3mV -1.2mV
8. 9.16V 8.76mV
IC4:
1. 1.5V -.2mV
2. 4.98V 4.62V
3. .9mV .3mV
4. -3.9V -3.7V
5. -8.6V -7.89V
6. 2.55V 6.36V
7. 1.41V 6.03V
8. 9.15V 8.74V
Ever trace down the whistling noise
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