GGG Klon Voltage problem

[Traumaman]

This is my first build, although i have some background in electronics. I built the pedal and it works but to get unity output  while the effect is on, my volume/output knob is very low, like 7-8:00 oclock. Is this normal? I know my layout is not ideal, and I've resoldered most of the connections and double checked the components on the board. Any ideas where to start? Bad IC, or some voltage leaking from a short?

IC1   1) 4.9     2)  4.9   3) 3.8    4) 0.0     5) 9.8     6)  4.8                7)  4.9                    eight)    4.9

IC2   1)  5.0    2)  4.9   3)  4.9   4)  -8.3   5)  16.6   6) 4.9                 7)  4.9                    eight)    4.9

IC3   1) 9.8     2)   4.4  3)   0     4) -4.1    5)   8.9    6) 6.6    7)    3.9       eight)  -8.2


http://www.generalguitargadgets.com/pdf/ggg_kc_instruct.pdf

This has the proper voltages

Thanks
TM

[Traumaman]

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/IMG_2045.JPG.

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/IMG_2044.JPG.

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/IMG_2046.JPG.html

[PRR]

Welcome.

Schematic!!
http://www.generalguitargadgets.com/pdf/ggg_kc_sc.pdf

> IC2   1)  5.0    2)  4.9   3)  4.9   4)  -8.3   5)  16.6   6) 4.9      7)  4.9        8)    4.9

If I am reading the schematic right, if the schematic is right, we expect +16V on pin 8 and -8V on pin 4. You got the pin 4, but pin 8 isn't near 16V, and pin 5 (should be +4.5V) says +16!

Bad drawing? Bad reading? Bad wiring??

[highwater]

Looks like you might be counting the pin numbers wrong. They're supposed to go like this:

Code Select Expand


    +--u--+
1 -|*    |- 8
2 -|     |- 7
3 -|     |- 6
4 -|     |- 5
    +-----+


[Traumaman]

OH, My bad. i think i did count the pins wrong.  I will recheck and get back with you.  Thank you for the much needed education. Feeling like a true idiot

[Traumaman]

Highwater, you are the Master Jedi. Rechecking my pin outputs in the proper way helped immensely.  Only issue I can see is voltages in pins 5-8 on IC3 are all about one volt low.  I'm guessing this is pretty close to spec. Should I try a new IC3?

Much obliged for the replies!

TM

[highwater]

to get unity output  while the effect is on, my volume/output knob is very low, like 7-8:00 oclock. Is this normal?

I definitely read that as "it's too quiet" at-least five times...

Yes, it is definitely normal for unity gain to be at a very low volume setting. The Klon was meant to be used as a boost, not a distortion -- the louder it can get, the better.

---

That being said, it's certainly worth figuring-out why some of your voltages are low... just because it works doesn't mean there isn't learning to be done.

Pins 1 and 8 (on IC3) are connected directly together on the circuit board. Even if there is something wrong with the chip, they should both have the same voltage.

But they are different. That means one of three-ish things:
1) The solder joint on pin 8 is weak.
2) The pin 8 connection with the socket (assuming there is one) is poor.
3) Something that is way beyond my pay-grade.

Often, a damaged PCB trace would make that list... but in this case, the PCB trace goes to pin 8 *before* it goes to pin 1. So, if there were damage to the PCB trace (lifted, scratched, etc.) pin 1 would also be low.

[Traumaman]

I'll look into my connections around IC3 pin 8. I appreciate the help on this highwater. Great information!

Tm