GGG ITS8 Debugging.

[VPIF]

Hi.

Just built the ITS8 tube screamer from GGG. Leg 6 on the IC reads 9,06V, and leg 7 reads 2,71. They should both be around 4,5. Cannot find any shorts or anything in the traces around leg 6 and 7. I am also using an on/on SPDT instead of a on/off/on SPST for the clipper selection. Could this be a problem?

Any help is greatly appreciated.

1.ITS8 from General Guitar Gadgets.
2.http://www.generalguitargadgets.com/pdf/ggg_its8_sc.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
3.Built on etched PCB, checked for continuity/shorts before populating.
4.Expencive boutique mod. Used on/on SPDT toggle instead of on/off/on SPST. http://www.generalguitargadgets.com/pdf/ggg_its8_mods.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
5.Negative ground
6.Bypass OK. Led light up when engaged, but no sound.

Battery: 9,08v

IC (JRC4558)
1: 4,58v
2: 4,85v
3: 4,5v
4: 0v
5: 4,73v
6: 9,06v
7: 2,71v
8: 9,06v

Q1:

C: 9,05v
B: 3,28v
E: 2,74v

Q2:

C: 9,03v
B: 3,30v
E: 2,74v

[VPIF]

Found it!

Tiny strand of solder shorting leg 8 to leg 6  Works great now.

[stuznu]

Still testing me newly built ITS8 and find that the when adjusting the tone setting there I am not hearing any audible difference. The pedal was first tested before being boxed.

To debug Tone issue I removed the pcb and repositioned and resoldered pot wiring but no change to Tone adjustment.

Any advice will be appreciated.

Thanks

[VPIF]

Still testing me newly built ITS8 and find that the when adjusting the tone setting there I am not hearing any audible difference. The pedal was first tested before being boxed.

To debug Tone issue I removed the pcb and repositioned and resoldered pot wiring but no change to Tone adjustment.

Any advice will be appreciated.

Thanks

Are you using a 25K LIN pot? I used those in my two builds, and the tone knob has a very limited effect on the sound. I have ordered some 20K W-taper pots (Tayda has them in stock) as I'm guessing they will solve this problem. Then again, there seems to be those who used the 25K LIN which don't complain about extremely subtle effect... I'll let you know in three weeks time, give or take, when I recieve the new pots. But hopefully someone else will chime in with opinions and experiences sooner than that.

[Govmnt_Lacky]

The "W" taper pot is essential for getting a proper Tone adjustment. Built my very first TS with the 25K pot and it sounded terrible. World of difference when I used the 20KW pot 

[stuznu]

Just checked my receipts and can confirm that the tone pot is a Lin Pot !!!
GGG BOM suggested 20 EQ Taper or (substitue 25k linear) - thanks for alerting me to this.

[stuznu]

Finding a W taper or a G taper EQ pot for tone is like looking for hen's teeth on this side of the world, they are either not stocked or identified by a different name.
I have tried 'w taper'. G Pot, EQ Pot and cannot find a supplier in Australia.

Has anyone tried the passive tone adjuster mod for linear pots?