Colorsound Overdriver Problem - Help Needed

studio1203 · Post by **studio1203** » 16 Mar 2017, 23:45

Hello Forum members!

So, I decided to build a Colorosund Overdriver but I am having some problems.
I am not getting that huge boost in volume that these boxes are known for, no Fuzz on 10 and the tonestack is very subtle. Apart from these problems the box sounds great (ahaha) tone wise.

Here's the layout that I used:
http://turretboard.knucklehead.dk/wp-co ... xxmods.pdf

And some values:

Transistors BC 109's

Q1

B= 2.28
C= 1.58
E= 3.07

Q2

B= 1.52
C= .001
E= 2.26

Q3

B= 2.01
C= 1.87
E= 2.68

Any help much appreciated.

Thanks!

mictester · Post by **mictester** » 17 Mar 2017, 01:14

All your transistor voltages are very low. The fault is around Q2 - the collector should be around 4.8V

studio1203 · Post by **studio1203** » 17 Mar 2017, 02:12

mictester wrote:All your transistor voltages are very low. The fault is around Q2 - the collector should be around 4.8V

Is the 1.8k resistor biasing Q2? If so, what value should I use to raise the voltages? Anything else I should keep in mind?

Thanks!

studio1203 · Post by **studio1203** » 17 Mar 2017, 21:04

Ok, I raised the C voltage on TR2 to 3.4v still no Fuzz sound and with all the knobs on 10 my level is the same as when the pedal is off.

Any ideas?

Thanks!

Post by **modman** » 20 Mar 2017, 21:25

All I can say is that I don't endorse turretboard.org because they don't publish schematics, just layouts....
That's all fine if you understand electronics, but not for beginners.
Beginners building off layouts without schematics will never get beyond beginner stage.
Pick a layout + schematic that was published and verified on FSB if you don't want to end up being discouraged.

poiureza · Post by **poiureza** » 21 Mar 2017, 09:06

You did notice that Q2 is inverted in the vero right ?
ECB from top to bottom, while Q1 and Q3 are BCE

Electric Warrior · Post by **Electric Warrior** » 21 Mar 2017, 11:43

mictester wrote:All your transistor voltages are very low. The fault is around Q2 - the collector should be around 4.8V

Not all of them. Some of them are rather high. It's the collector voltages that are low. With all the emitters measuring higher than the collectors there must be something way off. Two or three of the transistors may be installed incorrectly.

modman wrote:All I can say is that I don't endorse turretboard.org because they don't publish schematics, just layouts....
That's all fine if you understand electronics, but not for beginners.
Beginners building off layouts without schematics will never get beyond beginner stage.
Pick a layout + schematic that was published and verified on FSB if you don't want to end up being discouraged.

Having to trace a layout to find out what the mods are certainly is rather inconvenient....

poiureza · Post by **poiureza** » 21 Mar 2017, 13:48

There are lots of differences with the stock schematic.

I see that Q2c is connected to ground only via the drive pot while there should be at the very least a 12K resistor and a 10µ cap in series as well.
So if you turn the drive fully down (or up depending on how you wired it) you get zero resistance to ground and thus 0 Volts at Q2c ...

That 12k resistor in turn does exist but it is actually put in parallel ?!! with the 10µF cap right before the tone section, which makes no sense to me
etc ...

I might be wrong but I think that your layout is worth crap

Electric Warrior · Post by **Electric Warrior** » 21 Mar 2017, 14:54

poiureza wrote: That 12k resistor in turn does exist but it is actually put in parallel ?!! with the 10µF cap right before the tone section, which makes no sense to me
etc ...

Maybe someone misinterpreted the schematic...

studio1203 · Post by **studio1203** » 21 Mar 2017, 18:01

poiureza wrote:You did notice that Q2 is inverted in the vero right ?
ECB from top to bottom, while Q1 and Q3 are BCE

Yes, I did.

studio1203 · Post by **studio1203** » 21 Mar 2017, 18:05

I checked the transistors and they are installed correctly. But, I also noticed if I push the board down making contact to the enclosure, Q2 collector goes all the way up to 5V but I get no sound. Maybe I am having ground's issues?

studio1203 · Post by **studio1203** » 21 Mar 2017, 18:08

poiureza wrote:There are lots of differences with the stock schematic.

I see that Q2c is connected to ground only via the drive pot while there should be at the very least a 12K resistor and a 10µ cap in series as well.
So if you turn the drive fully down (or up depending on how you wired it) you get zero resistance to ground and thus 0 Volts at Q2c ...

That 12k resistor in turn does exist but it is actually put in parallel ?!! with the 10µF cap right before the tone section, which makes no sense to me
etc ...

I might be wrong but I think that your layout is worth crap

It looks like, from the schematic provided by Electric Warrior (thank you BTW) that Colorsound didn't use that 12k resistor for the Overdriver. Should I remove it?

Electric Warrior · Post by **Electric Warrior** » 21 Mar 2017, 18:21

It's there. It's a 10k in some units and it's connected a little differently in the Overdriver, but it's there. Don't remove it, wire it up correctly.