Colorsound Overdriver debug

[Cortex]

1.What does it do, not do, and sound like? => It sounds nice with single coil pickups [I have never played an original, nor a clone so I don't know how "nice" it sounds, I like it] BUT as soon as I plug a humbucker equiped guitar the sound becomes awful. It sounds so gatey and farty, even with the pedal's gain on minimum. It's unusable, almost as a Fuzz face with the pots cranked but bias on the colector of Q2 around 1V, or less. Awful.
2.Name of the circuit = Colorsound Overdriver / Power Boost
3.Source of the circuit (URL of schematic or project) = http://3.bp.blogspot.com/-RTnDcoOFYRk/UEUcoPV5XHI/AAAAAAAACT0/Kw0e5WvWB08/s1600/ColorSound+Overdriver.png
4.Any modifications to the circuit? No.
5.Any parts substitutions? No substitution, I used russian PIO caps, two electros are Panasonic, other or some chinese...
7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => 9.6V

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1
C: 1.66
B: 1.02  
E: 0.51

Q2
C: 5.02  
B: 1.66  
E: 1.05  

Q3
C: 5.01  
B: 1.53  
E: 0.95


I have trimpots in there so I adjusted the voltages on the collectors right. Here's a picture of the build



I read somewhere on the internet that one guy had a similar problem, I don't know which layout he used nor anything else...Really, I can't see what could be wrong. Transistors biasing right, pots doing what they should, really, this puzzles me a lot. Could it be electros? These old russian caps? I used them in some other circuits and they are great. I would appreciate some recommendations of where to look for mistakes etc...Maybe some point on the layout [schematic] where I could measure the voltage and report...Thank you all.

[Cortex]

Oh, and I used BC184B transistors with hfe's around 320.

[crane]

Hi!
I've built about 5 of these.
It is seems that collector voltage of Q1 is too low.
Check biasing resistors and collector resistor for wrong values or wrong connections.
Humbuckers have bigger output - so they can easier saturate a tranny - especiall so badly biased as Q1 in your situation.

[Pyr0]

Your transistor voltages look fine, Q1 will never have anywhere near 4.5v on it's collector with a 100k to Vcc
Here's my voltages for my last one, and it sounded fine with humbuckers.

Battery 9.25
Q1
C: 1.8
B: 1.1
E: 0.56

Q2
C: 4.91
B: 1.79
E: 1.16

Q3
C: 5.72
B: 1.51
E: 0.91

[Cortex]

Oh...thank you for the replies really guys, but now I don't know what to think  Crane made 5 of these and is certain that my Q1 collector is badly low, but I thought I got the voltages right [like in a textbook, these are the expected voltages] and Pyr0 agrees.

Hm, what voltages were you looking at Crane in your builds?
I'm almost color blind, so I can't that easily check for the resistor color codes and decipher the values, maybe some value is bad somewhere...Hm, it would be a massive help If someone could point to places on the schematics [components] that could be easily changed [by mistake of course] and still get the correct voltages on the trannies. I know it's a lot to ask but I don't know where to look, it's such an absurdly stupid and unexpected situation...

[Pyr0]

Humbuckers normally produce a higher output voltage, so maybe you have an electrolytic capacitor polarity the wrong way and only the higher voltage from the humbuckers is causing the signal breakdown. I had this once in a Rat pedal, once I turned the gain past 1/4 it would gate badly, turned out I had an electro in backwards that was in the signal path.

[Govmnt_Lacky]

Too lazy to provide this but...

Are the transistors oriented correctly? I see you substituted some of them.

Looks like there is a pinout difference between BC169s and BC184s. Look there 

[Cortex]

Thanks for the suggestions guys. I have the pinout definitely right, and the electros as well.
Theres no much left to consider, I'll have to try swapping the electros with some new ones and see if that will change the behavior of the pedal. I really hate desoldering but a man's gotta do what a man's gotta do...

One thing I forgot to mention, unless my perception of loudness is a little different than everybody else's I don't think that this thing is CRAZY loud, as the Colorsound PB has been frequently called, so maybe there could lie a symptom as well. It is normally loud it goes quite above unity volume level of course, but I expected excruciating loudness.

I really want this thing to work. Will be back with the findings as soon as I swap the electros with some new ones.

[crane]

Hello again!
Sorry for misleading you - Pyr0 is right - tranny voltages are fine. I shouldn't write posts late at nights
Some thoughts going through my mind right now - do you use C type pot for GAIN?

[Cortex]

Oh my God. Thank you all for participating but what was wrong was the stupidest thing that could be wrong. It was the layout. A bunch of people used that layout to make the CS Overdriver so I figured why should I put the layout / schematics relation to the test. But in the end I did just that, and one electro was turned wrong, I fixed that on my vero and everything worked beautifully.

I subbed the bc184b for the bc109c trannies and I think I like the sound better. These are a little higher hfe, 430 all three. I got more sustain and the grit is equally beautiful through the whole Gain pot rotation. I am very pleased with the effect so far.

I can't believe it was all wrong because of the layout. What a bummer. Thank you all for scratching your heads for me, a virtual beer to everybody!

[Pyr0]

Told you it could be a cap in wrong  Glad you got it working right in the end. It's a great pedal - just ask Jeff Beck. 
If I'm working from someone else's layout and I have a problem with the build, I will do a quick check for shorts, then wrong components, then I always start working out the schematic to verify if the layout is correct, I've come across quite a few that were bad, even though they were supposed to be "verified".

[Cortex]

Well that was some lesson for me...Definitely will be cross referencing layouts and schematics from now on.
And YES, I am a huge Beck fan
This thing sounds great, I'm loving it so far, definitely a keeper.

I was using it last night to give sustain and body to a volume-pot-on-my-guitar-cleaned-Fuzz-Face tones, and although it is a flat boost, it gave an unbelievable amount of mids to that kind of tone. Weird. I wonder if anyone used their Overdriver for a similar purpose, gotta start the topic like this and see what people are using for this.

Thank you guys, see ya on my next problematic build haha. Cheers!

[Georgedepinedo]

Hello there, I know that this post is old as hell, but would you mind sharing which cap was reversed?
Thanks !!

[Rob Strand]

Hello there, I know that this post is old as hell, but would you mind sharing which cap was reversed?
Thanks !!

You should post a link to the layout and schematic you are using.

When I look at the layout and the photo of the build in this thread I cannot see a cap backwards!

For that circuit (as far as I know), the cap polarities can be summarized as:
- if a cap connects to an emitter the cap+ goes to the emitter.
- if a cap connects to a collector the cap+ goes to the collector.

There was a thread back in 2013(?) discussing some points about this circuit.

[Rob Strand]

OK I think I have solve the mystery of the Colorsound Overdrive Colorsound Powerboost.
With the aim of trying to put this issue to bed once and for all I traced the Power boost pcb.

The summary is:
Fix 1) The cap's going to Q3's collector should have their +terminals going to the collector.
          In particular the cap from Q3's collector and the tone control which is shown the wrong way around
          on some schematics.
Fix 2) The 12k resistor connects to the emitter of Q1 and the collector of Q2, not the other side of the cap
          as shown in the original schematic.

The wrongs of the past:
- What's happened in the past is the 12k resistor connected to the wrong side of the cap on Q2's collector.
  This is how it is shown on the original schematic.  This removes any DC from the 12k resistor and upsets
  the DC biasing of Q1.
- The "wrong" fix was to reverse the electrolytic cap between the collector of Q3 and the tone control.
  Reversing the cap to the wrong way around causes it to leak DC through the 12k resistor.  This
  pushes the DC closer to what it should be so people think this is the fix.

In this old thread Electric Warrior posted schematics showing  the correct connections:
https://www.diystompboxes.com/smfforum/index.php?topic=103268.0

The problem now is there's dodgy layouts out there which need to be fixed:
1) The electrolytic cap which connects between Q3's collector and the tone controls should have its
    +terminal connecting to Q3's collector.
2) The 12k resistor which goes to the electrolytic on Q2's collector should connect to Q2's collector.


EDIT:
FYI for those who want to see the PCB.

[Electric Warrior]

2) The 12k resistor which goes to the electrolytic on Q2's collector should connect to Q2's collector.

In the Power Boost, yes,  but in the Overdriver it connects between the drive pot and cap-. Unfortunately I don't have a trace shot of an Overdriver, but you can see it in the reissue as the board is slightly translucent: http://www.macaris.co.uk/overdriver-by-stu-castledine/p/p1800

[Rob Strand]

n the Power Boost, yes,  but in the Overdriver it connects between the drive pot and cap-. Unfortunately I don't have a trace shot of an Overdriver, but you can see it in the reissue as the board is slightly translucent: http://www.macaris.co.uk/overdriver-by-stu-castledine/p/p1800

Ah, good catch.  Thanks.  I'll check out that pic and see what I can find.  I'm pretty sure I don't have any track side pics of the PCB for the Overdriver.

Interesting thing is people have been flipping the cap between the Q3's collector and the tone control on the Overdriver.   That's probably going to turn our to be wrong; the right way is shown on your schematic.    So maybe what that's saying is people actually prefer the biasing used on the Power Boost!

[Rob Strand]

In the Power Boost, yes,  but in the Overdriver it connects between the drive pot and cap-.

For the Overdriver I spotted another difference between your schematic and the factory schematic.

On the factory schematic the 12k goes to the emitter of Q1, however on your schematic it connects to the Drive pot.

In the case of your schematic, flipping the cap between Q3's collector and the tone control has no effect on the bias as each end of the 12k is AC coupled.  (The cap flip would put the cap around the wrong way.)

EDIT:
I can't find a track side shot for the Overdriver.

- The 12k resistor on the Overdriver is mounted above the Drive pot.  This tends to confirm
   Electric Warrior's schematic.

- I don't really know which order the Drive pot and the series electrocap are connected;
  ie. cap to ground or Drive pot to ground.

If the Drive pot goes to then this makes sense:
Assuming the 12k does connect to the Drive pot, it then makes sense that other side of the
12k resistor connects to the tone control side of the Electrolytic cap  on Q2's collector.
If it did not the 12k would place a DC load via the Drive pot on Q2's collector,
which is highly unlikely.  Also  with this connection the flipped cap can't do anything, so the flipped
cap must be wrong.  All this points to Electric Warriors Overdriver schematic.

Still not 100% confirmed.

[Electric Warrior]

That's what I was trying to tell you in the post you quoted. 

When I drew the schematic, I had the exact location of the 12k resistor confirmed by Stuart Castledine. I didn't just guess where it connected.  Though it was kinda obvious that it had to connect with the pot in some way

[Rob Strand]

That's what I was trying to tell you in the post you quoted. 

Sorry, I'm a bit thick today 

When I drew the schematic, I had the exact location of the 12k resistor confirmed by Stuart Castledine. I didn't just guess where it connected.  Though it was kinda obvious that it had to connect with the pot in some way

OK cool.  We will go with that then.  I was trying not to use the Re-issue in case it followed some historical bug.  It's not that I don't trust Stuart's work, I was just trying to find a real pic.  Stuart's probably clocked up more miles on Colorsound's than anyone.