Colorsound Overdriver Build !!

[petemoore]

 I had a hitch strand across the input wire, otherwise...
 I have it in a 20pin IC Socket, Q's 123 and the capacitor feeding the base of Q3 are swappable, 1.5'' x 1.5'' perfboard, assigning the IC pins as I go...that 'bass knob cap' [.1uf] feeding Q3B is good for me at .01uf.
 I raised the input impedance on Q3 because 33k seemed small to ground, so I opted for the 68k/270k I have.
 12k = ~14k [a FB resistor]
 Made Q2CR a 6k trimpot, nice value for this a bias feature.
 I dropped a 250k linear down to 94k using a 150k R across the outside lugs...it's taper is 'wavy' but still 'medium fine tunes' quite workably.
 I got it all right the first time !! I like having a big IC socket as the middle of the board, it would have been more cramped but I used some perfholes in the middle of the IC socket and populated a little bit there.
 All in all I'm just waiting to crank this thing up, it sounds great.
 tried it low/low/med volume..
 Harsh with the 2n5089's, I found a tin can unit for Q2 [2n2222 type], lower gain even than the 2n3904, then the 'CV-Ge's were pressed into service for Ge actives in Q1 and Q3 positions...very smooth like this.
 Still missing the 500pf.
Tone controls 'impressive' [sounds great to me] distortion tone quick dial style...interactive, 2 knobs, easy.
 Still missing the 500pf., it will go in there too, impressive.
 Seems to cleanup with my guitar volumes, more testing on this and other higher volume tests.
 Nice to start the New Year with a nice new distortion build !!!
  I had one that wasn't built right...there are some slick twists in this circuit.   
  The tone section is 'wirey' [aren't they all?], but Q1/Q2 look like a FB loop amp, similar to a FF but with some [what look to be well thought out, I should say 'sound to be' because the circuit sounds interesting], 'fancy' wiring in the Q1/Q2 circuit. Quite a large [6k8] resistor is used on Q1E...interesting bias arrangement and feedback loops equate to smooth sounding Distortion, Q3 must be distorting also.

[Bernardduur]

I just love my Colorsound Overdriver!


When I bought it, the shop claimed it to be a nutured fuzz box

[MartyMart]

It's a great sounding circuit, looking back at internal photo's ( as mine is a 3 knob with volume)
I must have "twisted" the bass/treble into a BMP type tone control, my volume is a 500k !
Can't see a 500pf, my Q1 C/B cap is 220pf ( 200 on schem? )
I did use all BC109's and it sounds more like a good opamp OD than a fuzz IMO
Good new years build

MM.

EDIT - I guess just adding a fourth knob for vol would keep it more original, I dont see a signal
pull down r at the end ? or I'm reading Q3 incorrectly, wouldn't there be a TON of vol without a
traditional vol control ?
Perhaps the 150k/33k at Q3 base, sets the overall vol to useable range ...

[Ge_Whiz]

First completed build of 2007 - boxed up my Colorsound Overdriver today and gave it a full workout - amazing. Works as a great treble boost with the treble up full and the drive at minimum. A real 'best of the 60s' guitar sound around mid-setting for the drive control, fuzz at the full drive setting. The output volume is moderate at most settings of the drive control, then it goes nuts at the 'fuzz' end. I did add a volume control at the output. I used BC182P transistors throughout.

A great start to 2007. Unfortunately, I've just vero'ed my second build of 2007, and it is yet to spring into life... 

[petemoore]

  Yes, this one is coming along nicely, knock on wood, it's 1/2 way in the box, nice oak'n clear box, four knobs in a recess across the 'mid'top, knobs and switch also recessed.
  I'm liking the grab an IC socket and lay it out on the fly, I probably got lucky, was real careful once again this time..lol..the input and output are on the left side of the board, pots wires out the top, the circuit does a 'backward C' shape across the IC socket in the board...twisted for sure.
 

[Xavier]

My board is already populated, so tomorrow I'll see if my perf layout classifies as verified or not . As a Jeff Beck fan, I'm really curious about this circuit ,since long ago. Can't wait to fire it up !!!

[hairyandy]

I built a Colorsound Overdrive with a master volume last summer and I loved it.  I took it out on tour with me and Peter Stroud ended up needing an OD for his "small rig" pedalboard.  I let him borrow it and he loved it so much he told me I couldn't have it back!  Bastard...what are you going to do when a guy that good digs your work?  Now I've got to build another for me...



Andy

[Xavier]

I have a wonderful Colorsound motorboater so far.

It's not a high pitch squeal, but a serious motorboating effect.

Q2 and Q3 have around 5v at the colector, but Q1 is no higher than 2v, even I have put the right 470R resistor . I guess with that 100k from 9v to colector that should be normal.

Following the signal with the oscilloscope, the motorboating starts right at base of Q1.

Any clue of what might it be?

[Ge_Whiz]

Have you got a 220 pF capacitor across Q2 b-c?

[Xavier]

Have you got a 220 pF capacitor across Q2 b-c?

500 pF. However I had a broken wire.......more tomorrow........doesn't seem to have much boost though...

[petemoore]

  The first two transistors are bias related, with the Q1C/Q2B connection, so this amp biased alot like a 2Q feedback amp, or, Fuzz Face, your voltages look ok here to me, near what I got.
  Q3 biases up like a regular amp, collector @ around 1/2v, base above emitter by..small amount, I had 2k2 and used that for Q3CR.
  5v on Q3 collector looks like a good number, as long as the base is .6v or so above emitter.
  iow, I don't see anything standing out as a place to look for problems voltage wise, they look alot like what I was getting. barring reversed transistor or miswire/misvalue, which can of course all be tested for using DMM in dogmatic application mode... 
  I would use the audio probe from input, or the 'buzztouch' method from output, if signal buzz from output signal path buzzes, and that makes it to Q3c, Q3B Should buzz louder/gainier, next back, the tone section is floating you should not find a ground in it. Q2C is the next thing back, the tone section should suck signal, so here should be not as loud as Q3B.
  Q1C/Q2B are exactly the same, Q1B should be the loudest point in the circuit [with gain up].
  Clip the voltmeter to the V+ rail at battery clip or PS jack, test the collector resistor values, Q1c = 100k, Q2 = 1k8, Q3=1k8. Same for the base resistors.
  Now clip to ground and repeat but to bases and emitter resistors values. beepcheck everything that connects to V-, on and offboard.

[petemoore]

  One pot is wired backwards and that's in there...cool thing about this is the taper is OIO reversed, and the way it works out is it's nice to keep them kind of parallel.
  Two CV-GE's and a 4401 w/2k2 collector resistor I had, make the actives, I put a 104 on the intput.
  A real joy to play with, went in bigwood enclosure, last position on PB. Loves having the input boosted, creamy Distortion, played the luschious tones for hours, the Ge's exhibited no discernable bias shift, excellent distortion from smooth soft to hard grind but not biting...
  Was noisy, guessing the tin can /now 4401 was it, because it's gain/noise performance is very...respectable...ground plane and partial shielding only !
  "C" building around the IC socket brought the output to the same side of the board as the input...short travels to switch.

[Xavier]

Thanks Pete for your HUGE explanation. Getting back to the circuit, perf is great because it allows smaller layouts than with vero and you can re-use it if you are careful, but it's very easy to make mistakes when soldering components. What happened is that I soldered the negative pole of the 4,7uF cap coming out of Q1C to the 4,7K resistor that goes to bass lug 3, instead of connecting it to the tone control node (to B1 and T3). What I'm trying to understand now is why that means motorboating, it may be some kind of feedback?

Now it works BUT the gain control doesn't do anything and unity gain is at 75% of the vol pot, so I gues something else is still wrong.

I think one good thing to add to the FAQ section would be hints on how to debug , or at least where should one start looking at when you have high pitch squeals, motorboating, gating, etc.... any kind of strange "sound fx".

Again, thanks for taking the time to answer Pete.
I have also found 2 reverse wired pots (gain is one of them), I thought it was my fault,so I reversed them and now they work OK.

[Xavier]

OK, now it works, and another lesson learned at debugging.

The transistors I've used are BC109 ,TO18 package (metal can).

Did you know that the enclosure IS the emitter? neither did I. It was in contact with one of the resistors, causing a short. I thought the enclosure was isolated , but it's not !!!!. I'e used instead of BC109 for Q1, a BC184 which is another of the specified transistors for this project.

BTW I've used a 10kC gain pot, much better than the 10kB with all the gain crammed at the very last 90% of the pot.

Instant Jeff Beck Wired-era !!!! It's kind of a OD-fuzz, with gobs of boost. To my ears sounds lightly misbiased but that's how all fuzzes sound to me anyway.