High voltage readings on Colorsound Overdriver? (Powerboost?)

[mth5044]

Alright, I built the Colorsound Overdriver from the layout and schematic from Fuzz Central and Bill Lawrence

Schematic: http://fuzzcentral.ssguitar.com/schematics/overdriverschem.gif
Layout: http://fuzzcentral.ssguitar.com/pcbs/overdriverlayout.gif

I followed the layout pretty closely. Substituted 22uF in for the 3 25uF, but wired them off board because I got ones that were way to big 

I am using 2N5088 transistors.

It does not pass any signal when engaged.

Voltages:

2N5088

Q1
C 8.75
B 7.79
E 8.88

Q2
C 9.44
B 8.75
E 8.94

Q3
C 9.44
B 8.81
E 8.93

Also, the pinout of the 2N5088 does not match the direction the transistors are facing in the layout provided at the top. Atleast I don't think so.

Any help would be greatly appreciated.

Thanks a lot 

[mth5044]

Alright, just connected the PCB to ground           

and am getting these readings:


Q1
C 1.40
B 0.59
E 0.12

Q2
C 6.56
B 1.40
E 0.63

Q3
C 7.52
B 1.10
E 0.51

Sound: I'm not getting a boost when the gain and volume are full, just some gritty (although nice sounding) tone. Tone controls work.

[mth5044]

Sorry, volume control works, gain does not.

[.Mike]

Hi,

I don't have any insight into what's wrong with your circuit, but I just went ahead and measured the voltages for you of the one I built. I used this schematic.

V+: 9.52

Q1
C: 1.66
B: 1.02   
E: 0.51

Q2
C: 5.06   
B: 1.66   
E: 1.05   

Q3
C: 5.41   
B: 1.53   
E: 0.95   

I don't know if that will help, but I hope it does.

Mike

[mth5044]

Thanks so much .Mike  I really appreciate you going through the trouble 

I couldn't seem to find any voltages out there for this project, so these definitly help.

Thanks so much!

[petemoore]

  Was gonna say Q3 looks a little high, of course the voltages are all relative to the supply voltage.

[mth5044]

Ah, sorry. I am using a power supply which read ~9.5v IIRC

[.Mike]

Thanks so much .Mike  I really appreciate you going through the trouble 

I couldn't seem to find any voltages out there for this project, so these definitly help.

Thanks so much!

You're welcome.

It's probably worth noting that, according to the schematic I used, the 1.8K resistors should be adjusted so that the collectors of Q2 and Q3 sit at 5V.

Now that I look at it, I believe Q3 on mine is misbiased, although it sounds fine to me.

Mike

[petemoore]

  Bias has always seemed like a ballpark thing.
  It does help to know where people are tending to hit homeruns, in any particular field/circuit.

[Axr280]

Hello
I've built a colorsound power boost 18v exactly from the original board, except transistors are BC109, and I've used two 4.7Ks and one 1K liked together instead of using a 10k resistor. The board connects to a 18v adapter, but bass and treble pots don't work and the volume pot (10k) doesn't work from zero, it starts working from about a quarter and when I turn it all the way up sound level is too low.
Does anyone know what is wrong?

[Rob Strand]

Does anyone know what is wrong?

It's possible you have some electrolytic caps installed the wrong way around.
To some extent, the fact two areas of the circuit are misbehaving confirms this.

Another possibility is shorts on the PCB or soldering.

FWIW, you might want to dig through some of the forum archives for posts by Electric Warrior.
There were some errors on the some of the Colorsound schematics and those errors
were transferred to some of the older layouts.