Colorsound Overdrive de-bugged :D

[MartyMart]

http://img78.photobucket.com/albums/v324/caseyseffectpage/

here's the schem from casey's page .... thanks BTW
I dont see much mention of this circuit... ? I build one about three months
ago and didn't get around to de-bugging it 'til now.
It sounds absolutely "HUGE" and is easily as good as the Jordon Bosstone
......  :twisted:

Here's how I got mine to sound so nice :
Q1's emitter - repaced the 6k8 with a 10k trim
Q2 - came up fine as is, though a 5k collector trimmer may be needed
Q3 - used a 10k trimmer from 9v to collector
All three transistors are BC109's

Tone Stack:
I decided to use a nice BigMuff tonestack to replace the bass/treble controls.
From Q2 is a 6.4uf cap ( 4.7uf in my case ) I just took that as the input
to the BMP tonestack.
From the output of the tonestack ( wiper of the 100k pot ) I connected a
0.1uf poly cap to the base of Q3, with the 33k to ground and 150k from
9v just before the tranny - as per the original.
Then I just kept the (trimmer) from 9v, 0.22 outcap to a 100k volume pot
the 22uf/470ohm to ground off the emiter ..... done !!

I VERY much recommend this circuit - its a "sleeper" and is a real nice
"kick ass" overdrive/Fuzz  

Cheers,
Marty.

[Rodgre]

Thanks for debugging, Marty. I've tried this one twice and haven't gotten it to happen yet. I'm hoping I can apply your changes tomorrow and get one happening!

Roger

[MartyMart]

Thanks for debugging, Marty. I've tried this one twice and haven't gotten it to happen yet. I'm hoping I can apply your changes tomorrow and get one happening!

Roger

I did have a couple of "mistakes" also ......
The most important "fix" seemed to be Q2/Q3  they must have as close to 5v as possible on the collector .... trim ... trim ... trim  !!
The BMP tone stack I used also makes it a bit simpler - works well BTW

Cheers,
Marty.

[Eric H]

The BMP tone stack I used also makes it a bit simpler - works well BTW

Cheers,
Marty.

You added a lot of gain at that point  ( doubled?)  maybe that's what it needed. I've never read a good report on this design before.

-Eric

[MartyMart]

That's true, there may well be less "drop" due to the simpler tone control
but all the "gain/clipping" is done on the previous stages .... no ?
There is definately NO low volume problem with this beast  !!!!  

Marty.

[Doug_H]

You added a lot of gain at that point  ( doubled?)  maybe that's what it needed. I've never read a good report on this design before.

-Eric

The funny thing about it is the "Overdriver" gets fairly lukewarm reviews while the "Power Boost" generally gets nice write-ups.  A lot of people seem to really like the Power Boost.

According to this

http://homepage.ntlworld.com/s.castledine/greenfuz/overdrv.html

the only difference is the output volume pot.

Of course this explains some of the comments about the PB being "really" loud and etc. But I'm guessing that the reason it reportedly sounds so good is because it is truly boosting the amp and getting some amp mojo going too.

Some boost circuits don't sound so great to me when the output is throttled, mainly because they really don't clip much internally. I'd bet Colorsound added the volume pot to make the circuit more flexible. But perception is everything. It's funny when you stick a volume pot on something how it can change people's perception of how something is meant to be used.

Sometime I'd like to give this circuit a whirl on the breadboard and just dime (or leave off) the volume pot and see what it's got.

Doug

[Bernardduur]

Hey, I have an original. Love it to death

[brian wenz]

Hello Hello--
    I built  a Colorsound OD a few years ago with BC184's and it is one of the BEST overdrives I've ever used.  I used them back when they first came out [early 70's] and liked them, so I had a good "memory" of what they sounded like.....I wasn't let down at all!    Like most English circuits, they sound best through Marshall or Vox- type amps.
Brian.

[cd]

Does yours do the annoying CSOD thing where the cool fuzz doesn't come in until the last 5% of the pot rotation?

[MartyMart]

The wierd thing is that i "added" a volume pot - simply because I had so
much "boost" going on, it was breaking up my tube amp all the time !!
I ended up with a 250k pot ( 500 + 500r ) as my last 100k pot is "duff"!!

Well worth a build, I can't stop playing it  !!
Thanks for the interest guy's .....

Marty.

[MartyMart]

Does yours do the annoying CSOD thing where the cool fuzz doesn't come in until the last 5% of the pot rotation?

Aha ..... it "was" .... 'til I opted for a "linear" 10k pot , now its better, comes on at around 1/3rd rotation - heavy fuzz at about 2/3rds

Marty.

[Bernardduur]

Does yours do the annoying CSOD thing where the cool fuzz doesn't come in until the last 5% of the pot rotation?

Yes, on mine is that feature...... heavy compressed FUZZ.

As I say, I love mine

[Stuart]

The original Overdriver didn't have a master volume, that's only on the reissue.  The later Power Boosts are the same as the Overdriver, but some earlier PBs have a slightly different circuit and run on 18V.

[brian wenz]

Hello Hello--
     HI Stuart!
  Yeah, mine gets REAL fuzzy at the last 10% of the pot.
Brian.

[psst]

There are some differences between "fuzz central" schematic of the Overdriver and this one you post here, some caps values are different and some resistors too.
Does anybody know which one is the real one?
It would be nice that an owner of an original one could clear this up...

Here are the differences marked in red:

[psst]

The most important "fix" seemed to be Q2/Q3  they must have as close to 5v as possible on the collector

Ok. And what about the trim at Q1's emitter? Did you use i t to achieve a certain voltage or you adjusted it "by ear"?

[MartyMart]

The most important "fix" seemed to be Q2/Q3  they must have as close to 5v as possible on the collector

Ok. And what about the trim at Q1's emitter? Did you use i t to achieve a certain voltage or you adjusted it "by ear"?

Sorry,
yes that's also important, but it didn't make the circuit sound "bad" or
out of "bias" .......
That 6k8 seems to help set the "range" of the 10k gain pot.
I made it variable with a 10k trimmer, as I liked the range with an 8k2
resistor there, but wanted to "tune" it in a bit.
With a 10k linear pot and that 10k trimmer, the "fuzz" comes on a bit
earlier and has a "nastier" top limit  !!

Worth a try anyway

Re: The schems ....
The posted schem at the top of this subject seems to be the "original"
colorsound schematic.
If you compare it to Phillips schem, most of the "red" marked values
match up.
the original didn't have a volume pot ( I think it is needed ) and had odd
values like a 6.4uf cap and 25uf caps ...... I dont have those, so have
used 4.7uf and 22uf's just like Phillips updated schematic.
Hope that clears things up a little

Marty.