Colorsound - Power Boost / Overdriver

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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cpm
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Post by cpm »

...
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overd_pcb_front.jpg
overdr_pcb_back.jpg
overlay.jpg

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clintrubber
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Post by clintrubber »

Thanks for the pics'n'files!
cpm wrote:Notice the connection of that 12k feedback resistor now it goes right into the gain pot, not to the emitter of Q1 like the old schem.
Won't make much difference, the involved caps are DC-blocking, not toneshaping. The 12k is already 'DC-less' because of the caps @ its other side.

Bye

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cpm
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Post by cpm »

so, can anybody tell the values of the components in the pictures? (previous page)

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cpm
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Post by cpm »

the colored cap looks like 47n?

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Post by jamiefbolton »

Image

is that a 6.4+ cap or a 64+ cap

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Post by clintrubber »

The one you indicated looks a 25uF, but you might want to know the other one connected to the collector of TR2 ? That one looks a 6.4 uF, looking at the number-spacing & the point-style they use at other components.

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Post by Aharon »

Some links expired /are missing so I thought I'd refresh the thread with this schem,you probably know this one.
http://www.schematicheaven.com/effects/ ... driver.pdf
Aharon

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Electric Warrior
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Post by Electric Warrior »

I just fought myself through dozens of Power Boost and Overdriver gut shots. Here's some variations of the circuit:
PBODschmeatics.png
any mistakes?

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Post by analogguru »

Electric Warrior wrote: any mistakes?
Yes... after a quick view at least the 22µF (4µ7) from the collector of the third transistor shouldn´t connect to the base instead it should be connected to the junction 4k7/0,01µF (one row to the left).

analogguru
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Electric Warrior
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Post by Electric Warrior »

uh :slap:
That one used to be right, but I had mistakenly used the symbol for a regular capacitor. must have happend when I "fixed" it.
thanks a lot for spotting it right away, AG!

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Post by tatter »

Is there a major difference in the sound between the 3 versions? I've just built an Overdriver and love it.

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Electric Warrior
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Post by Electric Warrior »

no idea, I didn't build one yet. I just had a close look at the circuit to get an overview. I think I'll go for the second version of the power boost..

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Post by tatter »

I have the 90s reissue of the Power Boost, it is 9v and the gain pot is 2k2. I think there are a few other minor differences as well.

Image

Image

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Electric Warrior
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Post by Electric Warrior »

another update. the smaller electrolytics in the later versions are 10µF, not 4,7µF

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Post by Dr Tony Balls »

I built one of these for a friend using BC109s. Came out sounding pretty damn good, and before sending it to him I added a master volume out the side upon request.

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he quoted "it's the best distortion I've ever had". I dont know if i'd go THAT far...but its a still a rad pedal.

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Post by pf_fan »

Electric Warrior wrote:I just fought myself through dozens of Power Boost and Overdriver gut shots. Here's some variations of the circuit:
I hope you'll find those pics useful as well :)
http://www.megaupload.com/?d=S3OUCL39

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Post by Aharon »

Dr Tony Balls wrote:I built one of these for a friend using BC109s. Came out sounding pretty damn good, and before sending it to him I added a master volume out the side upon request.

Image

he quoted "it's the best distortion I've ever had". I dont know if i'd go THAT far...but its a still a rad pedal.


Hey Dr Tony ,did you just stripboard it and which schem did you use...?
Thanks
Aharon

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Dr Tony Balls
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Post by Dr Tony Balls »

yup!, used this vero layout, which checked out against the original schematic that you posted.

https://aronnelson.com/gallery/main.php/ ... d.jpg.html

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Post by Aharon »

Thanks Dr Tony.
Aharon

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Post by .Mike »

I plan on building one of these. Out of curiosity, I modeled the three circuits with the gain up all the way to check out the difference in waveforms. In case anyone is interested, here are the results:

Image

I'll probably do the frequency response later, and if anyone is interested, I'll post that if/when I get it done.

:)

Mike
My website: America's Debate | My effects site: Just one more build...

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