Colorsound flanger schem? + Arbiter Booster pics :)

[Moonface]

what would be good substitutes?

BC547-549, BC550, BC337, 2N5088, 2N5089, BC237-239, BC182-184

[usbdevice]

BC547-549, BC550, BC337, 2N5088, 2N5089, BC237-239, BC182-184

Excellent, thanks!

-Lenny

[leonhendrix]

good work 

The pots are worn but it looks like they are all 25kA

yeah and the 4k7 from Q2 base to 9v should be 47K

[RickL]

Success! It works. I'd say the 47k resistor made the difference. It's a little noisy but that's probably because it's not boxed.

The bass control seems to operate mostly as a bass cut control but the treble actually adds high end.  I got a sound pretty close to bypass with the bass maxed and the treble minimized.

There isn't a whole lot of boost and what's there is mostly in the top little bit of the pot (I used linear pots for all the controls so that's to be expected). This might be due to the PN2222's I used since their gain is a little on the low side but I bet using higher gain transistors won't make much difference. There doesn't seem to be much difference when using a 100k volume control over using a 25k. I'd say use whatever is convenient.

I wouldn't call this a must build but it's simple enough that it can be thrown together in a couple of hours and it's certainly a nice enough addition to the booster family of effects.

[3/4 North]

Great! I couldn't figure it out last night, glad you guys did.

I updated the schem, flipped it for the transistors, then flipped the middle to get the pots reading the correct way.

[R.G.]

Nota Bene:
The circuit is an emitter follower driving a passive Baxendall tone stage, and the "plus" control is simply a volume control before the final boost.

Passive Baxendalls typically have 20db of loss in the flat position, and generally use audio taper pots for linear effect-per-rotation feel.

Active Baxendalls achieve the same thing by using the frequency selective stuff as feedback, and look similar, but use linear pots.

The Colorsound Overdriver is a similar setup, but uses two transistors in a feedback-pair arrangement before an active Baxendall tone section.

[usbdevice]

Sorry, I wasn't able to post this weekend after I breadboarded the circuit. I don't have much to add at this point, and can only agree with what Rick and R.G. wrote. There isn't a whole lot of boost. I used 2 2N5088s and didn't have 3 25k pots so I used a 25k for the bass control, a 50k for the treble control and a 100k for the plus control. It works fine this way but of course I have no comparison to the sound of 3 25k pots. Out of interest I bypassed the tone circuit and that did indeed restore a lot of gain, and it didn't sound bad either. Before I did that though I replaced the emitter resistor on q2 with a 1k pot and was able to tickle a little more gain from the circuit by adjusting that as well.

I wouldn't call this a must build but it's simple enough that it can be thrown together in a couple of hours and it's certainly a nice enough addition to the booster family of effects.

+1 on that. Overall it's a very subtle boost effect, but with nice tonal possibilities.
I wonder though. With this much of a gain loss through the passive tone control, isn't it a bad idea to run the q2 at a fixed gain and just attenuate the signal to that transistor? Won't the noise generated by q2 remain constant regardless of the plus setting? I'm thinking in terms of signal-to-noise ratio here.

-Lenny