Boss - PW-2 Powerdriver [schematic]

[roseblood11]

Hi,

does anyone have a layout for the Boss PW-2 Powerdriver?

It´s a quiet unique and interesting sounding distortion pedal that was only built for a couple of month ( <20.000 units made).
I sold that pedal cause I only use diy effects with a true bypass, but now I found out that I can´t copy the sound of the pw-2 ...

schematics:
http://www.schematicheaven.com/effects/ ... rdrive.pdf

info:
http://www.bossarea.com/loadpage.asp?file=boxes/pw2.xml

Where are the kings of the veroboard who bring this little machine back to life?

regards, Immo

[Entrant_21]

I think behringer has a clone of this..the Power Overdrive i think.. PO300 maybe?

http://www.behringer.com/EN/Products/PO300.aspx

Have you any soundclips of this pedal? I wouldnt trust the behringer samples..badly DI'd and compressed.

[roseblood11]

That silly spammer made me look into this old thread again...

Has somebody tried to clone the PW-2 in the meantime?

It's a very interesting pedal, quite unique sounding. I had one a couple of years ago. Remember U2's live shows in the "Achtung Baby" / "zooropa" era? Some of those extremely trashy "Heavy Plastic" sounds came from the PW-2.

Somebody at the tagboardeffects forum posted a vero layout of a stripped down version. Not a bad start, but I think it was a little too stripped down, for example the complex power supply was simplified a lot.

[roseblood11]

http://guitar-fx-layouts.42897.x6.nabbl ... 39641.html

[Matlevo12]

Hi.
Sorry about waking up yet again dead post.
If anyone reads this : there's another topic (on another website) in which someone noted 2 differences/errors on this schematic
(also available here just in case : https://www.audioservicemanuals.com/b/b ... -schematic)

First (easy one) : after the gain pot, the two lines are connected (the one from the 100R resistor going to A, and the one from the 2SA1048 collector going to the 1k resistor.

Second one : the resistor before the first opamp is a 47k, not a 4.7k

I'm thinking about replicating it (using an opamp instead of the discrete stage, and maybe change the EQ), and I have a question for you wonderful and nice people :

The first transistor after the bypass system is biased to 2V and "powered" with 4V. It doesn't seem to be related to the transistor itself, its datasheet is not very far from a 2N5088 (I might have missed something though).
Do you think it's done in order to increase saturation / drive ? It only seems logical
I'll just breadboard it when I have the time and use a switch to change between 2/4V and 4.5/9V to hear what changes there, but if anyone has an clue before that I'm really interested in your insight.

Thanks !

Mat

[Matlevo12]

It only seems logical

(yes I just quoted myself)
I knew I'd read that somewhere, and I found it, if was in one of Jack Orman's books "Distortion pedals explained", about the Maestro FZ-1 :
"The first version of the Maestro pedal used two 1.5 volt batteries as power, which limited the output to less than 3 volts peak-to-peak, but the FZ-1A revision used only a single 1.5 volt battery so it sounded even fuzzier because it had half as much voltage to work with."

Anyway today I was about to breadboard the first transistor stage only when I realised the whole "discrete opamp" stage that follows is powered with 4.5V and biased to 2.45V (between the 180k and the 220k).

If I compare the first stage (gain boost) of the FZ-2 and the PW-2 gain stage, it's obvious :


I've seen a video on youtube analysing the PW-2 in depth, and saying it had asymmetrical clipping, which makes sense with the 2.45 / 4.5V thing.

Anyway, one day I'll try it with a pot to change the power/bias and see how I like it.

[VitaliiBobrov]

I build my version of PW-2 some time ago using the schematic (the only one available here and on the Net) and it didn't sound the same as my original Boss PW-2. So I opened it up and verified all the values, plus measured voltages. I spotted a few mistakes: the value in Fat gyrator resistor 220R instead of 2k2 listed in the schematic (this causes the gyrator to be centered at 40Hz instead of 130Hz as it should be) and the resistor setting gain for the EQ buffer stage was 47k instead of 4k7 listed. I wasn't sure about Zener diodes values in the power supply stage and won't desolder them, so I did a SPICE simulation to find the values based on voltages in my original unit and changed them accordingly. All those fixes made a pedal sound like the original PW-2. Attaching my schematic, I tried to number all components as they are on Boss PCB and added transistor groups suffixes.

[Matlevo12]

I build my version of PW-2 some time ago using the schematic (the only one available here and on the Net) and it didn't sound the same as my original Boss PW-2. So I opened it up and verified all the values, plus measured voltages. I spotted a few mistakes: the value in Fat gyrator resistor 220R instead of 2k2 listed in the schematic (this causes the gyrator to be centered at 40Hz instead of 130Hz as it should be) and the resistor setting gain for the EQ buffer stage was 47k instead of 4k7 listed. I wasn't sure about Zener diodes values in the power supply stage and won't desolder them, so I did a SPICE simulation to find the values based on voltages in my original unit and changed them accordingly. All those fixes made a pedal sound like the original PW-2. Attaching my schematic, I tried to number all components as they are on Boss PCB and added transistor groups suffixes.

Thanks a LOT !

[roseblood11]

Updated layout from dirtboxlayouts:
https://dirtboxlayouts.blogspot.com/202 ... r.html?m=1