Anybody done this before? Morley PWA to PDW

Started by alparent, February 27, 2017, 12:53:02 PM

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alparent

Found the schematics. But guidance is always appreciated.  :)

Mark Hammer

So you want to add a distortion to a wah, and you specifically ant to add the Morley distortion?

alparent

The story is more like, I have a PWA with a 2/3 empty board and drawers full of components.
Is turning my PWA into a PDW not a good idea? Is the Morley distortion that bad?
Or should I just add the volume pedal section?

Mark Hammer

Fuzz-wahs are always a good idea, my friend!  :icon_biggrin:  The bigger question is whether you have a preference for wah->fuzz, fuzz->wah or want to be able to choose either one.  If Morley used the PDW board for the PWA, and simply left out the distortion section, then you have an easier job.  Looking at the schematic for the PWA, it seems a little bit different than the wah section in the PDW.  Not a lot different, but a little bit. 

I should mention that I am comparing the schematics for the PDW-II (which includes a volume pedal function, when the wah is bypassed) and the PWA, which is wah only, and does not have any volume pedal function.

The distortion is essentially a kind of Tube Screamer with a Big Muff tone control on the end.  The buffers on both the wah and distortion sections mean that sound/tone should not suffer negatively if you change the order (D-W/W-D).

Is the board legended, or is it just empty pads?

alparent

#4
What I have: http://www.morleypedals.com/pwa.pdf
What I'm aiming for: http://www.morleypedals.com/pdwes.pdf

The board looks like this: http://www.tdpri.com/forum/attachments/stomp-box/173881d1364672472-morley-wah-volume-swell-mod-cleaning-morley_pwv_1-jpg

I could even add a switch to go from WAH/FUZZ and FUZZ/WAH as you mentioned.

Mark Hammer

Okay, so we are looking at the exact same schematics.  That's a great start.
Judging from the legending that I can see, it looks like the same part numbers are legended for the distortion part.  If you can get a gut shot of a PDW somewhere, you should be able to simply install the missing parts, and confirm the connections to a second stompswitch with the picture.

Would you need to drill holes for additional controls/toggles-switches?

alparent

Yes extra holes are needed. But since Morley builds any variation in the save enclosure. All the space needed is available. No squeezing in things. (Only the W/F, F/W switch maybe)

I'm convinced this is a pretty simple upgrade.

I will just need to trace the thing to figure out the jumpers. As the schematic makes not mentions of the jumpers.

Mark Hammer

But you should be able to figure out what parts of the circuit the jumpers go to.

alparent

Yes.

Those jumpers are probably just used to jump the signal over those circuit sections that are not used.

gambitpawn1

I actually did this lol years ago. Better late than never to the discussion. Yes you have to remove some of the jumpers and add in a few others. You can skip the parts for it to work as a volume pedal, I did. Don't forget to remove resistors  R7 and R8 and populate R7A and R8A both with 3.3K.

I'm currently looking for mods for the distortion, looks like I should start with the tone circuit.

Also need to figure out what R2 does, schematics say it's supposed to be jumped but mine has an 82K resistor there?