Mold Spore Wah tip.

[digi2t]

Tip of the day...
from the Hen's Tooth Cafe!

To any of you that own a Mold Spore Wah, here's a little tip to help correct a unity gain difference between the overall pedal volume, and Ring Mod mode straight signal volume.

I noticed on mine that when the ring mod volume (VR3) was on minimum, and the ring mod straight volume (VR4) was on maximum, I would get a fairly significant volume difference between wah and ring mod modes. Turning the main volume (VR2) down doesn't help either, since this is the overall volume control for all modes. Here is the schematic;



After doing some tests, I finally replaced R28 with a 100K trimmer. Increasing the gain of the op amp did the trick. Now I have it dialed in so as the volume between the two modes is equal. It also allows just a bit more of the straight signal to bleed through into the ring mod allowing for more dissonance.

For those that have never tried this pedal, it really is something else. Apart from being a REALLY good wah, adding the ring mod to the mix can really kill whatever brain cells one might have left.

[armdnrdy]

These things sound pretty cool!

http://www.youtube.com/watch?v=OCMo-ynOFh4

[John Lyons]

Cool tip Dino.
This one has some juicy sounds as well.

[armdnrdy]

The thing that kind of sucks about building one of these is finding an enclosure the accepts two treadle pots. I haven't looked at the schematic accept for a glance.....maybe customize a dual pot?

I'll have to take a look.

[John Lyons]

Both pots are 10K audio. Should be doable...

[armdnrdy]

Yeah! I just took a look. At first glance it looked like the pins from the rotary switches were coming out of the pots. (if that makes sense)

I checked on the LM565CN. There's an NTE equivalent plus JAMECO sells the original.

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_24352_-1

I wonder if anyone knows of a "work alike" phase lock loop that can be used in this circuit instead. Looks like data sheet hell ahead.

[John Lyons]

http://www.ebay.com/sch/i.html?_nkw=lm565&clk_rvr_id=418980437446&adpos=1s1&crlp=10905661572_2416792&MT_ID=70&tt_encode=raw&keyword=lm565&geo_id=9932&adgroup_id=3043234572&crdt=0

The wah pot is 100kB, I was wrong....

[digi2t]

Yeah, it's twin 100k pots, but not ganged together. They're facing, gear to gear, sharing a double wide rack. That's the only thing that's holding me back from cloning it.

[John Lyons]

Should be doable by replacing the original pot bracket with two bent
aluminum stock mounts.
Or is there enough room for two side by side?
Where Gagan when you need him? 

[joegagan]

[joegagan]

[John Lyons]

Bam!

The Wah pot is VR1 (stockish Wah circuit there). Not sure what the other treadle pot is.

[armdnrdy]

I was just looking at the drawing and I think that the wah pots are the two 10KAs labeled VR3/Ring and VR4/Straight. VR3 is downstream from the vactrol just like in Craig Anderton's wah mod that's on R.G.s site.

I was looking at the "naked" wah shells from Mammoth and it seems like there would be room for a dual pot. It seems as if the rotary switch would have to be relocated away from the wah pot. Maybe that's why the mold spore was designed with two seperate pots and a custom made shell. Maybe the designer wanted the controls to be "right were he wanted them!"

[armdnrdy]

Joe's like a jeanie.....you just rub his wah and he appears!

[joegagan]

i have google alerts for my gmail. anytime someone posts on the web about loch ness monster+ sparkle red shoes i get summoned.

[armdnrdy]

So Joe,

The two pictures you posted. Is the first one the right way to do it and the second one.....well....to be honest....I thought that something caught fire in that one! I guess that picture proves that anything can be fixed with drywall screws, duct tape, and from what I see....plastic.

[joegagan]

thanks larry. neither one of those was for sale, and the kluged one has held up for over 6 years, including the wee little 9mm alpha pot.

posting that lower photo should be helpful for people interested in fast prototyping methods. i love sheet ABS and hot irons/100watt bulbs.

[armdnrdy]

Joe,

Thanks for the pics! Well the first one!

[Ronan]

Yeah, it's twin 100k pots, but not ganged together. They're facing, gear to gear, sharing a double wide rack. That's the only thing that's holding me back from cloning it.

I'll second that, I have one in pieces and definitely 2 x 100K pots.

Bam!

The Wah pot is VR1 (stockish Wah circuit there). Not sure what the other treadle pot is.

I have no idea where the second pot is on the schematic either.

There's also an error in the wah section of the schem, R6 and R7 are shown in parallel. Actually its not an error, because the pcb has these resistors in parallel too. I removed R6 (33k) on mine, it must have been a good change because I didn't put it back in. I think the original intention may have been to have the 33k across the inductor. An error that never got picked up!?? The toroidal inductor encased in foam rubber inside a machined steel cylinder grounded to the shell is unusual. Also the 2SK30AY at the output of the wah section (for a bit of boost into a dirt pedal) is just great, love it.

[armdnrdy]

Hey Ronan,
Thanks for the info.

Since you have one open can you follow the leads connected to the pot on the left? (looking at the bottom) That's the ring modulator pot but I'm not sure which one it is on the schematic either. I've been looking at some gut shots to figure out the off board wiring.