Lets make a Morley Mark Tremonti Power Wah

[Satan Of Saturn]

I'm planning to make a clone of Mark Tremonti Power Wah for my friend. Got the schematic from their official website

http://www.morleypedals.com/mark1es.pdf

I'm almost done with the schematic on CadSoft Eagle. But cant understand which component is controlling the wah. In other switched wah pedals, potentiometers control the wah. In this optical Pedal, does the Wah Off Adj (TP1 1M) controlling the wah? I've no idea... can anyone help?     

[Kipper4]

Welcome to the forum SOS
It looks to me like the led L2 drives the ldr at the bottom left of the schemo.
This variable resistance goes to the input of the filter again bottom left section

[Satan Of Saturn]

Thanx a lot..
I just discovered this
http://www.morleypedals.com/tttrippointadjust.pdf
it says the L1 is controlling the wah...
I'm new in this DIY stuff... can I get some gut shots??

Wah Off Adj (TP1 1M) controls the delay, I just realized that 

[Jdansti]

So a shutter moving between L1 and LDR1 controls the wah. Is there a shutter between L2 and LDR2?  And what does L3 do?  Is it an indicator light?

[Satan Of Saturn]

I think L3 is just an indicator.
According to this pdf
http://www.morleypedals.com/tttrippointadjust.pdf

there should be some shatter like stuff between L1 and LDR1 as shown in this article
http://www.thomann.de/gb/onlineexpert_137_4.html

cant get any idea for the LDR2 and L2. Any gutshot from owners may help us.

After making the PCB for this, I'll surely upload that stuff here...

Anyone notice C3 C4 and C12 in the schemo? 

[Jdansti]

I don't see those caps. They might have been in the prototype and then removed.

[Satan Of Saturn]

Thanx for confirming... I though I'm blind 

[greaser_au]

L1/LDR1 are switching elements (this is what tttrippointadjust.pdf is all about) to take the wah in or out of the signal chain, LDR1/U1/F1/F2 determine whether clean (direct from U2C)  or wah (from U2A) is fed to output buffer U2D. 100% toe-up blocks light from L1 to LDR1 (and clean signal passes via F2).  Any more than 1/16" toe down causes LDR1 to be fully illuminated - to go low-resistance - & switches the wah signal the the output buffer via F1.  The "Wah Off Adj (TP1 1M)" controls how long it takes for the wah to switch from on-to-off (a delay while C2 discharges through R1+TP1) - off-to-on is nearly immediate because of D2.

L2/LDR2 combo is the wah control element (this pair will have a tapered shutter that controls the light based on the depression of the pedal).

david

[Satan Of Saturn]

Thanx greaser_au
Every thing is clear now but tapered shutter part was a bouncer... any pic to make it clear to me?

[Satan Of Saturn]

Using cadsoft Eagle to get the schematic. which inductor footprint will be ok for L1? any Eagle user?

[Satan Of Saturn]

http://s1074.photobucket.com/user/Dipanjan_Das/media/Schematic_zps615785bb.png.html

Here's what I have. Haven't put the inductor yet. Any mistakes??

[greaser_au]

Every thing is clear now but tapered shutter part was a bouncer... any pic to make it clear to me?

The "tapered shutter"  is a tab/card/flap that is attached to the treadle that causes more or less shading between the LED & the LDR, depending on the position of the treadle.  Have a look under the  "Electro-optical" section of the thomann.de article you referenced - you see the tab is more shaded at the top than the bottom. This is where things get interesting -  unless you can obtain a copy of the shading profile (and LED/LDR pair), you are stuck figuring it out for youself. This is DIYstompboxes after all!

I tried to find one of the many images of this sort of thing that I have seen here in the past, but my search skillz are lacking (and many people's links have expired... ) The photos in this thread  may help http://www.diystompboxes.com/smfforum/index.php?topic=45611.0, it shows a blade obscuring a path between an emitter & receiver. you may even be able to do this reflectively.

Don't forget to have a look at R.G Keen's*  "The Technology of Wah Pedals" http://www.geofex.com/article_folders/wahpedl/wahped.htm, and Paul Marossy's* wah articles at http://diyguitarist.com/StompboxStuff.htm

david

*Thanks again,  R.G. & Paul - your contributions to the community are immeasurable.

[Satan Of Saturn]

Oh ya I noticed that...
Thanx for those awesome links.... it seems like someone has already designed optical pedals 
That will help me... thanx again
\m/

[Jdansti]

Thanks David!  So L3 is an external indicator?

SOS- I've got a Morley optical volume pedal that uses a shutter. I'll take a look at it later today and see if it sheds any light on the subject.

[Satan Of Saturn]

Thanx John

Btw it seems like LDRs plays the main role in this WAH pedal to change the voltage. If I want to ignore the optical design (which I'm trying too), can I replace the LDR (and the LED circuit) with Pots. As the two LDR's Voltage drop is different, I'd use two different rated Pots and just get the hardware similar to other Wah pedals but still the HEART of Morley (I just love Morley Pedals but they are not available in my country  )
Just asking :-P

[Jdansti]

Just FYI- Here's what the LED/LDR pair looks like on the Morley volume pedal. The last shot shows the LDR moved back so you can see the shutter.

[greaser_au]

Thanks David!  So L3 is an external indicator?

Sorry, I don't know the answer to that one, I'm just working from the posted circuit and trip setting notes.     I can see that L1 is paired with LDR1 at extreme top left, and L2/LDR2 paired at extreme bottom (just right of centre).  L3 seems to be  standalone.  Note that L2 & L3 are also controlled by the wah switching (that is are OFF when the wah is turned off by LDR1).

in lolokng for PCB layouts to help with the OP's shutter question, I did see that the morley volume pedals use L3 as an indicator...  (and the PCBs also pair LDR3 & L4). see http://worshipandmusictinkering.blogspot.com.au/2012/09/tearing-into-morley-mini-volume.html, this also shows the arrangement of their tapered shutter...

david

[Satan Of Saturn]

Thanx for those pics... Its beautiful inside

In Mark Tremonti Power Wah, I think 2 of those LDR-LED set would be there? Just like shown in this pic?

http://s1074.photobucket.com/user/Dipanjan_Das/media/Optical_zpsfc5d0bcb.png.html

(with heat shrink tube on them)