Bad Horsie Q-pot

[joepius]

Hi y'all,

Confused about the indexing of topics - apologies to moderator if this is in the wrong place, I stand corrected.

I've recently added a trimpot to my crybaby, in the place where the original Q-resistor sits. I'm very pleased with this mod, and ability to now control the Q-value.

My question is: how do I add a Q-value trimpot to my (rev. 3 - 1998) morley bad horsie? Anyone?

Many thanks!

[stallik]

I added volume, Q and sweep to my bad horsie a few years ago.
Will look up the details, get some pics and post them over the weekend. Very simple mods I recall

[joepius]

Cheers!

I did the "stinkfoot"-mod to my crybaby, and am very pleased with it (www.stinkfoot.se).

[joegagan]

just going from memory, if you look a the bad horsey schematic at morley's website, you will se a traditional 2 trans crybaby type circ in there. apply the same stinkfoot mods once you track down each component - it will work. i would assume the Q knob would be applied at the 33k that parallels the inductor?

[joepius]

just going from memory, if you look a the bad horsey schematic at morley's website, you will se a traditional 2 trans crybaby type circ in there. apply the same stinkfoot mods once you track down each component - it will work. i would assume the Q knob would be applied at the 33k that parallels the inductor?

Thanks Joe! I'm not adept at reading schematics hence I don't really know where to look for what, hence wouldn't know how to track down components that well. Any hints are welcome

[joegagan]

oh right on, i don't have time to do the research, but i am sure you can put it together like we all did when learning. trust me, you will not regret taking the time to learn to read schematics. many great resources online, but for your current endeavour, RG keen/ geofex  wah article is a great primer.

[Transmogrifox]

Referring to this:
http://www.morleypedals.com/vai-2es.pdf

Replace the 390ohm "gain resistor" with 330ohms.

This is R20, which is 220 in the BH.  You may find you like it the way it is (I like it).

Replace the 1.5K "Mid/Q" resistor for a 1.7 or 1.8K.

This is R13

    Change the 33K resistor in parallel with the inductor for a 68K.

R16 (33k) is the resistor you want to mess with.

    If the "sweep cap" isn't the stock 0.01uF (103) value – for instance, a JH-1 wah has a 0.022uF (223) here instead – replace it.

I believe he's referring to C9, which is already 0.01uF in the BH.

I hope that is helpful.  Since I don't know if Morley has changed part reference designators between revisions, it would be a good idea to take an ohm meter and verify the part you have removed is the value expected as I translated from the schematic.  My guess is it's all the same.

[joepius]

oh right on, i don't have time to do the research, but i am sure you can put it together like we all did when learning. trust me, you will not regret taking the time to learn to read schematics. many great resources online, but for your current endeavour, RG keen/ geofex  wah article is a great primer.

That's great, man; thanks for the confidence builder!

[joepius]

Referring to this:
http://www.morleypedals.com/vai-2es.pdf

Replace the 390ohm "gain resistor" with 330ohms.

This is R20, which is 220 in the BH.  You may find you like it the way it is (I like it).

Replace the 1.5K "Mid/Q" resistor for a 1.7 or 1.8K.

This is R13

    Change the 33K resistor in parallel with the inductor for a 68K.

R16 (33k) is the resistor you want to mess with.

    If the "sweep cap" isn't the stock 0.01uF (103) value – for instance, a JH-1 wah has a 0.022uF (223) here instead – replace it.

I believe he's referring to C9, which is already 0.01uF in the BH.

I hope that is helpful.  Since I don't know if Morley has changed part reference designators between revisions, it would be a good idea to take an ohm meter and verify the part you have removed is the value expected as I translated from the schematic.  My guess is it's all the same.

Thanks! So it's R16 I'm after.
Next is: what value pot do I use / log or lin pot, and: how to wire it up? I'm not eager to take out the PCB, I guess I could loosen the resistor on one end (cutting its leg in half) and then connecting the pot - or taking the PCB out and doing it properly. Any ideas?

[Transmogrifox]

If you're just doing set-and forget (trim pot) then log or lin doesn't make a difference. 

Probably 100k pot will be good if you're looking for something close to stinkfoot's mods. 

To wire it up, a trim pot has 3 leads coming out of the bottom.  Solder the middle lead to one of the end leads.  Remove R16 and connect each of the end leads to the pads where it was removed.

If you do this without removing the PCB, then clip the resistor leaving long leads coming out of the board.  Usually a trim pot is small enough you will need that extra wire to make contact, so you would just solder pot end leads to the resistor leads left behind after clipping out the resistor.

Before you install the pot, it's best to measure it with an ohm meter then adjust it to 68k.  Then you know your adjustments will be minor based off that center point.  It's also a good idea to note what direction of turn makes the resistance go up.  This will all depend on what end lead you solder to the center lead (and it doesn't make any difference except which direction you turn the pot to make resistance go up).

As for removing the PCB, if you find you need to do this, it is not a hard task.  The hardest thing for me was digging around in my shop to find the correct size socket to unscrew the input and output jacks.  They can be removed with needle-nose pliers, but you will bung them up cosmetically.  If you don't care about cosmetics, then needlenose works fine.

[joepius]

If you're just doing set-and forget (trim pot) then log or lin doesn't make a difference. 

Probably 100k pot will be good if you're looking for something close to stinkfoot's mods. 

To wire it up, a trim pot has 3 leads coming out of the bottom.  Solder the middle lead to one of the end leads.  Remove R16 and connect each of the end leads to the pads where it was removed.

If you do this without removing the PCB, then clip the resistor leaving long leads coming out of the board.  Usually a trim pot is small enough you will need that extra wire to make contact, so you would just solder pot end leads to the resistor leads left behind after clipping out the resistor.

Before you install the pot, it's best to measure it with an ohm meter then adjust it to 68k.  Then you know your adjustments will be minor based off that center point.  It's also a good idea to note what direction of turn makes the resistance go up.  This will all depend on what end lead you solder to the center lead (and it doesn't make any difference except which direction you turn the pot to make resistance go up).

As for removing the PCB, if you find you need to do this, it is not a hard task.  The hardest thing for me was digging around in my shop to find the correct size socket to unscrew the input and output jacks.  They can be removed with needle-nose pliers, but you will bung them up cosmetically.  If you don't care about cosmetics, then needlenose works fine.

Thanks so much, this is an excellent guide that totally makes sense to me! Also the setting the pot to about 68K as a starting point (I'm real dumb, it is evident, lol). As for removing the PCB: I've noticed one'll need to loosen those 4 bolts which on the other end seems to connect the treadle? I was just worried the whole thing'd fall apart and would be tough to properly put together again. Cheers!

[joepius]

Referring to this:
http://www.morleypedals.com/vai-2es.pdf

Replace the 390ohm "gain resistor" with 330ohms.

This is R20, which is 220 in the BH.  You may find you like it the way it is (I like it).

Replace the 1.5K "Mid/Q" resistor for a 1.7 or 1.8K.

This is R13

    Change the 33K resistor in parallel with the inductor for a 68K.

R16 (33k) is the resistor you want to mess with.

    If the "sweep cap" isn't the stock 0.01uF (103) value – for instance, a JH-1 wah has a 0.022uF (223) here instead – replace it.

I believe he's referring to C9, which is already 0.01uF in the BH.

I hope that is helpful.  Since I don't know if Morley has changed part reference designators between revisions, it would be a good idea to take an ohm meter and verify the part you have removed is the value expected as I translated from the schematic.  My guess is it's all the same.

[/quote

Transmogrifox:

According to the schematic, R16 is a 47 and is in series with the conductor, whereas R15 is 33 and in parallel with the conductor. The one to mess with then is R15, correct? Thanks!

[Transmogrifox]

I agree it's easier if you can do it without removing the PCB, but my memory is it wasn't as big of a deal as it appeared at first.

I had a mod where I converted the BH into an envelope filter -- drilled a couple holes for a footswitch to activate/deactivate, and a pot to adjust the sensitivity.  I had to completely remove the PCB for that job, as you might imagine.

I also modded that one a lot, tried all kinds of stuff.  I let a guy borrow it and he never gave it back .  I should get another BH.  I really liked it.

[joepius]

I agree it's easier if you can do it without removing the PCB, but my memory is it wasn't as big of a deal as it appeared at first.

I had a mod where I converted the BH into an envelope filter -- drilled a couple holes for a footswitch to activate/deactivate, and a pot to adjust the sensitivity.  I had to completely remove the PCB for that job, as you might imagine.

I also modded that one a lot, tried all kinds of stuff.  I let a guy borrow it and he never gave it back .  I should get another BH.  I really liked it.

Hunt the guy dowm! lol - hope you can find an alternative for it!

So, R16 is a 47 and is in series with the conductor, whereas R15 is 33 and in parallel with the conductor. The one to mess with then is R15, is that correct? Thanks!

[Transmogrifox]

The 33k in parallel with the inductor is what you want to modify.  That is correct.

[joepius]

The 33k in parallel with the inductor is what you want to modify.  That is correct.

Yup! Thanks dude.

This dude this something similar:

http://www.goethert.com/FrostBottomBoys/AndyHowe/WahPedals.htm

Cheers!

[stallik]

Made these mods a long time ago, based on a little net info which I cant put my hands on now. It was volume that I wanted as the standard pedal was just too loud when it kicked in. Really didn't know what I was doing at the time and although the changes to the sound are not massive, they've been working for me. Seems from this thread that these mods are incorrect so maybe I'll revisit it. Here's what I did anyway... 

Volume - replaced R12 with 56k in series with a 100k pot
Sweep - replaced R15 with 100k pot
Q - replaced C14 with .22Uf and R24 with 50k in series with 100k pot

Nasty work  but I didn't want to remove the board so clipped off the old components and used the wires as posts. I apologize for the Walls Cornish logo. I thought it funny at the time

[joepius]

Made these mods a long time ago, based on a little net info which I cant put my hands on now. It was volume that I wanted as the standard pedal was just too loud when it kicked in. Really didn't know what I was doing at the time and although the changes to the sound are not massive, they've been working for me. Seems from this thread that these mods are incorrect so maybe I'll revisit it. Here's what I did anyway... 

Volume - replaced R12 with 56k in series with a 100k pot
Sweep - replaced R15 with 100k pot
Q - replaced C14 with .22Uf and R24 with 50k in series with 100k pot

Nasty work  but I didn't want to remove the board so clipped off the old components and used the wires as posts. I apologize for the Walls Cornish logo. I thought it funny at the time

Wow, that looks great, Stallik! Neatly done. I think the logo is actually quite a match

How do you like the difference after you've altered C14? Cheers!

[stallik]

Difficult to be accurate. Playing, rocking and adjusting pots is a bit like playing twister. Volume is very effective from below unity to a bit too much, sweep goes from nothing to full range, Q interacts with the sweep and you have to be careful not to loose the quack. I tend to use the pots as trimmers. Adjust and then leave alone.

It's the only wah I have which sounds OK with both clean and dirty settings but my jem crybaby is so much nicer on clean.. Unfortunately it's rubbish on dirty settings. Keeping my eye out for a doner Morley pedal so that I can put something else in it