[Request] Promethium Boneyard Edition/KMA Wurm

dpsnacks

Member
Heyo! I'm here to humbly request a supermodified version of the Promethium a la the KMA Wurm. It has four bands of EQ rather than two, and the frequency for each band can be tweaked with a trimpot inside. I think this would be an absolute killer high-gain preamp pedal. The Wurm is extremely versatile at all settings until it becomes chainsaw at the very end of each pot's range. Is this something you could/would look into? Thanks in advance for your consideration and time.

Here's some more information about the trimpots and their ranges:
 

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Chuck D. Bones

Circuit Wizard
If/when PedalPCB revs the Tearjerker, I have two changes in mind.

1. Add the option for the emitter-follower input buffer à la the GCB-95.

2. Add the option for a Q trimpot in series with the choke. It work differently from the trimpot in parallel with the choke.

The mods I have in mind for the moment are a few component value changes and some external controls.
 

Chuck D. Bones

Circuit Wizard
Heyo! I'm here to humbly request a supermodified version of the Promethium a la the KMA Wurm. It has four bands of EQ rather than two, and the frequency for each band can be tweaked with a trimpot inside. I think this would be an absolute killer high-gain preamp pedal. The Wurm is extremely versatile at all settings until it becomes chainsaw at the very end of each pot's range. Is this something you could/would look into? Thanks in advance for your consideration and time.

Here's some more information about the trimpots and their ranges:

I can guess what's in there, but it would be nice to see a schematic...

It would appear that KMA added a 4th gyrator and separated their cut/boost controls. No idea what the DIP switch does or what else they might have tweaked.

Do you have one?
 

dpsnacks

Member

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Chuck D. Bones

Circuit Wizard
Photos are good, but they only provide about 50% of the info. Someone needs to lift the board and trace the circuit with a DMM. SMD ceramic caps are unmarked and need to be measured. Not a small job, but do-able. Have you scoured the usual websites for a schematic?
 

Chuck D. Bones

Circuit Wizard
Photos on reddit not good enough, can't read part numbers. Maybe someone on diy.pedals will figure it out.
 
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Chuck D. Bones

Circuit Wizard
I'll see how much I can glean from your photos and the HM-2 schematic, but the Wurm contains four more opamps than the HM-2 and we have to account for them. Do you have a DMM for when I need you to confirm some connections? Also, I need a photo of the area around the TL072 that is not obscured by the power leads. You should be able to unplug them from the board and position them out of the way for the photo. We'll still have a pile of unknown cap values, but we can burn that bridge when we come to it.
 

dpsnacks

Member
Do you have a DMM for when I need you to confirm some connections?
I am a novice, but I do. I appreciate your patience in advance. :)
Also, I need a photo of the area around the TL072 that is not obscured by the power leads. You should be able to unplug them from the board and position them out of the way for the photo. We'll still have a pile of unknown cap values, but we can burn that bridge when we come to it.
 

dpsnacks

Member
Just a thought, but if you want to send over the pedal I'll trace it and measure all of the SMD capacitors.
I'm open to it! By the end of the month I should have some disposable monies set aside to send this off to ya. Where's the best place to contact you for your addr?
 
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