King Midas Drive (Keeley El Rey Dorado) - Update

MichaelW

Well-known member
Build Rating
5.00 star(s)
Ok, I keep saying "I'm gonna take a break from building overdrives......" @fig thinks it's "cute".

I REALLY was planning a couple of modulation builds next and I've got probably the most challenging build attempted coming up in queue.
But when I I went to go gather the parts, I was STILL missing some stuff dagnabbit......hopefully I'll have everything here in the next couple of days.

In the meantime, I decided to get back to my series of MIAB's that I've been building. So far, I've built the Golden Falk, the JHS Charlie, and the XS Drive all of which are pretty awesome drives and do their own thing capturing that Marshall vibe in a pedal. This was one that popped on my radar not too long ago.
I've always liked Keeley's pedals although I don't have a ton of experience with them besides his compressor.

I do remember back in the day when he was selling modded DS-1's on Ebay and almost bought one just because both Steve Vai and Joe Satriani bought them.

Fast forward to now he's like a major player in the boooteeeek pedal world.

Anyway, the El Rey Dorado is his take on the Plexi in a box pedal and it sounds really pretty awesome! This pedal uses a quad op amp for the main push but then there's a toggle that roughly maps to a JTM45/100 Reissue (based on his own amp) and the other side of the toggle maps to a Super Lead.

Like the Golden Falk it's a pretty bass heavy sound, unlike the GF it's a bit hard to dial out that bass, so pairing it with the right guitar/amp will make a difference.
Or having some downstream eq pedal.

I'm not sure if this is just my build, my components, but there's a pretty massive disparity in volume between the "Lo Power" side of the toggle, which enables 3 Red Led clippers and the "Hi Power" side which enables the 3 BAT46 clippers. I was expecting SOME disparity but in order to match the volume between the two sides it's literally 9 o'clock vs 2 o'clock on my level knob. The demo's I watched were mixed on this. Mike Hermans demo looks like it acts like mine does where he has to make some wide compensation on the level and gain going from lo to high power. But other video's, including Keeley's own video on his website it doesn't seem like it's that huge a gap. But then, that might also be the video compression/limiter at play where it's not really coming through. Anyway, that's my only real complaint with the pedal, I'll just need to remember to compensate for the volume when hitting the toggle.

Very straightforward build, but this PCB looked a little different from the typical boards I've gotten from @PedalPCB, this one was all shiny:) Maybe a different mfgr?

One hiccup I had was also a first for me. I have a 9v wall wart on my work bench that I use to do a quick power check or do rough biasing before moving into my office to fire up the pedal. Well, it wouldn't turn on when I did my bench check. So I whipped out my handy dandy DMM and everything seemed to be checking out and it was a real head scratcher. Turned out to be a bad status LED. It was actually turning on, just no light. I've NEVER had that happen before so I didn't think to check that until the very end. Swapped it out for a new LED and all is well.

Glad to add this to my growing collection of MIAB's, couple more to go hahaha!

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Nice build, very good write-up. I had assumed that selecting the LEDs put it in High-Power mode because that's the louder setting. Not surprised that there is a big volume jump. If the King Midas is overdriving an amp in the demo, then there will be less of a volume change when switching modes.
 
Nice build, very good write-up. I had assumed that selecting the LEDs put it in High-Power mode because that's the louder setting. Not surprised that there is a big volume jump. If the King Midas is overdriving an amp in the demo, then there will be less of a volume change when switching modes.
Hmmm, maybe you're right and I have the notion of Hi vs Lo power reversed, either way it's a pretty big hit on volume going to the Bat46's. Someone reached out via DM confirming his did the same thing and offered a couple of suggestions of cap subs to reduce that volume disparity. I actually prefer the LED clipping to the Schottky's so I may just leave it alone.
 
The POWER switch is a set & forget thing, right? So who cares if the volume changes when you switch it? As long as you can get the settings you want, no need to make mods.

I don't get why Keeley used four opamps to do something that could be done with two, but I'm sure he had his reasons.
 
I don't think this would be a practical mod to put in place due to the pcb layout, but maybe you could change the last op amp stage gain using a DPDT toggle so it makes up for the volume drop.
 
Sure, that's an option. But is it necessary? There's already a Volume pot to make up for a volume change.
 
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Sure, that's an option. But is it necessary? There's already a Volume pot to make up for a volume change.
Not necessary at all, but maybe a nice user experience thing. Also I looked at the schematic closer and I noticed its a pretty similar topology to the carl martin plexitone, maybe it has the 4 op amps because it's an inspired design.
 
The POWER switch is a set & forget thing, right? So who cares if the volume changes when you switch it? As long as you can get the settings you want, no need to make mods.

I don't get why Keeley used four opamps to do something that could be done with two, but I'm sure he had his reasons.
I think the Power toggle lets you pretend you're playing a JTM or a Super Lead doncha know :LOL:

I think the toggles on the Golden Falk are more useful, 3 useful tones for different sounds.

The person that made the suggestion for mod swapped out C6 and C8 for 220n and it made a diff. I might give that a shot.

My other thought is to yank out the BAT46's and put in 3 sets of BAT46's in series. It's got a bit too much gain and compression in that setting anyway. That might make that side of the clipping circuit more useful both tonally and in volume.
 
Or.....I could just go build something different.....heh. It's a great pedal but not so great that I want to chase the rabbit down the hole....I got phasers to build, JFETS to match.....
 
Rather than stacking Schottky diodes, try stacking regular silicon diodes, such as 1N4148, 1N4004, etc. Will take fewer diodes to get the same amplitude. Or mix Si & Schottky. Or stick a resistor in series with the Schottkys for higher output and less compression. Many possibilities.

Lowering C6 and/or C8 will reduce the bass after the distortion. If you want to reduce the bass before the distortion, try lowering C3 or C4.
 
Also I looked at the schematic closer and I noticed its a pretty similar topology to the carl martin plexitone, maybe it has the 4 op amps because it's an inspired design.
Nearly identical designs. Which one came first? I'm guessing it was the Plexitone. The four opamps make sense with the CM design because the "extra" two opamps support the Drive bypass switch and the Boost function.
 
I built the Recycler this week, reputed to be a Billy Gibbons sound. It's pretty good and with a Les Paul through a 5E3 it does seem to capture a fairly Billy kinda tone. It has a heavy low-end emphasis too, which makes me wonder why more overdrive manufacturers do't use a bass knob?? Maybe it's a good thing. I have spent many happy hours adding bass knobs to circuits like these. Maybe I shouldn't let them take that away from me.
 
I think the Power toggle lets you pretend you're playing a JTM or a Super Lead doncha know :LOL:

I think the toggles on the Golden Falk are more useful, 3 useful tones for different sounds.

The person that made the suggestion for mod swapped out C6 and C8 for 220n and it made a diff. I might give that a shot.

My other thought is to yank out the BAT46's and put in 3 sets of BAT46's in series. It's got a bit too much gain and compression in that setting anyway. That might make that side of the clipping circuit more useful both tonally and in volume.
Come On, Who was it????
Alrighty then, it was me that suggested the C6 & C8 for 220n. I did that as it was easy to access!
I just put it on the Shelf & forgot about it & changed the Caps the day MichaelW asked in the Build report was it normal.
Bass Heavy or Boomy Stock pretty much describes it!
The Tone Control is limited to say the least!
Stock, I don't have much praise for the Pedal.
The Bat46 clipping is redundant to me & as I have no pedals to Build I WILL revisit now & probably try a LED for giggles with the Bat46's.
It can't sound worse than it already is in that mode.

My 2 cents
Cheers music6000
 
Come On, Who was it????
Alrighty then, it was me that suggested the C6 & C8 for 220n. I did that as it was easy to access!
I just put it on the Shelf & forgot about it & changed the Caps the day MichaelW asked in the Build report was it normal.
Bass Heavy or Boomy Stock pretty much describes it!
The Tone Control is limited to say the least!
Stock, I don't have much praise for the Pedal.
The Bat46 clipping is redundant to me & as I have no pedals to Build I WILL revisit now & probably try a LED for giggles with the Bat46's.
It can't sound worse than it already is in that mode.

My 2 cents
Cheers music6000
I didn't want to "out" you hahah.
 
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