# King Midas Drive (Keeley El Rey Dorado) - Update



## MichaelW (Sep 2, 2022)

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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## steviejr92 (Sep 2, 2022)

call me crazy but theres something wierdly satisfying about the way those leds are sitting in there..
awesome build as always!


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## MichaelW (Sep 2, 2022)

steviejr92 said:


> call me crazy but theres something wierdly satisfying about the way those leds are sitting in there..
> awesome build as always!


They light up when you toggle that side, kinda cool to watch them while you're playing


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## steviejr92 (Sep 2, 2022)

MichaelW said:


> They light up when you toggle that side, kinda cool to watch them while you're playing


i might have to build one just to experience this!


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## swelchy (Sep 2, 2022)

as always.. great write up and looks good!


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## Chuck D. Bones (Sep 3, 2022)

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.


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## MichaelW (Sep 3, 2022)

Chuck D. Bones said:


> 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.


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## Chuck D. Bones (Sep 3, 2022)

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.


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## swyse (Sep 3, 2022)

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.


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## Chuck D. Bones (Sep 3, 2022)

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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## swyse (Sep 3, 2022)

Chuck D. Bones said:


> 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.


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## szukalski (Sep 4, 2022)

MichaelW said:


> They light up when you toggle that side, kinda cool to watch them while you're playing


Can always do a “boutique” gimmick and use on the enclosure side so you can use them like you would a rate LED.

Nice build! As always


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## MichaelW (Sep 4, 2022)

Chuck D. Bones said:


> 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  

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.


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## MichaelW (Sep 4, 2022)

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.....


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## szukalski (Sep 4, 2022)

If the bass is overwhelming then it’s doing a good job of being a JTM45!


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## Chuck D. Bones (Sep 4, 2022)

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.


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## Chuck D. Bones (Sep 4, 2022)

swyse said:


> 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.


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## HamishR (Sep 4, 2022)

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.


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## music6000 (Sep 4, 2022)

MichaelW said:


> I think the Power toggle lets you pretend you're playing a JTM or a Super Lead doncha know
> 
> I think the toggles on the Golden Falk are more useful, 3 useful tones for different sounds.
> 
> ...


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


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## MichaelW (Sep 4, 2022)

music6000 said:


> 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!
> ...


I didn't want to "out" you hahah.


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## music6000 (Sep 4, 2022)

MichaelW said:


> I didn't want to "out" you hahah.


I did put an LED in D3 & it sounds similar in Gain & slightly less volume but compressed a bit more than Hi mode
Do you find it gets too much Gain & Bloom by 10 O'clock if 7.00 O'clock is minimum/Off on the Gain pot?


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## MichaelW (Sep 4, 2022)

music6000 said:


> I did put an LED in D3 & it sounds similar in Gain & slightly less volume but compressed a bit more than Hi mode
> Do you find it gets too much Gain & Bloom by 10 O'clock if 7.00 O'clock is minimum/Off on the Gain pot?


I find it bloomy at around 8:30. And that's with the tone control maxed. Matching it to a brighter guitar makes a difference. Doesn't sound very good on some of my guitars.


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## music6000 (Sep 4, 2022)

MichaelW said:


> I find it bloomy at around 8:30. And that's with the tone control maxed. Matching it to a brighter guitar makes a difference. Doesn't sound very good on some of my guitars.


I'm using a Telecaster, forbid what it sounds like with a Les Paul!


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## MichaelW (Sep 4, 2022)

MichaelW said:


> I find it bloomy at around 8:30. And that's with the tone control maxed. Matching it to a brighter guitar makes a difference. Doesn't sound very good on some of my guitars.


The best sounds I'm getting is on the LED side of the clipper, gain around 11:30, vol around 9:30, tone at 3:30 on the bridge pickup of one of my P90 guitars. Pretty killer sound. This might be a "one trick pony" pedal but it sounds good with this combination.


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## music6000 (Sep 4, 2022)

MichaelW said:


> The best sounds I'm getting is on the LED side of the clipper, gain around 11:30, vol around 9:30, tone at 3:30 on the bridge pickup of one of my P90 guitars. Pretty killer sound. This might be a "one trick pony" pedal but it sounds good with this combination.


The PedalPCB Unchained would have been a better option I just Found I think!?
It's being referred to as Brown Sounding which means Bridge Only One Trick Pony!!!


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## MichaelW (Sep 4, 2022)

music6000 said:


> The PedalPCB Unchained would have been a better option I just Found I think!?
> It's being referred to as Brown Sounding which means Bridge Only One Trick Pony!!!


Well EVH had a lot of tricks up his sleeve with that one bridge pickup!

I actually have a BSIAB2 on the bench I've been trying to get to for weeks now.


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## music6000 (Sep 5, 2022)

MichaelW said:


> Well EVH had a lot of tricks up his sleeve with that one bridge pickup!
> 
> I actually have a BSIAB2 on the bench I've been trying to get to for weeks now.


Chuck suggested changing R6 - 4K7 to 10K so the Diodes are not getting over saturated.
I went and put a temporary B25K pot and it is a big improvement with a happy medium of around 12K.
As I have already built it , I will use a Trimmer in R6 set to 10 - 12K!
The Tone Control becomes more Responsive also!
It is Designed by Fault to work in the Bridge position as when in Neck position , the Bass Response takes over Big time.
This Helps to get to use the Neck pickup also!

Thanks Chuck D. Bones


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## MichaelW (Sep 5, 2022)

music6000 said:


> Chuck suggested changing R6 - 4K7 to 10K so the Diodes are not getting over saturated.
> I went and put a temporary B25K pot and it is a big improvement with a happy medium of around 12K.
> As I have already built it , I will use a Trimmer in R6 set to 10 - 12K!
> The Tone Control becomes more Responsive also!
> ...


Awesome, I have some of those multi-turn trimmers stand up that should I could probably pop in without too much danger of murdering the board. I'll give that a shot. R6 comes after the clipping circuit, so it's actually "throttling" the diode saturation?


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## music6000 (Sep 5, 2022)

MichaelW said:


> Awesome, I have some of those multi-turn trimmers stand up that should I could probably pop in without too much danger of murdering the board. I'll give that a shot. R6 comes after the clipping circuit, so it's actually "throttling" the diode saturation?


After taking a Break & Revisiting, It works at 10K but it sacrifices the Volume (Headroom of the pedal), so you have to increase the Gain to get the Volume back????
I would settle for for around 7.5K, it's really a One Trick Pony that your other pedals can do without the Bloatiness, I'm not a BSIAB guy at all!
I'm not interested in the Unchained (Panama) either.
Pete Thorn did a brief demo & 90% is bridge pickup!


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## MichaelW (Sep 5, 2022)

music6000 said:


> After taking a Break & Revisiting, It works at 10K but it sacrifices the Volume (Headroom of the pedal), so you have to increase the Gain to get the Volume back????
> I would settle for for around 7.5K, it's really a One Trick Pony that your other pedals can do without the Bloatiness, I'm not a BSIAB guy at all!


Hmmm interesting, the pedal doesn't have a ton of volume or headroom to begin with. 

Actually I just built another dirt pedal couple days ago that is even more problematic but in the other direction. Too bright and thin. But that's for another thread. I'll post a built report.


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## music6000 (Sep 5, 2022)

Not a JHS, Is it?


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## MichaelW (Sep 5, 2022)

music6000 said:


> Not a JHS, Is it?


No, it's the Cornish SS-2. (Semi-Sweet)


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## music6000 (Sep 5, 2022)

MichaelW said:


> No, it's the Cornish SS-2. (Semi-Sweet)


Yes, Well join the club on that one also, It's already been a subject of Discussion!


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## MichaelW (Sep 7, 2022)

Update: Ok, second mod for today. I was chatting with @music6000 offline about this pedal too. Or maybe it was online? I'm forgetting hah.

Following @Chuck D. Bones's recommendation I also replaced R6 (4k7) with a 20k trimpot. I set it at 12k when I put it in and I think I'm going to leave it there. 

There's definitely some improvement on the BAT46 side of the toggle, a bit more usable and less overly compressed. But the volume discrepancy is still pretty profound. But I can dial up some nice sounds on both sides of the clipping toggle now.
Best of all, I could do the mod without taking the board out, WOOT! 

Very Marshally, I actually think it sounds way more like JCM800 territory than Plexi. The bass heaviness is still there but I think that's probably true of most MIAB's. The tone control is only a treble cut, it doesn't dial out the bass.

But it's definitely a worthwhile mod. Thanks @Chuck D. Bones and @music6000!


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## Snicksound (Tuesday at 9:12 AM)

MichaelW said:


> Update: Ok, second mod for today. I was chatting with @music6000 offline about this pedal too. Or maybe it was online? I'm forgetting hah.
> 
> Following @Chuck D. Bones's recommendation I also replaced R6 (4k7) with a 20k trimpot. I set it at 12k when I put it in and I think I'm going to leave it there.
> 
> ...



I know this thread is a few months old but I wanted to comment as I'm currently experimenting with that circuit on the Protoboard (have the PCB on order but I like to lock in my "mods" before I commit)

As you may or may not know, the El Rey Dorado is a Carl Martin Plexitone clone (the small box version). I love the Plexitone circuit but it does have overbearing bass which was my motivation for building my own.
The Panama (Unchained) fixed this by adding a variable high pass filter at the beginning of the circuit (the Damping control), an overly complex solution when you can just swap a cap... IMHO

The Keeley version already does cut more bass than the Plexitone, with a 100n input cap instead of 220n. I feel that's not enough, but I still wouldn't bother with the Panama version unless for some reason you really want flexibility in tightness.
What you can do... just replace C3 with a 68nF or even 47nF. This will rolloff bass frequencies pre-distortion so that the distortion cleans up (makes it more JMP than JTM).

As for the change in volume when changing mode, there's nothing that can be done really, you're switching from diodes that clips at 2V to .2V. I don't find that switch useful (and may actually omit it and jumper the "High" position), to me the LEDs in there are integral part to the Plexitone sound, but maybe Mr Keeley wanted to ensure it wasn't a direct clone by adding something. Going from LEDs to BATs is such an insane jump, plain old Silicon would have made more sense, but I guess some people prefer the clipping nature of BATs.

If the plan is to be able to switch between both easily, then that's not gonna work, it totally changes the gain structure of the pedal. For this to work, one would have to use a DPDT switch and use it to kick in a higher R9 value in "Low" mode. Obviously this wouldn't work with the current PCB.

For the sake of discussion, another difference between the Keeley and original Carl Martin is the Keeley uses a smaller tone cap (39n vs 68n) with a higher value tone pot (B10 instead of B5). I've experimented with the value there and I do prefer the 39n. One other issue I had with the Plexitone is it was a bit lacking in mids through some amps, the smaller cap there moves the rolloff frequency upwards, letting more mids through. Using a larger value pot means it gets darker in the lower range, but in practice I prefer it because now it sounds great at noon while the Plexitone I had the tone always turned down (the Plexitone also uses smaller C2, C5 and C9 caps, at 25p instead of 120p... I changed C9 to 470pF!)

Another change is R3, where the Plexitone uses a 47R which increases the gain range ten-fold! The Plexitone has too much gain as it is (they even released a low gain variant, which sub the 1M pot for a 100k). The 470R sounds good IMHO!


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