MXR - Custom Badass '78 Distortion  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Nocaster
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Post by Nocaster »

The first in a line from the MXR Custom Badass design team, the MXR Custom Badass ’78 Distortion is a factory-modded pedal that roars with huge amp stack tones and old school tube amp-like distortion.

We took a classic distortion circuit and hot-rodded it to the next level for over-the-top soaring leads and rich, saturated rhythms. With only three knobs, dialing in Badass tone is a cinch. The CRUNCH button allows you to choose between two different modes of diode and LED clipping, boosting the harmonic content of the distortion.

The '78 Distortion's wide open amp-like sound sounds great whether it's in front of a clean amp, a slightly dirty amp, or a full on overdriven amp. Under the hood, this high performance machine features top notch circuitry and hardware meant for a lifetime of use.
Was curious as to what it was based on so I took the attached pics. Pedal sounds really good. Especially for $78 new.

IC = 2262C

I count 6 transistors.
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Nocaster
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Post by Nocaster »

askwho69 wrote::applause:
Thanks. I am happy to provide values and more pics if someone is able to determine which classic circuit this is based on. 8)

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Post by Steven_M »

Assuming that a couple of those transistors are probably for the switching on the LED, 4 transistors and an opamp? Does it sound at all like a Big Muff?

Wondering if maybe the opamp is an in/out buffer. Just a shot in the dark.

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Post by Nocaster »

Steven_M wrote:Assuming that a couple of those transistors are probably for the switching on the LED, 4 transistors and an opamp? Does it sound at all like a Big Muff?

Wondering if maybe the opamp is an in/out buffer. Just a shot in the dark.
Not really. It has tons of high end and presence. Tone knob needs to be run around 10:00 to tame it. Doesn't sound big like a muff at all. There is a pair of 3mm red LED's in there for clipping. Before I opened it up, I was convinced it was based on the DS-1 based on how it sounded to me. The DS-1 came out in 1978.

I guess the opamp Big Muff came out in '77/'78 though, correct?

Here are a few videos of it for sound.




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Steven_M
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Post by Steven_M »

Nocaster wrote:
Steven_M wrote:Assuming that a couple of those transistors are probably for the switching on the LED, 4 transistors and an opamp? Does it sound at all like a Big Muff?

Wondering if maybe the opamp is an in/out buffer. Just a shot in the dark.
Not really. It has tons of high end and presence. Tone knob needs to be run around 10:00 to tame it. Doesn't sound big like a muff at all. There is a pair of 3mm red LED's in there for clipping. Before I opened it up, I was convinced it was based on the DS-1 based on how it sounded to me. The DS-1 came out in 1978.

I guess the opamp Big Muff came out in '77/'78 though, correct?

Here are a few videos of it for sound.



Yeah, that's too tight sounding to be a muff.

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Güero 2.0
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Post by Güero 2.0 »

Note that some of "transistors" could be diodes. They have the same enclosure.
Check the SMD code in the internet
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Post by ddpawel »

I bet that Badass '78 Distortion is really a modded version of Distortion+. Probably this one:

http://www.indyguitarist.com/temp/dist-plus-mod-406.gif

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celadine
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Post by celadine »

Looks like everything is labelled, ¨Q1¨, etc. Connections should be easier to trace than most smd stuff, judging from the 1st few photos. Another Mr. Huge design?

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Post by Rich_S »

I was thinking about picking one of these up on my next trip to the big city (next week), but would like to know more about what it is. If it's just a modded DS-1 implemented using SMD, I can save my money. I already have a modded DS-1, the final "keeper" after several different versions.

The Badass 78 is secksie, though.

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Post by neoflox »

Yeah, any news on this? Is anyone working on a schematic? :scratch:
:popcorn:

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coldcraft
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Post by coldcraft »

the 2262 op amps sound pretty good distorting on their own actually.
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

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Post by Ice-9 »

Bump - Just wondering if you have managed to make a schematic yet ?
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by houseofglass21 »

Don't have the schematic, but I bought one of these pedals tonight at GC. I A/B'd it with my old 1983 MIJ DS-1 and they sound almost identical except the MIJ DS-1 sounds better. Disappointing pedal. They basically came up with a way to sell a $20 DS-1 for $80.

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Post by FiveseveN »

"Better?" Do tell. How so? "Better" in which what way?!
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Rich_S
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Post by Rich_S »

MXR's own marketing materials state that the crunch switch selects between diode and LED clipping. It's the rest of the circuit I'm interested in... if it just a modded DS-1 I already have that covered and can spend my hard-earned gear $$$ on something else - like a greenback clone for my 18 Watter.

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Post by benadrian »

A Dunlop rep told some people I know that it is essentially a Keeley-style modded DS-1 with a few more changes.

I was a bit disappolinted at first. however, a lot of people seem to dig the sound, and $80 for any good sounding pedal can't be a bad deal. It's no less valid to me than a personally-tuned FF clone for $150.

Cheers!
Ben

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Post by Rich_S »

I used to own a Keeley SEM/Ultra DS-1 and yeah... the clips I've heard of the 78 Badass sound like they're in the same ballpark. Good to know, since I can now skip it; I like my Allums Recto Mod DS-1 better.

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Post by Ice-9 »

Ids anyone still interested in getting this one reversed ?
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by ddpawel »

Ice-9 wrote:Ids anyone still interested in getting this one reversed ?
Of course.

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Post by Nocaster »

Hey guys. I am the OP of the pics. Sorry I haven't been able to provide anything more than that. I'd be happy to take it apart again and list out all the values if you want. I'll admit that I have not gone down the road of trying to draw a schematic from a pedal before and I really don't have the time to attempt to do so right now. But if there is anything else I can provide (values, more pics, etc.), just ask. Sorry if this was a let down. I just thought the pics might have made it easily identifiable to the experts here! :mrgreen:

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