EHX - Big Muff Pi 1977 & 1978 version  [schematic]

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

i traced this from photos of an original,its the original PCB layout.
its not verified,i dont need to build it as i own one.(1322)

it probably wont fit in an enclosure much smaller than a bmp box tho.
i was gonna put it in an old bmp enclosure i have but then i bought the ic version and i dont need to anymore.

edit:this should have actually gone in the modern section as it wasnt made till 77 iirc.
you can buy the PCB mount pots from mouser and new sensor.
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Post by bajaman »

Thanks for sharing bumblebee :applause:
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Post by Bernardduur »

I have on in my Deluxe Muff; it is pretty bad :)

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Post by bumblebee »

i love the ic muff,i have a 1978 1322 version and its super nice.
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Post by Dirk_Hendrik »

I guess that so far I've played all Muff versions, and quite some clones based on, that were made. All practiced what they preaced, pure guitar porn, in variations form sweet anal to brutal hardcore... that's the IC one...indeed.

But bottom line is.
The never let me down.








oh my... did I really write that!?? :shock:
Sorry. Plain out of planes.

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Post by bumblebee »

never thought of the ic muff as brutal anal before,i'll never look at it the same again thanks to you. :mrgreen:
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Post by Dirk_Hendrik »

:shock:
That's another variation :applause:
Sorry. Plain out of planes.

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Post by bumblebee »

there was an error in the layout,its been corrected. if anyone saved it you might wana save the updated version.
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Post by seniorLoco »

If your tracing is correct, then this schemo has error

Image
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Post by analogguru »

I can´t understand why people are still using old and wrong schematics when correct schematics are available since years:
http://analogguru.an.ohost.de/193/schem ... _OP-77.gif
http://analogguru.an.ohost.de/193/schem ... _OP-78.gif

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EHX Big Muff Pi 1977 schematic
EHX Big Muff Pi 1977 schematic
EHX Big Muff Pi 1978 schematic
EHX Big Muff Pi 1978 schematic
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Post by bumblebee »

seniorLoco wrote:If your tracing is correct, then this schemo has error

Image
this is old and id go with AG's schem if i was you.

the tracing is correct,ive amended a error it had and that was more due to a lack in concentration while drawing more than anything else.

ive compared it to the high quality photos i have of the 1322 PCB and everything is spot on. i havent trace thru it with a schematic as theres no need to imo.
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Post by ShortScaleMike »

I just did this for an IC Muff, it's unverified but may help anyone wanting to build one:

Image

As always, build reports and corrections are welcome

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Post by devastator »

a member could post the schematic again ?

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Post by analogguru »

I think you mean these ones:
http://analogguru.an.ohost.de/193/schem ... _OP-77.gif
http://analogguru.an.ohost.de/193/schem ... _OP-78.gif

which can be found here (beside other schematics):
http://analogguru.an.ohost.de

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Post by devastator »

Yes I found them on your website in making google research. Thanks !

looks interesting, sounds similar to the original one (transistor version) or really different ?

the filter with second AOP, what's its frequency cut ?

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Post by snail »

Don't know what year this is but should be one of the old ones.
This one is leaving this week, if anybody needs some details ask quick.
Cheers
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Post by lolbou »

snail wrote:Don't know what year this is but should be one of the old ones.
This one is leaving this week, if anybody needs some details ask q
Could you please give the codes on the potentiometers? These would help to date. :wink:

Thanks for sharing anyway... :D
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Post by snail »

Sure!

They read 2 sets of numbers

Sustain:
ZA2124
1377805

Tone:
ZA2124
1377805

Volume:
XM2184
1377742

snail

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Post by theehman »

snail wrote:Sure!

They read 2 sets of numbers

Sustain:
ZA2124
1377805

Tone:
ZA2124
1377805

Volume:
XM2184
1377742

snail

That dates it to 1978.
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Post by snail »

Bummer, this puts my topic in the non vintage pedals forum (post 1975) :mrgreen:
Oh well...

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