Mutron - Octave Divider

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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mictester
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Post by mictester »

orngjuice wrote:Hey, this is only sort of related, but can any of y'all explain how this works. I have some electronics understanding, but this makes no sense to me, and it seems like a really cool effect.
Thanks
It's actually very simple, though the circuit looks complicated:

Essentially, the input from the guitar is low pass filtered first (it works better with some front-end filtering) then the signal is squared through a comparator-based clipper. This is then fed to a dual-bistable IC. This IC (the 4013) will divide applied frequencies by two at each bistable. Half frequency is one octave down, quarter frequency is two octaves. There is a crude level-sensing circuit that is used to vary the gain of the output part of the circuit in an effort to make the sub-octave signal follow the guitar envelope, and the latter part of the circuit is a set of filters used to try to make the sub-octave squarewave from the bistable IC sound a bit more "natural".

The circuit is as crude as the word f**k, but is give surprisingly good results. However, don't try playing chords through it - the horrible mess of noise that comes out of it isn't pleasant to hear!
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currituckco
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Post by currituckco »

Bump - has anyone tried this out? Very curious to know if it worked! :popcorn:

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squatch
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Post by squatch »

Historical note: I'm pretty sure Zappa used one of these units on his vocals for the '74 tour
He used it for his low basso profundo vocals on 'I'm the Slime' and 'Dirty Love' etc
I think the only other unit around back then was the dbx subharmonic generator, which I
doubt Zappa used 'cos it was a domestic hi-fi device
Zappa used lotsa Mutron gear anyway...listen to his guitar solo on 'Penguin in Bondage',
which I'm sure is a Mutron III going into a Bi-Phase with the optional sweep pedal

I used to have the whole set of Mutrons (including 2 Mutron III's in stereo..one going up and one going down LOL)
Now all I have is a Mutron III (plus a Blue Boy Deluxe and a HK Rotosphere heh)

Cheers from a newbie

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Post by borislavgajic »

squatch wrote:(including 2 Mutron III's in stereo..one going up and one going down LOL)
Now all I have is a Mutron III

those 2 mutrons.....did you get human voice kind of sound with that? like talking pedal or Dipthonizer?

cheers

Boris

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Post by squatch »

Hi Boris,
I was attempting to duplicate Zappa's sound on the 'Penguin in Bondage' live solo, but couldn't quite get it
I think Zappa had the sweep pedal on the Bi-Phase going at the same time, and he may have tweaked it with studio
outboard gear 'cos he did overdub some things on the Live Roxy album
(I never had the EH talking pedal so I can't really compare)
Most people go a bit over the top with envelope filters, but if you keep the peak and gain down you can
get a good usable lead sound with just a little bit of edge without it being too obvious
This subtle effect seems to work best with humbuckers..in the seventies I would just use the combination of
Gibson SG > Mutron III > Marshall 50 head & quad...it worked pretty good

These days I like using the Mutron III on acoustic...
Bill Lawrence soundhole pickup > Mutron III > Princeton Reverb & the piezo pickup into a Fender acoustic amp
This replicates Zappa's 'Stinkfoot' solo sound pretty well

Cheers

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Post by Scruffie »

squatch wrote:Historical note: I'm pretty sure Zappa used one of these units on his vocals for the '74 tour
He used it for his low basso profundo vocals on 'I'm the Slime' and 'Dirty Love' etc
I think the only other unit around back then was the dbx subharmonic generator, which I
doubt Zappa used 'cos it was a domestic hi-fi device
Zappa used lotsa Mutron gear anyway...listen to his guitar solo on 'Penguin in Bondage',
which I'm sure is a Mutron III going into a Bi-Phase with the optional sweep pedal

I used to have the whole set of Mutrons (including 2 Mutron III's in stereo..one going up and one going down LOL)
Now all I have is a Mutron III (plus a Blue Boy Deluxe and a HK Rotosphere heh)

Cheers from a newbie
He's been seen with an Arbiter octaver in photos....

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Post by squatch »

Scruffie wrote: He's been seen with an Arbiter octaver in photos....
Thanks for the info scruffie,
'spose I just assumed it was a Mutron on the '74 tour, 'cos he was using other Mutron gear
didn't realise there was other octavers at the time..thought the Mutron was the first...my bad
Cheers

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Post by Barcode »

can't wait to hear progress on the boards...

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Post by Scruffie »

squatch wrote:
Scruffie wrote: He's been seen with an Arbiter octaver in photos....
Thanks for the info scruffie,
'spose I just assumed it was a Mutron on the '74 tour, 'cos he was using other Mutron gear
didn't realise there was other octavers at the time..thought the Mutron was the first...my bad
Cheers
No Worries! May well have been this anyway, the guy had a few pieces of gear :lol: was just saying there is a possibility he could have used this.

Here's a picture of the man himself with it Image

And a very short thread on it... (Not even worth going, just one gut shot and a dead link) https://www.freestompboxes.org/viewtopic ... nd+Arbiter

And some speculation on it http://www.zappa.com/messageboard/viewt ... =3&t=15337

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Post by pedalgrinder »

I have read through all this thread. Has anyone managed to actually achieve a schematic out of the guts shots or are the schematics on page 1 it there not labeled as to what they are? It seems there was some progress on tracing this one but i couldn't see where it had got to??????
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Post by yiyorebel »

Hello Friends, I do not remember if I've posted before since my knowledge of electronics is very basic but I'm always visiting the forum, so I stand and I congratulate you for this great forum, well revive this topic and wanted to know what happened, someone built this pedal? , More information? .
Greetings from Chile.
pd.: sorry for the English, I used google translate. :lol:

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Post by Brainbender »

BUMP :)

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Post by deeno »

hi guys,
is there someone who has a good resolution pictures of the Mutron Octave Divider PCB?
pictures in the first post are no longer available!
thanks a lot!

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Post by CHEEZOR »

I own one of these. I would have to dig it out of storage to take pics. If someone else has the pics then it would be faster/easier to upload them. I'm leaving for vacation in a few days and I'm not sure I will have time to do it before then so it might be a while. Hopefully someone else can get to it first, but if not, I should be able to at some point.

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Post by Mbas974 »

googolized.
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MutronOct.jpg

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Post by deeno »

Mbas974, I already had the schematic, thanks anyway, what I don't find is the high resolution photos that were posted in the first post of this thread.
I just found on google previews of those pictures but they are too small, that's why my request!
CHEEZOR, thanks for your time, I hope to find them first, however, your help would be great!
I would like to draw the two PCBs to make a clone as close as possible to the original, as I have done for the Mutron III :)
good vacation!

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Post by bvanesch »

Hello everyone, I´ve finnished the biphase with excellent results and I want to start on building both the octave divider and a mutron III in one 1U rackcase. No trouble finding info on the mutron III, but all I have is a half readable schematic for the octave divider. Does anyone have a partslist for the octave? All the geocity and picture links on the first page of the thread are dead...

Much appreciated, Bram.

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karul
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Post by karul »

bvanesch, take a look at BYOC, Divided Octave
We took the Mutron Octave Divider and keep the circuit 100% original, but added some improvements. The BYOC Divided Octave is housed in a 1610 size enclosure, so it's much smaller than the original. We've replaced the wall plug and noisy AC power transformer with the MAX1044 charge pump so that the BYOC Divided Octave can be powered with a standard 9VDC power supply, but still provide the circuit with a bipolar power supply for all the headroom and range of the original. And last but not least, we made it true bypass. Even the auxiliary output has true bypass. Aside from those improvements, the BYOC Divided Octave is 100% true to the original. We didn't make any modifications or cut any corners.
http://buildyourownclone.com/products/dividedoctave

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Post by bvanesch »

Thanks Karul! I´ve seen the board but didn´t know they freely share the instructions and everything! Haven´t compared it to the original yet but at a glance it looks the same. I´m still drawing the (joined)PCB, hope to have one ready end of this month.

Greetings and thanks again.

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