bipolar 12v for Mutron Octave clone

Started by hank reynolds 3rd, April 08, 2005, 07:02:56 AM

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hank reynolds 3rd

Hello all,
I'm trying to clone the Mutron Octaver, (thanks to M wald and Stuart Castledine for extra schem help, unfortunately ,i dont have the other schems with me as I use the internet at the local library :(   )
http://matthias.grob.org/pEE/ppSchema/MutronOct.jpg

For the PSU, can I use a supply like this one (w/ 12v regs) but without the transformer??
http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

I want to be able to run it off an 12v AC adaptor (unregulated ,right?? as the reg's are onboard the pedal??)

would I have to take the gnd on the ggg schem off and connect a wire to the end of D2 to get +/- 12v?? (plus the extra set of caps/diodes for the two seperate audio/logic power rails...)
I've nearly finished a hand drawn PCB for this (missed  a few bits but got there finally!!) and this is the final hurdle....
Cheers

Sam
PS: i can post my pcb etc here once its finished cant i, as this pedal isnt in production anymore???

waldo041


D Wagner

Quote from: hank reynolds 3rdHello all,
I'm trying to clone the Mutron Octaver, (thanks to M wald and Stuart Castledine for extra schem help, unfortunately ,i dont have the other schems with me as I use the internet at the local library :(   )
http://matthias.grob.org/pEE/ppSchema/MutronOct.jpg

For the PSU, can I use a supply like this one (w/ 12v regs) but without the transformer??
http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

I want to be able to run it off an 12v AC adaptor (unregulated ,right?? as the reg's are onboard the pedal??)

would I have to take the gnd on the ggg schem off and connect a wire to the end of D2 to get +/- 12v?? (plus the extra set of caps/diodes for the two seperate audio/logic power rails...)
I've nearly finished a hand drawn PCB for this (missed  a few bits but got there finally!!) and this is the final hurdle....
Cheers

Sam
PS: i can post my pcb etc here once its finished cant i, as this pedal isnt in production anymore???

Sam,  

The power supply you referenced is designed for use with an AC adapter.  Check the datasheets for the regulators before you build it though.  I think that the negative regulator was oriented incorrectly the last time I checked the file.  It is drawn facing the positive regulator, when it should be oriented the same direction.  It may have been fixed by now, though.

Now about separate rails for logic and data.  I have read that it is desired to keep the audio free from whine or other clutter.  The principal is the same as star grounding.  The use of 100 ohm (or less) resistors and diodes is often employed for further isolation, also.

You can post the PCB here, as you drew it.  It is yours to do with as you wish.

Please post the results of your build.  I will be very interested to know how it turned out!

Derek

hank reynolds 3rd

thanks for the help D Wagner,

I'm still a little confused as to how I'd wire it up....I've made a psu and i've wired the regulators up (pretty sure the pinout is right..i remember the 7912 pinout is daft...) and took a source to ac from the positive rail (through a 4700 uf cap and diode) to +ve , and a source from the gnd rail (the -ve rail goes ,again through the reg into a 4700uf cap ,then a diode )..
i think i explained that ok....
i got the schem from mikeb's prophesy sound diy page , (again ,it got 15v ac without using a transformer..)
but unfortunately i cant get the diy section to load up...
this worked ok on my diy 'infinitphase' (it hass seperate outs for audio and logic power also), but all i get is a loud humming sound when i try it with the mutron clone...

any ideas???

Thanks again

Sam

Ps: the parts on the pedal are all right, i've checked and checked and checked,etc... :D  :)
Its just this final bit....