MXR Distortion III vero?

[philbinator1]

Does anyone have this vero that they could post/pm me?  I looked in the gallery and googled, came up zip.


cheers
phil

[philbinator1]

bump for extra vero-y goodness?

[slacker]

If no one has one, point me in the direction of the schematic and I'll see what I can do.

[philbinator1]

http://analogguru.an.ohost.de/001/schematics/Mxr_Distortion-III.gif

and the thread that goes with it:
http://www.free stomp boxes.org/viewtopic.php?p=255&mforum=free stomp boxes


EDIT:  I had to put spaces in there, it wouldn't let me post the name of that website!?!  crazy

[MikeH]

I don't know how helpful this will be to you, but it's AWFULLY similar to the Zakk Wylde OD, except it has clipping diodes to ground between stages instead of in the feedback loop.  And I know there's a ZW OD vero layout floating around somewhere.

[Brymus]

Can you post/PM me the Zak Wylde version schematic the link at the other place is broken?
Thanks Bryan

[slacker]

http://analogguru.an.ohost.de/001/schematics/Mxr_ZakkWylde.gif

[slacker]

Here you go



The component numbering follows Analogguru's schematic. I've left off Q4 and associated components, looks like that just mutes the input using the original switching, using true bypass switching it's not needed.

Shift a couple of components and you can build the ZakK Wylde with it as well.

[philbinator1]

Here you go

The component numbering follows Analogguru's schematic. I've left off Q4 and associated components, looks like that just mutes the input using the original switching, using true bypass switching it's not needed.

Shift a couple of components and you can build the ZakK Wylde with it as well.

thanks so much for doing that man!  i'll start tomorrow, really looking foward to it    

EDIT: do you know the value of c8?  its not on the schem.

[slacker]

thanks so much for doing that man!  

No problem, after I posted it I realised the vero had a couple of errors, I've corrected them now and uploaded a new version. The image should refresh to the new version, if not go here http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/mxrdist3board.jpg.html?g2_imageViewsIndex=1

I don't know what value C8 should be, on the Zakk Wylde schematic which has the same arrangement its 4u7 it probably doesn't matter much I'd guess 10uF or even bigger would work fine. R6 doesn't have a value either, it's 33k on the Zakk Wylde so I'd just go with that, it just sets the minimum amount of gain, which you're probably not going to use so any similar value would be fine.

Let me know how you get on with it.

[philbinator1]

just bumping this...

i'm itching to build this but don't don't have any 220pF caps.  i'm gonna buy some, but can i use regular old ceramics for this value? 
and do the kind of caps you use matter overly?


cheers
phil

[MikeH]

just bumping this...

i'm itching to build this but don't don't have any 220pF caps.  i'm gonna buy some, but can i use regular old ceramics for this value? 
and do the kind of caps you use matter overly?


cheers
phil

I don't see a 220pf cap on the schem... I see a 220uF; is that what you mean? Where is the cap you're talking about?

[philbinator1]

I don't see a 220pf cap on the schem... I see a 220uF; is that what you mean? Where is the cap you're talking about?

sorry my mistake, it's 120pf, it's C12.  tell you what don't worry about replying, i have other questions about the schem i'll ask tomorrow when i don't have brainfuzz...gotta go to bed now zzzzz   

[slacker]

It will work fine without C12 so you could just build it and add that when you've got a suitable cap. Any similar value will work fine, doesn't matter what sort of cap it is.

[CynicalMan]

I'd just like to point out that I've modded one of these and it sounds a lot better without C4.

[philbinator1]

Ok here are some q's i had about the D3 schem:

* Some of the resistor values have 'E' after them - what does this mean?  is it another letter for Ohms, like 'R'?
* Why is R15 and R16 missing off the schem?
* There are 2 symbols that could be ground; one looks like half a cap symbol, the other is a line with a dot through it.  which is ground, and which is the other?
* Do we have concrete values for R6, C8 and Q4?
* Are the caps with one side black/one white polarised?
* The three pots (VR 1,2 and 3) have either 'D' or 'W' after them.  What kinds of pots are these?  Lin, log, or reverse-log?  Or other?
* Can the IC (MC33178P) be subbed out for something else?  741 etc?
* Is 'S1a' and 'S1b' part of the jack(s)?
* Is it possible to use a ceramic cap for C12 (120pF)?
* What is that symbol in the top left-hand corner of the schem?


I know that's a hell of a lot of questions!     Very demanding of me but i like to be prepared/thorough...it will help others too.  If it's ok with Slacker I might take his vero and attach the info/component values (which got from Slacker) so you guys can download it as a single gif or jpg or whatever.  If someone could answer anything off the list i would be very grateful, thank you.   

Schematic:
http://i809.photobucket.com/albums/zz13/philbinator1/MXRDistortionIIIschematic.gif

Vero:
http://i809.photobucket.com/albums/zz13/philbinator1/MXRDistortionIIIvero.jpg

[slacker]

I can't answer all the questions but here goes.

* Some of the resistor values have 'E' after them - what does this mean?  is it another letter for Ohms, like 'R'?

Yeah, it's another way of saying Ohms.

* Why is R15 and R16 missing off the schem?

Who knows, the numbering is taken from the PCB, maybe they just didn't exist or were part of the LED switching, which isn't shown on the schematic. There doesn't appear to be any missing components on the schematic if that's what you mean.

* There are 2 symbols that could be ground; one looks like half a cap symbol, the other is a line with a dot through it.  which is ground, and which is the other?

The thick black line, like the one on the bottom of the output pot is ground. The other symbol is 4.5 volts made by R8 and R9.

* Do we have concrete values for R6, C8 and Q4?

Don't know about R6 and C8, the values from the Zakk Wylde will work fine, Q4 isn't on the vero layout so I wouldn't worry about it

* Are the caps with one side black/one white polarised?

Yeah, the white side is positive.

* The three pots (VR 1,2 and 3) have either 'D' or 'W' after them.  What kinds of pots are these?  Lin, log, or reverse-log?  Or other?

Not sure about 'D' log will work fine for the output and linear for the distortion. W is a special tapered pot, that's like half log and half reverse log. Smallbear sells them, or you can use linear but the "feel" of the tone control will be a bit weird.

* Can the IC (MC33178P) be subbed out for something else?  741 etc?

You can use pretty much any dual opamp like a TL072 or a 4558.

* Is 'S1a' and 'S1b' part of the jack(s)?

That's the stomp switch for bypassing the effect.

* Is it possible to use a ceramic cap for C12 (120pF)?

Any sort of cap will be fine.

* What is that symbol in the top left-hand corner of the schem?

If you mean the thing above the battery I think it's the DC jack.

Schematic:
http://i809.photobucket.com/albums/zz13/philbinator1/MXRDistortionIIIschematic.gif

Vero:
http://i809.photobucket.com/albums/zz13/philbinator1/MXRDistortionIIIvero.jpg

Not trying to have a go at you, but it's not really cool to host the schematic on photobucket, it even asks you not to on it
I don't care about my layout, you can do what you like with that.

[MikeH]

FWIW I've never been bothered by using a linear pot in place of a "W" taper.  It's the same as the tone control pot on a tubescreamer, and many similar clones.  Linear sounds just fine to me.

[slacker]

Cool, to be honest I've never tried it, if you can believe it I've never built a TS clone

[MikeH]

Cool, to be honest I've never tried it, if you can believe it I've never built a TS clone

No I can't believe it.  I wish you wouldn't lie to me like that.