MXR Distortion II

[BuGG]

Okay, I'm linking a zipfile that contains two schematics in both Eagle and DipTrace format.   One version has an integrated charge pump IC to run the circuit at 18V from a standard 9V supply, the other does not.

Feel free to change component footprints as needed.

https://drive.google.com/file/d/0BwPDUQBEhvJXTV91THlyWWR1U2M/edit?usp=sharing

[rullywowr]

Thanks Bugg, this is cool.  I think I found the thread on DIYSB which the schematic was from.  I took the DT schematic, massaged it a little, and added my take on a switchable 18v/9v power supply.  Fits sideways in a 1590BB like yours.  I was thinking about doing a 1590B/125B version but as blokes in GB say: "CBA."





The power supply section has a small solder jumper under the IC which allows use of any charge pump including the LT1054.  This jumper connects pins 1+8.  There is also a place in the middle to switch between 18v and 9v.  You can hardwire this or use a 2.54mm pin header with a jumper shunt like on hard drives (I like this approach).  You could also use it as an external switch but it would of course "thump" when switched.



Share and share alike...here are the files for Diptrace as I have them.   

Usual disclaimer:  I make NO guarantees that this PCB works, won't catch on fire, electrocute the user, or cause "a feeling of dryness" in sensitive areas.  Use at your own risk.  For DIY use only, reselling of PCBs using this artwork and layout is not permitted!  Feel free to build some for yourself and a few friends.  Commercial use of this PCB is not permitted.  All artwork is intellectual property of www.rullywow.com.  Basically, don't be a douche!

https://dl.dropboxusercontent.com/u/73135424/Dist%20II/Dist%20II%20v0.1%20by%20rWOW%20Diptrace%20Schematic%20and%20PCB.zip

I plan on uploading to OshPark as well, but the cost is going to be pretty expensive for a board of this size.  I will most likely put this in on my next PCB run to be a stock PCB item at www.rullywow.com  - the cost of the board will be a lot less than OSH. 

Let me know if you are down for a PCB so I can gauge interest!   

[BuGG]

Just like that?!  I've been struggling with this thing for WEEKS and you just pop up a nice board like that overnight? 

I don't know how you guys do it.... I really don't.     

[televisiondown]

Wow! This thread moves fast!! I'd be very interested in a board from Ben. It'll be a good excuse to pick up a King Tut, too. Great job BuGG and Ben

[the3secondrule]

I'd buy one!

[rullywowr]

Thanks guys!

Just like that?!  I've been struggling with this thing for WEEKS and you just pop up a nice board like that overnight? 

I don't know how you guys do it.... I really don't.     

Practice, practice...   Your schematic was really good!  I made a few tweaks to change to box caps, added supply net ports, and added the power supply with switching options.  The net ports (supply pins) really help make the schematic easy to read.  I've added a few in my latest DT library.

I reduced the size of the PCB down a little bit...plus a few revisions to clean up the layout and graphics.     Possible to go even smaller but its not really a big priority when using a 1590BB horizontal.  It doesn't even take up half the box.   

[BuGG]

The net ports (supply pins) really help make the schematic easy to read.  I've added a few in my latest DT library.

The net ports were visible on the Eagle version of the schematic.   Since I figured most people reading this would be using Eagle that's what I used to create the schematic, then I just exported to DipTrace format.      I didn't bother tidying up the DipTrace version because I know very few people actually use it. (a shame really!)

Using Eagle really makes me appreciate the functionality of DipTrace.     

The boards look excellent and the 9V / 18V switching option is super cool, I wouldn't have even considered it.   One thing I do wish I would have done is included a 15V regulator (the original actually runs on 15V, not 18V) but in my breadboard tests that required another stage of diodes/caps in the charge pump circuit to get that supply voltage just a little bit higher.      The difference is probably not worth the effort, so as they say, CBA.   

[rullywowr]

That's great feedback and makes perfect sense. I also read that the bias resistors for vr in the original were 470k which may starve the circuit for voltage. I went ahead and used 10k there instead to avoid this issue.   A simple resistor voltage divider.

So not much difference using 15v vs 18v I take it.  I threw in the 9v option as there is plenty of room on the board and it's fun to hear the difference.

[BuGG]

I also read that the bias resistors for vr in the original were 470k which may starve the circuit for voltage. I went ahead and used 10k there instead to avoid this issue.   A simple resistor voltage divider.

That is very likely a good idea.  The original circuit used a leftover opamp stage as a buffer for Vr.

Referencing your schematic, the stock values for R16 and R17 were both 10K.   I believe these were bumped up to 100K and 1M (respectively) to combat loading down the Vr supply.    I'm not sure why it was done this way rather than lowering the values of the Vr divider.

By lowering the values of the Vr divider network we could most likely go back to the stock values for R16 and R17.

[enjoyadrian]

id be down for a board of this if they were made.

[tcpoint]

I'd be down for one, as well.

[Hogharry]

You did a great job on the enclosure. There's something very satisfying about a vero build. Well, one that works...

[lars]

Awesome thread, and what a great build. Those are some clean guts for any type of board. Makes me think of building one of these. Some good things happen when you run a Dist II into an op-amp Big Muff.

[Kinki fuzz]

I'd a PCB myself too!

[the3secondrule]

Guys, I'm working up a PCB layout for the Dist II, if anyone's interested I'll post here when it's done...