madbeanpedals::forum

Projects => General Questions => Topic started by: teknoman2 on June 04, 2013, 01:51:42 PM

Title: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on June 04, 2013, 01:51:42 PM
I would like to build okko diablo + and
I want to put a switch for selecting power supply, 9 volt or 18v.
I just saw max 1044 datasheet and I am bit confused.

http://www.stanford.edu/class/ee122/Parts_Info/datasheets/Max1017-ICL7660.pdf

The datasheet indicates that I have to use 2 10uf caps and Scottky diodes.
So far everything is normal.
I am going to use this schematic
http://www.box.com/s/qz7r3bgncl3jzgugoe3e

My main issue is  where am I going to put the double voltage circuit and the switch on the schematic?
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: saxoftenest on June 04, 2013, 11:15:22 PM
I drew a up a Diablo awhile ago (sans +):

(http://imageshack.us/a/img534/6185/diablov2schematic.png)

Using my layout as a reference, you could also use the second column of a DPDT to bypass the 9V input of the charge pump.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on June 05, 2013, 11:39:27 AM
Thank you very much, your schematic was very helpful.
I am planning to use it in mine.
Did you finally etched it and box it?
Are you satisfied with the results?

Also I would like to ask something about okko diablo +
In my schematic the boost circuit comes after the gain circuit.
Is that correct?
Usually the boost section comes first and then follows the od circuit.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on June 05, 2013, 03:19:03 PM
I just finished my schematic without errors.

It's similar with yours.

Hope its ok for etching.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: saxoftenest on June 05, 2013, 03:59:56 PM
I don't etch, so I had OSH Park fab up my PCB design of this schematic - sounds great! Here's a look:

(http://imageshack.us/a/img823/7200/diablokd.jpg)

(http://imageshack.us/a/img268/4193/diabloguts.jpg)

Re: the boost section, it does come after the OD. I didn't include it because there are other boosters I like better and wanted to fit mine in a 1590B.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on June 05, 2013, 06:18:40 PM
Nice one mate.
Really its a very good one.

Did you find any issues with the trimmers?

Were they easy to adjust them?
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: cooder on June 05, 2013, 07:07:45 PM
Oh man I would love a fabbed board like that for a small enclosure size!
Would you have any spare boards for sale, saxoftenest?
Cheers :)
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: saxoftenest on June 06, 2013, 05:11:46 PM
No extra boards, unfortunately. I have a few PCB designs that I may offer up for sale this summer of which this may be one...
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: cooder on June 06, 2013, 07:39:48 PM
I would be definitly keen for two boards of this and also interested what else you cook up...!
Do you have a website for orders or how to find out about it?
Cheers!
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: juansolo on June 07, 2013, 07:37:39 AM
Likewise I'd take a couple of boards if you did a small run. It's been on my list of things to do for ages.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: Tremster on June 10, 2013, 08:22:59 PM
I'd take one of these Diablos as well!
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: dc001013 on June 13, 2013, 03:14:47 PM
Id love to have a Diablo board also... ;D
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on July 08, 2013, 08:08:16 PM
I just finished the schematic and the board section.

Probably by the end of the week I will send them to OSH Park.

If everything goes well I will make a dozen  of these boards also.

( I believe I have to change some drain resistors values to bias the J201 drain to 4.5v)
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: Tremster on September 02, 2013, 02:04:45 PM
Hello.
A humble inquiry about the state of the diablo.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: bordonbert on October 21, 2014, 02:55:53 PM
Just to put this as a CAVEAT for anyone who comes across it at a later date...

The schematic shown for the Okko Diablo above is the standard web version.  There is also an accompanying schematic for the Okko Boost.  They are both wrong in a big way!  In all of the stages the capacitors between the gate and source of the upper JFETs are attached to the wrong end of their source resistor.  They should all be connected to the drain of their lower JFET.  You cannot get your Diablo working properly with the circuit based on that schematic.

This link will make it all clear for anyone who is interested.   http://www.madbeanpedals.com/forum/index.php?topic=17962.msg172734#msg172734 (http://www.madbeanpedals.com/forum/index.php?topic=17962.msg172734#msg172734)  There is a link in that thread to a very good site where the circuit action is described in detail.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: teknoman2 on October 21, 2014, 03:06:16 PM
Thank you for the info's mate,
I ve never had the time to finish this project, probably cause it has those jfets....
Since now you verify that everything works well with these changes.
I should try to find some time to make a board of this one.
Title: Re: OKKO Diablo + Voltage Doubler using switch
Post by: bordonbert on October 24, 2014, 09:56:26 AM
Good to hear someone else is interested in it, on first listening to my prototype it seems to be a really well set up box and deserves more exposure.  Far better than the "diode clipping" approach which is never done properly for a crunch pedal rather than all out fuzz.  The controls are great, useful range without being overdone.  The crunch is well tamed and very gradual and allows loads of feel to your playing.  All in all one of the best overdrives I've heard.  Mind you if you play death metal look elsewhere, this pedal is more suited to the classic blues/rock player than the thrasher.

I built my own into the standard Hammond 1590BB enclosure and I got a bit creative with the layout.  I put the 5 pots and their associated passive components, and the 9V socket onto one board which mounted independently.  Each separate stage came out to pads on the edge of the board.  Then PCB mounting input and output jack sockets, the voltage doubler circuit and 9V/18V switch, and each active stage went on a second board.  I then wired up the connections between them.  It meant a very easy mount and breakdown procedure.  It oscillated!  I've played around with moving a few of the components from board to board and cured this but the pedal is so good I'm going to start again and do it all on one board in a more conventional manner.

If you come up with a working PCB I would be interested to see it.  I should also say that I've built the Okko Boost stage as a separate clean pedal again with voltage doubling and that works really well too.  While I'm sure there are improvements to be made by trimming values, (not myths like capacitor and resistor types and swapping semiconductors), it's a very usable setup as is.  Once you correct the schematic error of course!  8)