Blackstone Appliances MOSFET Overdrive

[strassercaster]

Just got a special request for this one from one of my old guitar teachers . I had never heard of it before last week. I now know Billy Gibbons and Ritchie blackmore have been known to use these so I am interested now as well after doing some research. this is a 2 pedal in one box effect i think or a gain with a boost looking at the schematic now.. I just heard of it the other day then saw it as number 2 on a top ten blues overdrive  list right behind King of tone .It is a really cool looking pedal as well. Strange that it uses a cd4049 for an overdrive. I cant wait to make it and have all the parts could be a fast verification ha ha

[rocket88]

funny you should post this one. i started a layout for this yesterday. i'll finish it up and put it on the main page.

[strassercaster]

Cool thanks Rockett. So since your doing it could you walk me through how this works as opposed to op amp or transistor distortion? It is a rather odd looking schematic. Also I need to watch a few more of the videos whats uup with the 2 foot switches. I also just realized i dont have any mpf102 i guess ill have to use a 2n5457 or j201 for starters thanks

[Silver Blues]

The CD4049 and 4069 are six CMOS inverters on one chip. A CMOS inverter can be biased to function like any old linear amplifier using only two resistors (e.g. R7 and R8 around IC2A, whereby the gain of the resultant amplifier is R8/R7), and so in this circuit these are configured as such. The CMOS inverter linear amps have a smooth and progressive distortion characteristic which is why they are used in some pedals. I find most CMOS-based overdrives and distortions sound really good. Also, the supply voltage to these amplifiers have a large effect on the tone; dropping the supply makes the distortion really heavy and thick. This isn't really a technical explanation so much as an anecdotal one but I hope it helps you somehow. If you want to know a bit more I recommend you read these application notes.

[Frank_NH]

There are a vero layouts here...

http://3.bp.blogspot.com/-zIc74V5p4_Y/TxCuO9eT5HI/AAAAAAAAAfI/KBYdIflc2Ic/s1600/Blackstone+Vero+Layout+Crop.png

and here...

http://www.sabrotone.com/?p=3080

You can try to get something more compact, perhaps.

[Neil mcNasty]

I did a redo of the SabroTone layout a while ago, but I have not had the time to build and verify it...
Feel free to have a look at it and see if you spot any mistakes...
Note that the TL071 is rotated 180/upside down...

EDIT: The pinout on the layout differs with the schematic

[strassercaster]

I checked out your Facebook link. Very impressive work Sir. I like the silk screen for the artwork. It is silk screen correct? I would love to get set up for powder coat and silk screen someday . I need to get that going. I just do photo stickers and clear coat. The Photo stickers  look great but dont leave them in the car on 100 degree day it will bubble up unfortunately i learned this the hard way with my entire pedal board boo hoo ha ha.


I saw there are two vero layouts already but the sabrotone has trimmers for gain and the other just looks like a mess to me its got a ton of wire jumpers that would have to be insulated wire for the jumpers.Im interested to see what you come up with.

[strassercaster]

Thank You silver Blues Thats exactly the kind of explanation that I can understand and get an idea of whats happening in laymans terms . I still dont completely get it but I have an idea of how and why which is important.

 Can you tell me some other gain pedals that use this method I havent seen any other than this that use the cd4049. I think I have used this chip in a chorus delay or flanger because i have a few of them ha ha. The link you sent went to fairchild but it was also a 404 idk I will look it up myself Hopefully ill find what you were pointing out. Thank You

[strassercaster]

Thanks Frank I saw those I didnt like the Sabrotone one because of the trimmers for gain . I could probably just run wires from there to the pot. I have done a few sabrotone layouts they all worked but they take more time to build because of the look of them and having to look down for the part sizeds and one really took a while because i missed a cut . ha ha. The other layout looks a little messy to me idk maybe im just picky ha ha. The guys here are the best and I wanted to see what you could come up with .I still appreciate the help on the boss chorus pedal last year that was huge if you ever want a custom decal or something let me know.

[strassercaster]

Hello Thanks for sharing Neil. I have a question about the 390k and 750k next to the cd4049 the 100k is supposed to connect to 3 and 6 not 2 and 5 ? They all look off am i not seeing it right  This is why im not doing layouts yet I guess. ha ha

[Silver Blues]

No problem man. Oh the link is dead? That's odd. The document is called "AN-88 CMOS Linear Applications" published by Fairchild, if you Google that it should come up.

One pedal that comes to mind immediately is the Darkglass B3K or VMT, also the Mad Professor Stone Grey, and the RoG UBE Screamer, 22/7, and Double D all use this amplifier system.

[Frank_NH]

 "I find most CMOS-based overdrives and distortions sound really good."

I've recently built the Aion Quantum Distortion PCB, which is a clone of the Ibanez Mostortion.  It uses the CA3260 CMOS chip, and to my ears is one of the best overdrive/distortions I've built so far.  It's like a tube screamer with more gain, a great three knob tone stack, and a more natural, almost "3-D" sound.  Though they are somewhat difficult to source, you can get the CA3260 chips on eBay.

I also like the the Stone Grey Distortion (and published a layout for a 4049 version here).  Very smooth.  I built a ROG UBE Screamer as well and liked it, but it was a bit noisy at high gain.  That's one of the issues with the CD4049/CD4069 - i.e. it can be noisy depending on the gain levels and filtering. YMMV.