L'Overdrive de la Révolution Deux - A tribute to FS.org!

briggs · Post by **briggs** » 13 Jan 2008, 22:24

Hi there marshmellow. Thanks for that. I keep getting an error when I try to open up the two layouts and the PCB at the moment.

Also one other thing, in my build I used the "Alt Tonestack" instead of the regular tonestack... Both sound good though.

Thanks again marsh!

marshmellow · Post by **marshmellow** » 13 Jan 2008, 23:08

Strange, works for me...

So here's another round:

https://i270.photobucket.com/albums/jj1 ... ts/PCB.jpg
https://i270.photobucket.com/albums/jj1 ... ayout1.jpg
https://i270.photobucket.com/albums/jj1 ... ayout2.jpg

briggs · Post by **briggs** » 13 Jan 2008, 23:25

That's the one! They both work now. It must have been me

ieatyouforbreakfast · Post by **ieatyouforbreakfast** » 17 Jan 2008, 01:23

im afraid i might mess up trying to build it using schematics..

can someone kindly do a perf or vero layout for me?

soulsonic · Post by **soulsonic** » 17 Jan 2008, 03:03

You could just use the PCB layout. Put it on unclad perf and follow the traces in the PCB layout with the leads from the components - just mimic the drawings of the traces with wires. That's how I started building perf. You could even print out a copy of the PCB and tape it to the perfboard to use as a template - alot of people have done it that way. When I started - I redrew the design on perf with a sharpie marker and followed it like that.

briggs · Post by **briggs** » 17 Jan 2008, 11:46

Yes, but if you want to use the "Alt Tonestack" you will have to alter the layout very slightly.

briggs · Post by **briggs** » 17 Jan 2008, 14:37

I just had a bit of a "Eureka" moment with this thing. I started playing with it and thought it sounded different to when I was last playing it - much more open, less compressed and "saggy" with lots more headroom, a completely different character but still a great sound! I check the power supply and I running it at 12v by complete accident. The increase in voltage changed the circuit in another great way. I think I'll get some more charge pump chips and see what this thing is like at 18v. I may even insert another switch to go from operating at 9v to 12v and maybe even 18v - that would be much more use than the "voice" switch.

This is turning into quite a useful little circuit without me even knowing it

mike_a · Post by **mike_a** » 17 Jan 2008, 23:56

briggs wrote:

Here it is! The LORD! heh. Any suggestions for mods/improvements?

This sounds like a really nice project! Great work Briggs! added to the "to do" list...

As for improvements: I think it might be good practice to make the MOSFET's drive like in the MOSFET booster (i.e fixed bias resistor and bypass cap with drive pot).
That way when you change the drive you won't alter the MOSFETs bias, like it happens now (and it won't crackle).

What do you guys think?

briggs · Post by **briggs** » 18 Jan 2008, 00:41

Yeah, you could do that. I just went for the typical SHO design for simplicities sake and to reduce parts count.

I'm sure it would sound just as good (If not better!) with a mosfet boost style setup. Give it a try, it's definately worth a build - especially if you have the resourses to run this thing at 12v or 18v! Very fun, much more (and I hate this saying!) "Amp like".

Feel free to post your mods to the scheme here. The more, the better

I'm looking forward to building in a 9v - 12v - 18v switch into mine. I just wish my parts would hurry up and arrive

marshmellow · Post by **marshmellow** » 20 Jan 2008, 17:33

Briggs, I finally had the time to update the schematic... sorry for the delay.

Apart from that, the other tonestack could also be fitted in the pcb. With upstanding resistors and connecting the RC-combo to ground in between with wires. Actually I thought about the possibility to use both on the pcb, but then I would have to use a jumper for the original one and I don't really like that so much

.

ieatyouforbreakfast · Post by **ieatyouforbreakfast** » 21 Jan 2008, 23:37

briggs,

can this beast do distortion sounds too? what kinda sound is this similar to?

briggs · Post by **briggs** » 22 Jan 2008, 15:01

Thanks marshmellow!

This thing sounds like a mix between a semi cranked marshall and a semi cranked mesa. Nice breakup at lower gains too - good for adding a bit of grit to your sound, pretty dynamic in it's clipping response. It does do some pretty high gain distortion when the tone control is bypassed. I like it, especially at a higher voltage. I'm going to install a voltage doubler in the case soon so I can switch between 9 - 12 - 18 volts.

Deaj · Post by **Deaj** » 03 Feb 2008, 20:02

Just put this one together on the breadboard this morning. What a great sounding overdrive! I have both tone stacks built and I like both of them. It's a pretty versatile circuit. Fantastic Briggs! Thanks

briggs · Post by **briggs** » 03 Feb 2008, 20:24

Thanks Deaj, I love this pedal too! Just a lucky accident really, you can tweak the values of the tone stack to your hearts content, I'm just installing the voltage doubler into mine and another tonestack switch

It's going to be a monster

briggs · Post by **briggs** » 03 Feb 2008, 20:30

The extra tonestack that I will be adding is this one here:

http://skreddypedals.com/circuits/ToneS ... ianMay.gif

I'm using a 50kB pot though, not a 100kB. You don't get as much low end roll off then....

marcao_cfh · Post by **marcao_cfh** » 20 Feb 2008, 03:31

Hey Briggs, do you have any sondclips?

briggs · Post by **briggs** » 20 Feb 2008, 10:01

Sorry, no samples. As I said in my other thread - my recording gear was nicked a few weeks ago

Many apollogees!

If anyone would like to make some - I would be honoured

marcao_cfh · Post by **marcao_cfh** » 21 Feb 2008, 15:51

No problem. It looks like a interesting OD, I just don't breadboard it right now because I'm out of parts

. I usually just buy what I need for the effect I'm building, and don't make stock of parts. But it's on my "to build" list

.

Post by **modman** » 14 Mar 2008, 13:33

Does the search function within the topic fool me or is there no value for D1?
Will go with 1N4148 then, ....

Post by **modman** » 15 Mar 2008, 12:50

modman wrote:Does the search function within the topic fool me or is there no value for D1?
Will go with 1N4148 then, ....

Ok, the diode D1 is just a protection diode for the MosFET - you could use red LED, 9.1V zener, 1N914 ... -- Briggs told me off-line. I started with the described transistors, but ended up using Q1 2N7000 , Q2 SK117 ( ) and Q3 2N5457 - had Q2 drain at 4,9V and Q3 at 6V - going to replace the trimpots to get some more accurate bias. Also had to sub R3 5k1 for 4k7 and R8 1k5 for 1k2.

Initially I left out the gain boost switch and C7 cap. As I said, my bias was not entirely on the mark and this showed (I hope it's the bias) in the sound at maximum gain with the tone circuit engaged. Quite treble heavy and not so equal harmonics. It's better when the gain is backed off though. Switching out the tone section, there heaps more bass and and a very fat distortion tone with more equal harmonics then in the other setting.

Seeing that I might need more gain, I just jumpered C7 in - no switch. This improved both setting still, but did not solve the somewhat canny tone of the tone section at maximum gain, it's much better up to 3/4 gain.

Just thinking about replacing the minitoggle with a footswitch -- and finding time to wire full size pots to properly check bias and then replace with resistors -- how I hate trimpots. Also didn't really have the time to try out changing the capacitors as suggested initially. But will report back....

At least, it sounds better than the Tubereamer I recently built, but that might be me...

thanks for this project, Briggs!