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good stuff. i like the finish too. what's the translation of that french writing?

I once "borrowed" a big old handful of tropical fish caps from the electronics lab at school. they weren't using them! they don't even build circuits in that lab anymore, it's all digital stuff.

anyway, you can try and find the old school electronics shop in your town. it's a good bet if they salvage electronics. stores that do usually have the old weirdo parts that you're after.

be careful with the power wiring for the DC jack, especially if you're building a positive ground version. I always get confused when wiring one of those up.

nice mojo parts selection, what transistor are you using?

VERY impressive, especially for a second build

nice build, how's the pcb held in place?

did you use the "stock" clipping diodes? i'm thinking about making one of these but I don't really want go out and find the unusual ones listed on the schem.

I suggest using the method pandadandan posted in this topic: http://www.madbeanpedals.com/forum/index.php?topic=15

Everything is kept grounded and it lends itself nicely to clean wiring jobs.

This reminds me of the Tri-Rat that Dano from Beavis audio built. It's simply three rat clones in one box. That man sure loves his rats.

One thing that I do to most of my distortion pedals is add a (footswitchable) slambox (super hard-on) in series with the main circuit. I don't normally add a pot, instead just replacing it with a 1k resistor. It's a great little boost for solos. It takes up about as much room as a 9v battery would and since I never use batteries anyway, it's no loss for me.

Another option might be to try the Double D at ROG. It was kind of planned as a two-amps-in-a-box project, and one channel was loosely modeled on a Boogie-style sound. It's simpler, sounds great (I've built one for myself), and can fairly easily fit in a 1590D enclosure.

Two Dr Boogey's would fit in a DD, but make sure you plan your pot placement. The switching would likely be very similar to the Double D project. I suggest checking that project out and basing your design off that. I'm not sure if this is an issue or not, but you may have some "popping" noise issues when switching between the two channels; perhaps someone can comment on this?

First thing's first, figure out the switching problem. Double check against your wiring diagram. A perfect circuit is useless if it's not switched correctly. So get at least the bypass working before you move on.

If you have a DMM (if you don't, you should!), check continuity for ground on jacks, switches, pots and on the board (compare to the circuit diagram). Keep an eye out for stuff that's shorted to ground or stuff that's floating when it shouldn't be.

Check the voltage at the drain of each of the mosfets (should be something like 8V, not sure offhand). Then check the voltage at the gate (should be really small, in the mV range). Keep in mind this is my really quick analysis without any numbers so if stuffs really off, don't freak out because I'm not certain.

If you're still stuck, can you post a picture of the solder side of the board? It's probably easier to troubleshoot from that side.

The G2 is almost certainly based off the big muff. If it's not based off the big muff itself, than it is based off something that's based off the big muff. The architecture of of both pedals is very similar, even though many of component values may not be, which is why the pedals don't sound particularly alike.

Both pedals have initial gain stages, followed by two clipping stages followed by a filter stage and followed finally by an output gain stage.

Just use 390k and 420k resistors. In +95% of cases, it won't matter. If it's for something like a filter or setting gain of an amplifier (two of the major applications in audio), it's virtually impossible to hear any difference.

If you need to get really close, buy a bunch of 5% resistors with the above values, and test individually for on spec units. Or buy the above values and a couple of 2k resistors and put them in series if you have room on the board.

It occurred to me in a dream that you owe it to yourself to call this pedal the dyana ross.

Definitely going to try that. I've never been a fan of FeCl, but it's all that i've used. I found an instructables tutorial on this method. so you suggest a 1:1 ratio? I saw somewhere else that suggested 2 parts H202 to 1 part HCl

i use the hydrogen peroxide, hydrochloric acid method. the actual etching has worked fine for me, but I for some reason that I've yet to determine, the solution looses ALL potency after sitting for a while. I've done two big batches of various PCBs, and each time I'm forced to make a new batch of etchant. I suspect something is evaporating (possibly the chlorine), but I'm not a good enough chemist to figure it out for sure...

The stock Crunchbox uses 5mm for the LED clipping. I don't believe there is a difference in forward voltage between 5mm and 3mm for red diffused LED's....

What about different diffused colors besides red?  Do they have differing forward voltages?
I have some 3mm diffused greens.  Should I stick with reds on the krunkee?

different leds will have different Vf. if you're using them for clipping purposes, it can make a difference, but if you're using them for an indicator, the difference isn't usually enough to bother changing limiting resistor values for.

in general, red led's have a lower value for Vf than most other types. they will clip a lower voltages than others. you can try looking up a datasheet for a similar led, it will give you a range of values for Vf. I believe your standard red led has a Vf value of 2.1V, while blue led's have Vf's in the 3.6v range.

That would be great! I already bought the 4pdt a while ago but it would help me a lot to understand whats going on here. In the mod schematic, it looked to me that the switch was either connecting from the positive pads, through the caps, to the ground or there was nothing running to ground.

As for the LED mod, do you think it would be possible with the 4pdt I have?

Thanks again!

First off, please excuse the ms paint wiring diagrams. Anyway, after I looked at it a little more closely, it's possible to do with a dpdt switch, including the LED switcher! The reason for this is because all the caps are simply connected to ground, the same node (take a close look and you'll see what I mean).

Here's a wiring diagram done with a 6pole 2position rotary switch which is bigger, but probably somewhat easier to wire. Notice that one pole is unused.



and here it is done with a 4pdt (but notice that 2 poles are unused). This might be tricky to wire up since you'd have to solder 4 caps to one lug. If I were doing this, I would probably build a little perf-board circuit to hold the 4 caps.

They are using the 4pdt as a 4pst, but I believe you'll need 4 poles as not all of the extra caps are connected to the same node (that node being ground).

One solution would be to use a rotary switch instead of a rocker switch.

A 2 position 5 pole (at least 5) would work perfectly, including the LED mod. I have to run, but if you're interested, I could draw out a little wiring diagram later tonight.