CMATMods - Black Plague

fret_burn · Post by **fret_burn** » 20 Dec 2010, 17:21

: P1020400.jpg (152.53 KiB) Viewed 1858 times

: P1020402.jpg (182.33 KiB) Viewed 1858 times

: P1020404.jpg (157.04 KiB) Viewed 1858 times

: P1020407.jpg (175.14 KiB) Viewed 1858 times

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Yellow lines = back
Blue = Top
There is a blue line that seems to terminate under the diodes on the left... i can't see where it goes from there.

: trace.jpg (709.64 KiB) Viewed 1858 times

jb351 · Post by **jb351** » 20 Dec 2010, 17:41

Looks like a tweaked Rat.

culturejam · Post by **culturejam** » 20 Dec 2010, 20:57

Man, what a convoluted layout. But at least there are no jumpers on this one.

Yep, it's a Rat of some sort.

Dingleberry · Post by **Dingleberry** » 22 Dec 2010, 20:15

Hi.
Just spent about an hour comparing those gut pics to various RAT schematics floating on the net and found out that the Black Plague is actually an 1:1 copy of early version RAT + the option of different clippers.
There is the correct RAT schematic:

-T

uncleboko · Post by **uncleboko** » 22 Dec 2010, 20:40

culturejam wrote:Man, what a convoluted layout. But at least there are no jumpers on this one.

Yep, it's a Rat of some sort.

What pray is the problem with jumpers???

roseblood11 · Post by **roseblood11** » 22 Dec 2010, 20:49

No real problem with jumpers,
but this pedal is another example of a self-appointed pedal guru who isn´t able to make a good layout for a small and well-known circuit like this. You could make a layout for a Rat on a single-sided board that is half as large as this one (or smaller), most likely without a jumper.

Dingleberry · Post by **Dingleberry** » 22 Dec 2010, 21:01

There is a blue line that seems to terminate under the diodes on the left... i can't see where it goes from there.

I think it'll have to go to the same point where the other ends of 1N4001 diodes will go=>
junction of 4u7 cap and filter pot.

Looks to me that the diode switch adds either one 4001 diode or back to back pair parallel with red leds.
Never seen that arrangement before but that is what I figured out from the pics.

-T

Dingleberry · Post by **Dingleberry** » 22 Dec 2010, 21:27

Just accidentally took a look at the Lovepedal Les Luis thread and noticed that there is same kind of diode clipping arrangement... initation? It's just made with 1N914's and BAT46 schottkys.

-T

roseblood11 · Post by **roseblood11** » 22 Dec 2010, 21:42

Dingleberry wrote:Just accidentally took a look at the Lovepedal Les Luis thread and noticed that there is same kind of diode clipping arrangement... initation? It's just made with 1N914's and BAT46 schottkys.

-T

So what? A clone that is cloned from another clone?

culturejam · Post by **culturejam** » 22 Dec 2010, 21:44

uncleboko wrote:What pray is the problem with jumpers???

On a one-sided PCB, there's nothing wrong with jumpers.

But if you have the luxury of having traces on both sides, there's no real need for a jumper. This is especially true for a circuit as simple as a Rat or Tubescreamer.

If you come to a situation, on a two-sided layout, in which a jumper that runs from one side of the board to the other is required, then the layout itself should be rearranged.

My comment was a reference the CMAT Signa Drive, which has a jumper wire on *both* sides of the PCB. There is absolutely no need for that...unless the PCB design was flawed and the wires were needed to make it work.

Either way, it's bad design. That doesn't mean it sounds bad, however. Just commentary from a guy who likes to do PCB layouts.

mictester · Post by **mictester** » 17 Sep 2011, 00:15

I try to avoid double-sided board layouts (except for RF designs). With some work, and if you're prepared to accept a jumper or two, most circuits can be built single-sided. This has the advantage that it's easy for anyone to make the board - I saw some beautifully made PCBs last week, that had used bright pink nail varnish as the resist, painted on each board by hand! The builder then etched the boards in Ferric Chloride, and removed the resist with Acetone after the etching. He then drilled the component holes by hand, and each board is slightly unique. The guy doesn't claim any additional "Mojo" for this type of process - it's just that he's always done it that way!

culturejam · Post by **culturejam** » 17 Sep 2011, 18:03

Since mic bumped this oldie, I thought I'd clarify something:

culturejam wrote:Either way, it's bad design.

Using jumpers on a 2-sided layout is bad design. Unless it's so that you can use the same PCB for different circuits, or something utilitarian like that.

CMATMods - Black Plague [traced]