LoFo MoFo: perfboard layout

[carrejans]

Hi,
I made a perfboard layout for Tim Escobedo's LoFo MoFo. It's not yet confirmed; haven't build it.
So, if you see mistakes, let me know.
I will probably build it next week. I hope it has a really nice low fidelity effect.

http://www.aronnelson.com/gallery/main.php/v/album171/lofomofo.gif.html

[carrejans]

I don't have a 500K lin pot.
I do have: 1M lin, 100k lin, 250k lin
What do you guys suggest? 250k lin?

[duckpow]

1M lin....

[carrejans]

I built it, but it doesn't work.    (although it's such a tiny circuit   )
The bypass works. But when switched on, there is no sound at all. (the led works)

Maybe there is a fault in my perfboard design, or maybe I made a mistake soldering it.
I checked, and didn't find any solder bridges.
Here are some voltage measurements:
- battery: 8.72
- emitter: 7.93
- base: 0 ()
- collector: 0

- I used a 250k lin pot i.s.o. the 500k lin
- I used a 1N4148 i.s.o. the 1N5817 (Could this be the problem?)

The schematic is from Tim Escobedo:
http://folkurban.com/Site/LofoMofo-724.html

[carrejans]

- I used a 1N4148 i.s.o. the 1N5817 (Could this be the problem?)

[CynicalMan]

I built it, but it doesn't work.    (although it's such a tiny circuit   )
The bypass works. But when switched on, there is no sound at all. (the led works)

Maybe there is a fault in my perfboard design, or maybe I made a mistake soldering it.
I checked, and didn't find any solder bridges.
Here are some voltage measurements:
- battery: 8.72
- emitter: 7.93
- base: 0 ()
- collector: 0

- I used a 250k lin pot i.s.o. the 500k lin
- I used a 1N4148 i.s.o. the 1N5817 (Could this be the problem?)

The schematic is from Tim Escobedo:
http://folkurban.com/Site/LofoMofo-724.html

Using a 1N4148 will change the sound of the circuit, but it won't break it. Same goes for the pot.
I don't know it it's a typo or not but, the emitter is grounded in the schematic and should be at 0V. The collector should be at a relatively high voltage.

[carrejans]

Yes, sorry, was a typo.

- battery: 8.72
- emitter: 0
- base: 0
- collector: 7.93

But still, the base is at 0V.
I made an audio probe.
The audio signal is before the 220pF; and after it there isn't any signal anymore.
I did replace the 220 cap; but still the same...


I also doublechecked the orientation of the transistor.
In this datasheet: http://www-micrel.deis.unibo.it/DATA_SHEETS/2N2222_CNV_2.pdf
The drawing of the physical transistor, with the little marking, is from bottem view, right?

[carrejans]

I replaced the 220pF capacitor again; now it's working.
(maybe I have a bad batch of caps)

[So, the perfboard layout is verified!]