Mosfet Boost build report...

[lessthanmatt88]

Well, I built this project not only becuase I wanted a nice boost, but it was my intro into PCB etching/drilling.  I used the layout from GGG and so far I would say its pretty successful but not perfect (my build that is).  I have only to wire up the output jack before I finish.  Some concerns of mine were my sloppy soldiering and the etching quality wasnt quite 100% as it took me a few times to get it down.  One thing to note, dont leave your copper boards out in humidity, i noticed my copper has a bit of oxidation, not bad but noticible.  When I get it up and running ill comment on it sound wise.  Other than that, its an easy build and good to develop some skills also.

[newbie builder]

Post back with how you like the sound of it when you're done wiring! It's a great little clean boost- love it for dark sounding amps to add a little treble/bite/clarity and also to run into the front end of an amp and make it distort. Have fun!

[lessthanmatt88]

Well, I finished it, but its not yet working.  So far I've checked the orientation of the mosfet but thats about it.  I imagine I left a bad solder joint as I somewhat rushed to get this done as can be seen by the sloppy technique and amount of flux left on the board.  Prehaps the copper being dirty has something to do with it as well.

For now im gonna look for a better layout as I dont care for the one found at GGG.

[lessthanmatt88]

Well I have it working... somewhat.  When I engage the circuit, the volume seems to be less than unity although the circuit is at max gain.  I'm seeing 6.1 volts at point A on the schematic, and im seeing 5.6 volts as the reference with a 9.4 volt source.  Tommorrow I will adjust the value of R2 to bring down the voltages and see if this makes the difference I am looking for.

In the meantime though, any one have similar problems or have any suggestions?

[newbie builder]

I had the same thing with the mosfet where it was slightly less than unity maxed out- flip the transistor. That's what did it for me. Even if you think the orientation is right, try it (assuming you have a backup- I don't want you to fry something and have me to blaim!) I could've SWORN I had it right, but i flipped it and mine worked and I had EXACTLY the same problem as you using the same layout.

[John Lyons]

You can always scrub up the dirty copper before you solder it up. Use a scotch bright pad, even an old dishwashing sponge with the scrubby stuff on it, same thing. Some super fine sandpaper, even a paper grocery bag will shine it up again if you give it a little elbow grease.

John

[lessthanmatt88]

The transisitor being flipped wasnt the problem.  I'm gonna lower the resistance of R2 in the schematic since I'm using a higher value than what is listed.  Since that controls the ratio for the voltage divider, it should make a difference.