RF Filtering on AMZ Mosfet Boost? (now with pictures!!!)

[mlabbee]

I'm designing a circuit board for the AMZ mosfet boost and I'm trying to make it as small as possible, so reducing parts count helps.  (I'm trying to squeeze as many different circuits onto an Express PCB board as possible.)

I'm using a mosfet with a built in diode, so I can get rid of the zener.  I also plan on putting this into an aluminum (or otherwise shielded) box -so I'm wondering if anyone has had any experience leaving off C2 - the optional small cap put in to filter out RF.

[bwanasonic]

I can Identify with trying to squeeze as much as you can onto a miniboard, but OTOH, the cap I used for C2 for the MosfetBoost was an impossibly tiny ceramic (smaller than a match head).

Kerry M

[MartyMart]

There was a very simple "veroboard" version by Dragonfly I think, posted about two weeks ago, search for "veroboard" or "stripboard" "layout" and you will find it.
That would fit nicely on a tiny board, 8 holes by 9 strips I think ?

Marty.

[Gringo]

There's an express pcb file with the layout fot that particular build at my site, and it's PD small.

[mlabbee]

Bwanasonic - good point.  I was just using teh component sizes that ExpressPCB gives you and didn't think to account for the very tiny ACTUAL size of C2!  Here's the partially complete layout - the one on the left is a Brian May Treble Boost, AMZ boost on the right. Now I just need to figure out what else to put on the board.  Any thoughts? (This only takes the top half of the board, too, so double the available size)

[bwanasonic]

A Fetzer valve is a good candidate. The Fetzer and the AMZ pair well together in my setup. I was just looking at the Ruby amp schem- that would be another small footprint project that comes to mind.

I am no expert at PCB layout, but you might want to consider keeping your Inputs and Outputs further apart as a general rule. I try to keep them as far apart as possible. Having them right next to each other might be asking for noise/oscillation trouble.

Kerry M

[mlabbee]

Cool - I'll check out the Fetzer valve.  I've built a Ruby and didn't care for it so much . . .

I didn't realize having the ins and outs close together could cause problems - aargh! Back to the drawing board!  

[jayp5150]

Just a thought:  to save space, you could just stand all of your resistors on end.  Of course, you would have to create your own little component in ExpressPCB, or just put the pads on there, I guess.