PCB design for MOSFET based HP amp?

[zebra100]

Hi all,

I am in the process of building a Szerkeres MOSFET based headphone amp http://www.headwize.com/projects/sho...e1_add_prj.htm (the amp on the addendum page with the CCS)which I am having one or two issues with. I am struggling to get the amp into the box neatly enough for my liking. I have built it on strip board, but it is no good for mounting the heatsinks on. As the amp runs in class A with a CCS at 250mA, heatsinking is quite important. Also, the LM317's and MOSFET's are uninsulated so can't touch the chassis.

I intend to fit the amp into the box I am using as a passive attenuator for my LM3875 Gainclone. A (stereo) input and a single (stereo) output. There will be a switch to switch the output from the attenuator between phono out's or the input to the headphone amp. Power for the HP amp is off board, DC 13.8v.

I am enquiring on the off chance that someone may have a PCB design for this amp (125mm x 75mm max.), or know how I can get my hands on some PCB design software (freeware if possible). I have been tearing my hair out trying to fit the CCT on stripboard. PCB is the way forward.


Many thanks,

Chris.