klewis

http://www.diyaudio.com/forums/solid...lifier-86.html
Pavel's scheme http://www.diyaudio.com/forums/solid...ifier-103.html

For LED's - Christer's thread http://www.diyaudio.com/forums/parts...er-diodes.html
An interesting method of grading zeners for noise, that I have used for years, is to monitor the noise across the devices with a scope while using my HP bench supply to bias them. The noise spectrum changes quite dramatically as you come into breakdown and then drops to it's minimum at it's prefered current flow. I note the current and voltage after it has settled down. I choose the ones to use by voltage match and bias them accordingly.

One other trick, if you want to know how quiet your supply is, choose a suitible coupling cap and hook the output of it up to a line input on your preamp and listen to it. Try this with and without a load and during normal operation of the supply. A good supply is dead quiet. author: MikeBettinger

http://www.diyaudio.com/forums/solid...urce-sink.html

Fets: http://www.diyaudio.com/forums/solid...relays-17.html

Pavel's Scheme http://www.diyaudio.com/forums/solid...ml#post2835407
Also see post #340, increase R1 to 100k and C3&4 to 47uf
recommendation for mosfets: #314
In general, you are seeking for a MOSFET with very high Vdsmax, very low Rdson and very high Idmax. Regarding Vdsmax, it must be higher than the sum of positive and negative supply rail voltage, and the output should be provided by clamping diodes connected to supply rails, reverse polarized. My tips are

Type Vdsmax Rdson Idmax
IRFB1227 200V 0.0197ohm 130A
IRFP90N20D 200V 0.023ohm 94A
IRF3710ZG 100V 0.018ohm 59A (too low Vdsmax to me)
IRFS59N10D 100V 0.025ohm 59A (too low Vdsmax to me)

Post #166 board layout
omron G6H2 12v relays
Motorized alps pot http://www.ebay.ie/itm/ws/eBayISAPI.dll?ViewItem&clk_rvr_id=300979180833&ite m=250467804650
Post #1062 for relays
Post 1031 cap tweak