power supply +20V and -20V 5A by LM338

Here is Circuit power supply +20V and -20V 5A,Use IC LM338.
Nick initially adjusted the quiescent current to 3.5A but found after listening tests that increasing this to 4A gave a noticeable improvement. Even at an Iq of 4A the amps run cool due to the substantial heatsinking (0.5degC/W for each output device and each LM338K). Variations in quiescent current and dc offset with temperature are minimal, with an Iq of 3.8A and a dc offset of less than 35mV at switch-on.

Read More Source:

http://www.tcaas.btinternet.co.uk/jlhesl.htm

Thank you.