On 7/7/07, Dr Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote: > With suitable modifications to allow individual adjustement/selection of > the bias for each JFET a pair of the more readily obtainable J310's can > be substituted for the U431. Vishay Siliconix U431 JFET pairs are available in single quantities from www.newark.com for ~$8.