03-04-2013, 04:06 PM
Many moons ago, I did do a 're-valve' job on an HRO using 2 6BA6 as the R.F. amps.: no problems, as I recall.
The 6BA6 and the ECH81 are a common choice for several Eddystone receivers: the S.888 / S.888A and the S.750 being two that spring to mind.
Having said that, for a mixer, I would use a 6U8 / ECF82 with cathode-coupled osc. injection: substantially lower e.n.r. as a mixer; excellent osc. / mixer isolation. Shouldn't present any serious problems @ 30 MHz; probably O.K. to 50 MHz.
HTH,
Al.
The 6BA6 and the ECH81 are a common choice for several Eddystone receivers: the S.888 / S.888A and the S.750 being two that spring to mind.
Having said that, for a mixer, I would use a 6U8 / ECF82 with cathode-coupled osc. injection: substantially lower e.n.r. as a mixer; excellent osc. / mixer isolation. Shouldn't present any serious problems @ 30 MHz; probably O.K. to 50 MHz.
HTH,
Al.
