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RE: I want to make an EICO HF81 or Rogers clone, sans preamp

Posted by Eli Duttman on August 11, 2017 at 23:06:56:

I suspect tone controls are present. EL84s are easy to drive. Look at Fisher's X-100. A 12AX7 voltage amplifier and a 12AU7 "concertina" phase splitter are all that's needed. The 7247/12DW7 shown in the schematic fragment is 1/2 'X7 & 1/2 'U7.

You might try a Mullard style circuitry using 6H30П (6n30p) as both the voltage amplifier and LTP. Unfortunately, it's most unlikely that the power trafo has the requisite heater current capability.

Most definitely, get the gain structure right.