This amp is based on a pair of new Mullard reissue matched EL34s with a universal driver tube. Any 12A*7 can be used as a driver. OPTs are Asian 3.5K 10W with 4 and 8 ohm taps. I have used the 5W 5K versions in other amps with outstanding results. The OPTs and power trannies are shock mounted on split rubber grommets to reduce resonance. The PS is external with over specced Hammond power tranni. A Sylvania 5U4GB handles rectification. 357uf of filter caps smooth and store 366V of HT. Further filtering feeds the driver tube with a 4uf PIO cap and 2.5K 2W resistor. The amp is very, very quiet.
Filament current is rectified with a 10A bridge and single Pi filtering - 9400uf of filtration. HT and filament caps are snubbed with 0.1uf polies to reduce noise. The chassis is a Hammond wood cheek and is made of steel for strength. The finish is black stipple. The chassis for the PS is cast Al with a black epoxy enamel finish. The PS is fused and earthed.
RCAs are Paladium plated and speaker posts solid brass with gold plate. Audio path wiring is fine silver plated copper wire. All wiring is point-2-point, no cct. brds. and no shielded wire. Not required. Sockets are ceramic and power is brought to the amp via three pin large XLR connection. The driver tube being used here is a Tung-Sol ECC803S gold pin. 6L6 and KT88 can be rolled here and any 12AX7 equiv. can also be rolled.
Amp presents full bass and a complex warm soundstage with smooth highs. It is a pure Class A amp. Not only good looking but excellent sounding and definitely worth the weeks of work. The EL34s I’ve had for twenty years so now they get to entertain as they are designed to do.
No comments:
Post a Comment