This line is from the British EL84 circuit, and the voltage is amplified and inverted by ECF80 (the domestic corresponding model is 6F1). This part of the line has not changed. The power supply is ordinary bridge rectification and CRC filtering.

The characteristics of EL84 and 6V6 are somewhat similar, the power supply voltage and the driving voltage are also relatively close, and even the output transformer can be used in common, so we keep the driving and inverting circuits unchanged, and the current amplifier circuit of 6V6 is calculated according to the characteristics of 6V6 itself.

The filament of this board is powered by AC, but the signal-to-noise ratio is quite high, and there is basically no noise. For grounding, you only need to connect the lower right screw hole to the shell. The shielding layer of the power transformer and the GND pin of the AC socket Directly to the shell, no other places need to be grounded.

The 6V6's sound tends to be thick, especially the mid-bass fullness

Details：

PCB size: 224×170MM

Thickness: 1.6mm

Tube model：6V6 *4+ ECF80 *2 （ECF80 can use 6F1）

Work voltage：
0-AC250V @300MA
0-6.3V @4A

Gold plated tube seat
SCR MKP Audio Capacitor + VISHAY BC Capacitor + Nichicon KZ Capacitor

Power transformer ：

https://www.ebay.com/itm/353322316824

Note ：

This is diy kit ，all parts need buyer to solder it ！（Not included 6pcs tubes）