Here is a real simple EL84 amplifier capable of about 5W's with a 2v input signal. Inverted regulated screens using an OB3. Single power, 2 power chokes, input EXO173 as a voltage multiplier by 2. R3 yet to be determined to give it like 1-3dB of feedback.

If you have a cap coupled preamp make sure the cap is at least 4uF or above, tranny a better method.
You could make this an integrated by subbing in a Transformer Vol control with +6dB of gain.
Power caps many come to mind, Black Gate, JJ both 100uFx2.
Pretty easy to make, not too complicated.

요걸 잘이용하몬 F1 같은 Zo 높은 one stage amp 맹길 수 있을 것 같은디....