The 2 RCA outputs allow it to be used in preamplifier / volume control, beyond its headphone amplifier appearance. Its manufacturing quality and selected components make this Little Dot a HiFi device with almost unbeatable value for money.
Regulator for filaments: LM317
Input Tubes: 6J1
Output Tubing: 6N6
The 6J1 can be replaced with JAN 5654 or M8100 / CV4010.
6N6 by 6H6PI / 6H6N.