Here are some electronic things that I built between 1963 and 1971

Stabilized power supply for tube circuits.
Designed by Jon Idestam-Almquist.

Tone generator combined with an Audio millivolt meter.

OTL Power amplifier 2x 15 W for 800 ohms speakers
Designed by Jon Idestam-Almquist

Uses one Telefunken ECC83 and two Telefunken EL86 per channel.
Anode supply 460 V!

Electronic calculator from a Philips design.