Gerard's Philips BX690A

66
Item nr.

Philips BX690A Table top

This radio was donated to me, a word of grace to the previous owners is in place here.

**Data for Philips BX690A**
Production	The Netherlands, 1949. Price was 425 guilders.
Bands	LW (715-2000m), MW (185-580m), SW1 (37-50m), SW2 (31-42.5m), SW3 (24-31.8m), SW4 (19-25.8m), SW5 (15.5-20m), SW6 (13-17m).
Tubes	ECH21 2xEAF42 2xEL41 EM4 AZ1.
Cabinet	Wood. Size 59x35x25cm. Weight 14,5 kg.
Power	AC.
Documents	Schema.

The Design

The Philips BX690A has a peculiar output stage, consisting of a push-pull output, but there is no tube working as the phase inverter. Instead, one tube is driven directly from the preamplifier and the other tube has no signal on its control grid. The two cathodes are connected to each other and carry the signal, fed back from the output transformer.

Thus the second tube is actually driven from the output of the first, like in the series-balanced output, but here the driving signal goes all the way through the output transformer (big job with 10 wires). Inverterless balanced stages are only possible if the output tubes are in class A.

The band indicator is also nice: rotating the band switch elevates the entire dial such that the chosen band is the lowest one visible. Just a BFO and the 10m and 80m bands would turn it into a nice ham receiver! Unfortunately, Philips does not like to have advanced features (BFO, RFamplification, double conversion) in its home entertainment sets.

Obtained	6/1997 from Hildebrand Boukamp.
Condition	8.
Disposed	Sold 8/1998.

This Object

I replaced almost all wax-paper capacitors in this set, and had to replace the ECH21 mixer tube. The knobs of this set are on the sides (left and right) and not on the front, which places it outside the scope of my collection.

Part of Gerard's Radio Corner.
Generated by SiteBuilder on 6/9/2025 by Gerard