170
Item nr.
World receiver for emigrants.
| Production | The Netherlands, 1950.
Price was 420 guilders. |
|---|---|
| Bands | LW (800-2000m), MW (185-580m), Tropical Band (49-150m), 4x SW (32-50.5m, 21-32m, 16.5-26m, 11-17.5 m). |
| Tubes | ECH21 (mixer), EAF41 (IF), EAF41 (det and AF), EL42 (output), AZ1 (rect). |
| Cabinet | Bakelite with painted wood motif. Size 50x31x23 cm. |
| Power | AC (90-220V) or 6V car battery, 28W. |
| Documents | Schema. |
It was the time of decolonization for the Netherlands, as Indonesia got its independence around that time. But still we had many people going to Asia for several years. Needless to say that good shortwave radios were vital for those emigrants to keep in touch with their home country. The BX505AV was especially suited for the (by then ex) colonies for more than one reason.
The receiving range was extended to no less than seven bands, and a Tropical Band (50-150m) was included. Here this band was called VisserijGolf (Fisher's Band) because it was used by sea vessels as well at the time for their communications. But also on the high frequencies this model is more extended: it goes as high as 11m, which makes it receive the 27Mc Citizens Band.
The set is powered from an AC net,voltage can be selected from 90 to 220 Volt. In addition it can be fed from a 6 Volt car battery, which then supplies the heaters directly, and the B+ through a vibrator. In order not to exhaust the battery too fast, the radio is designed to consume less power than its predecessors. The output tube is the EL42, designed for car radios, and a smaller version of its brother the EL41. EL42 only draws 200mA of heater current and about 25mA from B+, and like the EL41 was introduced around 1948. The sound of this radio suffers in no way from having an output tube that is "light". There is also a switch to switch off the dial lights, saving another Ampere or so from the battery.
| Obtained | Was never mine, Repaired for Pieter, 1/2001. |
|---|---|
| Condition | 7; many parts replaced, misses back. |
| Sound sample | PLAY SOUND I love the sound of heated glass! Nothing new, just heated glass! Recording from Radio Paradijs, March 2019. |
Why? Was the rectifier replaced because the transformer was defective and only an American replacement (with 5V winding) was at hand? Or was the transformer replaced because the AZ1 was defective and only a 5Y3 could be found to replace it? To facilitate 220V operation a seond transformer (autotransformer) was added. Another replacement was the mixer tube, the ECH21 was replaced by a 7J7, which appearently gives no problem.The inside photo shows the rectifier on the right edge of the chassis; this will look unfamiliar to people who know the earlier Philips multiband receivers. The AZ1 was at the same place and the hole below it had the voltage selector, see the inside picture of BX690. Right besides the chassis is the autotransformer.
In March 2019, I looked at the radio again, and found the power consumption to be very high: 58W. Measurements showed, that the voltage given by the replacement transformers is much too high. Indeed, a 115V transformer connected to a 220-125 converter would already be overfed by some 10%, but on top of that, or mains voltage is now 230V. So no surprise that the filament voltage is too high, 6.6 instead of 6.9V. But worse, the B+ is much higher: over 300V on C1, where 240 is the intended value. R30 (cathode resistor of output tube) had decreased from 470 to 380 Ohms, giving too much current in the tube. I replaced the resistor by 510 Ohms.