Lloytron N2405BK Calypso 2 Band AM/FM Portable Radio Review

I was browsing around Amazon and spotted this rather nice looking radio priced up at £20 with a time limited discount down to £15. I liked the look of the retro styling and wondered if the tuning dial hid a nice variable capacitor or if it was a digital encoder; despite (definitely) not needing another radio I placed an order for one.

The radio arrived in a nice cardboard box, inside the box the radio was wrapped in tissue paper. A figure-of-8 power cord was also supplied - a nice touch as these cables seem to vanish shortly after entering my house; I can never find one when I need it.

Can we guess what’s inside the radio?

The radio takes 4 x AA cells (or mains power) and draws about 80mA listening to FM stations at reasonable volume. This high current draw indicates to me that the radio is probably not completely analogue. I’ve been repairing old transistor radios with leaky germanium transistors and they haven’t drawn more than a few 10s of mA.

Another indication that the radio is digital (but not DAB or anything that could be called Digital Radio) is a noticeable step in the noise as your tune the radio, maybe a quarter second or so of less noise before the chip inside the radio locks to frequency.

Ok, so it isn’t the cheap source of decent quality variable capacitors of my dreams, so what is inside the radio?

Getting inside

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There are six screws that need to be removed to take the back off the radio. The are marked in the case with small arrows. You don’t need to remove the unmarked silver screw - this attaches the telescopic antenna.

The back of the radio showing screw holes, one is hidden inside the battery area

With the screws out, the case come apart easily, the back half of the case contains the transformer and some hot-glued down wires. The front has the speaker, PCB and rod antenna.

Inside the back of the case - a small transformer and some glue

Inside the front of the case - a small transformer and some glue

The parts

Central on the PCB is the encoder - no decent (or even shoddy) variable capacitors here. There’s three ICs visible, two small ones by the encoder and one 16 pin device under a bit of glued down plastic. One of the smaller ICs is marked as an LM358 (a dual Op-Amp), the other is unmarked.

The larger IC is a C&A Technology C9631 - an FM/AM/SW/LW Multi Band Single Radio Chip. The datasheet I was able to find for this IC seems to suggest it needs to be driven by a micro-controller via and I2C bus, but there’s not one in this radio. There must be a more complete datasheet floating around. It’s an interesting IC anyway, what data I have mentions a much wider frequency range than is exploited in this radio. If more data is available it wouldn’t be impossible to extend the coverage of this radio - perhaps by adding another switch.

Removing the well marked screws on the PCB and removing the knobs on the front of the radio reveals the other side of the PCB. It’s a single sided construction with all traces and surface mount parts on the back side (for want of better terminology) and just a TEA2025b audio amplifier and some capacitors on the front side of the board.

Some of the higher than expected current consumption is due to the audio stage and the use of a 2W amplifier chip.

How it performs

On a quiet evening just around dusk I was able to hear some distant stations in the quieter periods of more local stations. I believe I briefly heard Barcelona on 540kHz, but didn’t catch a station ident - just a short snatch of Spanish.

On FM the radio performs well and receives all the usual stations I’d expect and some french stations when there was a bit of a ’lift’ on a few weeks ago.

One issue I did find with the particular radio I purchased is that the on/off switch built in to the volume control doesn’t work. In the off detent position (a nice firm feeling detent) the radio mutes, but doesn’t stop draining current from the battery. I need to fix this.

On the whole I’m not disappointed by the purchase - it would have been nice if it was a modern take on a transistor radio with proper analog tuning, but that wasn’t to be. If you can ignore the digital sound of the tuning, it’s a nice sounding well performing radio with some hacking potential.