In-boat entertainment

January 6th, 2008

Once again I begin by apologising for not writing earlier – just when I’d settled back into life on the boat I became embroiled in the whirlwind of Christmas and have only just extricated myself again… happy New Year everyone! It’s odd to think that I was still at Fossil Bluff this time last year – 2007 was a pretty excellent year for me, so let’s hope 2008 is as good or better.

Anyway, a slightly geeky post this one, but perhaps one of interest to my fellow boaters. I’ve just this evening finished wiring my new stereo system in the cabin, which includes the rather nice new loudspeakers that Mum and Dad kindly gave me for Christmas. I’ve also been meaning to describe the work I did installing a DAB radio in the kitchen back in September, so instead I’ll describe them both here.

Starting with the radio, I quickly realised once I was living alone on the boat that I needed Radio 4 to keep me company. My little FM portable doesn’t work at all inside the boat, of course, so I had to look at getting a radio with an external antenna. The obvious solution is a car radio, of course, but I went and looked at a few and found them to expensive, ugly and with rather poor user interfaces. Anyway, I dawdled around the various electrical megastores in Newmarket Road and came across this Hitachi DAB radio in Currys. It’s a DAB/FM radio, which uses the NXT flat-panel loudspeakers, making the design very slim and light. However, the two clinching factors were that it runs on 12v from an external power supply (meaning that I could easily hook it into the boat’s electrics) and that the telescoping antenna supplied with it can be easily replaced by an external one. A quick trip to Maplin supplied me with a suitable power connector and cable, which got wired into the kitchen lighting circuit, and then I found a suitable DAB antenna kit in the Screwfix catalogue. The antenna is clamped onto the handrails up at the bows, and the feeder cable runs along the handrail and then comes down to the radio through the ventilator in the kitchen ceiling. It works well, although it suffers from the problem of all DAB sets – it uses a lot of power.

For the main cabin I wanted a system to play music from my little MP3 player, and found the intriguing Sonic Impact T-Amp whilst Googling for 12v amplifiers. The T-Amp is tiny, not much bigger than a paperback book, and all that’s in it is a little one-chip amplifier and a volume control. It uses a clever PWM-based circuit that lead some people to call it a “digital amplifier”, which it isn’t, it’s more like a switch-mode power supply. Anyway, some reviews on the internet suggested that various people in the audiophile community reckon that this is The Best Thing Since Sliced Bread, and at about £30 it seemed like a good buy. Then I actually tried to buy one. The things seemed to be in very short supply, so I ended up ordering one from Think Geek in the US because it was about the same price including shipping as the only UK stockist, and Think Geek had one in stock. I’m glad I did because the manufacturers have subsequently discontinued the basic model and replaced it with a more expensive second-generation model, which is basically the same circuit in a fancier case. Anyway, it’s sat around in its box waiting for a pair of loudspeakers since November. Today I’ve hooked it up to the pair of JBL Control One speakers that I got for Christmas (thanks again, Mum and Dad!) and also managed to wire it into the boat’s 12v supply. This was only slightly trickier than it sounds. One of the reviews I read said that the amp runs from a nominal 12V but won’t tolerate any more than 14V. Unfortunately, the boat’s alternator regulator routinely kicks out 14.5V with the engine running (this improves the battery charging performance), so I needed a regulator to protect the amp. Fortunately I found one in Maplin today – it’s a little compact multi-voltage unit which comes with a choice of DC plugs, one of which fits the T-amp – and it delivers the necessary 1.5A to the amplifier quite happily. I wired in an extra cigar lighter socket at the forward end of the cabin and plugged it all in – hey presto, music! The system does sound good, although it’s hard to tell given that the source is my tiny MP3 player with its compressed music and the boat cabin’s hardly an ideal listening room. Anyway, I now have to decide how best to mount the loudspeakers, as they’re currently just floating around the floor until I give them a proper home.

3 Responses to “In-boat entertainment”

  1. martin Says:

    The speakers are floating around inside the boat? I don’t know much about boats, but surely the water should be on the outside…

  2. Cy Says:

    So the amp just changes the PWM value to mimic a change of volume, nice. Could probably do that with my new Arduino – play time!

    The nicest sounding iPod dock I’ve heard is:

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