Pedals Rides Again

Pedals is a powerful tandem-towed 12V soundsystem which was built back in 2005 for the G8 Bike Ride. In February, while being used for Reclaim Love, the tweeters packed in, the midrange started cutting out, and then the main fuse blew. It languished in a state of disrepair until I was asked to try to get it running for the Merthyr to Mayo solidarity bike ride.

Pedals has had a tendency to blow tweeters so that was not a surprise and it is easy to replace the diaphragms. Unfortunately the place I used to get speakers and spare diaphragms has closed down and there didn’t seem to be anywhere else to get P-Audio stuff in the UK. Anyway, I decided to tackle the problem by fitting an active crossover. Pedals was originally designed to use an active crossover but it was not built in time so it has always run with a passive crossover to separate the mid and top. Due to the low order filters a fair bit of midrange reaches the tweeters and I think that is what was killing them. I had a partially built active crossover circuit already (a 24 dB/Octave Linkwitz-Reilley design) and all I needed to do was add an initial summing amplifier and a DC/DC converter to provide a balanced 5V supply to the op-amps using the main 12V battery. The midrange horn turned out to have a bad solder joint inside where the coil attached to the brass terminal post – that was easy enough to fix. Then there was the issue of why the main fuse had blown. I still don’t know but I decided to strip everything out of the box and rewire it from scratch, hoping that would sort things out. With the active crossover I figured I could get away with a single tweeter and I ordered an Eminence APT150 from Blue Aran.

While all the bits were out I took the opportunity to renovate the box and give it a new coat of paint. I removed the broken front storage compartment, made a new lid, and designed a compact structure to carry the midrange horn and tweeter. The other thing to look at was the trailer. The trailer arm was badly bent and there was no point just straightening it because it had happened before and it was clearly going to happen again. The problem was that the arm was only pinned to the chassis (so it could fold underneath for storage) and there was too much play in the system. I sourced a piece of square section tube, bent it to the right shape with a propane torch and some scaffold tubes, and got it welded directly to the trailer. I also got a new hitch, a ball and socket design as opposed to the old springy one. Last but not least, my housemate refurbished the trailer wheels by fitting new axles and ball bearings and replacing seven broken spokes. There were various setbacks which meant that the whole project took me the best part of two weeks. It was worth it though, and I enjoyed taking it out for a test ride. Here it is parked near Simmons in Hatfield town centre.

I managed to pack the whole system (including the tandem) into my car and on Saturday May 22nd I drove out to Merthyr. People organising the bike ride had booked a church hall for the evening which is where we attached the mixer to the tandem and wired it up to the trailer. Instead of running the wires along the trailer arm with connectors at the hitch I tried running them through a piece of inner tube tied to the back rack. This could simply be hooked onto the trailer and plugged in. The wires had enough slack to accommodate expected relative movement but the stretchy inner tube stopped them dangling down and fouling the back wheel. Once it was all set up we had dinner and then headed up to the campsite, which was in the same place as last summer’s Climate Camp Cymru. I didn’t have a tent but it was a warm night and it was nice sleeping out. We got up early and the site was a hive of activity as people packed trailers and panniers. I wasn’t going on the ride myself but I stayed around to watch people set off on the first leg to Swansea, from where they would be catching the ferry to Cork.

After helping clear up the campsite I left and drove up through Brecon and Lampeter to meet some friends on the beach at Mwnt. It was sunny and hot enough to persuade me into the sea for a bracing swim. We had a BBQ on the beach and saw dolphins in the bay – they were still leaping as we climbed the steps in the evening and watched the sun set over the ocean.

I stayed a few more days in Pembrokeshire, helping out in a friend’s forest and walking a short section of the coast path north of Mathry before driving home. I have since heard that the ride is going very well and I assume that Pedals is surviving life on the road – I certainly hope so. If it gets back to London in time then its next outing will probably be the World Naked Bike Ride.

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