Roland SH-101 T1 Terminated!

Found a broken Roland SH-101 on Gumtree. Couldn’t believe my luck!
I was hoping for a simple fix, maybe a dodgy power switch or something. When I started to investigate it soon became apparent that someone had been there before me. The T1 transformer, which does DC-DC conversion from the 9VDC plug pack to the various analogue stages was missing! Also, the surrounding components had been lifted out of there solder pads. This wasn’t going to be a quick fix!

T1 Terminated!

Searching around the net and it was becoming obvious that this problem was fairly common but with no one having fixed it! Also, the T1 transformer is not available for purchase anywhere. Continue reading

MiniDSP chassis done, at last

Not strictly related to the speakers themselves, but as the miniDSP is a core component in driving the speakers I’ve noted this in the “beyond-econowave” posts:
For a long time the miniDSP was sitting bolted to a lump of wood, the “temporary” test chassis, with a cardboard box sitting on top of it to cover it. But this test chassis was quite noisy.

I’ve made a simple pine enclosure that makes up in solidity what it lacks in sophistication. It still containes the miniDSP and 2 simple OPA2134 based pre-amps to give me a bit of gain over the quiet miniDSP output, but I’ve got a 4 channel stepped attenuator (actually two stereo stepped attenuators ganged together) as a master volume, plus the software volume control as a fine volume pot.

There’s also a switch to switch over to the analogue input for “guest devices” .e.g. mates dropping over with DJ mixers or synths – so the sockets are on the front for easy access.
Made with bits of pine from the local hardware warehouse, and painted with leftover stain/varnish from my big speakers so it matches.
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ZOG low budget battery powered party blaster system

This system was started off cobbling together assorted spare parts that were in the garage gathering dust, to create a small battery powered (and partially solar) system that can fit in the boot of the car and be moved on a small trolley. But of course then I added some extra bits as well to get it how I liked it, so it’s not really assembled from “junk” any more, but it is all inexpensive low power use.

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