Cheap Bastard

There are 4 posts filed in Cheap Bastard (this is page 1 of 1).

Cheap Bastard: Busboards are easy

Finally, I get some time to myself. But not much, so let’s crack-on.

First I connected-up the PSU to the mains. Now, if you are going to try this yourself I shouldn’t have to tell you to be careful, but I will anyway. BE CAREFUL. I’m not responsible if you fry yourself.

Anyway, I took no chances for first power-up. I stood well back and used a stick to switch it on, and I’m not ashamed of it 😛

But it works. So, out comes the multimeter to measure the veracity of the advertised voltages.

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All looking good. Nice and stable output, no vibration and barely audible noise. The trimpot allows quite accurate tuning, however, it affects all three busses at once, and there is slight variation between them. Not a big deal?

Next was to grab some stripboard, a couple of large capacitors and suitable headers. It turned out that I ordered the wrong IDC connectors. So I have female connectors for the busboard, and male cable clamps. But this is no problem, as they can easily undergo a sex change with the help of some spare pin headers.

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The connectors are wired as follows:

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Initially I won’t be using the +5 bus, so I’ll only need the 10-pin headers. Stripboard makes it easy to follow the busses, and the whole thing took just a few minutes. This is just a first run. I’ll probably reinforce the tracks later. But as it is there seem to be no problems.

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The capacitors are probably not even needed, but it’s no harm to ensure that the supply is filtered. Some details here.

After connecting the PSU, I measured the voltages at the pins and it seems that we’re in business!

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Let’s have a dance to celebrate:

[youtube http://www.youtube.com/watch?v=PeeOPR8bxac&w=400&h=255]

Cost of each busboard comes in well under 5euro. Now I just need a finished module to power 😛

Cheap Bastard: No need for Baugruppenträger

While I’m waiting for some parts and test cuttings for the 4×4, it’s progress has been overtaken by this modular monkey business. I’m in no rush.

So, after assembling the Baugruppenträger and RAST, as expected, I required mounting rails to complete the job as first envisioned. Since I had a voucher for MusicStore, it was used buy the only rails they had – 12HE Adam Hall thingies at a fiver per pop. I got 4 to keep me stocked for future requirements.

Silly me hadn’t reckoned on them being made from a thick steel. As I don’t have the means to cut them, another much simpler and less expensive option popped-out: I could just glue or screw some 2cm wooden strips and mount the Baugruppenträgers directly onto these. Or, as I quickly realised, I could even just mount the vector rails directly this way and not require those ugly rack ears at all.

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OK then – to hell with the Baugruppenträger!

However, it’s 4 vector rails can still be used to complete two 84HP racks, thus filling the RAST. So, for future reference, I will only need the Vector rails and the Thread strips. I could even do away with these altogether, but since I have them I’ll use them.

In depleting my voucher I couldn’t resist trying a Monotron delay, especially because it has exposed CV points on the board and would thus could be re-housed into a 4HE module. It’s nice but surprisingly noisy. That’s not necessarily a bad thing 🙂

Cheap Bastard: Power supply conundrum

As I’m quickly learning, starting a DIY modular is not for the faint-hearted. Of course it would be easy to cave-in, buy a basic setup and go from there. But that’s not in keeping with the skinflint ethos.

It’s when looking at how to power my modular that I fully realised how archaic and uncoordinated the Doepfer Eurorack format really is. Options for powering the thing are surprisingly limited, and connector conventions are known to vary between manufacturers. Just to get up-and running with the Doepfer PSU + Busboards + 5v converter comes to a total of 145euro. These are crazy prices. I went looking for reasonable alternatives.

The first question was whether I would build my own PSU based on the many specs found at Muffwiggler’s. After some consideration I decided not to go this route. Being still the newbie in this area, I decided against, if only because there is a real risk of frying myself and my surroundings if something goes wrong. So I’m better-off with a pre-fab PSU option.

Following-up a suggestion made on the Mutable forums (thanks yet again Frank!) I went for this one. For 24 euro it provides three power buses – 5v and +/-12v – and with a whopping 5A on the 5v bus.

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The unit is heavy and seems quite robust, with clear connector options – if somewhat exposed. Handy enclosure to protect little fingers. There’s a prominent trimpot on the fron for adjusting the +5v bus. Not sure yet how noisy it is when plugged-in.

There is also a 5v =/- 15v version which will probably find it’s way here at some stage. But let’s keep focus for now.

I’m thinking to build the busboards myself using perfboard and some nice big capacitors, and based on schematics I found at Muffs.

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Another option might be to just use a ribbon cable and connect the first modules in series until I can come to a more permanent solution. Much reading to do. Oh for some free time!

I have to face facts at the beginning that this modular won’t be a static device – it will likely grow and evolve as the addiction takes over. So I’ve got to be prepared to make big changes along the way, and try to anticipate my future requirements.

If I can get this PSU working as intended, I’ll be well-covered for power options.