Sunday, 20 December 2009

Soldering non talent...

I bought myself one of these iSpin mixers for 15 quid:

At first glance, and watching the videos you'd be right in thinking, "gimicky, silly scratch sound, very limited with only 4 proper effects."

At first glance I thought, "cool, a cheap way to charge my two iDevices (also has 3.5mm line in), a way to cross-fade between the two of them (both running some DJ software) and possibly hackable."

So it arrived, I briefly plugged it in and tried it out. The fader works, the microphone is a nice to have (sits in the fx path if you want) and the headphones can be either master out or cue, which is great. Yes, the "scratch" effect is awful. The other 4 effects though are rather good (reverb, flange, hi-pass filter, lo-pass filter in two switchable "banks" each with two fx). After a few minutes I got out my screwdriver.

First to go were the little "wheel" things, now replaced with some knobs I had lying around. Sadly the central "scratch spinner" is a rotary encoder, so that'll be replaced with a rotary pot soon.

Ok, onto the meaty bit. The fx chip is called the FV-1 by Spin Semiconductor. It turns out it is a much more capable chip than it seems from the built in two patches of fx. You see, it has 8 internal fx patches (with 2-3 fx on each patch) and an external sound bank, where the iSpin's own fx are housed. After a trip to Spin's website I found that you can switch between the internal bank and the external bank if you solder in a switch. You can also choose any of the 8 patches if you solder in 3 more switches (or an 8-position rotary switch, which I thought would be easier).

So some dremmeling and soldering later I've got the 8-position switch mounted into the case (top right corner, next to the right side iPod) and re-hacked the prog1/prog2 switch to select internal/external banks instead. The 8-position switch isn't quite working yet - it can select the first two patches, but nothing else...

A couple of observations thus far:
  1. Soldering onto the legs of a chip is a nightmare!
  2. My soldering iron is rubbish.
  3. My soldering skills are non-existent.
  4. I don't think my circuit skills are up to scratch! I thought I could hook "ground" up to the 8-way switch instead of 3.3v but something seems to be creating a short-circuit I think. I don't really know what I'm doing :o)
Next steps are to re-do the switch (a big job) and then somehow replace the rotary encoder with a linear potentiometer. Why, you might ask? Because the FV-1 allows analog control over 3 different parameters for each sound patch. Hence the 3 dials on the front of the device. They are not jog-dials, they control the fx!

Hopefully I won't fry anything, then I'll end up with a whole bunch of new fx, essentially becoming an extremely cheap fx unit that mixes and charges my two iDevices or any of my other devices with 3.5mm outputs.

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