My first issue 2 TM3030 fitted into the now obsolete case from RS Components (pt no: 222-020).
I should point out that the best performance will always come from using metal cases. Metal
cases are not only more rugged but they also provide screening. A good grounded case will
protect the TM3030 from extraneous radiation from CRTs, amplifiers and computers. The
TM3030's VCO is particularly susceptible to mains hum fields. Although the PCB layout is
carefully designed to minimise this, if you fit your unit into a plastic or wooden case, you may
find that you will get a little 50Hz (60Hz) or 100Hz (120Hz) wobble in the unit's pitch. You
can use some aluminium foil to shield the circuitry, this can be stuck down on the lower part
of the case, underneath the PCB, and connected to the GND pad of the TM3030. Do not
connect your screening to any lug of the power pack inlet socket though.
When using any metal case it is essential that the case is grounded so that the screening is
most effective. Grounded means electrically connecting the metal case to the 0V or ground of
the circuitry. The GND pad provides a handy point from which to wire your panel's metalwork
to. However, you will probably not need to use the GND pad at all if you have used metal
midi sockets or a jack socket with a metal bush. See the chapter on midi, power and audio
connections for more details on this.
For those of you fitting an internal toroidal transformer you must make sure there is no way
the bolt that secures the transformer can touch both the bottom and top of the metal case. If
the metal support of transformer together with the case makes a complete loop around the
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