User manual

3. A 1 amp silicon diode 1N4004 is wired across the lower current D2. This reduces

the voltage drop to the CPU from about 612mV to 545mV – a drop of 67mV.

The silicon junction voltage drop is intentional in the design, since (apart from the

drops in Q44 and R168 above), D2 is the only mechanism for providing the CPU

with its proper voltage. Since four fresh alkaline batteries can provide as much as

6.4 volts no load – hopefully less under load – there needs to be a way of

dropping the voltage down to the 4.5 to 5.5 volt range. Chips such as the CPU

typically have an absolute maximum rating of 6.0 volts, so there should be no

danger to the CPU in reducing these voltage drops inside the machine.

Altogether, these changes should enable the Devil Fish to function reliably with lower

battery voltages. However, the behaviour of particular CPU chips will vary, so it is not

possible to specify exactly what voltages a Devil Fish will work reliably from.

Version 4.1

[November 2005. Starting with SN 192.] This is sonically and functionally (LED

brightness etc.) identical to version 4.0C and therefore sonically identical to 2.1D. This is

a printed circuit board revision which does not change the functionality.

SN 206 for a customer in the USA was incorrectly labelled as SN 204.

In early 2009, around SN 238, we started using a new batch of polycarbonate faceplates.

The original batch were made in Melbourne in 1996 and were shinier – more brightly

silvery – than the new batch, which was made in New Zealand. The photo on page 1

shows one of the newer faceplates.

Version 4.2

[December 2009. Starting with SN 246.] This is sonically and functionally identical to

version 4.1 and therefore sonically identical to 2.1D. This is a printed circuit board

revision which does not change the functionality. The three Red LEDs in the Devil Fish

panel are a higher brightness grade, and so may appear slightly brighter.

[August 2010. Starting with SN 248.] We are now installing Omron B3W-4040 sealed

tact switches, with their stems modified to suit the TB-303 buttons. Previously, we

installed original ALPS SKHCAA switches, with a flexible plastic dust guard which

greatly prolonged their life. The Omron switches may last indefinitely, since dust seems

to be the only thing which causes tact switches to become unreliable – and the Omron

switches are sealed against dust and liquids.

We are also installing a 2009/2010 batch of Technology Transplant replacement pots for

the 6 small pots Tuning to Accent. We replace their friction grease with a lighter silicone

grease in order to make them very easy to turn. This is easier than the original ALPS

pots, and I believe this is best for the fast tweaking which is frequently performed with

TB-303s and Devil Fishes. These pots should be more reliable than the original ALPS

pots and previous generations of Technology Transplant replacement pots. Those earlier

pots could fail due to downwards pressure on the shaft, when the shaft is rotated, leading

to the outer part of the rotor cutting through the internal conductive tracks. This can’t

happen with the 2009/2010 batch, which is a completely new design.

The Resonance pot of this new batch is still a “log” at both ends type, whereas the

original ALPS pots were linear. But this doesn’t affect the range of sounds which are