Runes of the Earth Graffiti

[Lazy Luke]

Simple transistor circuit


Solder side


Some photo editing to extract runes


Flipped horizontally. Hey presto!

[Lazy Luke]

..........................................................................................................Tr2 output stabliser

Solder side + Runes

[Lazy Luke]

Rat Box pcb

Underside

[Lazy Luke]

This voltage controlled amplifier based on the LM13700 Transconductance amplifer is the second to be built. And yet I'm still not satisfied with the component layout
as I'm sure it isn't what the author (R.A. Penfold) had intended when designing the circuit.The capacitor and resistor network on the left of the picture should've been on the far right.

Like so:

...giving an aesthetic effect of the electric guitar. Aligning the six resistors with the LM13700 assimilate guitar strings and pick-up.
Even the two electrolytic capacitors suggest volume and tone controls.

But then, it is what it is. This circuit is only 1 of three, the other two yet to be assembled, and I just don't have time to built the VCA again.

Plus:

... there are some really good Runes I might be able to use
on the unit casing and front panel.

[Lazy Luke]

VCA - voltage control 2
Transistor amplifier and rectifier & smoothing circuits



Switched from Veroboard to Perfboard (rat's nest),
for some variation in circuit layout architecture.

[Lazy Luke]

Maybe not such a good idea building circuitry in reverse -
the VCA (LM13700N) circuit above was completed back in February!

VCA Input Circuit

The source (V)oltage for the output (A)mplifier can be used as a stand alone
effect (with just two additional components) and has quite a good
warm fuzzy lo-fi sound ...
However, this fairly straightforward circuit does have quite
a high signal to noise ratio. And although I'm sure the VCA output
will noise gate this, to some extent, it is still good to know there
is plenty of scope for a better more sophisticated (V) input.
(I have an NE570N compander IC in the junk box that could do the job.)


The best laid plans -
Once the input jack socket and switch assembly was finished
it was supposed to be the housing platform for the input circuit board,
mounted onto the upper side.


But, as it turns out there just might be room for the components (currently in the post) on
the available space next to and between the jack socket and switch.
Which would free up the upper side of the assembly for the Control Voltage smoothing/rectifier boards, and
VCA output Amplifier chip.

[Fist and Faith]

Just seeing this for the first time. Absolutely awesome, Luke!!