Source of Uncertainty 3

This is the stepped output which has a linear distribution. It is running from a 1000Hz clock and giving a nice 0->10V range.

Source of Uncertainty 2

The board being tested. Note the addition of a 10V reference to the CMOS sections at the bottom.

Source of Uncertainty

Have made two of the boards for the Buchla Source of Uncertainty. This board is the SRV or Stored Random Voltages. It is basically a Pseudo Random Sequence that is created from a couple of shift registers. The pseudo random sequence is 15 bits long and cycles every 32767 clocks. If you look carefully you can see the results of some simulation of the circuit on the paper behind the board. The resistor values that Don Buchla choose are a closest approximation from standard resistor values, hence the jaggies. The board is a layout by vtl5c3 and can be found here. I have found a couple of mistakes which I am currently fixing up and will post back to the newsgroup when I have verified the fixes.

Boardz

Cordz

258 Tweeks

The Verbos/Buchla 258 Clone requires a few tweeks -- if your using the SSM2220 you will need to turn it around a hack off the two unused legs. See the picture above, after I sort out the mixing FET I will put in the proper Tempco.

Busy Week

Whilst not much bloggin there has been a fair amount of activity in the background. I have added four new boards recently, there is a power supply based upon the Elektor Formant design (PCB by Jörgen Bergfors for the Bergfotron), two PCB's of the four PCB set for the Buchla 266 Source of Uncertainty (PCB by vtl5c3) and finally a voltage controlled HADSR based on a design by Jürgen Haible and again a layout by Jörgen Bergfors. I am waiting for a couple of resistors, a 4030 and the 2N3055 power transistors and we should be smoking!