Thursday, 18 June 2015


Latest project on the bench coming along nicely.  Prototype built and tested just in time for this year's synth-diy meeting in Cambridge.
Ring modulators are fun!

Wednesday, 21 May 2014

LEVIN is on the bench!

Finally, after some time to get things just right, the next CESYG module is almost ready for release.  LEVIN is an LED Voltage Indicator with a seemingly simple function: show an input voltage on a large LED bargraph.  I think it does it rather well.  Here's the first completed module after testing:

Note that in the above picture it looks like several LEDs are on at the same time, when in fact that is simply due to the LEDs sweeping upwards while the camera was capturing the image.  To keep the current consumption under control the display is always in dot mode.

All that remains to do is finish writing the manual, get it printed and bound, and then package up the first batch of modules ready for shipping.


Tuesday, 29 October 2013

Slow news.....

They say no news is good news, right?  Well, progress at CESYG has been fast and slow.  First and foremost, the SuMIX project has been shelved - but the idea lives on and may resurface one day. On a more positive note, the BUS5 and BUS5X are now available to provide a 5-channel routing system within and between modular synth cases.  Finally, design work is progressing well on the next CESYG module.  Nothing more to say on it yet until I get a prototype working on the bench, and then I'll post piccies to tempt you!


Tuesday, 13 November 2012

SuMIX Headphone Amplifier

Tonight I've built the headphone amp, and tweaked the design to achieve lower distortion (noise is now the  dominant factor).  30R headphones you're looking at around 0.01% distortion at 1kHz when pushing 120mW into the headphone (unlikely!). For 600R headphones you can go even louder with even lower THD, and then I'm starting to reach the limits of my HP distortion analyser (below about 0.005%).


Thursday, 23 August 2012

First panel mock up of SuMIX

As hinted at earlier, the next module I'm working on is an output summing mixer for the Eurorack format.  And here is the first view of the front panel.
Ignore the blobs on the corners, those are just for aligning the artwork with the panel mechanics.
Also this shows representations of the panel furniture (knobs, leds, jacks, switches) to give a better impression of how it might look.
And thanks to Cody for his useful input :)

Wednesday, 8 August 2012

DuaLFO Goes Even Slower!

After some discussion on muffwiggler I ran a test to see how slow the DuaLFO could really go with a negative CV input.  Internally it is limited to -0.6V, so I applied -3V just to make sure.

Using my Heath-Robinson-style low frequency counter I measured the period to be about 8,833 seconds, or about 2 hours 27 minutes.  Now that's slow!!!

Thursday, 28 June 2012

On to the next one

Now that the DuaLFO is finished and shipping it's time to start work on the next module.  This time it's going to be an audio mixer.  And I think it's going to be very interesting.