TTSH, miscellaneous mods

I started putting together a build post about the electronics side of my TTSH, but there really isn’t actually much to write about that. It’s a kit, and they just work straight-out-the-box when you learn even the details before starting and keep soldering sessions at reasonable lengths (don’t rush the build!).

That said, building mine was probably the first time ever in the ~20 years of electronics hobbies, that I managed to install a resistor of wrong value, in this case to VCO2 triangle-to-sine wave shaper circuit.. Live and learn; had some D’OH moments doing a part-by-part trace of the entire circuit :)

Anyway I thought I’d bundle some of the simple mods under this post. All these three were suggested by user Nordcore in the various TTSH build threads the Muffwiggler forum.

ProtoTypo PT2 – GRAM

One of the first modules I bought for this Eurorack 84HP utility skiff I’m putting together I was putting together to go with my TTSH, was a DIY kit of Ljunggren Audio‘s Roll Your Own (RYO) Penta sequencer. Upon building it I was delighted to notice that the PCB had marked solder locations on it, from which individual step gate output signals and a hold input (to pause the sequencer) can be sourced. Very modding friendly, just how I like it!

And that’s how Ljunggren Audio meant it too; they host a Penta modification page and also the Penta product thread at Muffwiggler forum has user ‘Stabilt’ (whom I assume to be among people behind RYO) suggesting a basic combined gate output circuit. I decided to use these two sources as a starting point for a gate output expander of my own, aka ProtoTypo PT2.

Basic gate output circuit by Stabilt @ Muffwiggler

If you’re looking for download links to pdf schematics, they’re at the end of this post. Let’s try it this way for a change, because why not ;)

TTSH, Gate Booster mod

If you’re all new into how analog synthesizers can be controlled, you may first want to take a look at this Wiki article on CV/Gate for some jargon busting. Other than that, let’s dive right in.

Among the first electronics mod I wanted to add to my TTSH was the Gate Booster. To fully open the ADSR envelope generator of TTSH a +10VDC gate needs to be applied, thus in it’s stock config the envelope can’t be fired properly by using eg. any external gear that outputs a +5V gate. Add to the common CV/Gate specs, the TTSH envelope generator also needs a trigger signal (very short pulse) to work properly. This can be used to restart the envelope without disabling gate signal.

So what the Gate Booster does is, it converts low voltage level gate signals to higher voltage and generates the trigger signal from the gate input. The particular circuit board I bought for myself is this modified version (sold by Oshpark) with a socket for a Midimplant MIDI-to-CV/Gate converter board. Having MIDI (keyboard) input just made so much more sense than eg. building a CV keyboard like the Arp 3620.

Gate Booster board all populated..

TTSH, speaker baffle mod

This was a quick “let’s see what happens” kind of mod for my TTSH.

In their stock config, the TTSH loudspeakers are supposed to be fastened to the circuit board, which is then fastened to the front plate. Handy approach eg. for having the electronics as a entirely separate, single ‘module’ for servicing etc. But problem with this is that it leaves a ~12mm gap between the driver and the front panel.