Saturday, January 28, 2023

NTSH

 

The NTSH is a mini joystick noise synth.

It consists of; 

- one white noise generator

-one square wave oscillator

-one 12db resonant LP filter

-one Sample&Hold/envelope generator



The controls;

The joystick on the left controls the Filter Cutoff and the Pitch of the Square Wave VCO, while the joystick on the right controls the Gate frequency of the Sample&Hold, and the frequency of the Triangle Wave that is being sampled.

The Gate frequency is also the frequency of the Envelope Generator.

The Gate/Attack Time switch will set the Envelope Generator to either Triangle or Saw waveform.

In Triangle mode, the Sample&Hold Gate time will be at 50% on/off ratio. This will cause the modulation to sweep at the Triangle oscillator frequency between samples. 

The Sample&Hold and Envelope Generator modulation sources can each be set to VCO Pitch, VCF Cutoff, or both VCO and VCF together.

The Mixer switch sets the Voice output to VCO, Noise, or both Mixed.

The Mixer switch set to QOSC will turn off the Noise and VCO to the filter, and set the Resonance to self oscillation. The Filter Cutoff sets the QOSC frequency.

In QOSC mode, the Q knob is disabled. In all other modes, it sets the Resonance of the VCF.

The Volume knob sets the output volume level.

The NTSH has a power ON/OFF switch, 1/4 inch output jack, and built in speaker.

The NTSH can be powered by 3 AAA batteries, or with a standard 6-9VDC center positive adapter.


The design;

 The NTSH is smaller in size to other NT boxes by about half. 

The electronics are all analog, and designed from scratch. 











The goal was to design and build a new NT box that was smaller and more accessible for people to buy and support my work. These small boxes are relatively easier to build than the other NT box designs that came before it. They still take several days each to make, but because of their small size and limited function, it is a much less daunting task. I have trimmed a lot of the build time by investing in better power tools for sanding and shaping the boxes, and rather than hand painting the the face-plates, I am using colored acrylic. It costs a bit more, but I just don't have the time these days to do everything by hand anymore. The only drawback is that the colors are pretty limited.

The signal path of the NTSH is pretty basic but it covers a lot, I think. I knew I wanted a white noise generator with a resonant filter. I just love that sound. There wasn't enough space for any kind of sequencer, so I thought a S&H would be nice. The first iteration of the circuit used a bunch of cmos oscillators at different frequencies as a modulation source, because I thought a real S&H would take up too much space, but actually it was the other way around, and the cmos oscillators were difficult to control together in a reliable way. The most difficult but also must interesting part of this build was to come up with as many practical and quality functions as possible with such a small footprint. The end result is such a tight fit in the box, but I think it is perfectly balanced in sized and functionality. The circuitry was also very helpful.. By that I mean, the final circuit seemed to offer up solutions or new features that I hadn't intended using, and usually didn't require too much effort. For one thing, the white noise generator required a charge pump circuit to generate 12 volts to work. However, the current didn't have to be much, so I used the VCO to charge the pump(pump the charge?). Then the S&H gate offered up a perfect synced envelope generator, and the switch to make the gate/attack time 1/1 made both the S&H and envelope so much more dynamic. The Qosc function was something I decided to add after I had already finished the first prototype. It had occurred to me that the self oscillating filter sounded really great without an input signal, and implementing this was literally adding one connection to the Mixer switch! Sometimes things are meant to be.

7 comments:

  1. This is so cool, and looks amazing. I also deeply respect the price point; realistically you could probably sell this for way more (a la JMT synths).

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    1. thank you! I think the price is just right, but then I am having trouble keeping up with demand.. for now, I'll just keep making more, and see what happens. I have a feeling interest will taper off. Then on to new ideas :)

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  2. From the sounds made on the original star trek series, to the machine and monster frequencies of forbidden planet, to the BBC radiophonic workshop and the aphex twin, boards of Canada, etc, etc all sources of aural wonder and curiosity, now the magical, mystical, mindbending catalogue of noystoise!!! Ahh life is very, very good, thanx for your determination and talents for imagining, engineering and building these brilliant I struments. Now where can I buy aNTSH 🙏.

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    1. beautifully put! thank you. I am in the process of making more NTSH and NT05 boxes. Covid finally found me, so I have been stalled :( email me to join the waiting list. it's not very long.

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  3. Really interesting, well done on the design and the price. would you consider making a version with CV inputs and outputs, and audio input?

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    1. thank you! these are actually very small. I don't think it would be possible to fit anymore jacks into the design, but in theory they could have CV in and outs.

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  4. were i can order one !?

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