Telex: Teletype expanders


If we’re talking firmware additions already, I have some ideas that have been pent up for a while … :smiley:



Store is now sold out for this run. Whew!

Just finished boxing up the final units. Here were the stragglers just before boxing:

Lots of questions about TXb - I will officially confirm that more will be on the way. Just ordered the panels today. PCBs are already awaiting them (some populated, some awaiting parts):

Given lead times - it will take a bit before everything is here. Just want you to know they are coming at some point in the next few months.

For those that ordered, it usually takes a day or so for things to show up in the USPS systems here in LA - especially for international shipments. Everything should start tracking soon… :slight_smile:



So cool that all of these moved so quickly! Congratulations!
Looking forward to those panel/PCBs if they end up in the store sometime soon :sunglasses:

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re: telexb plugs

(anyone want to go halfers?)

p.s. This lead me down a weird amazon mobile phone jewelry rabbit-hole aka the next big thing in eurorack.



I hadn’t seen the bedazzled ones! :slight_smile: In my searches I did find some fruit:

I ordered some of these rubber things from Amazon:

The look the least likely to break off. (Once bitten…) I’ll report here once I get them - but it looks like the lead time is ridiculous. Wish I’d have noticed that first…



Wow. Just wanted to comment about how great it is using the TXo as both an oscillator and an envelope on the same cv output. i must have forgotten after reading through this thread but I’m glad I tried it out tonight.



The Teensy upgrades and the TXn are lovely. Thanks for your efforts Brendon.



Found my jack protection solution! :smile:



Just installed my TXn (thanks @bpcmusic) and wondered what the included jumpers are for? (Everything appears to be working as expected)

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A small TXi question:

I’m trying to do simple quantized notes, so:

TI.IN.MAP 1 0 23

CV 1 TI.IN.N 1



both only return zero.

CV 1 N TI.IN 1 works, but as far as I understand, that bypasses the quantization completely?

What am I missing here?

EDIT: I obviously have an LFO plugged into the IN 1 of the telexi.

EDIT 2: Have also tried CV 1 N TI.IN.N 1 and CV 1 N TI.IN.QT 1…



According to the included paper manual, I believe it pads each channel by 6db

Here is a relevant post:



Anyone using TXn with MN Rosie?
I can’t seem to get any stereo separation using either the headphone out or the TRS out of Rosie.

I’m yet to try the TXn directly into a mixer.



Ah, I managed to miss the manual, wrapped up with the invoice in the outer box! Thanks.



don’t own a Rosie- but are the A and B inputs actually stereo, or are they summed to mono, and just the FX return is actually stereo?



Don’t have one either, but according to the Make Noise page, Rosie features:

Two Mono Inputs (Channel A and B) w/ LED indication of signal strength

Looks like you might be able to pass through some stereo signal using the Aux returns as additional inputs:

Good luck! :slight_smile:



I set up an LFO on my TXo’s 4th output that oscillated between 0V and 10V like this:

TO.CV 4 V 5

This causes an LFO with a 5V +/- swing to center around 5V. It was patched to the first input of my TXi. For TXo output 1, I wanted to just deliver the quantized CV value on each metronome pulse. For TXo output 2, I set it to 6V on the init script (TO.CV 2 V 6) and then set it to oscillate at the given pitch on each metronome pulse as well. Here is that metronome script:


That’s it. I patched the first TXo output into the 1V/oct input on my O-Coast. I mixed the square wave output of this in with the TXo output 2 (which is oscillating). With the tuning dial on the O-Coast, I was able to offset the two oscillators (which is why their chromatic sweeps happen at different times).

Hope this helps.

A bit more on Quantization on the TXi

TI.IN.QT x returns the voltage as a number (-16384 to 16383). The input voltage is quantized to the nearest note value in your selected scale (TI.IN.SCALE x - defaults to Equal Temperment). TI.IN x will show you the voltage that is read at the input. These two will differ unless the input value is exactly the same voltage as a particular note.

TI.IN.N x returns the quantized note number for the particular voltage that is read on the input (again, based on that input’s scale). This number is not a voltage - it is a note number. You can convert it to a voltage by either a) using the Teletype’s N operator (e.g. CV 1 N TI.IN.N 1 - where the scale automatically becomes ET) or by passing it to the TXo’s N operators (e.g. TO.CV.N 1 TI.IN.N 1 in whatever scale you have set on the TXo).

What is tripping you up, I think, is your MAP command. You are mapping all voltages to the range 0-23 - out of the full potential range of -16384 to 16383. I’m assuming all of those voltages are quantizing to zero. Depending on your input, you would want to map its voltage ranges appropriately. Remember, map is bipolar (as the inputs are -16384 to +16383). For example, TI.IN.MAP 0 16383 will take a bipolar +/-10V and map it to 0V-10V, centered around 5V.



Forgive my ignorance, but are there any more plans for busboards/backpacks anywhere, or does anyone have any partially built? I’m fine with some assembly, but I can’t do SMD soldering.

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I’m currently doing another run of the TXb. Should be done in a month or two. Just waiting on the panels. If you are antsy and want to make one yourself, it is open source and available up on my GitHub page for the TXb.

You can also grab/make a lovely TT-Busboard-Jr. Don’t be put off by the number of pins - i2c can be daisy-chaned. They are functionally identical from a “pull-up” perspective. :slight_smile:

Finally, you can make one of the original busboards that mount on the Teletype:

There are only 3 SMD parts. If you are comfortable with through-hole soldering, this would be only a small step-up in skill. Watch this video for 40 seconds and you will learn everything you need to know:



Thank you, fantastic writeup <3 Will have to dig in and see what I can learn. Much appreciated.

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I just got my ER-301 today, and started my first foray into i2c with Teletype / TXb / ER-301.

If I connect Teletype directly to the ER-301, SC ops work fine.

If I also connect Teletype to the TXb, SC commands cause Teletype to freeze. I don’t have power connected to the TXb, nor anything else (my intent is to use it for the 16n Faderbank).

I assumed the silver stripe on the TXb indicates the row of ground pins (making the middle SCL and the opposite side SDA). Is that incorrect? It’s not in the info that shipped with the module.

I also assumed I didn’t need to connect power to the TXb since my Teletype is recent-ish…