This guide explains how to install MIDI in a Wersi Bass Synthesizer using our OrganDonor interface.
Installation and pictures by AudioCircus . Thank you
You will need an organDonor with 3 switch boards. Each of the boards will control one octave of the synth.
The organDonor main board and switch boards can be fixed in the synth’s case as shown and need to be wired up as follows:
For each switch board, connect the first 12 common signals using the solder bridges on the back
Solder a wire to each common connection (3 wires total).
Connect the 12 analog switch outputs using a common ribbon cable. We can provide such a cable on request, or you can crimp your own
Next, solder the 12 wires and the 3 common wires to the back of the board as shown here:
Organ Donor will also need power.
In the organDonor configurator, you can select the MIDI notes for the switches you used. After uploading the configuration, MIDI input should work.
Thanks to Rob Rosen of Rosensound we now have an uniMatrix install guide for the Oberheim TVS (Two Voice). This only works for the Matrix keyboard version (see install guide). For the older version, you can probably use OrganDonor instead.
The upgrade allows MIDI note input and filter cutoff control.
From August the 29th, the US will stop the De Minimis exemption on imported goods from the EU. Previously, US customers did not have to pay tariffs on goods below a total value of $800.
Beginning on August 29th, US customers will incur a 15% tariff charge.
Furthermore, for the first 6 months, orders shipped via mail (anything that is handled by USPS) will face a flat $80 import charge—no matter the value.
Shipments handled by a 3rd party, however (DHL Express, UPS, FedEx…), will be properly charged with 15%.
For this reason, we have deactivated our mail shipping methods for the US. Customers can now only select DHL Express. It’s about 39€, so still affordable.
You will be charged with 15% import duties by DHL upon import, not during checkout.
Update:
Since writing the above, German mail (Deutsche Post / DHL) and many more mail services around the world have stopped shipping goods to the US entirely. DHL express does still work, so the above is still true.
A note about the 15%: Yes, it’s not great to pay more. If it is any comfort, people in the EU have pretty much always had to pay between 15% and 25% of VAT.
So in a way, you at least still don’t have to pay more than EU customers.
This guide shows how to install our OrganDonor upgrade into a Korg PS-3100 synthesizer. The installation is pretty easy: You will basically just need to solder one wire for each key. Currently, this manual shows how to get basic note on/off control, but might be updated with control over the filter and other parameters – this is already supported by the organDonor hardware.
Thank you very much to Ty Hodson who not only figured out how to install the kit, but also wrote a detailed instruction guide.
This guide explains how to install a MIDI input in a Casio SK-1 keyboard. We use uniMatrix to interface the keyboard matrix and simulate key presses.
The default configuration plays notes from C3 (Midi note 36), but this can be changed.
It is also possible to change instruments via MIDI program change messages.
ProgCh 0: Piano
ProgCh 1: Jazz Organ
ProgCh 2: Pipe Organ
ProgCh 3: Flute
ProgCh 4: Trumpet
ProgCh 5: Synth drums
ProgCh 6: Trumpet
ProgCh 7: Brass
ProgCh 8: Sampling sound
ProgCh 9: Harmonic Sound
The following CC control is also implemented:
CC 5: Portamento ON/OFF
CC 6: Harm Synth
CC 7: Env select
CC 8: Vibrato ON/OFF
Installing uniMatrix
Use double sided tape to mount the uniMatrix board to the big IC on the SK-1 board. Then, solder the wires to the points shown in the picture below. The numbers are the uniMatrix I/O numbers. Do not rely on the wire colors in the picture, these might be different in your version of uniMatrix.
Solder the two power wires Vin and GND to the points shown.
Overview
Solder points for uniMatrix I/Os
Solder points for uniMatrix power
Finally, drill a hole in the back using the drilling stencil provided in the kit, mount the MIDI socket using the two M3 bolts and plug it into the MIDI in connector of uniMatrix.
Notes played via MIDI will sound ca 50ct lower than when played on the keyboard. You can compensate for this easily with the tuning knob of the synthesizer, but you of course can`t play the synthesizer via Midi and by hand at the same time.
Overview
The M-500 version of OrganDonor offers the following features:
If the optional learn button is installed, it can be used to quickly change the midi receive channel of organDonor.
Connect midi out of a computer or keyboard to midi in of organDonor. Make sure not to send any notes.
Press the learn button and while it is pressed send a midi note on any midi channel. organDonor will set this note as the lowest note of the synthesizer and use its midi channel. These settings are saved.
Playing notes
Send midi notes on the configured midi channel (see above)
More configuration
Alternatively you may configure a lot of parameters using our organDonor configurator.
We recommend using the M-500 config file as starting point
1.) Save the file on your hard drive via right click -> save as
2.) in the configurator press “Load configuration” and select the file
There are several sample packs on Brainstep’s SD card already, however you can also create your own.
You will need up to 12 different samples with a maximum total length of 2.7s
You can use a lower number of samples and just duplicate them to use all keyboard keys. If duplicated, samples will only be saved once to save space.
Brainstep’s samples are rather LO-FI: 8-bit mu-law encoded with a samplerate of 24kHz.
To convert your samples into Brainstep’s sample pack format, you can use the web-based converter tool. If you want to be able to do this without an internet connection, just right click on the link, press “save as”. The html file works without being online.
Here are some investigations and improvements on the Juno-6 and Juno-60 noise performance. We looked at both, the original CPU as well as our Juno-66 upgrade
Both, the original CPU and Juno-66 create noise on the output. You can hear that by not playing anything on the keyboard, select SAW as input waveform (as this seems to reduce the VCA bleeding) and pull the gain all the way up.
The noise performance can be improved by adding additional filtering to the 5V supply. In case of the SH-101 for example which has a similar problem, an additional 10µF ceramic cap close to the CPU worked very well.
Now, at least in the case of my Juno, the original CPU has actually a much louder noise ( I assume because it draws more current), as compared to Juno-66.
However, the noise is not focused on one frequency, but a broader spectrum. This is due to jitter in the original CPU processing.
Juno-66 on the other hand, produces noise with a dominant frequency content and hence might be more audible – even though actually quieter.
To rectify this, I have created a firmware update that introduces additional jitter to broaden the spectrum a bit. Note, however that a good solution would of course eliminate the noise via supply rail filtering.
Noise of the original CPU, while a key is pressed the frequency is a bit different.
With the same settings: Juno-66 firmware 1.29. I press keys and change the portamento switch. Note, that this is already quieter than the original CPU
Same setting: Juno-66 firmware 1.3 – jitter is introduced
Soldering an additional 10uF capacitor between GND and 5V on the bottom of the board across the CPU supply pins, improved the noise even further.
If the optional learn button is installed, it can be used to quickly change the midi receive channel of organDonor.
Connect midi out of a computer or keyboard to midi in of organDonor. Make sure not to send any notes.
Press the learn button and while it is pressed send a midi note on any midi channel. organDonor will set this note as the lowest note of the synthesizer and use its midi channel. These settings are saved.
Playing notes
Send midi notes on the configured midi channel (see above)
More configuration
Alternatively you may configure a lot of parameters using our organDonor configurator.
We recommend using the Kawai SX-210 config file as starting point
1.) Save the file on your hard drive via right click -> save as
2.) in the configurator press “Load configuration” and select the file
Organ Donor will also need power.
