I don't know if it's obvious or not but I never knew the Buchla 259e had two simultaneous wavebanks. The notes from Buchla and Associates are skint and there has been a long standing tradition of encouraging users to learn and figure things out themselves in modular synthesis. By poking around with some of the other modules and studying the faceplates and buttons a bit more I am starting to see that there are all sorts of additional or alternative features built in. One of the more basic ones I've figured out so far is how to access, program, and morph between the two wave banks on the 259e
I have an earlier panel of the 259e which says "Complex" Waveform Oscillator on it. Current versions say "Twisted" and have a slightly different legend but both can run identical updated firmware so in effect the unit I am using is the latest "Twisted" version. The following info is based on the legending on my unit but it works the same on the same buttons, lights, etc on the current version.
Both 259E panels feature the morph feature in the upper right hand Timbre section. There one will find the vertical wavebank lights and directly under that the "select Button". On the left hand above this is a green LED which corresponds to the green LED on the left of the Morph knob above. Likewise on the right hand side above the selelct button is a red led which corresponds to the red led on the right of the morph button.
Simple enough? Well not quite as pressing the Select button does change the waveforms but only within the selected bank. In order to go from Bank A (Green) to Bank B (Red) you need to press and HOLD the Select button. This will then change the LED and pressing it again in short bursts will cycle through the waveforms within that bank as "normal". The picture on the left shows the module with bank A (Green) selected and in this mode pressing the select button will scroll through those waveforms. Also not the Morph knob is all the way to the left and only the green LED is lit. At this point only the Green waveforms are being heard.
Once you have selected the waveform you wish to use you press and hold the Select button until it changes to Bank B (Red). The picture on the right shows what this looks like. At this point only bank B is available both to scroll though and in the audio out.
The fun begins when you start to mix and match. By using the Morph knob you can manually adjust the volume balance of each bank in the mix. Again all the way left is 100% Bank A, all the way to the right is 100% Bank B. Dead center is a 50/50 mix of the two audio outputs.
Of course this a modular piece and a Buchla at that so there are many ways to mix and match the two wave banks. You can patch a CV into the upper right hand black CV In jack in the Timbre section and by adjusting the corresponding knob you can sweep between the two leaning one way or the other. Additionally the Mod Type section allows you to select "Morph" as one of the destinations of the Mod Osc so you can sweep through those options (use short presses of the gray Mod Type select button) until "Morph" is highlighted. Now you can adjust how much Mod Osc affects the morph by the Modulation Index knob above. As you would imagine a slow LFO type sweep with a softer waveform does a delicate mixing of the two banks. If you run the Mod Osc into audio levels and choose a pulse or similar waveform you get almost FM type oscillations. And none of this is actually modulating pitch in any way yet.
Here is an audio demo of the Morph feature:
Demo of Buchla 259e Morph Feature by DAEDSound
A future post will demo how radical CV processing can alter the 259e but as you can see with no external control at all there is a lot going on in just the Morph features.
As a side note, I don't know if they exist but I have never seen any info on WHAT the waveforms are inside the 259e. I'm not entirely sure how many there are even. I suppose this goes with the "plug in and find out" mentality but given the wide variety of modulations available, I think it would be useful to know a bit more about the sounds and options that you use as a base.