New video about it!!
When Intellijel? When…? 
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Nice! Wish he had another oscillator than a Surface to demo with, but can tell it sounds great still. I’m super excited for the Bifold. Already cleared a space for it. 
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I just wanted him to crank the resonance on the MUM M8 filter and use the sine wave. What can you say, young Mr. Tinez is not the type to give you a technical analysis and oscilloscope waveforms. You gotta be ready to vibe 
Any confirmation from the Intelllijel team on the design of the uFold II? (Buchla or Serge)
the original uFold was a series style folder inspired by the Serge circuit. The Bifold S folder is also a serge inspired circuit but the implementation is different from the uFold.
There are a lot of very carefully selected components in the Bifold, especially on the P side. We noticed quite big differences in tone based on the different opamps used and we choses ones that had very specific specs.
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Thanks so much for the quick response and for the amazing products! I love my uFold, but I’m looking forward to adding a Bifold once they come to market.
Would there ba a way to quantify the difference? I noticed on the oscilloscope that the two wave folders look very different at full fold. Was phase cancellation ever an issue between the two sides (maybe that’s why that feature being added)?
@Danjel and team - My Bifold arrived to complete my Intellijel Complex Oscillator, and join my Brenso and Cš-L! Congratulations and thank-you… what a fantastic machine.
So now I have a perfect Intellijel chain - Dixie2+, Rubicon2 and Bifold to make up a complete analog Complex Oscillator arrangement; with KorgasmatronII filter, Quadrax for envelopes and modulation, two LPG 1U low pass gates, and a Quad VCA.
Here is a demonstration that produces a three-part piece:
For this demonstration, I used a sequence from Frap Tools USTA…
-not my Intellijel performance set (Planar2+Tetê+Tetrapad)… my bad.
but, it’s a good demonstration of the Complex Oscillator package Intellijel has built, particularly Bifold and those wicked LPGs!
The patch consists of:
Dixie2+ zigzag wave into the Serial (Serge) wavefolder and an LPG on the right;
and Rubicon’s warp output going to the Parallel (Buchla) wavefolder to the left.
I also have Dixie2+ feeding the TZFM input of Rubicon2.
While those two trade-off alternating gates to the LPGs, I am sending additional trigger patterns to Quadrax, KorgasmatronII and a Quad VCA channel to send through the centre bass voice - which is the Rubicon2 Sub2 output.
The wavefolders are modulated with Quadrax Vascillators for variation.
Throughout the piece, I am manually adding through-zero FM to the Rubicon from Dixie via the Index and adjusting the base FOLD on the wavefolders to shift the intensity and add movement.
Enjoy!!!
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Sounds really good! thanks for sharing
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I did some messing around as well, using Bifold in stereo. The patch starts rather abstract and evolves into a stable sequence about half-way through. I still can’t get over the glorious timbres I’m getting out of this thing. Its ability to provide surprises that always remain musical makes it an amazing experimentation pal.
- Ts-L sine wave going to Bifold’s P input
- S and P inputs sent separately to Cold Mac Left+Right inputs for stereo crossfading
- Mostly X mode, with some manual switch to SYM at some point
- Quadrax modulating the crossfader and P and S (very slow LFO for subtle yet ever evolving waveform)
- Mimeophon with a lot of semi-randomization of params
A bit of filtered noise waves and René for sequencing. Hopefully it’s an interesting demonstration of the kind of timbres the module can provide.
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Sounds great! A lot of subtlety there
Thanks! René is actually being clocked by Steppy, so it allows for a lot of freedom of how “full” you want your sequences to be, it’s great for on the fly control over the evolution of your sequences.
Yeah, modulating the X/Y of Rene with a two-channel step sequencer was a technique I employed for a long time. I used to use Monome Meadowphysics for that back in the day, but Steppy would be a great option too.
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Hello, Intellijel community! I have been lurking here and in MW for a few months now, I’m relatively new to modular, and I think it’s finally time for my first post/question:
I’m having trouble understanding how the Bifold achieves ring modulation. I understand that the instructions say to send a carrier signal to input P and invert the carrier on “channel S”, then send a modulator to the XFADE input and set the XFADE attenuverter to fully clockwise. I don’t have the Bifold yet, so I’m trying to model this in VCV Rack with an inverter and a crossfade module (made by Bogaudio). Depending on where I set the crossfader knob, I can get something that sounds like “true” ring modulation, but when I look at a spectrum analyzer, the carrier is still present.
Can someone explain how this inversion-crossfade method is supposed to achieve ring modulation, and does anyone have any idea why I’m still seeing the carrier frequency in my VCV Rack patch?
EDIT: I think I understand why the carrier is still showing up, faintly: Because summing the carrier and its inverse isn’t cancelling it out perfectly. Not a big deal I suppose.
If you carefully adjust the xfade knob you should be able to get it to almost very perfect cancellation.
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The manual provides these instructions to achieve ring modulation (with a couple details omitted):
- Plug a signal into IN P. (With nothing plugged into IN S, the signal from IN P is passed to the Serial channel.)
- Invert the phase of the Serial channel.
- Balance the crossfade knob so the Parallel and Serial channels cancel each other.
- Plug your modulating signal into XFADE and turn the XFADE attenuverter knob fully clockwise.
The manual also says:
When the value of the XFADE knob and the attenuverted XFADE inputs sums to zero (or a negative voltage), then only the Parallel channel feeds the crossfader. When the value of the XFADE knob and the attenuverted XFADE inputs sums to +5V, then only the Serial channel feeds the crossfader. Summed voltages between 0V and 5V create a blend of the two channels.
What if you use a bipolar modulating signal? When you turn the XFADE attenuverter fully clockwise, aren’t you passing both the positive and negative values of the modulator? I think I’m misunderstanding what value the mix out reads from the XFADE knob in this configuration, because I keep thinking it’s reading zero since the two signals on the Parallel and Serial channels are cancelling each other, and with a bipolar modulator, it seems that the crossfader would be stuck on the Parallel channel whenever the modulator’s voltage is negative…?
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There’s another potential problem I thought of: Let’s say the XFADE knob reads “2.5V” when centered, so even when the modulator goes negative, the sum of the XFADE knob and attenuverted XFADE input is still between 0-2.5V. That would mean the XFADE knob would do a clean sweep. But if a negative modulator is multiplying with the inverse of the carrier, I could be wrong but I don’t think that generates ring modulation that will eliminate the carrier frequency…?
In the following images I have a 100 Hz sine modulator and 150 Hz sine carrier. Here is ring modulation:
And here what I believe this crossfading method would generate:
Very curious to hear more, Intellijel!
Ring modding is just xfading a signal with its inverse.
With Xfade knob in perfect center, the two sides cancel out. At full CW you get inverted signal %100 and full CCW you get normal signal 100%.
Put your modulator in XFADE control and turn up attenuator to full (while XFADE knob is in middle). Now your bipolar source modualting the carrier to 100% positive or 100% negative. This is ring modding.
So just to be clear: you carrier is going to IN P and IN S via normalling, the modulator goes to to CV input. We are expecting the modulator to be bipolar.
EDIT: if it is a typical modular waveform of +/-5V (like from a VCO) then you adjust the XFADE attenuator so that the modulator is half it’s amplitude. This would produce a modulation of -2.5V to +2.5V which is what you need to move the XFADE control from the center position to full CCW and full CW
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Ok, I know what I was getting hung up on now: I kept thinking that the modulator voltage was multiplying with the voltage of the signal being sent from the Xfade knob, it’s not. The modulator voltage is simply controlling the position of the Xfade knob.
My only other question would be about this comment in the manual:
How is there never a negative sum if the modulator is bipolar? It would appear that whenever the modular voltage is negative, say, -a, that the “Xfade voltage” would need to be greater than or equal to a to stay nonnegative. 
I forgot an important detail and edited my reply above. You need to attenuate your bipolar modulator to 50% of it’s value use the attenuverter control on the Bifold. So XFADE control in center position is equivalent to 2.5V (The knob range is 0-5V). Adding 2.5V pushes it to full CW, subtracting 2.5V pushes it to full CCW.
The resulting MIX output will be +/-5V (full range).
Also yes it is possible to get a negative sum, but at 0V the VCA is off and anything below is still “off”.
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