Wonderful new phase shifter module

[Dave Peck]

Hi all,

I have a fairly large Dotcom/MOTM modular synth and I have been on the hunt for some of the more unusual modules, and I have just found something really special.

I have been looking at the various phase shifter modules available from different manufacturers but IMO they are all missing important features - some only do positive-mix phasing, some only do negative, some just don't sound so great. Last year I was discussing this with a friend of mine, Rob Hordijk from The Netherlands. He's a synth genius (check out his amazing tutorials for tips & tricks on the Nord G2 Modular) and he has now gotten interested in producing some unusual and high-quality boutique analog synth modules and his Dual Phaser module is the first in a series of new devices.

A few specs:

It's a double-wide MOTM format module and works with MOTM or DOTCOM power systems, and the final production version may also have Doepfer power connectors as well.

It consists of two identical 8-stage phasers with some tricky routing and patching between them using switched jacks - patch audio into phaser 1 and out of phaser 2 and the two phasers will be routed in parallel but the second one will be inverted, which gives you all sorts of cool effects (more later). Also, patch a control signal into the phaser 1 1V/OCT input and nothing into the second phaser's 1V/OCT input and the first signal gets routed to both phasers' control inputs.

Perhaps the coolest feature - the MOD input has three functions, determined by a three position toggle switch:
1. SWEEP MODE - Standard frequency sweep, like other phasers, where all peaks sweep up & down as a group.
2. SPREAD MODE - The upper peaks and the lower peaks are spread apart & pulled closer together and cross over each other ( ! ) This produces amazing vocal timbres and all sorts of complex filter effects and sounds really wonderful.
3. HALF-SPREAD MODE - the upper peaks move further away & closer to the lower peaks and the lower peaks are not affected.

There is a second MOD input that is calibrated to 1V/OCT and this always acts as a SWEEP mode for all peaks, so you can SWEEP the peaks with one LFO and SPREAD the peaks with a different LFO at a different rate, which creates some really complex shifting timbres.....

The MIX control is bi-polar which adds even more sonic possibilities. Set straight up at 12 O'Clock you get dry only, no phaser (bypass mode). Turn it clockwise and you increase the phaser mix, and the phased output is positive. Turn it counter-clockwise and you increase the phaser mix, but now the phased signal is inverted which sounds very different from positive phasing.

The resonance control always provides positive (non-inverted) feedback, regardless if the mix control is set to positive or negative. By setting the MIX to negative and using an external feedback loop, you can easily get negative mix with negative feedback, so you have lots of sonic possibilities with pos & neg mix and pos or neg feedback. These combinations all sound different and this flexibility gives you a lot of options.

I'm attaching some photos here and I'll attach some short audio clips in some follow-up posts.

[Dave Peck]

Here are a few clips - These are all one sawtooth oscillator, no other filtering or any other effects, just the phaser module. And in these clips, you are hearing only ONE of the two phasers. These clips show what the negative MIX setting sounds like, as well as the SPREAD mode. One LFO is slowly sweeping the frequency (patched to the 1V/OCT mod input) while a second LFO is modulating the SPREAD between the upper & lower peaks. The three clips have different amounts of resonance.

[Dave Peck]

These two clips are similar, with SWEEP and SPREAD mod applied to only one phaser, but the MIX control is set to positive.

[Dave Peck]

This example uses both phasers for a stereo effect, with an LFO sweeping both phasers, but also uses an audio-rate osc to modulate the sweep for a unique distortion effect.

[Dave Peck]

These examples are two phasers in parallel, with the second phaser inverted (patched into phaser 1 and out of phaser 2). When the frequencies are set the same, the signal almost cancels. You can hear this near the beginning of the clips, just after it fades from the dry signal to the phaser signal. After that, the timbre changes in different ways by manualy adjusting the frequency controls of the two phasers while the LFO sweeps them.

[Dave Peck]

Taking a break from the rather technical audio clips for a moment, here is an example of this module in actual use, in all it's glory - the signal is just six raw sawtooth oscillators tuned to a drone chord (you hear them dry at the start of the clip). Then the phasers fade in, with some chorus & reverb added to show what this thing sounds like in a mix setting. I LOVE the way this thing sounds.

Next up, some really weird stuff that sounds nothing like a phase shifter....

[idiotboy]

fantastic phaser module!

[Derp]

...adding this one to the ever-growing wish list.

[Dave Peck]

....here's something a bit unusual - using the phaser module to generate tuned percussive sounds.

A very short envelope is patched to the audio inputs to generate a series of transient 'pops' (you can hear them at the beginning and end of the clip). The frequencies and spreads of the phasers are modulated by some random stepped control signals from some Sample/Hold modules. The feedback is set high so the short 'pops' cause the phasers to 'ring'......

[steveman]

Originally Posted by Dave Peck

It consists of two identical 8-stage phasers (eight resonant peaks per phaser) with some tricky routing and patching between them using switched jacks - patch audio into phaser 1 and out of phaser 2 and the two phasers will be routed in parallel but the second one will be inverted, which gives you all sorts of cool effects (more later).

Don't like being picky, but doesn't a phaser with 8-stages create 4 peaks/troughs? The number of peaks is always 1/2 the number of stages as each stage provides 90 degrees of phase shift. Maybe he doesn't mean 'stages' in that sense?

Nice to see someone doing a bit more with phasing than up/down sweeps. Negative feedback is easy to implement, as is negative mixing yet no one (?) seems to offer it. Sweeping notches in opposite directions always struck me as a good idea for creating vocal formant type timbres, again nice to see someone's done it. CV control of feedback amount would be nice though.

[Dave Peck]

Originally Posted by steveman

Don't like being picky, but doesn't a phaser with 8-stages create 4 peaks/troughs? The number of peaks is always 1/2 the number of stages as each stage provides 90 degrees of phase shift. Maybe he doesn't mean 'stages' in that sense?

Nice to see someone doing a bit more with phasing than up/down sweeps. Negative feedback is easy to implement, as is negative mixing yet no one (?) seems to offer it. Sweeping notches in opposite directions always struck me as a good idea for creating vocal formant type timbres, again nice to see someone's done it. CV control of feedback amount would be nice though.

Ah, you're right! My error. Each phaser IS an eight-stage phaser, so each phasor creates four peaks/troughs. A total of eight peaks/troughs in the two phasers. I'll fix the first post.

Here's another pretty strange effect - using the phaser to do audio-rate phase modulation synthesis. The audio source is just a simple SINE wave, nothing else. Really. It is patched to both the audio input and the control input, and the signal to the control input goes through a VCA with ADSR to control the mod depth. This creates all sorts of cool sounds reminiscent of additive synthesis or weird filter distortion effects. Quite a lot of different sounds from a single sine wave.

[Dave Peck]

These examples have the two phasers in SERIES rather than parallel, with one LFO used to sweep the first phaser up while sweeping the second phaser down. Feedback is gradually increased as the clip proceeds. The second example adds SPREAD modulation.

[ImJohn]

Sounds great, Dave!

[Reptil]

thanks for the heads up! I'll call/email Rob. He's a great guy and a walking synthesis encyclopedia. is there a website of some sorts? or did I miss that too. lol

I sold my moogerfooger phaser and I'm lusting over a 5u fx and filter rack so this'll fit right in.

sweet!!

[OurDarkness]

Will Rob produce more modules, or maybe a full size modular?

[Reptil]

dunno, found his website (was the same as before LOL) and will ask him.

for now the phaser looks peachy

[Reptil]

just got a reply from Rob
he also finished the prototype of a killer oscillator
I need both it seems. ay ay ay LOL
also a dual resonator based on his "blippobox" design
(FWIW I just bought another resonator, so in my case that would be overkill.)
and eventually a complete system is in the works
all modules work on both 12 and 15 volts, and the only difference between euro or 5u would be the faceplate
all custom built stuff. not cheap but that's the way it goes down for this level of quality I guess
this is really great -- more and more and more good modular stuff

[Reptil]

BTW, Dave can you post a picture of your current modular?

[yonny]

Wow! Nice.. As a phase-a-holic, I'll say this is a much-needed addition in an area of synthesis that has always been lacking. May I ask if these are currently being sold?

[Dave Peck]

Originally Posted by yonny

Wow! Nice.. As a phase-a-holic, I'll say this is a much-needed addition in an area of synthesis that has always been lacking. May I ask if these are currently being sold?

Yes, Rob is making them in small batches, all hand assembled. The quality is a "10", as you may be able to guess from the photos and the audio clips. He's a very easy guy to deal with and he told me to give his contact info to folks who are interested in the phaser module. He is in The Netherlands in Den Haag (The Hague) and you can contact him directly at

rhordijk (at) xs4all (DOT) nl

The price of the module is about $450 U.S., which is quite reasonable when you consider that it is not just a good phaser, but TWO independant phasers. BTW Rob is a friend of mine but I am not profiting from the sales in any way, I paid for mine and I'm just letting you guys know about this cool module.

I'll post a few more clips soon....

[Dave Peck]

Originally Posted by Reptil

BTW, Dave can you post a picture of your current modular?

Sure thing! You caught me at a rare moment - I just pulled out all the patch cords to start from scratch so you can actually get a good look at the synth. The new Dual Phaser is in the top row, fifth module from the right.

[Reptil]

nice! thanks

[yonny]

Thanks for the info, Dave. The 'Stereo sweep w/FX' audio clip was a religious experience. One question: do you feel that a phaser would benefit more by having, say, 12 stages as opposed to 8? I really don't know what the difference is, sonically speaking, and am fully aware of the old 'less-is-more' axiom. I guess I'm trying to figure out how this compares to, say, a Moogerfooger Phaser.

Also, would one need a dotcom instrument interface to run external instruments through Rob's Phaser?

[RobJB06]

Ooops!

[yonny]

Hey Dave, what is that you have underneath the Encore Expressionist -- some sort of I/O break-out box?
Nicely balanced system, btw. Must be nice having 6 oscillators and 2 State Variable and 2 Trans Ladder filters!! I just got a Lexicon MPX-1 myself (I think that is what i see in the pic), and that in itself will take some time to learn.

[clusterchord]

Originally Posted by Dave Peck

Taking a break from the rather technical audio clips for a moment, here is an example of this module in actual use, in all it's glory - the signal is just six raw sawtooth oscillators tuned to a drone chord (you hear them dry at the start of the clip). Then the phasers fade in, with some chorus & reverb added to show what this thing sounds like in a mix setting. I LOVE the way this thing sounds.

Next up, some really weird stuff that sounds nothing like a phase shifter....

awesome. just awesome. love how two phasers sound combined, and the spread function. and with audio rate mod hooked .. wow..

gonna visit this guy's site to see other goodies..


thanks a lot for posting these, Dave

[Dave Peck]

Originally Posted by yonny

Thanks for the info, Dave. The 'Stereo sweep w/FX' audio clip was a religious experience. One question: do you feel that a phaser would benefit more by having, say, 12 stages as opposed to 8? I really don't know what the difference is, sonically speaking, and am fully aware of the old 'less-is-more' axiom. I guess I'm trying to figure out how this compares to, say, a Moogerfooger Phaser.

Also, would one need a dotcom instrument interface to run external instruments through Rob's Phaser?

Phasers with different numbers of stages sound, well, different, and it's kinda hard to describe those differences. But in general, more peaks gives you a somewhat smoother and/or more complex phasing sound, at least up to a point. Think of it this way - if you know what a bandpass filter sounds like, one sweeping peak would be like a simple sweeping bandpass filter. Two peaks would be like two bandpass filters tuned apart at different frequencies, so you can picture how that would have a more complex sound. Four peaks gives you more complexity in the phasing effect in the same way.

But there does seem to be a point of diminishing returns. By that I mean there is a big difference between the sound of one peak and four peaks, but maybe not such a big sonic difference between, say, six peaks and ten peaks, IMO.

Regarding the question of running external signals through the phaser, it is currently set up to expect analog synth level signals, which are higher than line level audio. But you should email Rob and check with him. It may be very easy to add this feature.

[Dave Peck]

Originally Posted by yonny

Hey Dave, what is that you have underneath the Encore Expressionist -- some sort of I/O break-out box?

Yup, that's a breakout to bring the I/O jacks from the back of the Expressionist up to the front for easy patching into the modular. Gate1 and KYDB CV1 bypass this breakout and are patched directly from the rear of the Expressionist into the modular's Gate & CV buss panel at lower left. All other outputs from the Expressionist as well as some audio I/O on the Nord G2 are available on this panel. It's an off-the shelf panel with prepunched holes for 1/4" jacks, available here (Raxxess part number S16.25) :

Raxxess - Product Catalog

[yonny]

Dave, thank you for all this info! You are approaching synth guru status! If I ever find that I need an Expressionist I will surely follow in the same break-out-box footsteps.

Fortunately, I was able to do a little test with an old Boss RPH-10 half-rack analog phaser today. It has a unique 3-way 'mode' switch that allows a user to switch between 6, 10, and 12-stage phase shifting. I've been using it for about a year now, and, interestingly, I've found that I primarily use the 6-stage phase mode the most. The 10 and 12-stage modes are definitely usable and sound great, and it varies from instrument-to-instrument, but the 6-stage mode has a certain simplicity to it that I quite enjoy. I guess that the 10 and 12 stage modes are a bit overbearing, so perhaps 8 stages will suit me just fine.

I have received an email from Rob, and it was quite extensive. I had to print it out and spend some time throughout my day reading it! From a technical perspective it sounds like a very fine module indeed, and he seems quite passionate about what he's created. And yes, he can set it up to accept line level signals. This phaser is now officially high on my to-buy list, if only I can sell a Doepfer modular system and a Moog Voyager (in case anyone knows anybody in need)!

[Dave Peck]

I made a couple more clips last night. Here's the first one-

The TAU phaser was mentioned earlier and it got me curious to see if I could do something sort of like that with Rob's dual phaser. For those who are not familiar with the TAU, it is an unusual phaser that actually sounds more like a high-quality flanger than a phaser.

I did this clip by setting the phasers in parallel with phaser 2 inverted relative to phaser 1, as described earlier. The phasers are tuned to a high cutoff freq and swept down with an LFO, but one phaser sweeps further down than the other. So as they sweep down, their frequencies don't match and you hear both phasers. But the phasers momentarily cancel when they get all the way to the top of their sweep and their frequencies match.

AS the clip proceeds, you will hear different resonance settings, and the phasers mixes are changed from POS/POS to NEG/NEG about half way through.

(BTW, Rob JB06 I see you removed the post about the TAU - hey, it didn't bother me, glad to see you found a buyer!).