Clash of the Borgs

A quick comparison of the Malekko Wiard Borg 1 & 2, also featuring Plan B Models 12 & 13.



The Borg 1 (white knobs) employs slower vactrols, allegedly giving it a mellower sound and longer decay than the more aggressive, black knobbed Borg 2. I'm a big fan of the Plan B Model 12, but sometimes find it's response to CVs either too linear or lazy, so I was keen to hear the Borg 1 for myself.

Here's a fairly representative recording of the difference between these filters:


(Borg 2, Borg 1, Model 12)

I really liked the Borg 1's soft edges and muted tones. Its response is slower than the Borg 2 and this makes it a more natural sounding LPG. It might even have the edge on the M13, which tends to lose the initial transients. I don't find either Borg particularly useful for BP or HP duties and this is where the M12 shines. I tried patching both Borgs in a BP series, but didn't find the results as interesting as the dual-peak BP mode of the Cwejman MMF-1. That said, both Borgs are fantastic LPFs with attitude and character. Sonically, the B1 sits squarely between its more aggressive sibling and the rubber-funk of the M12.

You can download the full set of recordings, including the obligatory LPG 'thwap' test, here (3.2MB), but be careful with your speakers on the 'rumble' MP3!

Thanks to Schneidersbuero for the loan of the module.

PotD - We All Pass Out

Using the All Pass output of one of favourite filters - Plan B's Model 12 State Variable Vactrol Filter - to create a phasing effect. Inspired by this old thread at modularsynth.net




PotD - We All Pass Out

FM'd self-oscillating Cwejman MMF-1 filter sent to both a mixer and the M12, All Pass out returned to mixer. Gated by a Bananalogue/ Serge VCS which is responsible for much of the sequence's funk due to its inability to re-trigger.

The phase cancellations are clearly audible at around the 10 second mark as I fade in the all-pass signal to the mix.

The balance between original and all-passed signal is key to getting the phasing right. The M12 is capable of some very musical distortion (more on this below) and I think I pushed the filter's input too much in the first example. To compensate for the source material's lack of harmonics and to help set a better balance, in this example I first processed the sequence with my Ken Stone Lockhart wavefolder:


M12 as Phaser

This last clip demonstrates the Model 12's characteristic 'vactrol fuzz'. An FM'd Hertz Donut is fed into the filter, Maths sweeps the cutoff while I manually adjust the filter input level. I also compensated for the increased volume at higher fuzz levels by turning down the final VCA accordingly.


M12 Vactrol Fuzz

Normally, this is just the right amount of fuzz for my liking but, if you remember this, you'll know that the M12 is capable of some truly molten sounds.

CGS52 Simple Wave Folder

Here's a few clips of my first DIY module, Ken Stone's Lockhart/ Simple Wave Folder:



Basic run-through, unaffected signal first.



Various complex/ FM'd and filtered waveforms put through the mill. First minute and a half Doepfer A-105 filter, then Plan B Model 12. Ken Stone says the module must be fed a sine or triangle to work. I have to disagree ;)

I know I swore I'd never go near a soldering iron again after building the Trobetronic40 but, encouraged by Paul at Schneidersbuero and 'Roter Agent' at the sequencer.de forum, I gave it another go. Cheers lads! Added an extra attenuator and cap and an LED cos we all love blinkies, right?

CGS77 Serge 1973 Filter Demo

Sounds of the CGS77, Ken Stone's adaptation of the original Serge filter, are scarce. I hope these recordings help anyone considering this DIY build.



I'm really not a filter man, but the Serge VQVCF is something special. This circuit is its 1973 ancestor. The state variable found in today's systems has been refined with gain compensation and a trigger input. But Ken Stone tells me that the CGS77 is essentially the same core and my ears aren't about to argue.



If you want to hear more, please buy the EP for the unedited recordings and pictures of my build.



Building CGS modules for Eurorack presents the DIY-er with the problem of how to accommodate the PCB. Others have opted for 'best-of' panels, combining several PCBs behind one large interface. My solution was initially based on a false assumption - that I could cut below the CGS77's 'dotted line' to remove the unneeded buffers and mount it vertically.



I should have done this before populating the board, so I settled on another tactic. Using stand-offs and making sure the module in the row below is less than 4 cm deep, my '73 filter is a dashing 10HP. Here are the guts and here its installed.



On the mechanics, I used Charlie The Bad Producer's method of attaching the power via a perfboard add-on. I considered normalling the band-pass to the input for self-oscillation, but found in testing that the '73 doesn't make a particularly stable oscillator. The HP & BP are nice, but not as good as the Plan B Model 12, so I might leave them out on a future build. Other casualties might be the DC mode and LED. This filter responds well to modulation, so an additional CV input would be more useful: this can be added in at the points marked S & R on the schematic.

Thank you Serge & Ken for this wonderful filter, negativspace for BOM help and my brother for the boards!

Patch Tips #8 - More Feedback

Getting the Plan B M12 SVVF to self-oscillate and 'sine-shaping' à la Bubblesound µLFO. An update to this post and part of my ongoing drive to sell the Doepfer A-133 VC Polarizer.

If you've read that post, you'll know how I go about this so, without further ado, here's the Plan B M15 sine being fed back to varying positive and negative degrees:



And here it is being used as a modulator:



I don't have a µLFO and don't know the Bubblesound circuit, but this certainly seems to yield similar results:



I'd be interested to hear from any µLFO users whether the sine-shaping also causes a change in frequency as per my examples.

Feedback with the Model 12 yields some very interesting results! Depending on the amount of feedback, internal resonance setting and input gain, I got some wonderfully wild sounds. This is the bandpass output being fed-back negatively:



Part of the sound is down to clipping on the input circuit as you can see from these 'scope shots:



Surprisingly, I found that it is possible to FM the M12 at audio rates, although of course not with the precision or clarity you'd get with a non-vactrol-based filter:



The sine output of the M15 was used to FM the M12. The output of the filter was also sent to the sync input of the VCO, resulting is some pleasing, if groggy, harmonic stepping.

Patch of the Day - Long Way Down

Something gentle for a Sunday afternoon:

PotD_longwaydown  by  navs

Live, four-voice patch with manual tweaks.

Self-oscillating Cwejman MMF-1 dual-peak sine modulated by WB smooth out. A-Sol SH-NZ noise to Plan B Model 12 HPF, VCA VC'd by Doepfer A-147 VCLFO sine, itself VC'd by the output of a A-156 Quantizer. Ring Mod output of a VCO-2RM filtered by a Malekko/ Wiard Borg, envelope from Bananalogue/ Serge VCS VC'd by Woggle out. M15 VCO (linFM) gets WB stepped, gated by M10 envelope which is triggered by WB burst and VC'd by stepped out. M10 EOC to A-142 envelope which provides the voltage which is then quantized by the A-156.

Patches. They always start out simple, don't they ...