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WIGGLING 'LITE' IN GUEST MODE

MU low pass gates
MUFF WIGGLER Forum Index -> 5U Format Modules  
Author MU low pass gates
Jari Jokinen
I need help choosing a low pass gate.

If it was available for MU, I would get Rabid Elephant Natural Gate (Eurorack). Since it has no vactrols, it doesn't bleed. Lack of resonance is ok for me.


MU LPGs I am aware of:

- Cynthia Quad Low Pass Gate (Thomas White?): Discontinued. Needs hot CV to open fully?

- Krisp1 / Thomas White Triple Resonant LPG. Discontinued.

- MegaOhm VCFA: Discontinued. Too deep.

- FSFX 103: Out of stock.

- Synthcube / Thomas White triple LPG: Needs hot CV to open fully? If true this is a deal breaker.

- Club Of The Knobs C906A: Has no vactrol and thus no bleed? How does it sound? It has 30dB/oct filter so one might expect it to sound quite filter-like and not kind of neutral and natural like normal LPG...? How deep is the module?


Please, comment.
synthetic
I had the Thomas White in MOTM and I have the MakeNoise LPG in Euro. For some reason the TW didn't do anything for me but I love the MN. So I guess they're not all alike.
bwhittington
I've only used the Megaohm and Cynthia in 5U, along with a few of the MN Euro ones and the 292e. The Megaohm is amazing for percussive effects, but its response seems very fast and its resonance rather aggressive. The Cynthia seems slower and a bit better to me for classic LPG sounds (or what I want an LPG to sound like at least), but it does need about 10v to open fully, and I don't think any great effort was made to match the the vactrol response of each channel. This is okay to me, so long as you consider a little variation a feature.

The TW LPG seems to have been a very popular DIY project at a point, in addition to the commercial releases, but I've never had a chance to try one.
kindredlost
I agree!

Mr.W summed it up pretty well here. I only have the Cynthia Quad LPG and Mega Ohm Audio CdS in 5U. I would take the Mega Ohm Audio module over the Cynthia in off-the-shelf form any day, but Phil at Mega Ohm Audio reworked my QLPG and it helped quite a bit. I've also owned some of the Euro designs from Makenoise and Malekko and it's too bad someone (FSFX - cough) hasn't taken up the torch to bring these designs to the 5U world.

I wasn't aware that the Mega Ohm Audio VCF/A was discontinued. A shame. It is a great module and stays locked to my setup. The aggressive resonant behavior BWhittigton wrote about is true but it can be easily tamed. Using both inputs, one for the envelope/trigger and the other for velocity makes it very responsive and "playable".

It's usual to expect an "LPG" to be resonant due to what we all have learned to hear from the Buchla design, but in it's original incarnation the resonant ringing low pass gate was mostly a patchwork choice and became a happy fluke.

Naturally having a "slow" response, it's a source of amusement for me to read of someone criticizing an RO as a bit slow. Latter day sealed integrated circuits made things faster by replacing the lamps with LED's (wait... it's light after all?!) but the whole beloved point of the audio character was to dampen a fast trigger and render a "pop" into a "thud", thereby causing a softer gate and dull filter pass. I've read Buchla used these due to an economic decision but that may just be a broken historic tale. It makes sense to a point as those were the early days of digital devices and a "Vactrol" wasn't fast enough for the duty. They were being phased out and "cheap as chips", so to speak. Not anymore it seems and how times have changed.

Phil at Mega Ohm and some other designers like Roland at Makenoise and Thomas White have made a point to tailor the circuitry so to bring out the resonant "ringing" nature. Sort of a musical evolution of the original cadmium sulfide photoresistor circuit, which took it's roots from the selenium valve circuits and film scores of the early 20th century. Suites me fine. I like the nature of the new designs and the sound in general.

I would write Phil at Mega Ohm Audio and ask politely if there is a way he would be interested in making a run of these modules again. His design is excellent. Maybe a few orders from fellow Wiggler's would kick off the project?
Dave Peck
kindredlost wrote:
Latter day sealed integrated circuits made things faster by replacing the lamps with LED's (wait... it's light after all?!)


Yes, but an incandescent lamp (even a teeny tiny one) takes longer to heat up (and thus light up) than an LED.
Jari Jokinen
Thank you for comments. Still undecided though.

Here is megaohm's solution to Cynthia QLPG CV level problem:
https://www.muffwiggler.com/forum/viewtopic.php?t=171860
Jari Jokinen
kindredlost wrote:
I would write Phil at Mega Ohm Audio and ask politely if there is a way he would be interested in making a run of these modules again. His design is excellent. Maybe a few orders from fellow Wiggler's would kick off the project?

I would need a new shallower design. He has said one reason for discontinuing was uneven quality of vactrols.
josaka
Jari Jokinen wrote:
kindredlost wrote:
I would write Phil at Mega Ohm Audio and ask politely if there is a way he would be interested in making a run of these modules again. His design is excellent. Maybe a few orders from fellow Wiggler's would kick off the project?

I would need a new shallower design. He has said one reason for discontinuing was uneven quality of vactrols.


yep said the vactrols were a nightmare.. I want to know when his delta II is appearing.. !!

those looking for the 'bongo' res effect.. the oakley journeyman in high pass res cranked up is a thing of wonder .. a mighty h/p filter
Be Sandy?
I've only used the Cynthia LPG in MU format (used plenty in other formats).
It sounds nice but as others have said needs a good kick to get going.
I usually boost CV going into it with a dotcom Q125 Signal Processor.
megaohm
josaka wrote:
.. I want to know when his delta II is appearing.. !!


I would like to do this now.
Have a custom order for a dual banana jack version and was going to order the old pcbs. Decided against that after reminding myself of the wiring chore of that pcb. Also, I want to include a few refinements.
If there is enough interest, I can get MU Delta modules back in stock.

Will start a new thread with details about this today.
megaohm
josaka wrote:
Jari Jokinen wrote:
kindredlost wrote:
I would write Phil at Mega Ohm Audio and ask politely if there is a way he would be interested in making a run of these modules again. His design is excellent. Maybe a few orders from fellow Wiggler's would kick off the project?

I would need a new shallower design. He has said one reason for discontinuing was uneven quality of vactrols.


yep said the vactrols were a nightmare..


Very true. The circuit version I used is picky about vactrol behavior.
It got to be too much money and hassle to select them (erratic availability, wildly fluctuating prices, etc.). I do not plan to make these again.
josaka
megaohm wrote:
josaka wrote:
.. I want to know when his delta II is appearing.. !!


I would like to do this now.
Have a custom order for a dual banana jack version and was going to order the old pcbs. Decided against that after reminding myself of the wiring chore of that pcb. Also, I want to include a few refinements.
If there is enough interest, I can get MU Delta modules back in stock.

Will start a new thread with details about this today.


that delta filter is the electro king !! its the same filter as in the Korg Poly 61 which is the synth Hashim used for all his 80s electro killers..
will the delta II be 1U ? ..cause 2 in Series/parallel would be immense..




JohnLRice
Jari Jokinen wrote:

- Club Of The Knobs C906A: Has no vactrol and thus no bleed? How does it sound? It has 30dB/oct filter so one might expect it to sound quite filter-like and not kind of neutral and natural like normal LPG...? How deep is the module?

Are you sure it doesn't have vactrols? I don't have the C906A low pass gate but I do have the C906B high pass gate and it appears to have vactrols, at least that's what I'm assuming is inside the 16 pin black box? It's labeled as "filter_core" on the PCB so I can't say what it is for sure . . .


Typically COTK modules are about 78mm deep +/- a feww mm, with some of the larger modules being even more shallower or deeper?


I think the C906B high pass gate sounds quite good. I had put up a demo on soundcloud last year for a friend but I took it down to make room for something newer (I only have a free SC account with limited space). I can't recall if there was bleed issues or not.
Jari Jokinen
JohnLRice wrote:
Are you sure it doesn't have vactrols?

Now when I think about it, no. I somehow assumed that 30dB/oct filtering and vactrols don't go together.
Flareless
Just curious about that 14 pin connector on the PCB there JLR. Is it a power connector? The label reads Dotcom.

On the subject of LPGs and vactrols I built myself a Thomas White triple LPG a while back. I used different speed vactrols on each of the 3 boards; slow, medium, and fast.

Each section now has its own "flavour" which makes the module really cool and flexible.
JohnLRice
Flareless wrote:
Just curious about that 14 pin connector on the PCB there JLR. Is it a power connector? The label reads Dotcom.
The 14 pin connector is the COTK power connector. It looks like it's labeled DotCom but actually isn't, there is just solder pads for both COTK and DotCom power headers right next to each other. cool


Flareless
Thanks for the clarification John! Very interesting configuration. No chance of plugging the cable in backwards or yanking it out accidentally.

Do the COTK pins highlighted in red carry different voltages used only by their modules?
JohnLRice
Flareless wrote:
Do the COTK pins highlighted in red carry different voltages used only by their modules?
I "think" they are used for CV and maybe gate signals like for Moog clone VCOs and how 16 pin eurorack power headers are used but I'm not sure.
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