PastFx PX-101 Lowpass Filter (Moogerfooger MF-101 Clone)

[Charlie Tuna]

Phil, I've been doing a little A/B'ing vs the Meatball clone tonight with my OC-2 and Brown Dog clone and I have just a couple peeves with the PX-101, or rather the Moog MF-101 design:
#1: No control over attack or release speed of the envelope without an expression pedal. I've had an XD before and the toggle at least gave two distinct speeds. The Meatball has both Attack and Release speeds so I got spoiled even though the slowest speeds can sweep as slow or as wide as the XD. [EDIT: The Envelop Amount can help alter the opening speed of the filter but may require changing other knobs to get the same frequency response]
#2: When the envelope is used to filter, as resonance increases the lows start to drop out so for me it is a "flatter"/less dynamic experience than with the Meatball clone. I put my Spaceman Equinox afterwards and felt like it helped a bunch in this department.
So for me the Envelope/Triggering side is pretty weak and the achilles heel of the pedal in the octave/fuzz chain. With dry bass I felt the envelope/trigger side fared better but it doesn't compare with the Meatball. [EDIT: The 101 may require a lighter touch than some other filters. Additionally, you may have to lower the treble of preceding pedals since the 101 can have a wide sweep.]
Now where I think the PX-101 shines is as a static filter with its 2- or 4-pole choice. As a static filter it sounds like there are more lows retained and consequently it feels better to play through it as such. It can get deep here. I have to play around with it more but I doubt it would dethrone your XD unless you use an expression pedal all the time, which I still have to test out properly.
[EDIT: 2-pole static filtering on the PX-101 is very, very nice with the OC-2/Brown Dog in front. Very beefy with low-end retention, clarity and warmth. The Meatball gets close but no cigar and I don't thing the XD will be able to match it here either.]

Basically, take all my previous peeves and throw them out the window and chalk it up to lack of time spent with the pedal in the mix. Separate Attack and Decay speeds would be nice but there are some ways around it and it is not a deal breaker by any stretch. The PX101 pedal achieves synthdom in spades.

 

[sloppy_phil]

Definitely sounding synthy! Nice work and nice playing @Charlie Tuna. The tone you've got dialled up definitely reminds me of some late-70's P-Funk.

 

[Charlie Tuna]

Definitely sounding synthy! Nice work and nice playing @Charlie Tuna. The tone you've got dialled up definitely reminds me of some late-70's P-Funk.

Thanks Phil, I'll take it! It's definitely a tone on the verge of wet farts but that's the funk, right? I don't have an expression pedal right now so I can't check the sweep for you but really, at the current price it is well worth it.

 

[sunbeast]

-- I am taking back my previous comments about the PX101 not serving well in an Octave-Fuzz chain without an expression pedal. I sinned and was not testing it in a mix and ask for forgiveness lol. It is thick and it slays. It's so thick I will have to adjust my playing more and work on my timing a lot more. And I have to still get used to the sensitivity and am coming to realize a little change goes a long way. Anyway, headphones will sound best, I used DT770 Pro 80 ohms. Mistakes aplenty but I tried to incorporate different note durations and runs yada yada. \

Quick recording attached with backing track by:

Jam'in Backing Tracks

For educational purposes only.

The envelope character of the Moog is not my favorite and lacks some of the quirkier funky sweeps of many others, but the filter character is my favorite of all the low-pass filters I’ve tried for synthy stuff. I’d love to have the tweakability of the Agent 00 Funk envelope with the filter tone of the Moog (though the filter of the Chunk is great too in its own way!).

Have you messed around with the internal sensitivity trimmer? I did briefly when trying to diagnose the noise issue and it is pretty useful at allowing a full envelope sweep without having to crank the Gain up (something that the Moog has issues with- I pretty much have to crank the Gain to get a wide sweep, which on the Moog is potentially problematic because the Drive is active even when the pedal is bypassed!). I’ll need to play around more with the internal trimmer myself when my potential replacement shows up (the current one is too noisy with the sensitivity cranked up at all), though I almost wish it were an external control

 

[Charlie Tuna]

The envelope character of the Moog is not my favorite and lacks some of the quirkier funky sweeps of many others, but the filter character is my favorite of all the low-pass filters I’ve tried for synthy stuff. I’d love to have the tweakability of the Agent 00 Funk envelope with the filter tone of the Moog (though the filter of the Chunk is great too in its own way!).

Have you messed around with the internal sensitivity trimmer? I did briefly when trying to diagnose the noise issue and it is pretty useful at allowing a full envelope sweep without having to crank the Gain up (something that the Moog has issues with- I pretty much have to crank the Gain to get a wide sweep, which on the Moog is potentially problematic because the Drive is active even when the pedal is bypassed!). I’ll need to play around more with the internal trimmer myself when my potential replacement shows up (the current one is too noisy with the sensitivity cranked up at all), though I almost wish it were an external control

Your first paragraph mirrors my thoughts. I have two other envelope filters that aren't going anywhere: an FTelettronica Meatball clone and...an Agent 00Funk II clone. lol That thing can get spacey and wet. Definitely a fun filter that can get a little out of control. The PX101 is fairly predictable which seems to be more in-line with how a synth keyboard handles in my little experience with them. That's not a bad thing at all.

I messed with the sensitivity trimmer when I first got it but need to have a look at it again now that I have a better understanding of dialing in some tones. I feel like I can get the sweep I want without cranking the gain past noon but I need to explore more and see what I'm missing. Thanks for the reminder! Maybe you can ask PastFX to send an extra backplate if they have one and drill a hole in it until you can configure the trimmer to your liking, then just put the clean backplate on. Not sure how that would affect noise though. Just a thought.

 

[Luke the Fluke]

I am new to envelope filters - well analogue ones, the various zoom and line6 ones down the years and then until recents for years the ones in the C4

The c4 sounded very very good but was clean, having to use a screen to set-up has its positives but for me wasn’t really fun… so in the last few months I sold it and got a Mutron diy kit which I added a release knob too, and the PF101 which arrived a day or so ago …

First thoughts… mutron clone is bright funky and a bit dirty. pF101 can just do so much and has a warm musicality to it - I kept coming up with very usable things I could use live.
Still learning the controls - how would you explain that inside trim pot does to the sound? Does it set where the seeep stops?

 

[OhulahanBass]

Still learning the controls - how would you explain that inside trim pot does to the sound? Does it set where the seeep stops?

Sensitivity effects how sensitive the envelope is to your signal, if you increase sensitivity you should get more depth/travel from your envelope’s sweep without increase your input volume. So if you have a weak/low volume signal and it isn’t triggering enough travel in your envelope sweep turning the sensitivity will help that.

I like to set sensitivity so when I play soft it doesn’t open all the way but when I dig in it sweeps to the tip top. I also like having sensitivity at the top so I can tailor to the input signal, it seems on this pedal drive helps in that department which might be why Moog thought it redundant.

Disclaimer, I don’t own this pedal…yet.

 

[sunbeast]

I am new to envelope filters - well analogue ones, the various zoom and line6 ones down the years and then until recents for years the ones in the C4

The c4 sounded very very good but was clean, having to use a screen to set-up has its positives but for me wasn’t really fun… so in the last few months I sold it and got a Mutron diy kit which I added a release knob too, and the PF101 which arrived a day or so ago …

First thoughts… mutron clone is bright funky and a bit dirty. pF101 can just do so much and has a warm musicality to it - I kept coming up with very usable things I could use live.
Still learning the controls - how would you explain that inside trim pot does to the sound? Does it set where the seeep stops?

There are two trims inside I believe- I’ve only fiddled with the Sensitivity one, while the other seems to work in tandem with the Frequency. The Sens control as mentioned above when turned up allows you to trigger the envelope when you play more lightly. The Drive control essentially does the same, except that the Drive also adds some clipping/distortion/compression when turned up. So if you want to get the widest possible clean sweep with potentially a lot of dynamic volume spikes turn the Sensitivity up, if you want more saturated tone and less dynamic volume spikes then turn up the Drive instead. The original Moog only had the Drive control and so triggering a full sweep usually required dialing in some grit and compression as well- this new internal trimmer on the PX101 allows you to get a more clean full sweep if you want (or you can use a bit of both to find a balance)

 

[Charlie Tuna]

Excellent explanation and tips @sunbeast

 

[Funkinthetrunk]

Always and forever friend! Got anything new you suggest? I bet you have a few more pedals and basses since the last time we we had a chat.

I’ve been off on synth pedals, they never track or sound as good or satisfying as my synths. Fuzz into a juicy filter or phaser is always awesome though.

PM'd

 

[rowandg]

There's a new version btw, with a selectable true bypass option.

 

[sunbeast]

Did the empress get fixed without any other compromise to tone/audio quality?

I'd been holding off getting one of these waiting for a few more reviews A/B ing it with a Moog - Which have been provided in the last page or two.

However I might hold of a little longer if the crackle can be removed in a new iteration.

Did you ever get a response, sunbeast?

So I wanted to update about the noise issue I was experiencing with my PX101.

Verlie (PastFX guy) and I went back and forth on Instagram messages for awhile trying to see if he could recreate the issue with one of his pedals in Australia and he wasn’t able to. So he sent me one of his new updated pedals (it doesn’t sound like that had anything to do with the difference, just that’s what he had to send) and even sent a snazzy limited white version at my choice (always liked those white Moog versions).
The replacement has no noise issues whatsoever, even with the volume cranked to unreasonable settings, so I can confidently assume my original pedal was a fluke!

Wanted to update for everyone- my issue was resolved and Verlie from PastFX went to great lengths to make sure I was happy! I just saw a Moog CP-251 clone teaser of his on Instagram so I think I’ll probably have a few PastFX pedals on my board in the future!

I’ll see if a mod can add my resolution to my original post about the noise as I hate potentially dissuading people from picking one up

 

[rowandg]

So I wanted to update about the noise issue I was experiencing with my PX101.

Verlie (PastFX guy) and I went back and forth on Instagram messages for awhile trying to see if he could recreate the issue with one of his pedals in Australia and he wasn’t able to. So he sent me one of his new updated pedals (it doesn’t sound like that had anything to do with the difference, just that’s what he had to send) and even sent a snazzy limited white version at my choice (always liked those white Moog versions).
The replacement has no noise issues whatsoever, even with the volume cranked to unreasonable settings, so I can confidently assume my original pedal was a fluke!

Wanted to update for everyone- my issue was resolved and Verlie from PastFX went to great lengths to make sure I was happy! I just saw a Moog CP-251 clone teaser of his on Instagram so I think I’ll probably have a few PastFX pedals on my board in the future!

I’ll see if a mod can add my resolution to my original post about the noise as I hate potentially dissuading people from picking one up

I also recieved a second one (not the updated version) and still have the same noise issue.

All that was added is a true bypass switch, right? So did this one fix it in both positions?

 

[sunbeast]

I also recieved a second one (not the updated version) and still have the same noise issue.

All that was added is a true bypass switch, right? So did this one fix it in both positions?

Good question- I haven’t tried the switch yet. My understanding is that the switch just allows you to keep the Gain circuit even on your bypassed tone (the way the original Moog worked), but I might be wrong about that- in other words, the original PX101 is already True Bypass while the update allows you to always have your clean tone go through the Gain circuitry (which is a love or hate aspect of the Moog MF101). I don’t think it should have anything to do with the noise though. I’ll check to be sure after work this afternoon

 

[Luke the Fluke]

so update from me and a week or so of owning it... it's been crazy busy so it's literally grabbing 4 min here and there on work breaks (perk of working from home!)

So - I've got the LED noise issue. Which is annoying, I think it's mainly the drive one. I have had similar with some other pedals I've made so it's not unusual - but

Generally if we ignore the LED noise it's quiet and makes the whole instrument sound fat and warm and a bit compressed.
As a filter It's harder to get to sound "funky" than my mutron clone, but the sound seems to be so much more organically attached to the instrument, its super responsive and you can turn down the resonance and just get this amazing envelope shaper, not as a funky effect but as a tone shaper - there's been a few times where I've been playing and not realised I've had it on in a subtle setting, and it just sounds good.
It prefers richer sounding basses to thinner, (eg the Bartolini equipped Lakland 55-91 vs sadowsky metro will lee), doesn't love drive/fuzz infront of it but sounds great with modulation or reverb after it.
But the nicest thing is it just feels like an extension of your bass, it's simple to use (I sold my SA C4 synth to buy) and it makes me play new things and play musically - which in all things is the aim!

 

[bassboysam]

mine has the LED noise issue too, but in a band mix it's not an issue

 

[johnk_10]

mine has the LED noise issue too, but in a band mix it's not an issue

hmm. i don't hear any noise whatsoever from the led on mine.

 

[stambroker]

So I wanted to update about the noise issue I was experiencing with my PX101.

Verlie (PastFX guy) and I went back and forth on Instagram messages for awhile trying to see if he could recreate the issue with one of his pedals in Australia and he wasn’t able to. So he sent me one of his new updated pedals (it doesn’t sound like that had anything to do with the difference, just that’s what he had to send) and even sent a snazzy limited white version at my choice (always liked those white Moog versions).
The replacement has no noise issues whatsoever, even with the volume cranked to unreasonable settings, so I can confidently assume my original pedal was a fluke!

Wanted to update for everyone- my issue was resolved and Verlie from PastFX went to great lengths to make sure I was happy! I just saw a Moog CP-251 clone teaser of his on Instagram so I think I’ll probably have a few PastFX pedals on my board in the future!

I’ll see if a mod can add my resolution to my original post about the noise as I hate potentially dissuading people from picking one up

This is an awesome story on his customer service and confidence in the product and has definitely convinced me to look at the CP-251 he cooks up. I want one for my MF-101 and I'm assuming any clone will allow the same CV messages.

 

[sunbeast]

hmm. i don't hear any noise whatsoever from the led on mine.

Try Mix to 100%, Amount all the way down, Gain up enough to get red light engaging when digging in, then turn the Frequency knob down to get a dubby signal and turn up the Volume to match unity gain when bypassed. The subby fixed filter setting made it easy to hear the LED noise on my first one (though it was there all the time on top of the filtered signal)- there is a Velcro-like high-frequency scratch every time the Gain LED changes color states. It may not affect every one, my new release one doesn’t have it.

mine has the LED noise issue too, but in a band mix it's not an issue

Yeah I probably would have been happy with mine as it was too, but I have been doing some dubby recording stuff with just drums and bass and using fixed-filter sounds where the noise would have really bothered me. I was happy the replacement seems to have solved the issue completely for me!

 

[sunbeast]

so update from me and a week or so of owning it... it's been crazy busy so it's literally grabbing 4 min here and there on work breaks (perk of working from home!)

So - I've got the LED noise issue. Which is annoying, I think it's mainly the drive one. I have had similar with some other pedals I've made so it's not unusual - but

Generally if we ignore the LED noise it's quiet and makes the whole instrument sound fat and warm and a bit compressed.
As a filter It's harder to get to sound "funky" than my mutron clone, but the sound seems to be so much more organically attached to the instrument, its super responsive and you can turn down the resonance and just get this amazing envelope shaper, not as a funky effect but as a tone shaper - there's been a few times where I've been playing and not realised I've had it on in a subtle setting, and it just sounds good.
It prefers richer sounding basses to thinner, (eg the Bartolini equipped Lakland 55-91 vs sadowsky metro will lee), doesn't love drive/fuzz infront of it but sounds great with modulation or reverb after it.
But the nicest thing is it just feels like an extension of your bass, it's simple to use (I sold my SA C4 synth to buy) and it makes me play new things and play musically - which in all things is the aim!

Yeah when I’ve done some jams with my Moog MF101 I’ll often have it set for a very subtle envelope sweep and just taking advantage of the Drive and a little touch-sensitive movement and you’d be hard-pressed to tell it was a filter effect at all. The PastFX version makes this even easier to accomplish due to the Volume control.