MichaelW
Well-known member
- Build Rating
- 5.00 star(s)
Ok, here we go again......on another roll with compressors!
I'm also waiting for @Robert to get the Uber-Squeezer boards in. (Actually I don't think thats what it's called but its the PPCB of the MXR SuperComp
)
The Aion Meridian is another compressor that I never got around to building, mostly because I wasn't all that interested in the "exciter" aspect.
But after reading the build docs a little closer the exciter is easily defeated by leaving the control at noon.
Anyway, this circuit can basically be viewed as 3 separate circuits. At the front end is an almost direct copy of a Dyna Comp compressor circuit with the exception of converting the use of a 3080 IC into a LM13700. (Which is essentially 2x 3080's. And incidentally, the best price I've found for the LM13700 is right here.
Stupid cheap and I've been throwing a couple onto each order.)
The second section of the circuit is the "exciter" which is similar to the BBE Sonic Stomp. At noon it's neutral, CW adds even order harmonics and CCW adds odd order harmonics. It's rather subtle but the effect is magnified under gain. So I can see dialing up a gain tone and fine tuning it with this control.
The 3rd and probably most USEFUL section is a BMP style tone stack in a single "Tilt" style knob just like on a Muff.
All 3 of these sections work remarkably well together and it feels and sounds well integrated as opposed to "tacked together".
I went "commando" with this build and used a "raw" enclosure. With the tariffs lately, I have to be more careful with what I order from Tayda and when I'm in between cycles of my "retired hobby budget" I've been grabbing raw enclosures off Amazon in a pinch.
And oh by the way, if you plan on building this board, make sure to get some of the "small footprint WIMA 1uf caps". Or you can use poly caps or greenies and just leave the legs long. The default footprint for the 1uf film is pretty skinny. I wouldn't have any problem using C0G 1uf caps or even XR7 MLCC's either, but I just got a buttload of the skinny WIMA's so thats what I used.
So I have to say, again, like my Creamery Compressor build I really wasn't expecting much from this except to add to my collection of compressors.
But holy crap AGAIN, it sounds REALLY good! This is another pedal that I think bass players will really dig. (You can also build the PS-020 Bass version on this board with like 5 component changes).
Built stock, the compressor circuit is more laid back and acts more as a limiter. But there's a "more sustain" mod which is a single resistor and a pot change which I did.
My initial impression is that "this sounds like a really really really clean and quiet Dyna Comp". It's got that Dyna Comp sound and feel. Even the Level and Sustain knobs work like a bone stock Dyna Comp. (E.g., you can set the knobs at 3 o'clock level and 9 o'clock sustain for the "Nashville session player setting" and it sounds spot on).
The addition of the "Color" knob, (tone control) really lets you dial in the tone of the compressor which you can't do on a Dyna Comp.
The Exciter knob I've messed with a little and tbh, I don't really know how to use it. For now it's staying at noon, or inactive.
The overall tone of the pedal is big and full and (can be made) warm and musical. With the "more sustain' mod it's got a TON of compression on tap.
But I've got it dialed back quite a bit and it's a lovely "always on" pedal. Unlike the Dyna Comp and most of the other Dyna/Ross style compressors I've built, this pedal has a nice, big, rich and full soundstage, just like my General Tso and the Creamery. It has kicked off my Median compressor (Wampler Ego76) off my compressor board for now and it's taken a place as one of 4 compressors I have hooked up at the beginning of my chain. I do have a Dyna Comp build that is pretty stock but it's SOOOOO incredibly noisy and susceptible to power issues that I have to put on my floor pedal board away from everything else so it won't "chitter" at me when I turn it on. But NO MORE! I can get that Dyna Comp sound now thats as quiet as my other compressors. That makes me feel all warm and fuzzy
I've been on a quest to build an "as vintage accurate as possible" MXR Dyna Comp. I even snagged a Metal Can 3080 and there's a dude on Etsy/Reverb that sells vintage layout Dyna Comp boards. But now I'm kind of wondering....why? Heh, I'll probably still build it but in the meantime the PS-021 fills that gap extremely well!
Another HIGHLY RECOMMENDED build for compressor users. Especially if you're a Dyna Comp user struggling with the inherent noise floor of the MXR.
I'm also waiting for @Robert to get the Uber-Squeezer boards in. (Actually I don't think thats what it's called but its the PPCB of the MXR SuperComp

The Aion Meridian is another compressor that I never got around to building, mostly because I wasn't all that interested in the "exciter" aspect.
But after reading the build docs a little closer the exciter is easily defeated by leaving the control at noon.
Anyway, this circuit can basically be viewed as 3 separate circuits. At the front end is an almost direct copy of a Dyna Comp compressor circuit with the exception of converting the use of a 3080 IC into a LM13700. (Which is essentially 2x 3080's. And incidentally, the best price I've found for the LM13700 is right here.
Stupid cheap and I've been throwing a couple onto each order.)
The second section of the circuit is the "exciter" which is similar to the BBE Sonic Stomp. At noon it's neutral, CW adds even order harmonics and CCW adds odd order harmonics. It's rather subtle but the effect is magnified under gain. So I can see dialing up a gain tone and fine tuning it with this control.
The 3rd and probably most USEFUL section is a BMP style tone stack in a single "Tilt" style knob just like on a Muff.
All 3 of these sections work remarkably well together and it feels and sounds well integrated as opposed to "tacked together".
I went "commando" with this build and used a "raw" enclosure. With the tariffs lately, I have to be more careful with what I order from Tayda and when I'm in between cycles of my "retired hobby budget" I've been grabbing raw enclosures off Amazon in a pinch.
And oh by the way, if you plan on building this board, make sure to get some of the "small footprint WIMA 1uf caps". Or you can use poly caps or greenies and just leave the legs long. The default footprint for the 1uf film is pretty skinny. I wouldn't have any problem using C0G 1uf caps or even XR7 MLCC's either, but I just got a buttload of the skinny WIMA's so thats what I used.


So I have to say, again, like my Creamery Compressor build I really wasn't expecting much from this except to add to my collection of compressors.
But holy crap AGAIN, it sounds REALLY good! This is another pedal that I think bass players will really dig. (You can also build the PS-020 Bass version on this board with like 5 component changes).
Built stock, the compressor circuit is more laid back and acts more as a limiter. But there's a "more sustain" mod which is a single resistor and a pot change which I did.
My initial impression is that "this sounds like a really really really clean and quiet Dyna Comp". It's got that Dyna Comp sound and feel. Even the Level and Sustain knobs work like a bone stock Dyna Comp. (E.g., you can set the knobs at 3 o'clock level and 9 o'clock sustain for the "Nashville session player setting" and it sounds spot on).
The addition of the "Color" knob, (tone control) really lets you dial in the tone of the compressor which you can't do on a Dyna Comp.
The Exciter knob I've messed with a little and tbh, I don't really know how to use it. For now it's staying at noon, or inactive.
The overall tone of the pedal is big and full and (can be made) warm and musical. With the "more sustain' mod it's got a TON of compression on tap.
But I've got it dialed back quite a bit and it's a lovely "always on" pedal. Unlike the Dyna Comp and most of the other Dyna/Ross style compressors I've built, this pedal has a nice, big, rich and full soundstage, just like my General Tso and the Creamery. It has kicked off my Median compressor (Wampler Ego76) off my compressor board for now and it's taken a place as one of 4 compressors I have hooked up at the beginning of my chain. I do have a Dyna Comp build that is pretty stock but it's SOOOOO incredibly noisy and susceptible to power issues that I have to put on my floor pedal board away from everything else so it won't "chitter" at me when I turn it on. But NO MORE! I can get that Dyna Comp sound now thats as quiet as my other compressors. That makes me feel all warm and fuzzy

I've been on a quest to build an "as vintage accurate as possible" MXR Dyna Comp. I even snagged a Metal Can 3080 and there's a dude on Etsy/Reverb that sells vintage layout Dyna Comp boards. But now I'm kind of wondering....why? Heh, I'll probably still build it but in the meantime the PS-021 fills that gap extremely well!
Another HIGHLY RECOMMENDED build for compressor users. Especially if you're a Dyna Comp user struggling with the inherent noise floor of the MXR.