MichaelW
Well-known member
- Build Rating
So in my last "2 Compressor Builds" thread I mentioned that the General Tso's (Thorpy Fat General) was going to be my last DIY compressor build until a Cali76 project somehow made it's way to existence.
I "sorta" kept to my word.....even though this is a 2 Compressor build report
I was ordering some MMBF5457's from the AionFX site when I noticed the "Convex Compressor" project and discovered that it's a clone of the pretty rare Dinosaural OTC-201 designed by Dan Coggins. Dan now works as a design engineer for Thorpy and the Fat General is essentially the same circuit with some updates and tweaks. The Convex uses Vactrols and the Tso's uses LDR's, so I thought it would be neat to build both and compare.
Comparing the two schematics it looks like the parallel compression paths are pretty much the same. The Fat General adds a treble control that makes it a bit more flexible. I was chatting in DM with my Chief Pedal Enabler @szukalski and he was saying how the treble control makes it easier to dial in switching between hum buckers and single coils.
These two pedals are the 6th and 7th DIY compressors I've built and I have to say right up front, they are my favorites. (With the MBP Oracle coming in at a close second).
The two pedals sound "nearly" identical which surprised me slightly. I was expecting to hear a bit more difference between the very controlled Vactrols vs the more variables in the LED/LDR combination. (How the LDR is facing, how far from the LED's they are etc). But I guess that doesn't make much of a difference as long as you're "in the ballpark" with the configuration.
Both are very transparent compressors, even more transparent than my "other favorite" compressor the Constrictor. They can both get pretty squishy at max compression settings but not as much as the Cornish OC-1 (AionFX Oceanid) which so far has the most amount of compression on tap for an optical compressor.
Of course compared to a VCA or Ross, all bets are off. The Oracle (Boss CS-3) has the highest amount of compression out of all the compressors I own both DIY and retail.
Playing them side by side I have a very slight preference for the General Tso's. I'm not sure if it's because I'm hearing a slight bit of coloration (in a good way) or what but it sounds a little fuller than the Convex. But it's really splitting hairs, they are so close. If I were forced to choose one to build it would definitely be the Tso's for the treble control. The Convex has toggle for level cut/boost (+/- 3db or flat) whereas the Tso's has a volume pot. (Oddly called "Balance"). They both share the exposed toggle switch to allow you to choose Blend mode or 100% compressed mode. With the way I like to use compressors, the blend mode works the best with about 60-70% blend.
I've heard so many people rave about the General Tso's I'm not sure why I put at the back of my build list. I dunno, maybe because I don't like crappy chinese food and there was a subconscious association going on But I am really stoked about the pedal and it's probably going to be my goto Optical compressor and sit right next to the CS-3 on my mini board.
Smooth build with no major issues except that I only had one green diffused LED so I almost didn't get to box it up this afternoon but Amazon showed up and saved the day! They brought me some 5mm LED's and the Chicken Head knobs I ordered. Love these things! I might get some different colors.
Both of these pedals have buffered outputs and the AionFx Convex has his usual SPDT slider to select between True and Buffered Bypass on the daughterboard. I installed the slider but probably could just as well have hard wired it in Buffered bypass I never touch those. The Buffered ByPass 3pdt wiring boards from PPCB are out of stock so I wired the 3PDT directly. (which looks messy to me but........whacha gonna do? heh)
The Burnt Orange Tayda enclosure I used for the Convex was not their best example. I love the color but this particular one has extra orange peel and the powder coating chipped when I was center punching. Hence the washers on the toggle switches to cover up the chip and the slightly wonky positioning of the status led. I was pretty annoyed at the prospect of wasting an enclosure but was glad to be able to recover gracefully. The Convex uses a TL072 where the Tso's called for an OPA2134, which I used. (I was finally able to score some OPA2134's from amplifiedparts.com, woohoo!)
Off the top of my head the only other differences I recall are 1N4148's in the Tso's and 1N914's in the Convex and a few different cap and resistor values. But remarkably similar builds.
The AionFX Convex (Dinosaural OTC-201)
PedalPCB General Tso's (Thorpy Fat General)
I "sorta" kept to my word.....even though this is a 2 Compressor build report
I was ordering some MMBF5457's from the AionFX site when I noticed the "Convex Compressor" project and discovered that it's a clone of the pretty rare Dinosaural OTC-201 designed by Dan Coggins. Dan now works as a design engineer for Thorpy and the Fat General is essentially the same circuit with some updates and tweaks. The Convex uses Vactrols and the Tso's uses LDR's, so I thought it would be neat to build both and compare.
Comparing the two schematics it looks like the parallel compression paths are pretty much the same. The Fat General adds a treble control that makes it a bit more flexible. I was chatting in DM with my Chief Pedal Enabler @szukalski and he was saying how the treble control makes it easier to dial in switching between hum buckers and single coils.
These two pedals are the 6th and 7th DIY compressors I've built and I have to say right up front, they are my favorites. (With the MBP Oracle coming in at a close second).
The two pedals sound "nearly" identical which surprised me slightly. I was expecting to hear a bit more difference between the very controlled Vactrols vs the more variables in the LED/LDR combination. (How the LDR is facing, how far from the LED's they are etc). But I guess that doesn't make much of a difference as long as you're "in the ballpark" with the configuration.
Both are very transparent compressors, even more transparent than my "other favorite" compressor the Constrictor. They can both get pretty squishy at max compression settings but not as much as the Cornish OC-1 (AionFX Oceanid) which so far has the most amount of compression on tap for an optical compressor.
Of course compared to a VCA or Ross, all bets are off. The Oracle (Boss CS-3) has the highest amount of compression out of all the compressors I own both DIY and retail.
Playing them side by side I have a very slight preference for the General Tso's. I'm not sure if it's because I'm hearing a slight bit of coloration (in a good way) or what but it sounds a little fuller than the Convex. But it's really splitting hairs, they are so close. If I were forced to choose one to build it would definitely be the Tso's for the treble control. The Convex has toggle for level cut/boost (+/- 3db or flat) whereas the Tso's has a volume pot. (Oddly called "Balance"). They both share the exposed toggle switch to allow you to choose Blend mode or 100% compressed mode. With the way I like to use compressors, the blend mode works the best with about 60-70% blend.
I've heard so many people rave about the General Tso's I'm not sure why I put at the back of my build list. I dunno, maybe because I don't like crappy chinese food and there was a subconscious association going on
But I am really stoked about the pedal and it's probably going to be my goto Optical compressor and sit right next to the CS-3 on my mini board. Smooth build with no major issues except that I only had one green diffused LED so I almost didn't get to box it up this afternoon but Amazon showed up and saved the day! They brought me some 5mm LED's and the Chicken Head knobs I ordered. Love these things! I might get some different colors.
Both of these pedals have buffered outputs and the AionFx Convex has his usual SPDT slider to select between True and Buffered Bypass on the daughterboard. I installed the slider but probably could just as well have hard wired it in Buffered bypass I never touch those. The Buffered ByPass 3pdt wiring boards from PPCB are out of stock so I wired the 3PDT directly. (which looks messy to me but........whacha gonna do? heh)
The Burnt Orange Tayda enclosure I used for the Convex was not their best example. I love the color but this particular one has extra orange peel and the powder coating chipped when I was center punching. Hence the washers on the toggle switches to cover up the chip and the slightly wonky positioning of the status led. I was pretty annoyed at the prospect of wasting an enclosure but was glad to be able to recover gracefully. The Convex uses a TL072 where the Tso's called for an OPA2134, which I used. (I was finally able to score some OPA2134's from amplifiedparts.com, woohoo!)
Off the top of my head the only other differences I recall are 1N4148's in the Tso's and 1N914's in the Convex and a few different cap and resistor values. But remarkably similar builds.
The AionFX Convex (Dinosaural OTC-201)
PedalPCB General Tso's (Thorpy Fat General)
