Guardians of the analog
Papi Fuego
This is a passion project of mine that I've wanted to do for years. I used my original pedal from the late 80s as the bench mark and test subject that I took voltages from and checked values. Unfortunately, this project is currently on the back burner and is likely not going to be released any time soon which is a real bummer because we put a lot of effort and time into getting it right. So what is the phabio and what went wrong?
The phabio is a faithful recreation of the boss PH-2 super phaser. The PH-2 is a 12 stage phaser with 8 stages +4 fixed stages. Two modes and a very wide range on all controls. It is OTA based and the pedal uses two IR309 ICs. It is also the first phaser I've seen using a compander much in the same way an analog delay uses one. It's a fairly complex circuit that gives a lush and smooth sound with an LFO that can go from super slow to super fast. At times it can border on cusp of faux flanger territory. So what went wrong?
The pedal uses the proprietary Roland IR3109 chip that was made for use in some Roland synths of the late 70s and 80s. As far as I know, the ph-2 was the only pedal to use this chip. The 3109 is a complex IC that houses 4 ota's as well as dedicated buffers and what not. The chip was EOL in the late 90s. The 3109 was brought back to life by alfa as the as3109. The problem is that the original 3109 never had a data sheet released so when alfa made their version it was an estimated guess based on a circuit diagram in the Roland Juno synth service manual. Plain and simple this chip does not work in the ph-2 circuit. It clips, sounds off and does not give the lush phasing of the original chip. I tried many different component changes on the prototype board but when I put the original ICs in it was perfect. The Alfa chips in the OG boss pedals gave the same disappointment.
So in the end since I already pulled the chips from the boss pedals and put sockets in for testing I decided to box this one up. Keefe did an amazing job with a fantastic layout and no noise, such a shame this is being shelved. I did do the lower noise mods in the service manual as my original pedal had them as it was made after 1987. If you saw my recent workbench thread then you saw the broken ph-2 I pulled ICs from to make another one, the saga continues.
For the enclosure I used a matte black tayda 1590BB2 and UV print. For the phabio theme I went with THOR, the god of margarine. The calibration did require my scope to get the timing right on the phasing. Maybe one day we can revisit this or a newer reissue chip that functions better will be released. Until then this is likely to be only 1 of 2. I tried to get this to y'all but it's gonna be a while longer
