gtfields13
Well-known member
- Build Rating
Although I haven't cased this, I wanted to post my build report on the Byzantium Flanger so I can share some details on how I tuned this PCB. Stay tuned for a Phido Sound name and case...
There isn't a build guide for this PCB (Hi, @Robert ), but maybe this is a good thing, since the BF is likely a project that is better intended for those who have built enough and understand component selection well enough that they can build without one.
I needed to purchase a handful of components to accommodate the 7mm height. There is a link of recommendations by PPCB, but some of the capacitors in that list are obsolete. I am sharing a Mouser/Cart for the items I used, but I just noticed that even the 100µF electrolytics that I purchased in December are backordered until June. So a new builder is still going to need to find some 7mm 100 µF on their own.
I didn't follow these instructions exactly, but they steered my in the correct direction. Here is what I did:
I did find a point of difference between the two pedals (beyond the stereo out for the SFL-1). With modest and low resonance, the BF and the SFL-1 can be made to sound indistinguishable. But as the resonance is increased the sounds become distinct. I am going to guess (since I am not knowledgeable enough, yet) that there is a difference in the feedback circuit's filter in the two pedals which affects the width or shape of the resonance. I don't know how to technically describe the difference, but I would say that the Arion filter's resonance is a vocal "ow" sound or formant - a bit more like filter on a wah pedal. The BF-2 seems less distinctive and just more like a peaky filter.
Given my log of projects to move into cases, I don't think I'll have this one in a pretty case for a while, but at least I do have a 4-knob generic case on order from Tayda right now.
Build
This was the last of the PCBs I bought in my summer 2025 purchasing spree, I save this double-layer project until I had worked through enough other projects that I was sure I could do a good job on the solder work.There isn't a build guide for this PCB (Hi, @Robert ), but maybe this is a good thing, since the BF is likely a project that is better intended for those who have built enough and understand component selection well enough that they can build without one.
I needed to purchase a handful of components to accommodate the 7mm height. There is a link of recommendations by PPCB, but some of the capacitors in that list are obsolete. I am sharing a Mouser/Cart for the items I used, but I just noticed that even the 100µF electrolytics that I purchased in December are backordered until June. So a new builder is still going to need to find some 7mm 100 µF on their own.
- Mouser Project Access ID: 4ee0a59dff
Tuning
I searched forums to see about getting info on how to tune this PCB. As part of a Troubleshooting Post from last September (@mkultra69 Sep 25), @owlexifry pointed to a guide for the original BF-2 that provides some basic instructions. (Boss BF-2 Schematic)I didn't follow these instructions exactly, but they steered my in the correct direction. Here is what I did:
- (identical to link) Set Manual and Depth full CCW, using oscilloscope at TP 1 adjust the CLOCK trim pot until the frequency was 40kHz. I noted that when Manual is turned full CW, the frequency increases to 640kHz. This is a bit lower time than in the BF-2 reference, but spans the desired range
- (different) Set Depth and Resonance full CCW. I fed a 200Hz 2Vpp signal to the input and connected my oscilloscope to the output. I adjusted he BIAS trim pot for maximum amplitude. The output is generally pretty flat until you get to the correct bias point where it jumps up maybe 20-40% over a narrow range.
- (slightly different) Set Manual and Depth full CCW and Resonance full CW. Jumpered the input to ground, and connected oscilloscope to the output. I started with RES trim pot fully CCW and turned it until oscillation appeared in the output signal, then backed down a bit. The oscillation shows hysteresis (i.e. it doesn't stop oscillating when you back it down slightly) so I had to make note of trimmer position, reset to full CCW and come back to the set point.
Sound
First. The BF definitely flanges. I think the controls are suitable - you can go from subtle to just the start useless resonant noise, with pretty much the entire control ranges leading to meaningful and musical variation. For once, I also have a pedal against which I can compare this build, my 40-yr old (!) Arion Stereo Flanger (SF-1).I did find a point of difference between the two pedals (beyond the stereo out for the SFL-1). With modest and low resonance, the BF and the SFL-1 can be made to sound indistinguishable. But as the resonance is increased the sounds become distinct. I am going to guess (since I am not knowledgeable enough, yet) that there is a difference in the feedback circuit's filter in the two pedals which affects the width or shape of the resonance. I don't know how to technically describe the difference, but I would say that the Arion filter's resonance is a vocal "ow" sound or formant - a bit more like filter on a wah pedal. The BF-2 seems less distinctive and just more like a peaky filter.
Given my log of projects to move into cases, I don't think I'll have this one in a pretty case for a while, but at least I do have a 4-knob generic case on order from Tayda right now.
