XC Phase Modifications Thread

Big Monk

Well-known member
Inspired by my studies over the last few days and the recently posted @caiofilipini XC Phase build, I thought maybe a repository of the many known Phase 45/90 mods might be in order.

Let's list them and see what we can add/subtract/clarify:

1.) Intensity/Depth Control
2.) Rate LED
3.) "Resonance"/Feedback Control
4.) Volume Control
5.) Dry/Wet Mix Control
6.) Univibe/Warble Mods
7.) Expression Mod (Speed)
8.) Lower/Upper Limit Speed Trims
9.) Phase 45/90 Switch*
10.) Script/Block Switch*
11.) Slow/Long Cycle Mod

*Already accounted for in the XC Phase

My plan is to incorporate many of these into an Orange 1590BB. I have not started planning yet but will likely do this in tandem with my Hydra build.

Let's talk about it!
 
On top of the dry/wet mix control, you can always just do a dry kill switch if you don’t think you’ll ever use a 70/30 mix or any like that to warrant the additional space for a pot, and that’ll give you something relatively similar sounding to a magnavibe.

I’ll post my planned layout for my Modded XC later on or tomorrow (seeing Todd Rundgren tonight, so I might not have time today before I leave)
 
In a BB there’s probably enough room to add a modified take on RG keen’s easyvibe speed ramping method by eliminating the LFO portion of his circuit and just using it to control the resistance where the speed pot would be
 
Having been down this road before myself, I have tried to incorporate some of the mods above but ultimately went back to the stock pedal. The most useful mods are incorporated into the pcb already. A blend may be useful to some but this isn't an overpowering effect to begin with. You could ditch the script switch and make a depth pot. Some mods may require an external bias pot to change bias of the jfets like in the Univibe mod. I think the one I would like the most is the fast/slow mod.

The list was really a conversation starter.

In addition to the stock pedal, I like the idea of the following:

1.) Intensity/Depth
2.) Resonance/Feedback
3.) Univibe Mods
 
Having been down this road before myself, I have tried to incorporate some of the mods above but ultimately went back to the stock pedal. The most useful mods are incorporated into the pcb already.
as far as guitar goes, I wholeheartedly agree. I have an MXR variphase, which has the depth control (the 1M pot off of the wiper of the bias trimmer) and it’s extremely subtle. The mix knob is mildly useful, but frankly a switch to go from 50/50 to 100% wet is more useful. I’m only doing those two mods on mine because I’m planning on using this one for keys, and the full frequency range of a 6-octave keyboard is where these mods really become useful. If this was for guitar I’d just build it with the two switches that are already on the PCB, and leave the rest ‘stock’.

The univibe mod is cool on guitar, but takes up a lot of space unless you only do it to the first two stages, in which case it’ll only really be the “univibe mod” in the 45 mode, and it’ll only make a marginal difference in 90 mode. Still potentially worthwhile, but ymmv.
 
A simple slow phase without any mods sounds immense. I’m again fan boyin’ over Tommy B here but it feels appropriate to leave this here -


I always figured that I would want a mix knob on a phase 90 but i am sold on just a slow phase.

It would be cool to hear the effect of that mix mod if you do go for it @Big Monk

Also @Big Monk - you definitely need to do the univibe mod so you can have three univibe pedals on your board 🤣 I don’t think you’ll be able to choose between the electrovibe and good vibes!
 
A simple slow phase without any mods sounds immense. I’m again fan boyin’ over Tommy B here but it feels appropriate to leave this here -


I always figured that I would want a mix knob on a phase 90 but i am sold on just a slow phase.

It would be cool to hear the effect of that mix mod if you do go for it @Big Monk

Also @Big Monk - you definitely need to do the univibe mod so you can have three univibe pedals on your board 🤣 I don’t think you’ll be able to choose between the electrovibe and good vibes!

Funny you say that. I’m starting to sour on the Good Vibes. It seems impossibly bright now and the overlap with the Electrovibe is easily served by my Script Phase 90.

What would be really great would be a Super Phase 90/45 that had decent enough Univibe tones to kick all three off my board!

Just need to find these FETs now!
 
A simple slow phase without any mods sounds immense. I’m again fan boyin’ over Tommy B here but it feels appropriate to leave this here -


I always figured that I would want a mix knob on a phase 90 but i am sold on just a slow phase.

You could use the Trimit! and put the resistor that sets the lower threshold of speed on that.
 
Thanks. I just placed a Tayda order for an enclosure for my build and am definitely gonna do this mod before it shows up.

I guess it would depend on whether the rate control is faster or slower at its max resistance.

Does slow speed correspond with zero resistance on the pot? If so, then lowering R26 should lower the floor for slow speed.

I guess. I’m new to building modulation pedals so I may not be the best person to ask.
 
The univibe mod is cool on guitar, but takes up a lot of space unless you only do it to the first two stages, in which case it’ll only really be the “univibe mod” in the 45 mode, and it’ll only make a marginal difference in 90 mode. Still potentially worthwhile, but ymmv.

Well, I’m scheming on that in my head now. I see a 4PDT switch and a custom breakout board for it the hold 8 caps. This will involve flying leads, 8 to be exact, but will allow footswitchable univibe mode in both 45 and 90 mode.
 
J113 should be workable, but may require some modifications. People have used them and documented their experience on other forums.
 
J113 should be workable, but may require some modifications. People have used them and documented their experience on other forums.

My goal is to breadboard and tweak before going the PCB route anyway. The J113 had Vgs values right on the money for the 2N5952 and 2N5457 sheets that I looked up.

I figured 30 was enough to get a good quartet!

EDIT - I did some searching over at DIYSB and marked down some posts detailing tweaks to accommodate different JFETs here. Thanks again @benny_profane
 
Last edited:
Back
Top