Phase II (Mu-Tron Phasor II)

MichaelW

Well-known member
Build Rating
5.00 star(s)
I have very little experience with phase shifters. I owned an MXR Phase 90 in high school and that was more decades ago than I care to count, hahah.

I had no idea what to expect with the Phase II. I mainly built it because @fig built it and I thought his looked real purty.
Also @Betty Wont says it's the coolest Phasor on the planet (or something like that) so I decided to try it.

The project got delayed a couple of times due to not having all the parts I needed. I originally was planning to use GL5516's then at the last minute decided to order the KE-10720's from Tayda so that was the first delay. Then I planned to build it with 1/4 watt resistors standing up until I went to go pull the parts for the build and looked a little closer at the board and decided "naahhhhh". So I ordered 1/8 watt resistors....sigh....another delay.

Finally had a couple hours today to concentrate on the build and got it all together. Fired it up and it sounded like it was farting.
I DM'd @fig and asked "Does yours fart?". He said "Most certainly NOT, mine is a real lady......."

Anyway, turns out I pulled a dumbass move. Won't be my last I'm sure...heh, I had installed the TC1044 in upside down. Flipped it around and getting real nice phasey sounds. Still messing around with the trimmers, I'm not exactly sure what they do. One seems to control the brightness of the LED but I'm not sure what exactly that does to the sound. I can't tell what the other trimmer does. Frustrating that you adjust until it sounds good, them put the cover on and the the sound changes. I think I got it pretty close to a clean phasing without the weird artifacts from having the LED trim too high (after many tries with the back cover one and off)

I'll probably play around with the trimmers a bit more tomorrow but this is a pretty cool phase shifter. Doesn't sound anything like the MXR Phase 90 as I remember it. (I have the XC board coming to build that one).

Also my first time using 1/8 watt resistors. Part of the reason I wanted to build this board was to get some experience with the little suckers before trying an even more complex build with them.

This thing takes a LOT of TL072's...and 4k7 resistors....holy moly.

Anyway, really digging it, especially with some gain. I have a part shaping up in my mind for an upcoming "Shut Up and Play Your Guitar" episode.

As I was building this I was also following the responses to my "How do you clean your PCB" thread.
I incorporated some of the ideas in that thread while building this board, so thanks guys!
(And no, I did not try @Mentaltossflycoon's rock tumbler suggestion).
Mainly the use of compressed air to dry off the board after brushing. I think it came out pretty clean.

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I completely forgot about running the input signal wire on the other side of the enclosure, but mine isn't exhibiting any of the ticking so I think I'm going to leave the wiring as is. The only sub I made was a 2N5088 for the 2N4401 the BOM called for.

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Deperduci

Well-known member
niiiiiice, the mutron is wicked, I have 1 from the other guy uses 8 instead of 6 leds, but that last spot is almost tremelo territoryand uses a sideways bb instead of the tidy 125. if it doesn't have artefacts, leave the trimmers as set. when you get that jazz bass, run it through a flanger then this, it'll be your own 50's scifi villain soundtrack ;)
 

Dan0h

Well-known member
You inadvertently made the coveted Fart pedal, and then fixed it. Kudos, I have yet to brave this build.
 

Robert

Reverse Engineer
Staff member
One trimpot controls the amplitude of the sweep, the other controls the midpoint.

Adjust them in a dark room. I shoot for the largest smooth transition from light to dark without completely bottoming out at fully bright or full dark.
 

MichaelW

Well-known member
One trimpot controls the amplitude of the sweep, the other controls the midpoint.

Adjust them in a dark room. I shoot for the largest smooth transition from light to dark without completely bottoming out at fully bright or full dark.
Not sure I'm understanding this. "Light to dark transition" of the LED? or the sound?
 
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Robert

Reverse Engineer
Staff member
The LED. You're shooting for the widest possible smooth transition without any "flat" spots where the brightness isn't changing.
 

Robert

Reverse Engineer
Staff member
ok finding a "dark room" is going to be tricky in this house......heh

It's not really necessary if you're adjusting visually by watching the LED.

You just won't be able to hear your changes as you adjust since the room light will affect the LDRs.
 

MichaelW

Well-known member
Ok I think I got it. I adjusted the LED to where it had the widest low to high brightness in the sweep without completely going off.
Then I adjusted the mid point to just when it stops "warbling" and gives me a clean phase.

Wow, this thing really sounds interesting at the extreme ends of the depth range. I'd probably never use it this way but it sounds cool!
 

MichaelW

Well-known member
Love it! I've built tons of these. I don't ever touch the trimmers. If you use the suggested led and lrds, it should be perfectly calibrated with the trimmers at noon. They are there to accomodate alternate led/ldr combos. The Nu-tron that this is based on was the same.
You know, it's pretty funny, after all that messing with the trimmers, I'm looking at them and they're right about..........noon. HAH!
 

Deperduci

Well-known member
think mine was set at between 11 and 12 and othe a bump towards 1, I used an orange/highway lines yellow instead of lemonish yellow led.
 

MichaelW

Well-known member
I built the Phase II (in the Pines at Mar Gables) a few months ago. It truly is the best phaser. A Bi-Phase is two Phase II. What’s better than one great phaser pedal?…
I'm trying to imagine how a dual phasor will sound. Do you have any sound clips? Thanks dude!
 
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