Friday, 16 May 2014

MXR Phase 90 with Script Switch

A few people have requested this so I thought I'd better do it.  This one includes the Script mod on a switch so you can choose either mode.  Don't forget that you really need to match the JFETs for this.  You may get lucky with an unmatched set but the better the match the better the effect, so it's worth a bit of effort.  Use something like a Peak DCA75 if you have one, or this simple build will also allow you to choose the 4 best matches.

Info about the original:
This device has found its way into many of Eddie Van Halen's recordings, adding a shimmery velocity to lead passages or a more dramatic swoosh to muted strumming. Not just for guitars; it works well with bass, keyboards and even vocals. Vary the speed from a subtle, long cycle to a fast, watery warble...and myriad vintage vibrations in between.





[Updated 21st May 2014 - re-jigged to make better use of space but all connections as per the original verified layout]



Modified version with added depth control.  The Depth 1 wire needs to connect in the hole under the link, so it's probably advisable to raise that link slightly to give you room.


95 comments:

  1. Yeeeeeeeeeeeeees! I've seen a million Phase 45 layouts, but the EVH obsession in me needed this! Thanks!

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  2. any chance of a phase 100 layout.

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    1. With 6 ICs and 4 transistors it's something that I would always use a PCB for. I may still do it one day but it's not going to be in the near future any time.

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    2. The idea of a vero Phase 100 is super exciting though. That would be a fun challenge.

      I have a version 2 Small Stone and a Boss PH-1r so I should take it easy on 4 stage phasers. Been curious about the Phase 100 since noticing the guitarist from Wooden Shjips uses one

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  3. Shit, 2N5952, and you need a quad! Sheer unobtainum! Phasers are a real bitch to build, so i'd recommend if someone's interested in the build, to purchase a previously matched quad, as for this kind of builds, the model and the match of the trannies is critical.

    Have just ordered a quad at Musikding (4.50€), will check the build once the order gets here. I still remember getting two quads for the Phazex (2N5457 and BF244) and it was a real pain in the ass :P, never again, and even less with 2N5952, pretty scarce and expensive.

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    1. I think 2N5457 would work fine too. 2N5952 aren't unobtainium though, I've got hundreds :o)

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    2. Lucky you, I have... 4 pieces :P, but no problem, the quad at Musikding is reasonably priced if you think that you'll have not to check about 100 pieces :P.

      Will do some checks with the 2N5457 too when the board is finished.

      J.

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    3. I think I either used 2N5457 or J201 as I have plenty of those. I got a larger batch of J202's too for nuts, I'll try them too at some point I think.

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    4. I've used the Musikding's quad for the pase 90 and it worked as a charme

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  4. Banzaimusic has 2n5952 and a lot other matched jfets and transistors...and good prices to.

    /Mortua

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  5. am build with j201, and bc550, so far so god, and 10uf +4,7uf for 15uf

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    1. I think I went with a 22u cap that actually measured about 17u. I also swapped the 1M resistor going from the trimmer to the gates of the fets to a potmeter, this gives you a nice depth control.

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    2. Thanks for the tip about the depth pot

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  6. Already done one with the sabrotone layout and it fired first shot but I do like the shape of this better, easier to box. I have to say that the script mod is a must. I won't even bother with the stock setting anymore as I really do not like how it sounds. Also I've always found this too bright and thin sounding - I'm more of a small stone guy. I did a few mods to it to make it sound more to my taste. To my shame I really cannot remember all of them (always make notes goddamnit!) but I'm sure that I upped the input cap for a thicker and creamier sound and it made wonders! Also I found that it boosts my amp so I added a master volume trimmer to the end of the circuit and dialed it down a little bit. Overall it's a great build!

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  7. The 2n5087 should also work in place of the 2n4125

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    Replies
    1. Or an easy and cheap to get 2N3906

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  8. Ah, I sold the one I built with tonepads PCB and lately wanted to build another one.
    Mark, would you mind adding a layout with the deep control ?
    It's very usefull and adds a lot of versatility to the phase 90
    http://diy.musikding.de/wp-content/uploads/2013/06/phaserschalt.pdf
    Basically I think it's just the 1M resistor going from the gate of Q1 to the bias trimmer that is splitted in a 500k rev log pot wired as variable resistor in serie with a 470k resistor

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  9. I noticed the pinouts for the 2N5952 was the opposite to the normal arrangement I seem to use for the common JFETs, and so have reversed the JFETs in the layouts. Remember if you use something else like 2N5457, then they will need rotating 180 degrees

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  10. Just finished the normal version (without the depth control) - fired up first try(just had to adjust the trimmer), so this one's verified.
    I also built it as per your layout with no substitutions - Thanks Ivlark!

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    1. Awesome Frank, thanks for verifying! Post a pic if you can please so I can add it to my collection :o)

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    2. Here's a pic:
      http://tinyurl.com/oraaemn

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    3. Excellent, thanks Frank

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    4. A few things look different from the layout. Like the 6th 47n, and the 2N4125 is in a different location, or am I overlooking something?

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    5. I updated it a few weeks ago, but just rejigged things to make a better use of space as per the note under the video. All the connections remain the same though, so if you have an earlier version of the layout that's good as well.

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  11. Hi Mark!
    Looking at Tonepad's schematic, shouldn't Sw1 of the script mod go to pin 6?

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    1. No. I don't follow the opamp channels specified in schematics unless the opamp types are different and used for a reason, because there is no reason to, and the results will be identical. Instead I always use the channels that allow the best flow of the layout. So I used the left hand channel for that part of the circuit. 2 is the inverting input of the left side, 6 is the inverting input of the right side.

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  12. Cool! Thanks!
    Just wanted to double check before I give it a go.

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  13. Replies
    1. They may be ok but you can only try and see. The problem is that the cutoff voltage in the 2N5458 can be higher than in the 2N5952 and so they may need to be more carefully selected.

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  14. ok,about elco 15u, cant i change to 22u. thank before

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    1. It's part of the LFO and so any change may affect the timing. Personally I'd get the correct value unless you just want to socket and test

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  15. I just finished this one (depth knob, script mod) and during the build I found out that the schematic has a fault. There is a 4 point link in line 15 (from left to right) on the second pic of the schematic which is just showing the links and cuts. If you look at the full schematic including all the parts, you can see that this link is in line 16 (from left to right).

    I built the effect based on the full schematic.
    The problem I now have is that the effect is not working. When I turn it on, the signal just gets weaker and there is a repeating noise coming temporally in the background like on - off - on etc.

    What could be the reason for this?

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    1. Thanks for the heads up, I'll correct it. I assume you have altered yours, or put the 150K on the other side of the link?

      If you've corrected yours post all the IC and JFET pin voltages to see if it gives any clues.

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    2. I just used the schematic on the left and took out the link of line 15 after I saw that it was supposed to be in line 16. I did it the same way you just corrected it.

      The voltages are:

      IC (upper)
      1: 8,13 (sometimes 1,51)
      2: 1,66 (sometimes 5,87)
      3: 3,73
      4: 0
      5: 0,72 (sometimes 3,68)
      6: 3,69
      7: 5,87
      8: 9,07

      IC (middle)
      1: 3,73
      2: 3,73
      3: 3,73
      4: 0
      5: 3,73
      6: 3,74
      7: 5,8
      8: 9,07

      IC (lower)
      1: 3,73
      2: 3,74
      3: 2,53
      4: 0
      5: oscillating 3,26 and 3,37
      6: oscillating 3,99 and 4,05
      7: oscillating between 3,77 and 4,27
      8: 9,07

      2N5952 (from left 1)
      D: 3,68
      S: 3,68
      G: 1,40

      2N5952 (from left 2)
      D: 3,73
      S: 3,73
      G: 1,40

      2N5952 (from left 3)
      D: 3,73
      S: 3,73
      G: 1,73

      2N5952 (from left 4)
      D: 3,73
      S: 3,73
      G: 1,40

      2N4125
      C: 0,91
      B: 3,3
      E: 3,73

      I noticed that the voltages on IC1 change and they are not oscillating like on IC3. How can that be?

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    3. Well the obvious thing straight away is pin 1 of the top IC. If that is changing intermittently between 8.13 and 1.51V then it makes me very suspicious of the cut between that and pin 8 which obviously has 9V on it. Redo all the cuts to make sure there are no burrs in them which could be causing the issue, and to make sure they are complete. See if that affects the voltage on pin 1.

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    4. I changed the IC and it works perfectly now. The only thing that was still there was the background noise. Surprisingly it was the LED which was a rainbow one. The background noise was the changing from one colour to the next one...

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    5. Aah, yes the LFOs in those LEDs are well known for being noisy and so not recommended in an audio circuit. Glad you got it going.

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    6. Thank you so much for your help and all the great layouts! I'm enjoying them a lot :)

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  16. Struggling to get a hold of Rev Log pots. Can I just use Lin if I don't mind the "sweep" being different?

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  17. Hi,
    Perhaps a silly question since I am rather new to electronics, but can I use a spdt switch for the script instead?

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    Replies
    1. Yes you could, just use the middle lug and one of the other lugs, only single throw is required though. Although you do see more SPDT toggles and so you could probably get those cheaper even with the extra throw.

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    2. Thank you very much. The site I purchase from has pretty much anything (http://www.newtone-online.nl/catalog/) but spst toggleswitches aren't in their arsenal.
      May I just say that I love what you do here and I am glad I found this place early on in my new found addiction. You'll probably keep me busy for many moons to come. Thank you for your amazing work :)

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  18. Just finished building, and mine sounds fine, but the level is a hair low. It doesn't sound as if anything is wrong with it, just a slightly diminished output. The phase effect is working great. Is this typical of this pedal, or might there be something slightly off in my build?

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  19. verified, great sound. I've build with 2N5457 and 2N5087 . I noticed only one problem - I dont hear any differences when I use switch. I've build phase 45 previously,but this one sounds much better for me. 45 has only one great setting - max pot - vibrato
    Is it possible to build phase 90 and get the vibrato from 45? It would be the best phaser on the world :)

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  20. IvIark hello, I'm very interressado to mount the pedal, I would like to know if you already fixed the defect in the layout mentioned by Manuel May 28, 2014 16:46?

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    Replies
    1. Yes I always do corrections as soon as I see them

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  21. fired at once!great pedal!i've used 4x2n5458 and a 2n3906 as javi mentioned.
    great effect. it's really good to build and have one...
    i haven't played with a phaser since 2003 when i through my zoom707II out of my life... FOR EVER...
    thanks Mark!

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  22. Hey guys do you think a 2n5245 could work? I wasn't able to find any 2n5952

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  23. Hey Mark, can you tell me which schematic you used? I've checked several ones, and none fits this layout. The most similar is the GGG, but the trimmer and pot sections doesn't fit either.

    J.

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    Replies
    1. OH, I see is the tonepad one, sorry :P

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    2. how much of a difference is there from the other ones?

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    3. In the LFO and bias trimmer, there are many differences. I'd say that every schematic is different :)

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  24. Three hours deguggin when the problem was clearly isolated :P Plugged, battery on.... and a low and distorted output, nothing even similar to you would expect.

    Quick voltage measurement:

    ic 1
    8,22
    8,22
    0,77
    0
    4.95
    4.40 -5.40
    1,50-8
    8.94

    So something's wrong on IC1a side, anyway, I probe it: sound gets distorted on the very IC1a output. Just 5 components to check... eveything seems ok, cannot find the problem: I measure the rest of ic's and trannies, with really strange measurements.

    I started to check ALL the fucking layout, cannot find a bridge, or a cold solder, everything seems OK, I swap ic's with 4558 ones, swap the 2n3906.... nothing.

    Three hours debuggin and can't find anything wrong.... but the signal still gets distorted and with low output, at the IC1a output... I'm stupid? Yes! 470k resistor from Ic1 3 to trimpot and so on, was not soldered at the ic side :P And knowing where the probem is, was unable to see it for 3 hours XDDDDDD

    By the way, I used 4x BF245B that I had in a bag, in order not to risk my 2N5452 quad... and holy shit, the phaser sounds really great wit the BF! I've not measured / selected them, so I don't think that 4 trannies you get from the bag are even remotelly matched..... but sound great! Not sure still if should i use the quad, or stay with the BF's

    J.

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    Replies
    1. Haha see it can happen to anyone! :o)

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  25. Hi there! I just build this one! :) But it sounds like a ambulance siren.... Can anyone tell why?

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  26. well, I'm with the flu and I can not work, and I remembered the matched JFETs that pedi month, I spent a long time waiting for this project and it started on the first try and it sounds incredible, Realise the first design, I'll do the other controlled deep. one more time thank you very much for making this possible
    Greetings

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  27. Thanks for the layout! I built this, but it sounds bland. It isn't getting the full deep sweeping sound, just a mild one. Is there anything I might do to get the full-on phasing sound? Can you help me find whatever the problem is and fix it?

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  28. Replies
    1. Yes, I bought a set from general guitar gadgets.

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  29. This comment has been removed by the author.

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  30. This comment has been removed by the author.

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  31. ive built this without the depth control, sounds great!!!
    im just curious, because there are 6 ICs in the script, reissue and latest version of phase 90... could this be just a buffer?

    http://s196.photobucket.com/user/wahwahwells/media/IMG_0559.jpg.html

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    1. The photo shows six 741s, and the layout here has three dual opamps. The number of effective opamp channels is the same.
      +m

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    2. The UA741 is a single channel op amp. Mark drew this using the TL072 dual channel op amp to keep the size down. It makes no difference to the sound.

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  32. mirosol and ciaran... thanks for the info...
    im actually a newbie... i just follow whatever is drawn to this blog... still learning though,.. thanks for the help!...

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  33. just wanna share my build :D im so happy with this and i will definitely use this for my gigs
    credits to the maker of tagboardeffects.blogspot.com, IvIark and mirosol!!!
    -vahnrondel from philippines

    https://www.youtube.com/watch?v=dpePntGB75Q

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  34. Would matched J201s be ok with this build? Would I need to somehow compensate for the additional gain the J201s have over 2N5457s?

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  35. Hi, well I finished my phaser 90 works well, only prob I have discovered, its noisy when I use a power supply, quiet when I use a batt., Same power supply used for all my pedals, all seem to be fine, So, any one have any ideas how to fix this, I was thinking to replace the 47uf electro cap with a 220uf , any thoughts on that , regards Peter

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    Replies
    1. Yes a bigger filter cap may help. Is it boxed yet? That always helps with noise too, and you could try a low value cap from input to ground as well, maybe around 100p

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  36. hi everybody,
    i've just finished my phaser ! Houaaaa what a super effect ! i love it, really warm effect !
    When i've connected it, no work at the first time… when i've pot my finger on transitor, worked whith low noises… So, I welded it and work very good at first time !

    Any idea about the the electric consummation in ma of this stompbox ?

    Franck

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  37. Hi,
    Do you think that this veroboard would fit in a 1590B enclosure? I would like to build a small phaser stompbox, but I prefer the phase 90 in comparison with the phase 45 :D
    Thanks

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    Replies
    1. I just figured I'd find out by myself by cutting a 21x23 veroboard and trying it in a 1590B enclosure. It fits exactly in, but I won't have enough room for a switch AND a battery :/
      I usually use batteries for my pedals, so if you know a trick to spare space and get everything inside the box it would be more than appreciated!
      Or else I'll just have to stick with a DC jack

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  38. Can I use 200K trimmer with this?

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  39. Could I put a pot in place if the 150k resistor between the collector and base of Q5 to get somewhat of a volume/gain control?

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  40. I just built this one and it works. But when the speed knob is on full it's not very fast at all. More like what a regular phase 90 sounds like when the knob is about centre. Any idea why this is?
    I used a 500k rev log pot (c500k alpha).

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    Replies
    1. check to make sure you have no bridges, and that the pot is wired correctly. there's definitely a build error. even if you don't see any bridges take and run a knife in the trackts to be sure. if that doesn't fix it, take some good pictures aof the top and bottom of the board and create a thread on the forum under the "open topics" section.

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    2. I'm 100% sure there's no bridges now. Still the same problem. Seems strange that the knob works.. but slower.

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  41. donde va pin 1 speed y pin 3 pot depth

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  42. which will speed pin 1 and pin 3 pot depth

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    Replies
    1. not sure about your question, but for the speed pot you will only use lug 2 and lug 3 (lug 1 is not used at all), and for the depth pot you will only use lug 1 and lug 2 (lug 3 is not used at all).

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  43. Finally ordered some 2N5457s and answered my own question. (from Feb 2015)

    Much, much better with the 5457s!

    The matched J201s resulted in a weak, shallow effect. The matched 2N5457s produce a much more lush phaser.

    BTW, the J201s had resulted in such a weak sound, I didn't even realize I had wired the depth control backwards! The depth control has come alive with the 5457s.

    If you used J201s and are not thrilled with the sound, swap them for 5457s.

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  44. What does the script switch do???

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  45. Can someone help me? I built it, and works right away, but no phasing at all. I triple-checked every component, and looked for bridges 100 times, so that should not be the issue. I matched the 2n5457 JFETs with the JFET matcher on this site, but also tried with several different ones (2n5457, bf245c, 2sk117, j113).
    I checked on lower IC, and the 5,6,7 pins are oscillating the way it should.
    Whatever I change on the pots or the trimmer, nothing really happens, I only hear the clear guitar sound (adds a bit of low end, and some clarity), with no phasing at all.

    Can someone help me, where to look the error?

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  46. I built this a few weeks ago, and like you i had nothing but clean signal when i first fired it up. I found that the trimmer position was critical and quite sensitive, i'd start there. Once the trimmer was set right it worked fine. I also brought a matched quad set of 2N5952's from germany.

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    Replies
    1. Thanks for the reply, but with really slowly changing the trimmer, every setting gives me only the clean signal (maybe I hear just a tiny phasing effect, but I bearly hear it when I really listen).

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  47. I had the same issue: clean guitar - no effect.

    I went through testing voltages and connections. Then I realized that the transistors (1-4) were in backward. The pinout on the 2n5457 causes it to have the flat side on the opposite side (facing left side). I thought I had checked but I must have looked at the wrong document. Now it is working beautifully.

    If you are still having the problem double check your transistor placement.

    Note: the Trimpot has a small window to work with. I turned up the speed to gauge the sweet spot.

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  48. This comment has been removed by the author.

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  49. I have great phasing but a 'tick' goes along with the rate setting. Any thoughts?

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  50. Done mine, very nice tweakable Phase. Although...I can't say I hear a MAJOR difference between the two positions of the switch...just a little fatness in the script mode, but that's it.
    Also, it kind of depends on the place where the depth knob is.
    But, it is great, so here is another clean build from me (HGE Contraptions)
    Thank you Mark!

    https://hgecontraptions.blogspot.ro/2016/12/mxr-phase-90-clone-with-added-depth-pot.html

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  51. Completed this just now, version with depth control exactly as per layout with the exception that I don't have 2n5952's on hand (just ordered a set from banzaimusic for backup) but I matched a set of 2N5485's (bought about 20 from Tayda) within 5 millivolt range and used them. I built R.G. Keens FET improved matcher (from this site, thanks!) and used 2N5485's as reccomended substitute by R.G. Keen. Bought 15uf cap from http://www.diyguitarpedals.com.au/shop/index.php this guy also sells low profile elec caps if you need them. Works mint, turned up speed to dial trimmer to that sweet spot. Beautiful phase, now it's on the frontline in my setup. Thanks for the layout Mark!

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