Thursday, 26 July 2012

MXR Phase 45

I thought a small and simple phaser would be another good addition and so the Phase 45 is the automatic choice to remain 1590B friendly.  For the best results the JFETs need to be matched so you can either swap and change to select the pair that give the best sound, or measure them using a method like this one so you know they are a close match. 

Info from MXR about their currently available 75 Vintage Phase 45:

The '75 Vintage Phase 45 reissue from the MXR Custom Shop reproduces the rare little brother of the Phase 90 to exacting specifications. With two stages of phasing, the Phase 45 offers up its subtle and musical voice via hand-matched FETs and hand-wired circuit board. Authentic tried and true components and hardware such as a Carling switch, CTS pot and Switchcraft jacks. Texture your tone without over powering your sound with the limited-edition '75 Vintage Phase 45.




Geiri's video of his build:




BUY A KIT

83 comments:

  1. Thanks alot Mark!

    I found this moded 45

    would you like to do an update for this?

    http://www.lynx.bc.ca/~jc/phase45modded.gif

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    1. Yes I've got that one lined up to do, but I'm waiting until we get this one verified first so I know it's a solid base to do the modified version from.

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  2. Not even gonna try :) I'll get a matched set.
    +m

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  3. Is there a way to plug a jfet into my multimeter similar to how you can measure the hfe of an npn or pnp transistor? My multimeter has a spot to plug in transistors and measure them instead of using the the test probes.

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    1. The sockets on the multimeter are used to measure the gain of a bipolar transistor and I'm not aware of a meter that will directly measure JFET characteristics. The Peak Analyser will identify pinouts but doesn't give this sort of info, and although there may be something commercially available I haven't come across it yet.

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    2. This article on matching the jfets is slightly over my head and im having trouble deciphering the schematic on how to make the jfet matcher. Do you know of or could you make a vero layout to build the tester, with a socket for the transistor and two leads to attach the multimeter probes to? I would greatly appreciate it.

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    3. http://tagboardeffects.blogspot.com/2012/07/jfet-matcher.html

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  4. Any variants on the jfets or diode...or indeed where i can source them..had a look on the bay and my normal suppliers with no joy

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    1. I think you can get both from dpi4parts on eBay, I use them all the time and they have very good prices. But you could just use a more common JFET like the 2N5457 (turned 180 degrees) and any 4.7V or 5.1V zener to replace the diode.

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    2. many thanks mark, il have another ( proper ) look tomorrow
      any links to that ebay shop ??

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    3. http://stores.ebay.com/dpi4parts

      I've just bought some bits from him though and he only lists the packs of transistors one at a time for some reason, so I'd wait a couple of hours to give him a chance to add the new auctions to see more of the stuff he sells.

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  5. In measuring the jfets, is there some optimal value to get close to or is it just a matter of making sure that they match each other?

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    1. Just choose the pair closest to each other. Then if you get two sets that are close you can try them both and see if you have a preference for vgs.

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  6. Hello, Does speed one go to speed two?

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    1. You can do but it isn't necessary

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  7. so what jfet characteristic is important to match for the phaser?

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    1. Use the simpler version of the Greatly Improved JFET Matcher and choose the pair with the closest Vp AND Idss for the closest match.

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  8. Guess who's back from the coutryside! Tag it.

    I got small stash of matched 2N5259s from UralTone when i visited them on my way to the summerhouse. They have really nice shop with lts of good stuff and Catalinbreads and ZVexes on site. Plus they have their own designs sold as kits (not very cheap i'm afraid). Anyway.

    First of all, i didn't have 7K5 resistors at hand, so i put in 6K8 and 680 in series (equaling 7K48 :)). Other thing that i didn't have was the 1N5230, which in reality is 4,7V zener. Used 5,1V (1N4733) instead. Other choice that i had, would have been 4,3V (1N4731), but this seems to work fine with 5,1V zener.. Now that i think of it, a socket would have been nice, since the zener seems to affect the bias trimmer. Oh well. It works, so why bother :) Bias trimmer needs to be just on spot for this to work right. Just a fraction of a millimeter off, and you lose your phase.

    It's mild when comparing to demos of Rick Holt's phaser(s), but good sounding thing. It sounds exactly like ProGuitarShop's demo. Maybe just a tad milder. Or it could be that my trimmer is just slightly off..

    I need to restock on couple resistor values, but i think i'm building another one soonish. I want this as is, and i want to put this in same box with Vox Repeat Percussion. Just can't decide which to put in first and which as second :)

    Thanks for great layout. Once again!
    +m

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    1. Awesome cheers mate, I'll do the modified version now I know this is ok. Oh and Phaser > Trem :o)

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    2. Why? I'm currently figuring out if it would be doable to use some 3 position switch to switch between "pahse after trem / only trem / phase before trem"... Or it could be two switches. One to switch phase on/off and other to determine if it's before or after the trem. Spacious experimentation. Me likes.

      Makes me think if i should build one delay for this monster too :)

      Do you by the way have any clue what that zener really does in this circuit? I don't :) My guess is that it sets the voltage for the trimmer...
      +m

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    3. I just think that you'd get better results by phase shifting the clean signal and then chopping it up, than try to phase shift a chopped up signal. But you could always use an 4PDT order switcher and then give each effects it's own stomp, or toggle, or whatever so you can use them independently.

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    4. Hey IvIark, how difficult would it be to add a rate LED to this layout? I like the modded one thats posted, but I really have no use for all that stuff. At times I like the KISS theory.

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    5. Hi Mike, Marks living it up in the sun for a week so wont be able to answer anything till then ;o)

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  9. [expletive deleted] Thats ok, I can wait a week. Probably wont even be ordering parts until then

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  10. BTW. I just soldered in a 510K resistor in parallel with the pot as it was too slow in the slowest setting - to my taste at least. Starts a bit fast now. I did calculate the best probable setting, and that would be to solder 1M5 resistor to lugs 1 and 3 of the pot. That makes the pot 375K, and thus eliminating "too slow" settings.

    ---

    Yup. Works just like i wanted it to. 1M5 works perfectly.
    +m

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  11. And pic for this one too...

    http://mirosol.kapsi.fi/varasto/boxes/Phase45.jpg
    +m

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  12. Probably a silly question, but none of the boards I've purchased from Mammoth or DIYstompboxes have more than 19 rows. Where cab I get one that has the required 20 for this one? Thanks.

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    1. Hi,

      The most recent I did get, were:

      http://www.bitsbox.co.uk/hardware.html#stripboard

      36 rows, i think would be enough :)

      BR

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    2. You can make anything out of one of these :o)
      http://i76.photobucket.com/albums/j6/IvIark_2006/DIY/IMG-20120216-00167.jpg

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    3. Thanks JaviCAP. Unfortunately, no shipping to Canada.

      Wow - where'd you get those Mark?

      I think I'll just add a strip from another board. It'll be fine once I solder it to the other strip with the components.

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    4. www.rapidonline.com/Tools-Equipment/Stripboard-29453

      The bottom one

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  13. Hi,finished this one last nite ,very nice swirly sound ,not too over the top and dosent effect amps tone.I might try Mirosol's 1M5 resistor mod later to see what its like.
    Thanks and happy soldering over Christmas and New Year to everyone.

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    1. And the same to you matey, glad you had good results. The 45 isn't as extreme as other phasers but still great sounding to me. I haven't built this yet but this is one of the ones I'll be doing over Christmas

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  14. Hi, I have tried to build this MXR 45, but I still get no phase. I matched 2 JFET: -1,82V and -1,81V. It seems good enough for me, isn't it? I tried to move very slowly the trimpot to get the spot, but I could not hear any phase.
    I replace the diode by a Zener 4,7V and I use 2 JFet : F245B. I have the sound of my guitar (which is a little bit "clearer" with a little bit more of treeble). When I move the trimpot I can hear some very little change in the sound. But I hear nothing when I move the "speed" pot.

    I check the solder 2 times, check the components 3 times, I checked the cut was well done. I am totaly stuck, do you have any idea on what could be the issue?

    Are there particular points to check in order to make the phaser working ?

    thx for your help.

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    1. MIne does exactly the same - did you ever work out what was wrong with yours?

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    2. Did you get both those cuts underneath the 150k resistor at the top left?

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    3. Yes, got that - but whilst I was checking the rest of the board I found that the 150kΩ resistor in the bottom right was placed one row up from where it should have been. I suppose I should solder during the daytime when I'm actually awake, instead of stupid o'clock in the morning...

      D'oh!

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  15. Got this up and running a few days ago after some tweaking with the trimpot and it sounds good! Picture: http://imageshack.us/photo/my-images/442/dsc00721xw.jpg/

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  16. It phases nicely but there is a noticeable volume drop when engaged.

    I am wondering if I can mod the circuit slightly in order to achieve unity gain.

    Initial thoughts are that increasing the value of the 150k resistor between output and ground may boost volume...

    Any suggestions?

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    Replies
    1. I don't think increasing the 150K will do anything, that's just a pulldown resistor on the output. The gain of the final opamp stage is the value of the top right 10K resistor divided by the 10K resistor 5 columns to it's left. 10K/10K = 1 and so unity. If you increase the 10K top right resistor it will increase the gain of the final stage. You don't want to go too far because you don't want it to get dirty, but replacing that resistor with something like a 50K trimmer so you will be able to get anywhere from zero gain to 5x gain.

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  17. I'm getting phase, but im also getting a click, what sounds like a tick at each end of the sweep, what could cause this?

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    1. Turned out to be a bad trace cut, all worked out now! I doubled the .047 to .1 to make this more bass/downtuning friendly, and I love it!

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    2. Hi Mike, wich one .047 did you change? all of them?

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  18. Hi! I finish today my pedal but didn't work :(
    I check soldering, layout etc a few time but is all ok.
    When i turn on effect it don't phase.
    This is value:

    TL072 up:
    1 4.18
    2 4.18
    3 4.17
    4 0.00
    5 4.17
    6 4.18
    7 4.18
    8 11.29


    TL072 down:
    1 4.18
    2 4.18
    3 3.99
    4 0.00
    5 from 4.16 to 7.18 (this value change) ?
    6 from 4.39 to 7.07 (this value change) ?
    7 from 1.30 to 10.53 (this value change) ?
    8 11.18

    JFET 2N5952 left:
    D 4.17
    S 4.18
    G from 0.80 to 1.29 (this value change) ?

    JFET 2N5952 right:
    D 4.17
    S 4.18
    G from 0.80 to 1.29 (this value change) ?

    I don't know how to match JFET. I don't understand how i can.
    Please. Help me.

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  19. Can someone tell me or is the capacitor 47nF polybox ? ... thank you !

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    Replies
    1. Yep, can be any non polar capactitor, it doesn't really matter what type. The value is more important than the type.
      Cheers
      Dave

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  20. Hello there from Greece. I just finished this one before but i have problems. I finished it with a pair of TL072CN and there was just an annoying sound and no guitar signal at all. At bypass mode i had my original guitar tone. I open this again checked every solder and swap the TL with another pair of TL072CP, at this time it works not as a phaser but more like a fuzz :). the speed knob seems to do nothing, also the bias do nothing... Any help!!! Is there any possibility to check my circuit with my multimeter? There is no cold soldering or unwanted bridges but i am not sure for a fault component... Where i have to test and what to measure??? Any guide for this one?
    Thanks a lot!!! :)

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    Replies
    1. I have similar problem :( it would be great if any one post voltage values on TLs and JFETs.

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  21. Hi! I have the same problem... fuzzy sound... Is there any solution?

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  22. hi there! is this possible to control the phase position with the foot, using the circuit into a wha enclosure? where to link the pot?

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    1. It's not as simple as that. At the moment it's the variable resistance in the JFETs that is providing the phase shifting and so a significant portion of the circuit would need to be changed. I've been thinking of doing this recently but was thinking of a 4 or 6 stage phaser rather than the Phase 45 because the circuit would still end up fairly small without the JFET, LDR etc and LFO. I'll have a look at it at some point and decide the best way to go, so just keep checking the site.

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    2. That s a good way i'll check. Tanks lvlark

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  23. This comment has been removed by the author.

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  24. Hey! I'm bying the kit on bitsbox, but JFET included are 2N5458 like on the mod, but here are 2N5952. wich one?

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    1. The 2N5458 will work fine, Bob uses them because the 2N5952 are discontinued and hard to source now

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    2. okay, i was just not sur because on the schematics of the mod version, they're reversed.

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    3. That's just because the pin order are opposite so the transistor needs rotating 180 degrees

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    4. Hi, Carrefull, the 2N5448 are GSD and non DSG as on the drawing, seems that a lot of people have the same issue than me : sound a bit clearer and distorted when JFET are in the wrong way but no effect at all !!!!

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  25. I recently purchased the mxr phase 45 kit, I have had no real problem with the board its mainly the off board wiring im struggling with. I have searched and looked at forums for how to wire this. The kit was supplied with a switc that has 9 lugs, as far as I can tell a 3pdt. I can only find wiring methods that include an LED (which wasn’t in the kit). Wiring it without the LED uses a 6 lug switch. I have tried to wire it up and include a battery snap. When I plug in I get normal guitar tone, hit the switch and no sound. If I take away the battery I get normal guitar tone, hit the switch and I get slightly quieter normal guitar tone. Realistically how bad have I ballsed this up and is there a picture/guide on how to wire these things up (I have looked at the guide on tagboardeffects and on beavis audio) I literally need the simplest version as ive little experience with these things!

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    Replies
    1. did you tried it without the switch? like connecting your guitar to the input of the board and from output to the amp...just to be sure that your board/effect is working..if it does, then we can talk about the wiring, which is exactly the same as the offboard wiring except you leave the LED pole of 3pdt empty.
      like this
      1 4 7
      2 5 8
      3 6 9

      and leave 123 empty. no LED no resistor

      but if your effect is not working, you must do some debugging first!
      hope i helped

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    2. Hi

      I would also like some help in wiring the offboard components. Any help or a quick diagram of this would be extremely helpful.

      Thanks

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    3. At the top of the site there is a tab marked "off board." If you click it, you will be brought to a section of the site that has off board wiring.

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    4. Thank you, I have already seen this and used it however what I am unclear on is where the pot attaches to? There is a speed 2 and speed 3 points but how does this relate to the pot?

      Thanks

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    5. http://mirosol.kapsi.fi/varasto/boxes_other/pots_switches.png
      Lug 1 not connected.
      +m

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  26. Hey there! Let me start by thanking you guys for keeping up this blog, love it.

    I ordered this kit from Bitsbox (excellent), managed to get it working properly without too much of a hassle (even though it was my first attempt at building a pedal) and I really like it.

    I do have a question, though. I noticed that the speed pot (500k linear) didn't give me a good enough control over the faster phaser speeds; the last bit increased the speed by too much, compared to the first ~90% of the pot's travel. I decided to switch it for a 500k rev log and it seems much better now, in terms of speed control.
    Just wondering if the schematic is off, or if I just messed something up and got lucky that it still works

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  27. IvIark ? are here ?
    a lot of time i don't see you here…
    Evrythings Ok ?
    I've few questions, maybe if you have few minutes…

    Thx

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  28. please help me

    When i engage the pedal the sound is phased but very low like -15 db or -10 i don't know… Any idea ? Franck

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  29. Anyone have a picture of the finished board?

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  30. Hi,

    I just finished this build today yesterday. It works fine when plugged with a single DC adapter, but the effect is not working when I plugged to my mooer power supply, with which I power my pedalboard.

    Any idea where would that come from? Would the voltages of my circuit help?

    Thanks

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  31. it might be a silly question, but is it possible to add a depth control to this circuit? and if so where? thanks in advance :o)

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  32. This comment has been removed by the author.

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  33. Hi
    I have the same issue as above: pedal seems to work but no phase.
    When i push the switch, i just have a slight volume drop
    I have tried to turn the bias pot while my looper was playing but no sound change at all
    These are the measurments i have made:

    Top TL072CN
    4v =|-----|= 9.33
    4v =|-----|= 4
    4v =|-----|= 4
    0v =|-----|= 4

    Down TL072CN
    4v =|-----|= 9.33
    4v =|-----|= moving between 2v and 7v
    4v =|-----|= moving between 4v and 6v
    0v =|-----|= moving between 4v and 6v

    Both JFETS have 4v to their 3 legs.

    Do you have any advise ?
    Thank you

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  34. Built this today, works fine. Used a pair of unmatched 2N5458 (the only two in the shop!). Biasing was easy - it's fairly distinctively "Not working, working, not working" when you turn it. I haven't compared the effect volume vs bypassed volume, but it's all good so far.

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    Replies
    1. if it's not working, then working, then not working, etc. it's most likely due to the 2n5458s not being matched. it's really important in phasers for the FETs to be matched to work correctly.

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    2. I believe Willy was referring to the turn of the bias trimmer - working only in one position.
      +m

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  35. Yep, I was referring to the turn of the trimmer - it's a pretty distinct sweet spot

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  36. This comment has been removed by the author.

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  37. Can I use 2n3819 transistor as replacement to 2n5458? It has DGS pinout, not DSG like in layout...
    Thank You in advance!

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    Replies
    1. Try it, and let us know if it works. Just bend the feet so that G and S go to where they should be in the layout. (Add insulation if necessary to stop them from touching each other.)

      -- other Derek

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