Thursday, 7 February 2013

Colorsound Phazex

This is a great sounding phaser so I thought I'd still do it even though it probably doesn't fit with my philosophy of when I would and wouldn't use vero.  Similar in some ways to the Phase 90 but I haven't seen a layout for this one and so decided it would be a good addition.  Like the Phase 90 this is going to work best with 4 matched JFETs and so it may be worth buying 4 matched rather than buying in a greater quantity and having to mess around.   The internal trimmer sets the bias point and so tweak that until you get the sound you want.  The original also had the Depth control as an internal trimmer but I thought it made much more sense to have that control external to make it a bit more versatile.

If you mount this one sideways it should fit in a 125B but a 1590BB may be the order of the day if you don't want to have to squeeze everything in. Thanks to Analogguru for the schematic.




Image from effectsdatabase:








And a revised layout making better use of the space so it could fit more easily in a 1590B, and based on 2N5457 JFETs for their availability.





Bill of Materials:

Group Value Qty
Resistors 6K8 2
Resistors 10K 10
Resistors 22K 4
Resistors 47K 3
Resistors 100K 1
Resistors 150K 3
Resistors 470K 2
Resistors 680K 1
Capacitors 180p 1
Capacitors 10n 2
Capacitors 47n 6
Capacitors 2u2 1
Capacitors 10u 1
Capacitors 33u 1
Diodes 1N5817 1
Diodes 4V7 Zener 1
IC LM1458 3
JFET BF244A or 2N5457 4
Trimmer 1M multi-turn 1
Pot 10KLog 1
Pot 470K Rev Log 1
Pot 1MLin 1

48 comments:

  1. Wow, talk about throwing the gauntlet down :o)

    ReplyDelete
  2. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. I Second the Tweak Fuzz... the buggers are becoming rare and are fantastic fuzz/drive pedals...

      Delete
  3. Would subbing a 5.1V Zener make much difference? Mammoth doesn't carry the 4.7V it appears.

    ReplyDelete
  4. Hi Mark,

    Do all four jfets need to be matched with each other or will two matched pairs work (if you know what I mean)? Also, ( the perennial question), which would be suitable subs? Bitsbox have bf 244 bs in stock. Not sure what the difference between the two is. Cheers

    Mark

    ReplyDelete
    Replies
    1. They need to all be matched, and I suspect the BF244B should be OK, they are mostly the same spec but with a different range of Vgs and Idss which are the characteristics you will be matching. Or you could try these:

      http://www.ebay.co.uk/itm/360529047424

      Delete
  5. I'm worried about the 1.5M resistor, I have none at present time, and I'm afraid that being the one that biases the jfets gates is not a value to play with.... have 1.3 and 1.8.... why on earth there's always a value you lack? :P

    BR

    ReplyDelete
    Replies
    1. Hey, why not daisy chain your 1M3 with a 2K? I know it doesn't always look pretty but it'll get you up and running and you can always replace them when you get some 1M5.

      Delete
    2. Yeah, i'll put a 220k in series, it looks awfull as there's just 4 rows gap, but as a tryout it could be fine. I'll ask this evening in my local store, but I'm afraid that they have not this measure, will have to order at Tayda.

      Anyway, the pots will come tomorrow, so no real hurry, have time to find a workaround.

      BR

      Delete
    3. Or put a 4M7 and 2M2 in parallel if you can get them in side by side. That would probably look neater

      Delete
    4. Sure! Was thinking just in series and didn't think about parallel :P. Yes that's a better solution :) Hope to have the circuit ready tomorrow evening (if pots are not delayed)!

      Delete
  6. Wel,, finally after so many months: Tag it! Works fine, very smooth and noise free.Will have to get a better matched quad, but with the one i used (about 15-20% tolerance in the match) sounds very sweet and nice.

    Nice an funny build to rest from the dirty pedals :)

    BR

    ReplyDelete
    Replies
    1. Nice one Javi. Have you messed with the trimmer at all to see how that affects things?

      Delete
    2. Yes, let's say that the trimmer is the key of the sound of these effect.

      When first plugged the pedal, I thought that there was something wrong as the phaser effect was barely noticeable. But once you play a bit with the trimmer, the effect appears, and what a sound! I told you that my quad is not perfect at all, and still sounds really really cool, way like the audio demo upside, so I'm not really in a hurry to get a perfect quad at all, sounds really fine.

      I've used 2n5457, as they're virtualy the same than BF244, but I had to twist some legs.

      On the other hand, Depth pot is a good idea. I have very clear how i like this parameter set in a phaser, but is good to be able to change it depending of the other effects active on your chain.


      All in all, a really cool phaser, and if you want, is perfectly doable in a 1590B with solder side up. I'll use a Milkit's enclosure as they're way similar to the Colorsound One, but had I not it, would use a 1590B without any doubt.

      BR

      Delete
    3. Excellent thanks for the info mate, I'll look forward to your pics.

      Delete
  7. http://www.sengpielaudio.com/calculator-paralresist.htm

    guys, if ya ever need to make an odd ball resistor value, the link above can be a real help.
    i like to use it to add parallel resistors to stuff that's already on the board to see what it will do..sometimes it's easier than desoldering something.
    check it out, hope ya find it useful.

    ReplyDelete
  8. Hey guys, I have this quad at my disposal, do you think is right (BF244)?

    2.85 077
    2.82 076
    2.79 079
    2.80 077

    So it's 2%/ 3,8%, under a 5% match that is usually what you get when buyin' a matched quad. I think it would be ok, but would like to hear more opinions.

    BR

    ReplyDelete
    Replies
    1. Yes I think that would be described as a close match. JFETs are so inconsistent you may have to go through a couple of hundred to get any closer than that. Did you get the tester working?

      Delete
    2. Well, the matcher is "working", measures seem right on every fet I've tried, so, I think the problem is in the switch.

      Well, I've tried the quad, and to my surprise, is imposible to bias with the 100k trim, seems that this quad is out of scope for this trim. Depth pot is very sensitive too, with the "not very well matched" 2n5457, had to bias with this pot fully CCW, maybe with the BF's will have to find another "depth sweet spot".

      Will take another look this evening, to see what I can get.

      BR

      Delete
    3. Try swapping the 1M5 because that sets the minimum resistance for the trimmer.

      Delete
    4. Well, the 2N5457 are in the range 1.20 - 0.20, so the values are very different to theBF244As... 1.5M resistor I see is too high, but you have just 100k (the trim) to find the sweet spot, so I think that best solution would be swappin the resistor with a 680k or similar and get a good multi turns trimmer of 1M, so you can use a very wide range to find the point.

      I have no 1M trim, so will have to wait until tomorrow.

      BR

      Delete
    5. Well,

      Measured my "non matched" 2N5457's quad, and two of them were a perfect match, so, as I had about ten more in a bag, measured all of them, and was lucky enough to find 2 more close to the matched pair, so the previous 18% matched quad, is now a 5,2% matched one. It really shocks that after measuring about 40 jfets, I´ve found differences of even 75% in fets of the same model. BF244 are by far less consistent than the 5457's.

      Sound has improved with these 2 new kids but there's not a drastical difference with the previous ones.

      I'm afraid that the BF244 quad has an extremely high vgs off (specs: from 0,5 to 8v, hay que joderse) and they won't be of use in a phaser, so the 2N5457 will stay as they sound really fine, and so will have not to deal with another resistor and trim.

      Enclosure is finished now, so i think tomorrow I'll be able to finish it. It really sounds way better than my original EHX The Worm, another factory pedal that has earned a long vacation :P

      BR

      Delete
  9. New informations :)

    I was the whole day thinking about the BF244 quad, the imposibility to bias it, the vgs off.... and decided that something had to be done as maybe I was wrong, and the problem was the trim + resistor and not the vgs off.

    So I purchased an 1M multiturn trimmer, desoldered the 100k trimmer and the 1.5M resistor and soldered the new trimmer and a 680k resistor, plus the BF244 quad. So the resistor + trim were now 1.68M instead of 1.6M, a little more to the top, but with a minimum resistor half lower

    Battery on, and began to bias from full CC to full CCW......... and nothing. Phaser effect refused to sound.

    When I was just about to install again the 2N5457, i decided to take a last voltages measurement and, did check the fresh battery just unpacked on Tuesday, just for doing it and..... 7,8 volts on the battery! Well, it seems that the fu**** one was not very "fresh".

    In order to avoid blowing power supplies, I always do the sound checks with a 9v battery. As the circuit was tested, I pluged my PS (9.6 volts) and voilá! the phaser sound was there! Just had to do a final bias.

    Anyway, even with the power supply, would have been imposible to bias with the 100k trim + 1.5M resistor, as the final bias has been 680k from the resistor + 427k from the trimmer= 1,1M, so 1M resistor + 250k trim would be very useful too.

    Sound is even smoother with the matched BF244 quad, really really sweet and cleaner at full speed and reactance. Different from the 5,2% matched 245457 quad, but would not say better, just different and sweeter, but the previoous one was great too, and I'd say, a little closer to the sample one.

    Pics:

    Vero with 100K trim, 1.5M resistor and 2N5457 with twisted legs:

    http://img834.imageshack.us/img834/2539/phazexgutsold.jpg

    Pedal guts, build finished. 1M trim, 680K resistor and BF244 quad:

    http://img96.imageshack.us/img96/425/phazexgutsnew.jpg

    And pedal finished with Milkit's enclosure:

    http://img33.imageshack.us/img33/626/phazexfinished.jpg

    BR

    ReplyDelete
    Replies
    1. Great stuff Javi, thanks for the excellent info, especially useful to me because I've got BF244A's and 2N5457's so I know what sort of value resistor and trimmer I will need to be able to use both types.

      Pics look great, as per the comment on Facebook! :o)

      Delete
  10. Hey guys,

    I took on this build recently but I'm not getting any phasing unless I manually turn my depth knob. I have triple checked everything, no solder bridges, correct trace cuts, and off board wiring. Maybe the (speed 2 to depth 1&2) wiring or JFETs might be my problem.

    I have four BF244A's I matched for VGS off:
    -0.72 v, -0.7 v, -0.67 v, -0.66 v

    That's a good set right, and good cut off voltages?

    I also did like JaviCAP and swapped the 1.5M resistor for a 680k and used a 1M trimpot too.

    ReplyDelete
    Replies
    1. Take a look to the presence pot. Is a set and forget control if using the same or similar instruments (humbuckers / single colis), but a bad setting can make the phase sound completely dissapear.

      Set the 680k + 1m trim to a total of 1,1m. Set the presence fully CCW push fully clockwise the other two pots, and start to play as you sweep the presence knob until you get the phase effect. After this, is jus a little ear tweak to find the correct spot.

      The quad seems ok to me, it may be better, but this one has to work pretty well.

      Take it easy, this is one of the most difficult to set effects that I've ever built.

      BR

      Delete
  11. Damn I tried that and played with the settings and trimmer and still no phasing!

    I'm double checking again, but for now could I get a picture or a diagram of how your speed and depth pots are wired JaviCAP?

    ReplyDelete
    Replies
    1. I', afraid that a pic s not posible ah I'd have to open de pedal, and nearly disasemble it in order to show thw wiring, but is not difficult:

      - Wire from board to Speed 1
      - Wire from board to Speed 2
      - Wire from Speed 2 lug to Presence pot 2 pot lug
      - Wire from board to Depth 3

      And it's done. Hope it works for you.

      BR

      Delete
    2. Wire from board to Speed 1? Maybe you refer to Speed 3?

      Delete
  12. Greetings to all!!! Just another newbie here! It seems that I can't find anywhere a 470k rev log pot, can I replace it with a 500K?

    ReplyDelete
  13. This comment has been removed by the author.

    ReplyDelete
  14. happy merry holiday xmas new year!!
    is there a good sub for LM1458?

    ReplyDelete
    Replies
    1. MC1458 :P

      Seriously: when a build asks for a 1458 or a 741, is not a good idea to sub the IC with any other double or single opamp.

      It may work ..... or not. Many builds have been unverified until the correct IC has been used, in nearly all the envelope filters that you can build, and many other effects, the 1458 is mandatory, so, i'd advise to use just LM or MC1458's in this phaser.

      Delete
    2. thanks javi.
      I ordered a few LM1458 and -for once-will be patient and wait to do the build.

      Delete
  15. I guess LM1458 correct orientation is with the locating dot heading up? :-P

    ReplyDelete
    Replies
    1. Yes if you look closely at the symbols you can see the half moon on the top edges of the IC which always denotes the top like this

      Delete
    2. Actually I was talking about the stripboard drawing, but after a closer look I noticed the locating dots on the IC, not visible on my print :-P

      Delete
  16. Hey guys!
    I just finished the Phazex, plug it in and of course no phase effect :-P
    I started biasing, turning every pot and trimpot and still got nothing. I read somewhere above that maybe the 1,5M resistor it's a little bit high, so I replaced it with 1M+220k.
    As I was trying to bias it, all of sudden the phase effect appeared out of nowhere.
    After a few more tests I realised that the phase effect works when I remove the 1,5M resistor (or the 1M+220k) and use just the trimpot at around 80k.
    I used carbon resistors on this one and I wouldn't called them very precise, as for example the 1,5M reads out 1,74M on my multimeter.
    Do you think guys that this might be the case here? Maybe an overall increment to the resistance due to not precise resistors values?

    ReplyDelete
    Replies
    1. I don't think so.

      For my experience, the trannies are the main thing here, so you need an extremely open wide operation resistor. If I ever build this pedal again, instead of a trim + fixed resistor, will use a 2M multiturn trim to avoid all the problems I had :)

      BR

      Delete
    2. Thanks a lot JaviCap! That's what I was thinking about after spending the last night trying to bias it.

      Nikos

      Delete
  17. Had to wrestle with this one -- successful only thanks to Javi's comments above. In the end I dropped the 1M5 resistor to 1M2 and replaced the trimpot with a 250k pot -- being able to change the bias at will really opens up the variations of how this one can sound. Also replaced the 10k reactance with 100k as it didn't seem to be doing anything before.

    It's really thick and beautiful -- love this one!

    ReplyDelete
  18. Just wiring this one up, using the top diagram, but can't see were speed 1 wire should be situated. Can anyone help? Thanks in advance.

    ReplyDelete
    Replies
    1. you can leave it un-connected, or you can connect it to speed2 with a link on the pot.

      Delete