Monday, 2 May 2016

Ross Phaser

This was a request.
The video is for reference only:



30 comments:

  1. Woah you're on a roll!! I thought this was a Phase 90 clone. I'll be building this one for sure

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    1. The first version of the Ross Phaser was a Phase 90 clone. Later versions were more like Small Stone Clones. More info on the Tonepad and Home-Wrecker sites.

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  2. Thanks Alex! You're the veromaster!!

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  3. Hi! I didnt see Int 1&2(sorry newbie ;))? Is it ok to use LM13700? Thank you in advance!

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    1. Int 1&2 goes to Sw 2 (it is written in the layout notes). LM13700 should be ok.

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  4. Cool. First OTA phaser in the library!

    Since you seem to be friends with LM13X00, when will we see a compact layout for for DOD FX22? :)
    +m

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  5. Hey Miro!
    I'll be glad to but how would you get rid of the switching system?
    Input at C13 (220n) and output at C11 (220n)?
    Schematic is here:
    http://www.freestompboxes.org/viewtopic.php?f=1&t=5426&hilit=fx22&start=20

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    1. You'd probably want to keep the input/output buffer for stability. Get rid of Q2-6 and everything at the bottom. Take your output from the same place as the schematic. That way the OTA is isolated from what comes before and after it. I think anyway.

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    2. Thanks Ciaran.
      I've added a schematic in the forum chat.
      Is that what you've meant?

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    3. Threw my 2 cents in there. Can't wait :)
      +m

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  6. The layout is confirmed. I built it and it is great.

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  7. Good job . I assume you used the proper lm13600 ota's. i have two lm13700 i had three and used one for a compressor i sold last year. The only suppliers i use that had them are ebay and aliexpress. it will be about three weeks before i get them. im excited about this one.

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  8. Thanks for doing my request again Alex. I like these ota phasers. I used to have a peavey classic with built in phase. it used the ota type phase similar to the small stone i assume. Man i cant wait to do this one . ill start it soon. I have three or four pedals to build for some customers. Man they are coming out of the woodwork. Its how i fund my keepers so its worth it.Thanks again.. I ordered 5 lm13600 just in case you decided to do the daughter board on tonepad. that would be a nice addition.Thanks for fueling the fire ha ha .

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    1. You are welcome.
      I'll add the "quite large" Extra Phase Stages board in the Forum Contribution section.

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    2. Thanks Buddy. I ordered 5 in all so I should have enough. Ill definitely build the daughter board . It will be a few weeks before the chips come in from china. I need to get caught up on some boxing and trouble shooting before then anyway.

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  9. Hello Everyone,

    Has anyone built this using LM13700's? Thanks Heaps!

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  10. Thanks for the layout!
    I am a newbie, and I have built the modded version with LM13700 and it doesn't work preperly. I can hear my clean signal, but it sounds like the LFO is changing the gain instead of the phase.
    I don't have any cold solder joints or solder bridges, but I suspect that it happens due to a silly mistake I don't know yet.

    These are the measurements of the chips:
    TL072:
    1: 2.95 | 8: 9.35
    2: 2.95 | 7: 3.7
    3: 2 | 6: ~3 - 3.22
    4: 0 | 5: 2.95

    Top Right LM13700:
    1: 1.18 | 16 : 1.1
    2: 0.1 | 15: ~0.15 - 0.16
    3: ~2.1 - 2.95 | 14: ~2.1 - 2.95
    4: ~1.6 - 2.95 | 13: ~1.6 - 2
    5: ~2.1 - 2.95 | 12: ~2.71 - 3.05
    6: 0 | 11: 9.36
    7: ~2.07 - 3 | 10: ~2.75 - 3.01
    8: ~2.07 - 3 | 9: ~1.65 - 2

    Top Left LM13700:
    1: ~1.11 - 1.14 | 16: ~1.11 - 1.14
    2: ~0.08 - 0.12 | 15: ~0.23 - 0.24
    3: 2.95 | 14: 3.08
    4: 2.95 | 13: 3.53
    5: ~4.32 - 4.5 | 12: ~1 - 1.24
    6: 0 | 11: 9.36
    7: ~4.32 - 4.5 | 10: ~1 - 1.24
    8: 2.95 | 9: ~1.42 - 1.63

    Bottom Left LM13700:
    1: ~1.11 - 1.14 | 16: ~1.11 - 1.14
    2: 0.15 | 15: ~0.11 - 0.12
    3: 2.94 | 14: 2.97
    4: 3.8 | 13: 2.97
    5: ~4.78 - 5.2 | 12: ~0.68 - 0.8
    6: 0 | 11: 9.36
    7: ~4.77 - 5.2 | 10: ~0.68 - 0.8
    8: ~4.66 - 4.7 | 9: ~1.26 - 1.3

    (Tested with DMM, black lead to circuit ground)
    Is something looking not normal?
    Thanks!
    (Sorry for spamming, I wasn't sure how to edit a comment)

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    1. Found it: I somehow managed to forget to solder one end of one of the jumpers. I can confirm that this circuit works with lm13700.
      And the rate pot should be flipped, it is reversed.

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  11. This circuit uses the LM13600, not the LM13700. Try it with the right ICs

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    1. 13600 and 13700 are interchangeable. That won't cause any issues.

      I'd suggest triple checking all component locations and knifing the strip gaps. A tiny solder joint short would be my first bet.
      +m

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  12. Built, tested and verified with LM13700.
    Seems very quiet (noise-wise) and subtle compared to the Mutron Phaser 2, works best with a high input level and some adjustment like any ota-based layout.
    Good enough to box, this one. Thanks for the layout Alex and keep them coming!

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  13. building this next, I can't find 50n caps from my usual place, Will there be much difference if i use a 47n instead?

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  14. I am working on the modded version of this pedal. Couple questions on this one. Can I use 1n4148's instead of 1n914's? I was all out of 914's so I tried the 4148's. So far all I am getting is clean, uneffected signal. I can hear a bit of a mid-range bump when I switch the vib/phase switch. Other than that the controls don't do anything to effect the tone.

    I tried with both 13600 and 13700. Both sounded the same, no effect. I checked for solder bridges and knifed all the gaps like crazy.

    I am going to reflow all the solder joints and can take voltage readings later today, just thought I would double check if using the 4148's would cause an issue.

    Thanks!

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    1. Mate I have just built the modded version and I get similar results to you although I used 1n914's and tried with both LM13600's and LM13700's; same result. I added the extra stages which required 2 more cuts to the main board and splitting a jumper into 2 and then wiring the extra stages board and I got next to absolutely nothing. Quadruple checked EVERYTHING and re-flowed all solder, no difference. I took the extra stages off and reverted back to the modded version and yeah the most subtle phase/vibrato effect, back to the drawing board with this one...

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  15. Ah, fixed it. Even if you checked the layout 100 times, check it again. So I had a 100k resistor where a 10k was supposed to be, works perfectly now. Everything as per layout, it works with either LM13600 of LM13700, I thought the LM13700 had a slightly stronger effect but I could have been hearing things. I built the modded version first but it didn't really appeal to me, the intensity mod won't be useful for me and I couldn't understand the phase/vibe switch being connected to the intensity switch. I actually wired this switch as per Mark Hammer's advice "As per usual, vibrato would be achieved by lifting one end of the 27k resistor between pins 1 and 6 of IC1" and it works fine. Added a 10k log to adjust the width as per more of Mark Hammer's advice which works really well to narrow the width and added a 10uf electro between GND and the LFO, again Mark Hammer, thanks mate. Last but not least I built and wired in the extra stages making it an 8 stage phaser. It sounded great with out the extra 4, but the 8 stages does sound impressive. Probably more than what I need but they are in there now and it's not worth removing the board now, the effect can be tamed nicely with the depth and width control. Fit the whole lot in a 125B with room for a battery with not 0.5 of a millimetre to spare, seriously just squeezed the main board in solder side up right at the bottom where the box is widest. Reverse the RATE Sounds damn good, this is the phaser I have been looking for. Alex, thank you my friend for your time and genius. Just a note though, when I added the extra stages as per your layout it didn't work initially, so looking at Tonepad schematic everything checked out except R, I couldn't see a reference for that on Tonepad schematic nor could I relate it to yours so I removed that link and the unit then functioned perfectly! Have I made a mistake, I don't know but it works like a charm, thanks!

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  16. Ah I was trying to say above, reverse the RATE pinout as suggested by others so that it works as you would expect it too.

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  17. I didn't have any 50N caps So I wired a 47N and 3.3N in parallel to get close. The sound of 8 stages started to remind me of the ADA Flanger I built.

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