Tuesday 27 September 2016

Electro Harmonix Octave Multiplexer

Here is a layout for a classic pedal.
I've drawn 2 versions: Vintage and Modern.
There are 2 layouts for the Vintage: with and without output boost.
I've added a boost to the Modern layout to avoid volume loss.
You can find the original FSB thread here.
16/01/2017 Layout updated! I've changed the vintage layouts because there were some errors in the schematic.
Thanks to Barcley for pointing out the corrections that I needed to make!





117 comments:

  1. WOW! Alex you are unbelievable. Thanks. Man my build list is getting big. Respect!

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  2. Hi Alex. Thanks for some great layout once again. I build the modern one but I have some problem, I can't make it works. I tried to check my build but I wasn't able to find errors (it's maybe on my side but I didn't find). I also tried to change IC's and trannies in case of faulty one but nothing better. Any help would be very appreciate.

    Here is my voltage :

    5457 / D 5.44 S 4.62 G 4.66

    5459 / D 3.5 S 3.5 G 0

    4013 / 1/ 5 2/ 3 3/ 0 4/ 2,5 5/ 0 6/ 2,5 7/ 0 8/ 0 9/ 8.63 10/ 0 11/ 2 12/ 8,67 13/ ABOUT 7 14/ 8,72

    LM324 / 1/3,5 2/ 3,5 3/ 3,5 4/ 8,72 5/ 3,5 6/ 3,5 7/ 3,5 8/ 4,13 9/ 3,9 10/ 3,8 11/ 0 12/ 3,9 13/ 3,9 14/ 4,1

    4558 TOP / 1/ 7,35 2/ 3,5 3/ 3,5 4/ 0 5/ 4,17 6/ 3,5 7/ 2,3 8/ 8,73

    4558 BOTTOM / 1/ 1,5 2/ 3,5 3/ 3,5 4/ 0 5/ 3,8 6/ 3,6 7/ 2,6 8/ 8,72

    To finish, pics of my build :
    http://dl.dropboxusercontent.com/u/9520625/20161001_112634.jpg

    http://dl.dropboxusercontent.com/u/9520625/20161001_112718.jpg

    Thanks a lot for all your work

    ReplyDelete
    Replies
    1. Hi Thomas.
      Did you compare the layout to the schematic?
      I think it's ok but I won't be able to check again until Monday.
      I'm not able to see all the cuts from the pictures but I assume you already double checked everything.
      From your circuit picture, I think both transistors are reversed. Have you checked the pinout?

      Delete
  3. Thanks for the comment. I checked cut and pinout..
    I placed the tranies by respecting letters but I tried to reverse them without success.
    I tried to look at the schematic also but I don't hAve the knowledge to understand. I just know building.

    ReplyDelete
    Replies
    1. Hi Thomas!
      Had a look again and there were a couple of mistakes:
      from the 2n5457 Ground there is a 1M resistor that should go to ground, one row below (it goes to Vref on the previous layout).
      The 100n cap at the bottom right corner should be removed.
      I've already changed the layout.

      Delete
  4. OK I made the change and.... it's working. The modern version is verified. Thanks a lot for giving us another great layout).

    ReplyDelete
    Replies
    1. Cool! Thanks Thomas!
      Does it sound like the original?
      Is the JFet boost helping with volume loss?

      Delete
  5. It sounds very nice. I don't really know the original but from what I heard on the web it's close, maybe a bit more artefact (not on every setting).
    The boost help a lot, you can even have a volume boost so it's perfect.
    Thanks again for your work and the help you gave me.

    ReplyDelete
  6. IMO it's a bit misleading to talk about "volume loss". I own the reissue and modern XO version, plus a former bandmate has a vintage specimen. None of those have volume drop issues. Like johnk says in the FSB thread: "I found that it could use a bit more output so I added a Jfet boost to the output with a volume control". Boost afterwards isn't a bad thing and adds to usability. But nevertheless, the original is an octave pedal and always performs at unity level, no matter the source instrument. Adding a JFET stage and volume control are extra features that are not essential.
    +m

    ReplyDelete
    Replies
    1. My bad.
      Drawn the layout a while back and forgo why the boost was there.
      Glad it work though.

      Delete
    2. Damn i sound mean :) That was not the intention.

      I'll be building one soon(ish) too. And super great work man!
      +m

      Delete
    3. You are a mean! :)
      Don't worry.
      At least now people know the Vintage version without the boost should still work without any problem.

      Delete
  7. Verified the vintage with the boost. Sounds close to the YT vid but doesn't seem to track quite the same. Mind you those vids on YT make everything sound amazing.

    ReplyDelete
    Replies
    1. Thanks Gavin!
      Which video have you watched?
      The ProGuitarShop's above the layouts?

      Delete
    2. Yeh the one above the layouts.

      Delete
    3. PGS videos always sound perfect (different from reality).
      You should check some videos of the "Vintage" version.
      Don't know if they've been modified later for tracking issues.

      Delete
  8. hi alex..im so confused about number of the switch, any switch pinout images for this...im newbee..sorry for my bad english.... thanks

    ReplyDelete
    Replies
    1. Hi Agus.
      "Regular" Switches are always numbered the same on this blog:
      SPST:
      1
      2

      SPDT
      1
      2
      3

      DPDT:
      1 4
      2 5
      3 6

      3PDT

      1 4 7
      2 5 8
      3 6 9

      You can check Storyboardist page here:
      http://effectslayouts.blogspot.fr/p/general-layout-notes.html

      Delete
    2. oke,thankyou very much for suggest... i will try it....

      Delete
  9. Did anyone successfully build the vintage version (the one without boost)?
    Mine doesn't work and I can't quite figure out why :-(

    ReplyDelete
    Replies
    1. Hello Ozzy,
      ICLM324 parallel with the IC4013 has a lot of mistakes to the original shematics.
      1. The diodes D1 and D3 should tourn poles
      2.The connection betwen 2-13 should be discontinued
      3.Make to bridge 1-13 pin
      4.Bridge 10-6 should be discontinued
      5.Make bridge 10-7 pin
      Everything else is fine althoug there is a slight disagreement with some components.

      Delete
    2. Hi Barcley.
      There are no mistakes.
      The layout is identical to the boosted one and that's been verified.
      This is the schematic:
      http://www.freestompboxes.org/download/file.php?id=27474&mode=view
      LM324 is a quad op-amp and pins numbering can be swapped around to suit the layout.
      Please, next time, if you think there are any mistakes point them out to the person that has drawn the layout.
      That way we can explain all the possible changes we have made or correct the mistakes if there any (of course is more than possible, we are human).
      That way we'll avoid confusing people.

      Delete
    3. Thanks so much for your reply, Alex! Please can you check my wiring here, as I am not sure if I am doing it correctly?
      https://drive.google.com/open?id=0B8HeRqgTRGTCODI4WUpxTFYxSzg

      Delete
    4. Hello Alex,
      I do not want to convince you
      But you're wrong
      It is possible that you have misunderstood
      I guarantee what you publish
      All that I announce the first try.
      So this scheme octave Multiplexer(Vintage70`s)
      If you want to see for yourself, so try.
      My works perfectly and I am very satisfied.
      Oh yes, and I replaced the FET transistor with a J 201
      And finally, I do not intend to confuse people but to help advice, thank you.

      Delete
    5. Hello Alex,
      I do not want to convince you
      But you're wrong
      It is possible that you have misunderstood
      I guarantee what you publish
      All that I announce the first try.
      So this scheme octave Multiplexer(Vintage70`s)
      If you want to see for yourself, so try.
      My works perfectly and I am very satisfied.
      Oh yes, and I replaced the FET transistor with a J 201
      And finally, I do not intend to confuse people but to help advice, thank you.

      Delete
    6. Now I am really confused...
      Alex, please, could you check my board if you can see anything suspicious? Thanks a lot again!
      https://drive.google.com/open?id=0B8HeRqgTRGTCeUYyblVRSkk5RUE
      https://drive.google.com/open?id=0B8HeRqgTRGTCcGRjM1hfTzVEYW8
      https://drive.google.com/open?id=0B8HeRqgTRGTCbTk0bFJJblpmMnM

      Delete
    7. Hey Barcley!
      Sorry but I didn't understand what you've meant with
      "I guarantee what you publish
      All that I announce the first try.
      So this scheme octave Multiplexer(Vintage70`s)".
      Of course I could be wrong and any help is more than appreciated.
      What I was saying is that the vintage layout (with or without the boost are pretty much the same) has already been verified by Gavin and I trust his judgement.
      And I wasn't sure the schematic was correct until that moment.
      I have to relay on other people verifying them, I can't build all the layouts I draw.
      If you write a post addressed to Ozzy where you say that half layout is wrong and that there are parts missing people are gonna get confused because the layout had already been verified.
      And that doesn't mean you are wrong!
      If you address a post with your suggestions to "me" first, I would be more than happy to check them because none of us like to keep wrong layouts on the blog.
      That's what I was saying.
      Which schematic did you compare the layout to?
      This:
      http://www.freestompboxes.org/download/file.php?id=27474&mode=view
      or this:
      http://www.freestompboxes.org/download/file.php?id=26589&mode=view ?

      Delete
    8. Hi Ozzy!
      Can you add those pictures to the Debugging section of the forum with a description of your problem and ICs and JFet voltages?

      Delete
  10. Hi Alex
    I did not say that half of the schedule is not true.
    I'm pinpoint what is not good.
    I'm staying in their assertion.
    Maybe you did not understand me, my bad English is the reason, I'm sure.
    http://s514.photobucket.com/user/midnight_liberation/media/EHOctave_Multiplexer_1975.gif.html
    The first data schema for the vintage version is 99% of the match.
    Exscept apart from what I said.
    Check and see.
    I have made vintage version as the blog (not good).
    With my correction works perfectly.
    I have not invented anything new, I just applied logic.
    When something is not good, find the problem.
    Thank you for writing,I'm here if you need to clarify anything.

    ReplyDelete
    Replies
    1. Ok. Now I understand.
      I thought you've made your changes based on the schematic from FSB!
      Never seen the one you've used!
      What I don't understand is how the layout have been verified.
      Hey Gavin! Is the layout you've built working properly? (Apart from the tracking. I think the tracking is not as good as the newer versions anyway)

      Delete
    2. Mine never sounded what i expected so i think its in the debug pile at the moment. The sound and tracking were weird in not a good way, if i remember correctly. What exactly is the problem? Maybe i can try a fix.

      Delete
    3. Hi Gavin.
      I've thought it was working.
      Barcley has found a different "corrected" schematic:
      http://s514.photobucket.com/user/midnight_liberation/media/EHOctave_Multiplexer_1975.gif.html
      Try his suggested changes:
      1. The diodes D1 and D3 should tourn poles
      2.The connection betwen 2-13 should be discontinued
      3.Make to bridge 1-13 pin
      4.Bridge 10-6 should be discontinued
      5.Make bridge 10-7 pin

      Delete
    4. Thanks Alex. Don't know how missed the five steps by Barcley. I'll try and give it a go later. Have to run some errands first and fix my guitar hanging slat set up to the wall.

      Delete
  11. http://topopiccione.atspace.com/pjimages/EHOctaveMultiplexer.sch.gif
    Here is a link with two JRC4558 instead LM324.
    Link in the previous message with two LM324.
    I hope that now everything is clear.
    Greeting.

    ReplyDelete
  12. Hi guys,
    I've solved the problem,In 5 easy steps,and for me it's finished.
    I'll be satisfied if I helped someone.
    If someone wants my advice, I'm here.
    My pleasure.

    ReplyDelete
    Replies
    1. Hi Barcley, many thanks for helping me out. I will try your 5 steps and will report back with the results.

      Delete
  13. Ok, applied the changes mentioned by Barclay and its sounds much more like it should. Before it sounded like two signals out of phase, but i just wasn't sure if it was correct or not. Now its definitely correct. Cheers Alex and especially Barclay.

    ReplyDelete
    Replies
    1. It's crazy but mine doesn't work even with the above changes applied. Only hum comes out (sounding same like when touching an unplugged input jack). Please, can you recheck the layout once more? My ICs and JFET voltages are as follows:

      JFET 5459
      D - 4.3
      S - 4.3
      G - 4.6

      LM324 (upper one)
      1 - 4.3
      2 - 4.3
      3 - 3.8
      4 - 9.3
      5 - 3.8
      6 - 8.6
      7 - 0.6
      8 - 4.3
      9 - 4.3
      10 - 3.8
      11 - 0
      12 - 4
      13 - 4.3
      14 - 0.6

      LM324 (one next to 4013)
      1 - 8
      2 - 0.9
      3 - 0.9
      4 - 9.3
      5 - 0.9
      6 - 0.9
      7 - 0
      8 - 0
      9 - 0.9
      10 - 0
      11 - 0
      12 - 0.9
      13 - 8
      14 - 0

      4013
      1 - 9.3
      2 - 0
      3 - 0
      4 - 0
      5 - 0
      6 - 0
      7 - 0
      8 - 0
      9 - 9.3
      10 - 0
      11 - 0
      12 - 9.3
      13 - 0
      14 - 9.3

      Delete
  14. Hi guys,
    I'm glad that I helped a little.My greetings to Alex and Gavin,cheers.



    ReplyDelete
  15. Hi Ozzy
    Some voltages are not good.
    5 steps should only be used LM324 parallel with the 4013, not on the first above!
    How you apply?
    I'll give you my voltages but you must be a mistake somewhere.
    Also I see if your input voltage is above 9v,and that after passing through the diode D4.This shows that you do not have stabilized voltage 9v.My power suplie is exactly 9v after diode D4 8.39v in all integrated circuits.Although I think that this is not a real problem at your place but this is the basic thing.Application L7809 in power suplies.
    The following message sending these voltages.
    Check once more,do not give up man!

    ReplyDelete
  16. Hi Ozzy, i was just starting to measure my voltages when i discovered that after the pedal is on for a bit my voltages right across the pedal drop.Plugged it in and i lose the octave effect. It seems i may have an additional problem with my build. If i can figure it out and get it working properly i'll post the voltages for you.

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

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  18. J FET 201

    D - 4.19
    S - 4.20
    G - 2.60

    LM324(upper one)

    1. 4.20
    2. 4.20
    3. 4.17
    4. 8.39
    5. 4.17
    6. 4.21
    7. 4.20
    8. 4.20
    9. 4.20
    10. 4.13
    11. 0
    12. 4.15
    13. 4.20
    14. 4.20

    LM324(parallel with 4013)

    1. 7.11
    2. 4.13
    3. 4.20
    4. 8.39
    5. 4.20
    6. 4.20
    7. 0.02
    8. 0.015
    9. 4.20
    10. 0.02
    11. 0
    12. 4.20
    13. 7.11
    14. 0.03

    4013

    1. 1.70-2.50
    2. 3.20-4.10
    3. 0
    4. 0.03
    5. 0
    6. 0.015
    7. 0
    8. 0
    9. 4.90
    10. 0
    11. 3.40
    12. 4.90
    13. 2.50
    14. 8.39

    With these voltages works perfectly.
    If you find a mistake you made,I'm not sure it will help you a lot.

    ReplyDelete
  19. Thanks, Barcley!
    btw what vero layout did you use? The one that Alex had posted here originally?
    I rechecked everything and still didn't find what's wrong. Any tip where to look please?

    ReplyDelete
  20. Ozzy,yes, I used the schedule which is set Alex,with 5-step changes.The first schedule.It is now taken care of and you can see it.I will try it by your voltages to find something.You check under the scheme on the blog, now with the changes.Look at my voltages,Look at my voltages,where there is disagreement regarding check components.Lm324 upper one,pin 14 must be the same voltage as pin 13.Chek capacitors 22n which connects them.The same voltage must be on pin 6.Further,Lm324 parallel to 4013,the quad-opamp output pin1,7,8,14,must be a voltage.Check it out and diodes D1 i D4.Fet transistor is eccentric.That's what you've got brum is proof your signal goes to ground.Monitors signal from the start and the end.That's all I can do this.I hope that you will succeed.

    ReplyDelete
    Replies
    1. Great tip, Barcley. It finally works!!! Somehow I managed to miss a hair-thin bridge at one of the cuts.
      Thank you guys so much for helping me out! I truly appreciate it!

      Delete
  21. Congratulations Ozzy,
    we're here to help.
    Greeting.

    ReplyDelete
  22. hello guys...i've just finish to build, but there's a tremendous volume loss, even with pot volume all turned up...i changer just one thing: i put 2n5458 instead of 2n5459 (hard to find)...could it be the problem? i've build the modern one, is it verified?
    thanx

    ReplyDelete
  23. ok, solved it: it was just a solder bridge!
    an information: i used MPF102 insted of 2n5458, and it works better!

    ReplyDelete
  24. Hello alex where is the resistor clr for?
    And what it is

    ReplyDelete
  25. CLR= Current Led Resistor, i presume
    so, it should be between 2K2 and 4K7 (at least, these are what i use)

    ReplyDelete
  26. Hi guys. I also plan to build a clone of this pedal. So I found PCB in Sprint-layout format here. http://www.komitart.ru/guitar/716-sobiraem-effekt-octave-multiplexer-electro-harmonix.html

    ReplyDelete
  27. Sorry mates. but were are Sw1-4 and Sw2-4 connected to? I made it, i didnt connect Sw2-4 and Sw1-4 nowhere and the signal passes through, every knob does something... but it isnt remotely close to octave effect :P (i meesed up somewere)

    ReplyDelete
  28. I have some problem with the modern+boost version. (Is it verified, it isn't?)

    I replace the 2N5459 with a 2N5457.

    I have a big pop engaging and disengaging the circuit. I see just one 1M resistor in the boost section. Do I need of a pulldown resistor?

    Someone can tell us the right voltages of the JFET boost.

    Thanks!

    ReplyDelete
  29. In the vintage layout with boost, the small jumper near D2 needs to move up a row.

    ReplyDelete
  30. I'm having a good look at the schematic over at FSB and I noticed that it has two switches labeled "range" and "bass". Also near the Blend Knob is written "Toe Down". After a bit of digging I discovered there is a Treadle version of the Multiplexer. Looks like a wah. Im starting to think this is the schem for that version which might be exacty the same,but maybe not...

    ReplyDelete
  31. Hello, I keep waiting for help, please.
    Somebody else can confirm the modern+boost layout?
    Effect works, but I got pop when I switch the effect, and the volume can't be boosted, I can reach just the unity volume. Nonsense.
    I don't want to try a different layout.

    Thanks.

    ReplyDelete
  32. What flavour pop is it lemonade or coke

    ReplyDelete
  33. It is the classic bump we get sometime when we built true bypass effect.
    I left the circuit away until now. I hope I can check it again this month.

    ReplyDelete
  34. Volume boost isnt the deal man

    ReplyDelete
  35. The mod is to stop volume DROP, volume boost isnt the aim of this, does the pedal work at all man???

    ReplyDelete
    Replies
    1. This comment above says that I should have a volume boost:
      http://tagboardeffects.blogspot.com/2016/09/electro-harmonix-octave-multiplexer.html?showComment=1475578232657#c6426579283797435756

      The pedal works fine, except for the loud pop when I activate and disactivate the effect.
      I'm using a toggle switch for test it. And, I can get a barely decent volume (maybe even a bit quieter than the bypass) just if the volume pot is at max. Then the output booster is useless.

      Delete
  36. You get pop with mechanical switches man, no way round this, put 1 m resistor to ground might help a bit

    ReplyDelete
    Replies
    1. I guess I tried it. On the two narrow stripes INPUT and SW 1-5 (it's on ground). And maybe between the tip and the sleeve of the input jack.
      It's sometime ago, I don't remember well, but it seems pretty logic to try it.

      The layout should be verified, I can't get how I have this issue.
      Expecially this strange thing about the useless booster. If the work of the booster is to avoid the volume loss why I have tu used it at max and get the same output without it?

      Delete
  37. Ok man, im gonna build this in the next month, i will tell you what i find, ive built the dyna comp and small clone from this site and had no issues so i take it these are verified

    ReplyDelete
    Replies
    1. Thanks, it could be useful!
      I built the Modern Version, the third layout.

      Delete
  38. Hi, has there been any update on the "popping switch" issue? Getting this on mine - built the 70`s version with a jfet booster and getting the same popping problem everyone else seems to have.

    ReplyDelete
    Replies
    1. I was waiting some news from Gutbucket. It's not a good news if you get the popping switch even with a different layout. I used the modern version.
      I soldered temporarily a toggle switch for the bypass, the jfet booster doesn't boost but just cut volume.
      Where did you buy your parts? I used to buy from Tayda, but the toggle switch should be from Musikding. The 2N5457 I don't remember exactly, probably I found it in an italian shop. I think I try a J201 and a 2N5458.

      Delete
    2. Hi, many thanks for the update :)

      I buy my parts from a variety of sources, but the main one is bitsbox.

      Going to have a play around and see if I can get rid of the popping.

      May try a soft switch to see if this helps, or a 1M on the input. Will put my scope on it and see if I can cut it a bit.

      Delete
    3. There's the 1M pulldown resistor in both layouts with the jfet booster, but not in the '70 vintage, I think.

      Anyway the Modern and the Vintage with boost should be verified with any issue. Refractions and me got the pop.
      I'm just trying to guess, but maybe the popping problem is in the jfet added. I can't do it now, but maybe, Refractions, you could try to exclude the boost in your board and see what happens.

      Delete
  39. Hey man gutbucket still here, alive n kicking, just lol
    Started this build in nov,
    Life got in the way, not finished yet
    Will get it done soon, apologies

    ReplyDelete
  40. Version with JFET booster does not work. I built modern version but I was unable to use JFET booster. I simply removed this part of circuit by unplug 2N5457 FET and Volume Pot. Blend 2 connect to SW1-3. Now, modern version without booster works perfectly. For other FET I replaced 2N5459 by BF256B. Very nice working effect.

    ReplyDelete
    Replies
    1. I built the Modern Version, effect works fine, but I got two problems.
      1. The Volume pot works, but it really doesn't boost, I have to keep it at max to get the unity bypass volume.
      2. There's a loud pop when I engage and disengage the circuit. I couldn't take off this pop trying to include an input pulldown resistor (which I think there's already on the board).

      So I guess there's something wrong with the JFET booster section, but I still have to try to exclude that, (thanks for the instructions, Icziko). Though I find it really strange, I mean, a booster in the end of the circuit should control the output volume, right?
      I seen a PCB version that does it.

      Delete
  41. HI what is the difference between the vintage and the modern version???

    ReplyDelete
    Replies
    1. I think it's just one of the two LM324 is replace by two 4558, but it should be change nothing in the sound.

      Delete
    2. the modern version has something else different, the high filter is A100K and a few values change too. Check it on the schematic I put in the debug section

      Delete
  42. Thanks for working for us. I'm still busy to work with my popping modern + boost version.

    ReplyDelete
  43. Hi! I made a new layout from a new schematic in the debug section. Could anyone please give it an eye? Maybe it could be the solution to the pop issue. I hope it 'cause my pop is really loud! :S

    ReplyDelete
  44. after 2 years i've builted it, i've just finished boxing it; and i noticed the volume loss: with pot at max, it still gets a little volume drop...how can i solve it?

    ReplyDelete
  45. Hi, which one did you build? vintage or modern? with boost? I experimented with different jfets and I see those components change a lot about the volume. The one I made has no problem in boosting

    ReplyDelete
  46. i've built the modern one (i prefer modern sounds); i tried 5457 and 5458 (i dont have 5459); but since you say ll try some others...!!! thanx!

    ReplyDelete
  47. trie every sort of jfet i have: bf245, j201 (dont work with it), 2n5458, mpf102, and the best results are with 5457/5459...anyway, there's probably something wrong in my build: treble pot dont work well, and blend pot doesnt affect sound at all!!

    ReplyDelete
    Replies
    1. my build works nice for the boost section, I used a j201

      Delete
  48. This comment has been removed by the author.

    ReplyDelete
  49. i! for anyone who has the "pop" issue:

    1. put a jumper between Sw 1.1 and Sw 1.2
    2. take away the 100nF between Sw 1.2 and OUT Jack
    3. take away OUT jack wire
    4. IN Jack becomes IN
    5. Vol2 becomes OUT
    6. Sw 1.5 becomes GROUND

    then make it true bypass with the classic 3PDT connections

    ReplyDelete
    Replies
    1. sorry, number 1 (put a jumper) is useless if you take away the 100nF :S

      Delete
    2. even taking away the 100nf is useless unless you want to save the component. so:

      1. take away OUT jack wire
      2. IN Jack becomes IN
      3. Vol2 becomes OUT
      4. Sw 1.5 becomes GROUND

      Delete
    3. andrea, thanks for your help... And the rest of connections of the dpdt switch?
      I mean... what I have to do with Sw 1. 3,4,5 and 6? Take them away?

      Delete
  50. really your circuit woks well with j201?? mine doesnt even make a sound with j201...:-(
    about "pop" issue, do you mean with "octave" switch, or normal bypass switch?

    ReplyDelete
    Replies
    1. The problem with the pop is in the bypass switch.
      I suspect you have some other problem with this circuit.
      My sounds fine, as it should. But I have no boost volume, just max unity gain, and I got this loud pop every time I use the bypass switch.

      I would like to try to modify the original Modern Version + Boost for a classic true bypass, and I hope I can get more volume modifing the boost section. Suggestions about this last step?

      Delete
    2. Hi Crustone, I put a 2n5458 in the circuit and a j201 in the boost section. check for the right pinout

      Delete
  51. today i unmounted everything; debugged it for more than an hour, and nothing was wrong; and we i tried it again, it worked!!! i guess it was just too compressed in the box!
    now it has a huge amount of volume;
    and about the popping of elijah, i can say that mine doesnt pop at all with bypass, it pops just with octave switch (i use a toggle switch, so i dont really care if it pops)
    Could it (the pop) be due to improper wiring (or, mostly, not proper enought) like 3pdt connections for example, or not enough shielding (now i use to put negative wire on earth,to the box)??? just to say...
    anyway, about volume loss, believe me that if it works, it has really more than enough volume

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    1. well done crustone! what did you use as jfet?

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    2. C'mon! How heck you did?! No pop and loud volume!
      What's the problem with this project? Why some of us have this problem? Has someone else pop and volume problem like me?

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  52. i used the original jfets: 5457 and 5459:-)
    for elijah: i've built 20+ diy stomps, always with veroboard
    ALL the times i had problems (half of total:-), it was just my fault...ne solder joint, one connection not really connected, wrong wiring, wrong parts wired, wrong transistor pinout, faulted or burned transistor, boards too heavily compressed into the box, etc.etc....all these verified projects are really working and verified...maybe sometimes can be a little difference due to the transistor itself (different model, or different gain), but it should be a little difference
    it's always a good habit to double check everything...and then, triple check everything:-)
    at least, in my case, it's always MYSELF the only "error" in the circuit:-)

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  53. anyway, if you read the previus posts, you are not the only one that experience pops and low volume, but i guess in every case there is some error of the builders, and not of the designers:-)

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  54. Thanks for your reply. I checked my board a lot of time, and probably this is my best and cleanest build, though you're right. Sometime i made some mistake, then I sovled. But now I can't see any mistake, and it's just a bit weird that some people got the same issue. I tried a pair of maybe more JFET.
    My board is out of the box, it's just wired with the switches, sounds good enough, except those issues.

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  55. good idea to replace jfets: it's happened to me to have replaced transistor, and circuit didnt work...only when i replaced for the third time, it worked:-)
    upper in this thread theere is a list of voltages: you can try to measure yours and compare them (here: https://tagboardeffects.blogspot.com/2016/09/electro-harmonix-octave-multiplexer.html?showComment=1484506237750#c2409698487636249710 )

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    Replies
    1. anyway, i know how you feel!
      everytime i make a mistake, then i learn from it; so next time something's wrong i dont make the same mistake again (usually, at least)...but i always find a new way to make new mistakes:-)

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  56. This comment has been removed by the author.

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  57. Hi everyone, one question...

    I have finished the vintage mod with booster and i don't know sure where conect the grounds. I have built always with 3pdt and now i am confused.

    I have made:

    board ground--- to--- dc ground---- to----input ground----to output ground....

    Is that correct? or have i to joing also with dpdt?

    thanks for you help

    thanks

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  58. I finally worked on my Multiplexer Octave Modern version. My problem was the lack of volume though Volume pot maxed and the huge bump when I switch the bypass DPDT.
    I made the usual true bypass wiring, and it doesn't bump anymore!
    I just noticed, even before the off board wiring, a bit of noise, like a rumble, especially with single coil. Less in some combination with two single coil and humbucker pickup.

    Is it normal this rumbling noise?

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    Replies
    1. It was me, I written the post above. Sorry, I wasn't logged!

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  59. What does that trimmer actually do? Doesn't seem to do a whole lot in my build.

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  60. Hello, I would like to know specifically what would be the Transistor used in the first layout. Please anyone who knows tell me I need soooo much.
    Thank you in advance.

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  61. Hello, I would like to know specifically what would be the Transistor used in the first layout. Please anyone who knows tell me I need soooo much.
    Thank you in advance.

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  62. it's written on the side, dude: it's 5459!
    i've made the second one, and they are 5457 and 5459

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  63. Hello ! First thank you for the great job ! I am a beginner (That's just my 2nd stompbox), so i don't understand where i should connect SW2-3 in 6th line... (i read the thread, viewed pictures which are still available but didn't find the answer). Can someone help please ?

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    1. I think i finally found... according to this schematic : https://www.freestompboxes.org/download/file.php?id=27474&mode=view
      I think SW2 is identified as BASS switch and so SW2-3 connects to point between C13 R25 and R26. This doesn't totally solve my problem of connection but now i just have to try to find teh good place in totally right side.

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  64. Hello! Nice work and as far my Modern Version works well. But is it normal that I've got a little fuzzy effect? Saw some videos with the original one, but didn't mind this "side effect" just because I would build a clean Octaver so I'd choosed the Multiplexer. For me it's a bit annoying ;) So if there is a solution I appreciate any help :D

    Greetz
    Thomas

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  65. On the modern version: CD4013 has a jumper between pins 9 and 12 which is correct. However it also has a 27K resistor between the two pins. There should be a cut between the top of both the jumper and the 27k resistor.

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  66. Sorry the cut should be at the the bottom of both, not the top.

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