Pages

▼

Wednesday, 25 October 2017

JHS Twin Twelve V1

From the source:

The JHS Twin Twelve is the first effects pedal to go after the sound of the short-lived but revered Silvertone 1484 Twin Twelve. Available through the Sears catalog from 1963 - 1967, the Twin Twelve was not regarded in its day as a premier amplifier. However, modern players looking for a vintage sound have increasingly turned towards this Silvertone as a primary stage and recording amp. Artists such as Beck, Death Cab For Cutie, Vampire Weekend, The White Stripes and even Coldplay have used the Twin Twelve amp on stage, making it the vintage amp with the most indie-cred. With the market for original specimens drying up and prices increasing, JHS has come to the rescue by putting that sound in an easy-to-use pedal.

 The original was a 60 watt, all-tube head with a separate 2x12 cabinet. At the heart of its sound was a Baxandall tone circuit, powered by a pre-amp the broke up in a way that few other amps do. It wasn't as glassy or snappy as a Fender Tweed, or as treble-rich as a Vox from that period. Rather than going into harmonic crunch like a dimed Marshall, the Silvertone 1484 would get borderline fuzzy, with a very saturated and thick natural overdrive. Its satisfying clean-ish grit and woolly overdrive have become a defining sound in modern indie rock.

Part of the magic is in the charge pump, which ramps up the standard 9V power it takes to 18V, giving the Twin Twelve pedal even more headroom and punch. The Twin Twelve then uses a series of discrete transistors that mimic the valve stages of the original Silvertone. Bass and treble controls remain true to the ratios of the original amp, while separate Gain and master Volume knobs help you achieve the thick, high-gain saturation at low volumes that was only possible by diming the amp back in the '60s.  



at

51 comments:

  1. Anonymous25 October 2017 at 23:13

    Oh boy.. I've been waiting for this one for a LONG time. Thanks for posting it!

    ReplyDelete
  2. neal gardner26 October 2017 at 04:32

    Which IC are you using with this one? Missing from layout. Thanks!

    ReplyDelete
  3. vince26 October 2017 at 05:00

    I think there is a problem here on this perf layout. if you look at the incoming 9+ bat voltage it goes nowhere and shorts the IC.

    ReplyDelete
    Replies
    1. Zach26 October 2017 at 17:44

      the ic is a MAX1044 and isn't shorting out, it's a voltage doubler.

      Delete
  4. Unknown26 October 2017 at 08:54

    making this for sure, when biasing the trimmers to 50% are we talking 4.5v or 9 v at it runs at 18v

    or are we talking see what the max and min the trimmer goes to and use half of the number?

    I've had nothing but trouble with J201's in the past, they're a pain in the arse

    ReplyDelete
    Replies
    1. Zach26 October 2017 at 15:47

      Bias to 9V since the charge pump puts out 18V.

      Delete
    2. Duncan26 January 2018 at 16:16

      I can get the first 3 trimmers to 9v, but the last one will only go
      to a min of 10.5v

      Delete
  5. HamishR26 October 2017 at 12:32

    I think you might need to look at the cuts around the second transistor from the bottom - you have the voltage going to the supply rather than drain. Can that be right?

    ReplyDelete
    Replies
    1. Zach26 October 2017 at 15:47

      You're right, the voltages sound be going to the drain not supply. I was moving stuff around and missed that. I'll fix it later today.

      Delete
  6. Zach26 October 2017 at 17:45

    layouts's been updated with the IC and fixed the transistor.

    ReplyDelete
  7. Hozy3126 October 2017 at 17:59

    This comment has been removed by the author.

    ReplyDelete
  8. Dutcheffects27 October 2017 at 09:47

    Can I also use an ICL7660S as IC?

    ReplyDelete
    Replies
    1. Blackwing27 October 2017 at 12:11

      Pretty sure you can. Also, lt1054.

      Delete
    2. Dutcheffects27 October 2017 at 13:03

      Great, going to try it this weekend.

      Delete
    3. Duncan25 January 2018 at 12:58

      @hans - did you build this with a ICL7660? I am using one and i think pin1 is NC?

      Delete
  9. D.C.28 October 2017 at 05:28

    Is there any proof that this is the real JHS Twin Twelve schematic?

    I first saw this circuit pop up on effectslayouts.blogspot.com. It's the first result if you Google "JHS Twin Twelve schematic." They state that their source schematic is this image: http://guitar-fx-layouts.42897.x6.nabble.com/file/n18170/destijl%2520revision%25202.jpg

    ...which, interestingly enough, comes from this very website's forum. Just do a search for "Silvertone"; it's the thread titled "Silvertone 1485/Twin Twelve." That thread traces back to a post on freestompboxes.org titled "eighty seven percent - De Stijl."

    This circuit is an individual's attempt at doing a tube -> FET conversion of a Silvertone amplifier circuit. I have seen no evidence that this is the actual schematic for the JHS Twin Twelve.

    However, I'm glad to be proven wrong, if someone can provide a source.

    ReplyDelete
  10. Krik28 October 2017 at 16:07

    Hi,
    Nice Layout. If you swap 12k and 47R on the rifgt side, you have open lugs for the volume pot.

    ReplyDelete
  11. Krik28 October 2017 at 17:07

    Oh, and +9V should go to the upper right corner, not the left I think.

    ReplyDelete
  12. Krik28 October 2017 at 17:20

    and Q3 seems to be upside down, drain should face toward supply

    ReplyDelete
    Replies
    1. HamishR29 October 2017 at 11:05

      Yeah Q3 still isn't right. I didn't want to be Mr Poopypants because I already mentioned it was a bit dodgy and I'm sure Zach knows more than I do! But I don't think it will work as-is.

      Delete
    2. HamishR29 October 2017 at 11:06

      Yeah Q3 still isn't right. I didn't want to be Mr Poopypants because I already mentioned it was a bit dodgy and I'm sure Zach knows more than I do! But I don't think it will work as-is.

      Delete
    3. Zach29 October 2017 at 14:02

      No worries. Yea it's still wrong. I quickly tried to fix it during the height of my finals, so I wasn't all there if you know what I mean. It's real quick easy fix and I'll fix it when I get home.

      Delete
  13. Zach31 October 2017 at 03:02

    Finally got home and fixed the layout. super quick easy fix. Q3 should now have power going to the drain as it should.

    ReplyDelete
  14. Zach1 November 2017 at 01:29

    fixed the location of the +9V, had to flip it to the other side of the IC.

    ReplyDelete
  15. Baldness8 November 2017 at 21:30

    Couple of stupid questions here, please forgive me. Volumes 1,3 and gain 2 are on the rim of the board. Is there a reason for that? I have never seen that before. Is it a mistake? Again please forgive me if that is a stupid question.

    ReplyDelete
    Replies
    1. Zach9 November 2017 at 03:46

      my fuck up when i was moving stuff around. fixed the layout, cause it should have been 20x20 making those connections to the board.

      Delete
    2. Baldness9 November 2017 at 04:27

      Awesome tyvm. NOW thinking about it I feel pretty stupid lol I should have known that was the case. anyway thank you for fixing it. I plan on making it in the next week or 2. I have a very busy schedule and a huge honey-do list from the wife, but it is next on MY list lol.

      Delete
  16. Zach10 November 2017 at 00:45

    updated the layout again. there were a few misplaced components and gain 1 wasn't connected as it should have. should be good to go now.

    ReplyDelete
    Replies
    1. Unknown10 November 2017 at 07:47

      glad I've just caught this, populated the board let night but gone with the old 19 x 20 so will get creative with the wiring of the pots. nothing else changed from what I can see?

      Delete
    2. Alex10 November 2017 at 09:13

      Hey Zach!
      It could still be a 20x19 layout by eliminating row A if you want(not a major difference).
      The 2nF - 12K connection on row E-17/18 can be lowered to G-17/18 (the 2nF would span 3 rows).
      Add a cut on G-12.
      D2 should go from row E-5 to B-5 (instead of A-5).
      Now you can lower the 10uF cap, D1, IC1 (and their cuts) and the +9V connection 1 row down.
      It could also become a 20x18 but you would have to move more components on the right side (again, it would not make much difference)

      Delete
  17. Unknown17 November 2017 at 11:27

    Hi, made this one using a TL1044s and biased all the J201's to as close to 9v as I could, sounds bad ass, loads of low end boarders on fuzz at higher gain settings. can consider this one verified

    ReplyDelete
  18. Elijah-Baley7 January 2018 at 11:16

    Did someone make work the updated layout 20x20?

    I also found this one older pretty similar layout: http://guitar-fx-layouts.42897.x6.nabble.com/file/n18809/1485.png

    This is the the basic schematic: http://guitar-fx-layouts.42897.x6.nabble.com/file/n18170/destijl%2520revision%25202.jpg

    You can read the thread here: http://guitar-fx-layouts.42897.x6.nabble.com/Silvertone-1485-Twin-Twelve-td18170.html

    ReplyDelete
  19. Brad Graham8 January 2018 at 19:09

    The 20 x 20 worked for me. I tested it a few weeks ago but haven't boxed it or played with it since. I think I was getting ~15V with the IC I used, so I biased to half that.

    ReplyDelete
  20. Elijah-Baley9 January 2018 at 21:02

    Thank you.
    I'm still thinking about if I have to build this pedal, of course I like it, especially if it really sounds as the original.

    Anyway, I should to get an ICL7660S. Your 15v seems a bit low. I assumed to get at least 17v.
    Do you remember the IC you used? Did you check some possible mistakes?

    ReplyDelete
    Replies
    1. Brad Graham10 January 2018 at 18:37

      It's a Max1044 from Tayda. I was measuring at D1 before. I checked it at D2 and it's about 17.5V.

      Delete
  21. Unknown15 March 2018 at 23:45

    Need some help. I built it but volume is low. All the way up is just above unity and bass control is practicly useless.

    ReplyDelete
  22. Unknown18 March 2018 at 09:03

    Hello. I can't rule any Voltage using the trimmers. They just lower the voltage from let's say 17.5 to 17, it doesn't go lower than that. What could be wrong?
    Thanks!

    ReplyDelete
    Replies
    1. Jcows24 March 2018 at 19:59

      My guess is wrong value trimmer, bad jfets, or something is connected that shouldnt be. Try different jfets, then double check your cuts and links, then check your trimmer values.

      Delete
  23. Jcows24 March 2018 at 19:56

    Thanks for your hard work on this great layout. I do have a small issue and it is concerning the bass knob, it has very little affect? I built two and both behave the same. Is there anything I could try to get more bass action?

    ReplyDelete
    Replies
    1. Jcows24 March 2018 at 20:00

      ..

      Delete
    2. Unknown1 May 2018 at 03:13

      I have the same issue. the bass is not as powerfull as the videos, and the bass pot doesn't boost the bass that much...

      Delete
    3. kg9016 May 2019 at 18:51

      you can calculate the values of the eq section easily with this program, james passive bandaxall type http://www.duncanamps.com/tsc/
      i suggest to lower the 22n to 2n etc.. it will have more effect on bass side

      Delete
  24. Ffdream6211 October 2018 at 20:38

    Hi guys ! How does it sound on your sides ?

    ReplyDelete
  25. Iago10 December 2018 at 15:55

    Is the circuit in a metal enclosure? Have you wired the grounds correctly? I'd also recommend trying more jfets. After the bias is adjusted to your liking, remove every jfet trimmer, measure their resistance and use fixed resistors in their place.after all of this is done, if its still noisy it has to be a particularity of the circuit.

    ReplyDelete
  26. Duncan28 June 2020 at 16:42

    Im having a bit of trouble with this - My bass control is non responsive. According to this schematic, which is the BASS control? http://guitar-fx-layouts.42897.x6.nabble.com/file/n18170/destijl%2520revision%25202.jpg

    Any tips how to debug the bass control?

    ReplyDelete
  27. Cochois2 September 2020 at 17:55

    Hi,
    Did you manage to avoid that noise ?
    I have the same problem, checked everything, I’m out of idea..

    ReplyDelete
  28. JaySharp5 February 2021 at 19:28

    Mine is very noisy as well. Anyone found a solution?

    ReplyDelete
  29. Philip G7 February 2022 at 15:29

    Hello Zach,

    Thank you so much for all your great work, I really appreciate it, I’ve learned so much on your site. I just built this and initially I absentmindedly biased the J201s to 4.5V and the pedal was working. I then remembered that I needed to bias to 9v but when I did so I got no signal. It’s just dead quiet. I then looked at the charge pump and noticed it’s only outputting 9V. I tried an LT1054 and the result was the same. I’m fairly sure that the connections on my build match your layout, have you come across this before? Just to make sure I’m doing it right, where should I be measuring ~18V output from the IC?

    I tried consulting the IC’s datasheet to confirm the charge pump’s layout, however I’m not quite as proficient at that as I might have liked.

    Thanks again for your work,
    Philip

    ReplyDelete
  30. Ian15 August 2022 at 19:13

    This comment has been removed by the author.

    ReplyDelete
  31. Ian22 August 2022 at 21:23

    If you want better bass response, change the 68K resistor connected to the bass pot to 27K and the 100k resistor nearest to the 1n capacitor to 1K

    ReplyDelete