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Thursday, October 18, 2018

Hughes & Kettner Red Box Mk. II

Here's a nice utility box for home recording or even live application (if you've run into a sound guy who hates guitar amps 😠). It's a direct box but also a cab sim (4x12). It won't run off phantom power, so just power it with a 9v wall wart or a battery. Also, connected to the Speaker In pad should be another jack for "speaker through" (so you don't blow up your amp). Here's the schematic and original user manual for reference.



Update Nov. 15:
I removed the extra components for ground lift application as most reported it not working and they had better success with placing an on/off switch between XLR pin 1 and ground. YMMV
at

49 comments:

  1. FilinOctober 18, 2018 at 11:06 AM

    Will you made 2nd ver with phantom power?

    ReplyDelete
  2. UnknownOctober 18, 2018 at 3:01 PM

    The layout seems to be lacking the "speaker through" jack that appears in the schematic. You could fry your tube amps output transformer, if you plugged it in this without a proper speaker load!

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    Replies
    1. Effects LayoutsOctober 18, 2018 at 3:52 PM

      Info added to the original post. Thanks for reminding me about that!

      Delete
  3. andrea83October 18, 2018 at 5:09 PM

    Great thing! Thanks!

    ReplyDelete
  4. AnjangOctober 21, 2018 at 10:26 PM

    Ground/lift spst is wrong i thing...
    Closed switch XLR1 must be direct to ground.. and open switch XLR1 bridge to 100n & 10 ohm to the ground...

    ReplyDelete
    Replies
    1. Arnold DikstaalOctober 27, 2018 at 7:05 AM

      I think so too: http://www.patentsencyclopedia.com/imgfull/20150087187_09

      Delete
    2. Arnold DikstaalOctober 27, 2018 at 7:16 AM

      This comment has been removed by the author.

      Delete
    3. Arnold DikstaalOctober 27, 2018 at 7:39 AM

      Hmmmz, although I also found this: http://stompville.co.uk/?p=359, but look like all ground should go to the RC couple and then to ground instead of the construction here that XLR1 only goes to the RC and then to common ground. Any thoughts?

      Delete
    4. Arnold DikstaalOctober 27, 2018 at 7:54 AM

      And then there is this: http://sound.whsites.net/articles/mic-splitting.htm#s8
      same as in the layout except that the RC network is always connected to XLR1 and ground and the switch only connects XLR1 to ground.

      Delete
    5. Arnold DikstaalOctober 27, 2018 at 9:36 AM

      and finally: http://www.epanorama.net/documents/groundloop/groundlift.html

      Delete
  5. AnjangOctober 21, 2018 at 10:29 PM

    I relayout this.. and put some resistor & diode for phantom.. its work

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    Replies
    1. UnknownOctober 22, 2018 at 12:53 AM

      Hi, can you post a picture of your layout? very interested in this...

      Delete
  6. AnjangOctober 22, 2018 at 1:12 AM

    This circuit cannot be direct from instrument, line in is mean the signal come from preamp out.
    So we need some preamp before line in.

    ReplyDelete
    Replies
    1. UnknownMarch 9, 2021 at 9:57 PM

      can it be like pedal preamp? or just head amp?

      Delete
  7. ElRuso82October 22, 2018 at 3:24 PM

    Hello! Why are the 1UF capacitor drawings so big? Are they polyester? Are more than 16V?

    ReplyDelete
    Replies
    1. andrea83October 22, 2018 at 4:07 PM

      hi, they're not electrolytic. yes they can be polyester

      Delete
    2. ElRuso82October 24, 2018 at 7:56 AM

      Thank you very much for your answer!!!

      Delete
  8. Arnold DikstaalOctober 25, 2018 at 7:58 AM

    And for those who want it, here is the manual:
    http://oldies.hughes-and-kettner.com/Red_Box_Mk%20II/REDBOXMK2.PDF

    ReplyDelete
    Replies
    1. Arnold DikstaalOctober 25, 2018 at 8:02 AM

      oeps... sorry, was already in the original post :)

      Delete
  9. UnknownNovember 5, 2018 at 5:17 AM

    This comment has been removed by the author.

    ReplyDelete
  10. rock561November 6, 2018 at 7:57 AM

    Я сделал этот макет и он работает! Всё в порядке. Вместо TL062, я использовал попавшиеся под руку TL072, но позже я заменю их на TL062. Я собрал без переключателя, потому что здесь есть небольшая ошибка. В положении А штекер №1 должен идти на землю, в положении №2 всё правильно через резистор 10 Ом и конденсатор 100uF. Так же вместо разъёма XLR я поставил обычный Stereo Jack, но позже я его тоже заменю на XRL. В наличии просто не было)) Если кому нужны фотографии, то есть несколько - пишите.

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    Replies
    1. Arnold DikstaalNovember 6, 2018 at 8:03 AM

      English? But ok, google translate was my friend :) I agree there is a mistake in the groundlift. PS I hope u used a 100nF and not a 100uF.

      Delete
    2. rock561November 6, 2018 at 10:55 AM

      Yes, 100nF :) But I removed these components and installed a simple jumper from the XRL 1 to the ground. And added a light indicator.

      Delete
    3. rock561November 6, 2018 at 10:57 AM

      This https://yadi.sk/d/aZwDPQBqRM6Jwg

      Delete
  11. rock561November 6, 2018 at 10:57 AM

    This comment has been removed by the author.

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  12. UnknownNovember 19, 2018 at 6:16 PM

    can we use tl072 with this circuit?

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  13. jgpedalesDecember 7, 2018 at 9:38 PM

    where is the ready for transfer?

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  14. sinaiDecember 13, 2018 at 3:14 AM

    Hi i did not find transfer image in library kindly help.

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  15. jgpedalesDecember 14, 2018 at 8:24 PM

    For use with bass need some capacitor changes?

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  16. sinaiDecember 18, 2018 at 11:34 PM

    This comment has been removed by the author.

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  17. sinaiDecember 19, 2018 at 1:34 AM

    This comment has been removed by the author.

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  18. sinaiJanuary 12, 2019 at 5:52 AM

    Hi i have made this and working but very low output kindly help, to increase output i have removed input ground 10k resistor it increased some out put but still very low and hissss sound is coming anyone can help me?
    Thank you.

    ReplyDelete
    Replies
    1. jgpedalesJanuary 13, 2019 at 9:32 PM

      It must be conected to a mic input

      Delete
    2. sinaiJanuary 14, 2019 at 11:42 PM

      hi tnks, but i have connected this circuit to xlr mixure input and problem remains same in xlr input thats why i need help, i have used tl072, diode 1n5819, 68nf tantalum and removing ground to xlr 1 creates horrible noice so in my circuit it is must to ground always connected, i have checked all resistors are properly connected.

      Delete
    3. jgpedalesJanuary 22, 2019 at 9:07 PM

      ok, you need a line level input or output of amplifier as user manual explain. If you are conected like that maybe is a problem in the pcb or even a bad CI.

      Delete
  19. sinaiJanuary 12, 2019 at 5:53 AM

    I have used TL072CP ic and can be reason for low output?

    ReplyDelete
    Replies
    1. jgpedalesJanuary 25, 2019 at 9:30 PM

      ok, you need a line level input or output of amplifier as user manual explain. If you are conected like that maybe is a problem in the pcb or even a bad CI.

      Delete
  20. UnknownMarch 9, 2021 at 9:55 PM

    i was looking out the manual and i have a very important question... its just for guitar amp? or can i connect it at last of my pedal chain and use it to go direct to pa/mixer?

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    Replies
    1. Effects LayoutsMarch 10, 2021 at 10:06 AM

      You can connect it to your pedal chain and run it to the PA. Though I would suggest putting some sort of preamp before it.

      Delete
  21. Zaraki1337July 31, 2021 at 9:40 AM

    Can this be used for bass?

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    Replies
    1. Effects LayoutsJuly 31, 2021 at 9:56 AM

      Don't see why not

      Delete
    2. Zaraki1337August 11, 2021 at 10:48 PM

      Cool.
      And what to do with line in and speaker in? Sud we connect speaker directly?



      Can u elaborate im quite dumb in this DI thing

      Delete