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Friday, 11 January 2013

Runoffgroove "Big Grace"

Big Daddy and Grace circuits have this at the end of their document page: The two circuits are very similar and it may be possible to use a switching system to alternate between the buffer and the gain stage versions. (ROG)

 Now did i really have a choice? :) Instead of using some monstrous 4PDT switch, i thought it would be just easier to accomodate both, the JFET buffer and JFET gain stages, on the same board and use 2PDT switch to switch between them. Takes more components, but i think you can build three of these circuits for the price of a single four poled switch.. So. I dubbed it, the "Big Grace".



Demo of his build by Madferret.  Thanks mate :o)



New demos by Geiri.


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24 comments:

  1. Dave11 January 2013 at 11:47

    Good work Miro, i also read that comment and was going to build both and make them switchable. This way i will save some vero though, cheers!
    Dave

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  2. Grizzly11 January 2013 at 14:32

    This looks interesting, thanks both for your hard work! What diode is being used? And, any plans to do the ROG Umble?

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    1. mirosol11 January 2013 at 15:06

      Diode is for polarity protection, so 1N4001 or 1N5817 will be fine.

      Umble is in the to-do list... Might take some time though.
      +m

      Delete
  3. Grizzly11 January 2013 at 15:13

    Brilliant, thanks!

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  4. Madferret11 January 2013 at 20:04

    Hey guys, you can mark it as verified. Thanks for this Mirosol, it's pretty interesting to compare the two circuits with a flick of a switch and it feels like you're getting two for the price of one. Overall I think I prefer the Big Daddy side with my tele and the Grace side with my SG copy. The buffer seems to help the humbuckers sparkle more but seems a bit harsh with the single coils.

    If I take out the 100nf cap and replace it with a DPDT switch would it be possible to use two different cap values to alter the treble/bass coming through? Or am I barking up the wrong tree?

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    1. IvIark11 January 2013 at 22:49

      Nice one man, you're on a roll! :o)

      Switching the 100n cap will potentially let more low frequencies out of the effect, but those frequencies may have already been removed by high pass filters if there are any earlier in the circuit. I'll have a look at it tonight when I get a chance to check.

      Delete
    2. Madferret12 January 2013 at 00:12

      Thanks, I probably should have socketed it so I could have a play with it, hindsight's a wonderful thing eh?

      Delete
    3. IvIark12 January 2013 at 00:27

      I think the 6n8's may be a better choice looking at the schematics. The 6n8's before the opamp, and 100n after it are both in series with the signal path and because the 6n8 is a much lower value that will have taken a lot of the low frequency meat out already, so swapping the 100n may be largely pointless. So I reckon experimenting with them would give more noticable results. You may need a 4PDT toggle :o)

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    4. Madferret12 January 2013 at 10:38

      Once again Mark you're spot on with your suggestions, the two 6n8s are the crucial caps, one each for the buffer and gain stage. Luckily due to some freak good fortune, I'd actually socketed these as I only had ceramic 6n8s and wanted to swap them later, how's that for some synchronicity eh? After trying a few values I found that they're probably so low because the IC doesn't seem to like too much bass going through and anything above around 22n gets a bit mushy. In the end I stuck with 10n just to warm things up a little, thanks for the help with this.

      Delete
  5. Jon the Art Guy12 January 2013 at 00:40

    Any chance on someone on here, fan included, making videos of these builds? Maybe a private channel or something? Wouldn't want anyone getting in trouble.

    I would, but I'm not even a little set up for it. It'd be nice to get a breadboard, into a cab sim like the Bulldog or the Condor, or through a cheap amp like the VOX ADV15 I have.

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    1. Madferret12 January 2013 at 10:40

      If you're after some videos of this I don't mind recording some but you'll have to put up with my crappy playing, I think the only way I'll get in trouble is if the riff police come calling ;)

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    2. IvIark12 January 2013 at 11:54

      That would be great if you could, we'll embed it in the main post.
      And don't worry I don't think the riff police come by here, if they did I'd be in trouble, I haven't practised in a while :o)

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    3. Madferret12 January 2013 at 14:33

      Ok here's the demo: http://www.youtube.com/watch?v=pvQ8UcMDdg8, I think I can hear the sirens already ;)

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    4. IvIark12 January 2013 at 14:51

      Cheers I'll post it now

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    5. mirosol12 January 2013 at 15:20

      That's so cool. Thank. You!
      +m

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    6. Jon the Art Guy12 January 2013 at 18:38

      big ups, guys! thank you so much! When I get the rig all together I'll do this as well.

      Delete
  6. Unknown17 April 2013 at 13:46

    heyyyy....
    I use Dpdt (6 poles) with Millenium Bypass...how can I make the "LED"?

    help me, plase!

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    1. Unknown2 May 2013 at 15:33

      help, please.

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    2. mirosol2 May 2013 at 17:36

      How did you do the millennium bypass? That would mean that you have a buffer and a spot for indicator LED.
      +m

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  7. Unknown6 May 2013 at 15:07

    Millenium: http://experimentalistsanonymous.com/diy/Schematics/Buffers%20Switchers%20Mixers%20and%20Routers/DPDT%20TB%20w%20LED.gif
    "LED +" perfect work if I used 3PDT.

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  8. Unknown24 May 2013 at 21:18

    .......

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  9. Larry Plaxco24 November 2013 at 14:01

    I'm a bit new, but the top right of the circuit: "LED" is in a resistor looking format? Is this a true LED (put a 3mm LED there?) or what is it?
    Thanks!

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    1. mirosol24 November 2013 at 15:57

      That's the resistor for your indicator LED.
      +m

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    2. Larry Plaxco2 December 2013 at 00:18

      Well.... that just made things easier in a "DUH" kinda way. haha
      Thanks!

      Delete