Tuesday 1 January 2013

Jordan Bossboost

*There was an issue with the board powers, my mistake. Now fixed. (2013-04-08)

We've taken on a few classic Jordan designs before, so i thought this one would be a nice addition to the library. It's simple and quick build. What i can tell from the demo, it's not that bad of a Rangemaster alternative....

There's a great article and lots of very nice photos of the original unit at ToneMachines blog. Check it out!




Posted by at 08:08
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8 comments:

  1. Madferret23 April 2013 at 19:18

    I've just built this to test it out and it's good to be tagged. To be honest I wouldn't really recommend it though, it's more of an active EQ and doesn't have that much boost, although different transistors would probably help (I went with 2n3904s). It's got touch of rangemaster about it but with less gain, the bass dial doesn't really boost the bass that much either. I think I'll stick with the Rangemaster I built with adjustable input caps.

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  2. Piltdown Man18 July 2013 at 22:48

    I found the same thing. I was looking for something quick to build and happened on this. It's basically a nice tone control. There is no real boost, but there is a little sparkle. I had to use a 22p for the 10p, would that do it? I assumed with two transistors that are capable of great loudness, there would be more bang. What is holding them back?

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    Replies
    1. mirosol19 July 2013 at 08:27

      I've missed Madferret's post completely.. So this is going to be tagged right away.

      Anyway. To get more volume out of it, one could tweak the following:
      -Swap the 10K resistor from the diode to the collectors with a 20K-50K pot.
      -Swap the lowest link (between two lowest rows) with 2K trimmer and place a 10µ-22µ cap there as a bypass cap.

      Those transistors are in Darlington configuration, so by biasing them better should result in massive boost.
      +m

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    2. Piltdown Man19 July 2013 at 18:03

      Cool. I get the first part, but on the second bit, I remove the link, put a 2k trim in its place. Got that. But where does the cap go? I'm not sure what you mean by as a bypass. As always, thanks for all this.

      Delete
    3. mirosol19 July 2013 at 21:04

      Positive to emitter of Q2 and minus to ground. It's called bypass cap as it "tricks" the ac signal to believe there's no resistance between emitter and ground - which has a grave impact on the gain available.

      http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SSE1502
      http://www.seattlerobotics.org/encoder/jun97/basics.html
      +m

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    4. Piltdown Man21 July 2013 at 00:06

      Thanks. I will try that

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    5. mirosol21 July 2013 at 07:47

      Let us know what happens :)
      +m

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    6. Piltdown Man23 July 2013 at 04:35

      I made the changes and I didn't notice any difference. The pot replacing the 10K did starve the power when turned down. But the I didn't have a 2k trim so I used a 5k regular pot. Is 5K too much because I didn't hear any difference. does it matter if the bypass is to the left of the pot connection? I just put it where it would fit. I will keep messing with it. Thanks

      Delete

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