Sunday 10 July 2016

Mesa/Boogie Flux-Drive

A slightly modified version of Xotic BB Preamp from Mesa Boogie.
You can find original thread and schematic here.


28 comments:

  1. Ok, this will be at the top of my list once verified.....

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  2. building it now so i should be able to verify tonight if i get around to wiring it up

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  3. building it now so i should be able to verify tonight if i get around to wiring it up

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  4. Sorry I have one question: LED+ means that a wire has to go to the positive of the LED only? or do I have to connect that positive also to the DCjack? thanks :)

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    1. From layout Led+ a wire go to positive led.Negative led leg go to 3pdt footswitch.

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  5. Hi, I just want to pint out that the lower op-amp was indeed a TL072 instead of an 4558. Did anyone already verify the schematic/layout? Tracing the pedal was a bit hard due to the black solder mask...

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  6. Verified! Tried 4558 in both positions and TL072 in bottom position. With both 4558s you get a faint hiss in the background but not with the TL072. Thanks Alex.

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    1. Thanks again, Gavin!
      Thanks also to Kenfoe for tracing his original pedal.

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    2. Thanks for your props, Alex! Thank you for your nice layout, well done - very compact, I really like it!

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  7. Hello, sorry if it´s a dumb question but, what are those transistors?

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    1. 2N5089. It says so on the right side of the layout.
      +m

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    2. great... right in front of me! Thank you! :)

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  8. HI guys,
    I cannot find 19k resistors anywhere. So, can I use something else like a 20k or perhaps solder together an 18k and a 1k? Would this still work?

    Thanks

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  9. Hi Mark, you can always put 2 resistors in parallel e.g. 47k+33k gives 19.38k, or 150k+22k gives 19.18k.

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  10. Is the bass and treble wiring correct in the layout, I can´t seem to get it to work..

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  11. The basspot works when I disconnect lug 1, the treble does´nt work at all, no effect there. When I wire the gain according to the layout the gain is reversed.

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  12. can i substitute 2N5088 instead of 2N5089?

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  13. do you have the flux-five diagram?

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  14. Hi,i have a question abaut capacitor C3 and C9 from the schematic. C3 is 51pF,and C9 is 151pF. On the layout C3 is 51,but the C9 is 180pF. is that making any diference ? This is mine first time,so please help.. and wich tipe of capacitors they are ? ceramic maybe ?

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  15. Great layout Alex, really neat!!

    If i may note something, there is a small mistake in it though: the wiper of the gain potentiometer shou!d be bridged with leg 3, ie. one cable goes to leg 1 and the other to pot 2 (and three). Everything else is working as expected, so one more verification!

    Thanks again!!

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    1. That doesn't make any functional difference at all and is not a mistake.

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    2. Second. The resistance between lugs 1 and 2 is exactly the same wether the lug 3 is tied to lug 2 or not. I tend to omit those as well.
      +m

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    3. I agree with Panagiotis. If Gain 1 is connected to Gain 2 the pot works backwards. If you instead connect Gain 2 to Gain 3, the pot works as it should.

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  16. I built this one today, everything works fine but I have a low output : with level pot full CW, I am only at unity volume. I think it lacks a bit of gain but otherwise the pedal sounds great I really like it.
    I carefully chechked everything I can't see anuthing wrong. Any idea ?
    Thanks

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