Tuesday, 19 March 2013

Gaspedals Dumbbell

Request. This is a demo of the single knob version, the layout is for the 3 knob version.







Video of Geiri's build of this layout:



32 comments:

  1. How critical is the 7.15K resistor? Is it worth waiting 2 weeks to get it shipped?

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  2. If you have any other that you can either put in series or parallel then you can make up a resistor close to that one.

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  3. To me it seems like it sets the minimum gain before the gain pot - so you should be golden with 6K8, 7K5 or 8K2.
    +m

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  4. It just is part of the filter created with the Tone pot, and using a 6K8 won't change anything noticeably. So it's resistor + tone pot followed by a 10n cap to ground.

    7K15 - 17K15 gives a corner frequency at either end of the pot's rotation of 928hz to 2.2khz. Using a 6K8 gives you 947hz to 2.3khz.

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  5. Thanks guys. I am never quite sure when a substitute is okay or problematic.

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  6. But what about the 2 switches on the original and only 1 on this layout? I always like to see a schematic, but haven't found one.

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    1. This has two as well. The stomp I've shown is the boost stomp, the normal bypass stomp is wired as per usual on the offboard wiring page.

      Scheme is here

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    2. Schematic can be found from FSB for registered users.

      Second switch is for bypass.
      +m

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    3. oh, of course, how stupid of me! Thanks for the link.

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  7. While looking for YouTube Clips on the "Gaspedals Dumbbell" I came across this clip on the "Gaspedals GasBender MkII" and believe it too would be a good request.

    http://www.youtube.com/watch?v=ZpAJXJaJ8EQ

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    1. Just Built the "GasPedal DumbBell" and also agree with everyone. A very nice sounding pedal. Thanks once again Mark for giving us this pedal. Great Stuff.

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  8. thanks for posting this. i didn't know they built this one. I've been trying to track down one of their other pedals. The Carb model. Killer pedal.

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  9. I just built it and it does sound good but I'm not convinced it's sounding as it should. The volume pot doesn't do anything, it's just unity no matter how much I turn it. If I turn it all the way back the volume drops and it sounds thin and fuzzy.
    I don't know really how much gain it offers but the gain knob doesn't do very much gain change but some. The extra switch has a very subtle effect. I can hear the gain just slightly go up and the overall tone get a tiny bit thicker.

    I wired volume 2 and output together and then one wire from volume 2 to the output part of the circuit. Should be fine, right? Why no volume 3 anywhere? I feel something isn't right here.

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    1. Board output goes to Volume 3, layout labels corrected

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    2. So do you wire volume 3 to output?

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    3. Lemme clarify, to jack output...

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  10. Built this tonight. Couldn't get it to work. Looked through everything 3 times - nothing. Until I catch a glimpse at the IC. It came from Tayda in a baggy marked N5532 but actually had N555's in it. I didn't bother to look. I had a JRC4558 and put it in and it fired right up.

    Anyway, I don't see alot of change in the Gain control. Is it tied to the LED's and should i have used 5mm instead of the cuter and better fitting 3mm? Just wondering. I really like the sound, though. Thanks

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  11. This comment has been removed by the author.

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    1. Never mind. Found it. Sounds good now :)

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  12. Any tweaks to get a touch more gain from the boost? Great sounding pedal!

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  13. Hello, I'm very interested in building this pedal but before I do I want to make sure it's what I'm looking for. how close does it sound to the YouTube demo's for the gaspedal dumbbell? I'm looking for something that will give me dumble coloring to my tone. I really like john mayers tone so that's what I'm really going for with this pedal. any of you who have built this pedal please let me know if that's the kind of pedal this is. thanks.

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  14. Ok, have everything wired up and boom nothing works. which side of the resistor do you wire the board to when wiring to the LEDs +

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  15. Just for clarification, D1 and D2 are separate diodes from the LEDs that alert you when switch is active right?

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    1. Correct, they are there as clipping diodes, although one or both of them may light up as you start playing which looks pretty cool.
      Thanks
      Dave

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  16. My boost LED is not turning off. the od LED is however. anyone possibly know why? Used the pre-boost off board wiring schem from the link above. that's the right schem correct? Still not getting any sound though. completely rewired it today. have no idea what's wrong.

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  17. up at top left where the wires are going to switch 1&4. When I take switch 4 out of the equation then the boost led turns on/off. otherwise I can't get it to turn off. anyone know why? Thanks in advance

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  18. hi guys, sharing my experiments with the gpdb,
    http://youtu.be/xcDy_kaO8R0
    everything is maxed, boos is on. testing some red led;s for clipping. they don't light up, but seams to be doing their thing.
    at the moment tone knob does almost nothing ... I'll have to investigate that.

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    1. some more findings. the pedal sounds really nice, for now I get the best clipping with couple of yellow LEDs. with the boost off the gain knob does little. I also get significant volume boost - unity around 10o;clock.

      by some reason the bypass led is quite dimmer than the boost led which freaks me out, because I don't understand it. - same LEDs same resistors. faulty resistor?
      Tone control is a bit anaemic - if I want to remove it completely should I jumper the 10n cap?

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