GasPedals - Dumbbell  [traced]

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Lucifer
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Post by Lucifer »

That agrees with what I'd managed to sketch out (and what I described earlier).

The only bit I hadn't fathomed was the 'boost' or 'channel' switching.

Thanks for that bit - and for the full schematic.
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Post by Lucifer »

Just missing the value of the 47nF on the input.
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sonicmojo
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Post by sonicmojo »

Thanks for the schematic. Does anyone have an opinion what this is modeled on? I'm thinking partial TS circuit and the 100pf cap parallel to the Red LEDs is smoothing things out. Does anyone have any idea of earlier one knob version of this and what may differ?

BTW, I've got a few extra PCB boards that I made up last year. PM me if you want one. I'll trade for another OD or fuzz board.

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Post by Greg »

This is a nice sounding OD.. definitely worth a build or play with IMO.
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Post by sonicmojo »

Greg wrote:This is a nice sounding OD.. definitely worth a build or play with IMO.
Greg, I agree. A guitarist friend of mine has kicked himself for getting rid of his early one knob, one switch version. With the tone and gain mods that I mentioned in my first post, I think he got back in the ballpark on V2 with the ability to lower the gain a bit. Your version was sort of the in between model...I think.

Here is a clip of him using the original Dumbbell in a live gig into a house amp. I did the video for this:


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Post by strat100 »

Wow that sounded fantastic and very well played :thumbsup

Vero needed please :scratch:

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Post by Manfred »

Hi sonicmojo
Thanks for sharing.

Was it possible to recognize the IC type?
In the drawing appears the 5532 type is this the right one?

Hi Dr Tony Balls
Thanks for drawing.

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Post by sonicmojo »

Manfred wrote:Hi sonicmojo
Thanks for sharing.

Was it possible to recognize the IC type?
In the drawing appears the 5532 type is this the right one?

Hi Dr Tony Balls
Thanks for drawing.

For sure a TI NE5532.

Image

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Post by Manfred »

For sure a TI NE5532.
Hi sonicmojo
Thanks a lot for divulge the information.

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Post by Intripped »

i've breadborded it and for sure there is something wrong:
the sound looses way too many bass freqs, gain pot not gaining very much

sonicmojo, are you sure about the 22nF cap?
could it be 220nF instead?
with this value the sound is ok on all frequencies and also the gain pot is now functional

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sonicmojo
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Post by sonicmojo »

Intripped wrote:i've breadborded it and for sure there is something wrong:
the sound looses way too many bass freqs, gain pot not gaining very much

sonicmojo, are you sure about the 22nF cap?
could it be 220nF instead?
with this value the sound is ok on all frequencies and also the gain pot is now functional
You are correct. I must have misread it from my handwritten sheet when I drew up the typed layout. I just updated the original layout graphic. The schematic needs to be fixed also.

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Post by Intripped »

no, wait!
you've corrected the value of the 10n cap and left the 22n untouched :secret:
thanks anyway for confirming 220n!
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Dumbschem.png

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sonicmojo
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Post by sonicmojo »

Yeah, I noticed that and fixed it before I saw your post. Thanks for doublechecking. The layout is correct now.

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Post by Intripped »

little mistake in the schematic:
LED resistors (R11 - R12) are 2k not 150k

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Post by Manfred »

The input circuit topic of the Gas is same as the Zen, but at the Zen the C1 value is 470nF, the R2 Value is the same.
So the roll-off frequency of this high-pass filter at the Gas is ten times higher.
Is the value at the Gas really 47nF?
The roll-off frequencies are then 7,2 Hz and 0,72 Hz, but it is questionable if this diffrence is audible.

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Post by Intripped »

The full range of human hearing extends from 20Hz to 20kHz
some texts put the limit down to 15Hz, but definitely 7.2Hz is too low to hear

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Post by sonicmojo »

Manfred wrote: Is the value at the Gas really 47nF?
The labeling on that one didn't hold up during degoop for me to see but I took all components off the board and it measured .047 uF on my meter. I just checked my notes again.
These labels don't match the current schematic but you can see the exact measurements for everything I could not actually see.
Image

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Post by Manfred »

Hi sonicmojo

thanks a lot , I appreciate your work very much.

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Post by bluesman007 »

Hey quick q. What does it mean by dumbbell "V2". Does that mean version 2? The pedal I was looking for was the single knob 2 switch (one boost one od) version I see on YouTube but if this is the same pedal just more knobs or something then thats cool! Another question, where can I find this specific IC at? And does it have to be 2 red LEDs or can I change up the colors? Thanks for all the help!

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Post by bluesman007 »

Looks like all the pics are cut off on the ride side. Do the pics extend out or full versions somewhere?

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