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EgoDrive LED Clip mod

Started by musovern, March 05, 2012, 12:06:17 AM

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musovern

My LED Clipping mod doesn't seem to work for me, Have tryed a few different types of  led's . Had the gain and tone on full can not here any change in the sound and still no luck.

Any thoughts on a led type and spec. mine current one is a 5mm RED CLR 12,000mcd 2.3v  which doesn't work either.

Any suggestions very welcome.

Great sounding pedal other than the clip mod.

pryde

It seems like everything is wired up correctly in the picture. Did you try to re-flow the ground to R3 just to be sure? It is a tight area so maybe a solder bridge or something?

Do the LEDs light up at all when playing?

BTW: I used 5mm water clear high-brightness in mine and there is a difference at higher gain vs normal clipping. Good luck

mgwhit

Which pad do you have D4 soldered to?  I can barely see the pads on your photo as they're obscured by the LED and the wire, but I feel like I see solder in the square pad and the round pad appears (through the LED!) empty.  Apologies if I'm seeing it wrong.

musovern

#3
I did a Re solder  didn't make any difference. Led's do not light up even with all knobs on full.  :( Would of be nice to here the difference in the clipping.

Led 1 (+) to square of D3 and LED 2 (-) to the round of D4

cheers

madbean

It must be LED type. I just had a look and I believe mine were from Tayda. They list their water clear high brightness forward voltage at 3.2v or so and the MCD at 16 - 20k (for the white). Do you have any others you can try? I might have some more of those particular LEDs left, so I could always drop a couple in the mail to you.

oldhousescott

Gain at max through the first stage is about 500. Even if your LED had a forward drop of 3.5v, it would only take a 7mV input signal before the LED started to clip. As noted, the forward drop for most LEDs is in the 2-3v range. Note, too, that the opamp will start to clip at just slightly above that, maybe around 4 to 4.2v on a standard 9v supply. It's possible the LED clipping is getting lost in the opamp clipping for certain high-threshold LEDs. This is an instance where an 18v supply would be beneficial.

pryde

Quote from: madbean on March 05, 2012, 12:42:56 PM
It must be LED type. I just had a look and I believe mine were from Tayda. They list their water clear high brightness forward voltage at 3.2v or so and the MCD at 16 - 20k (for the white). Do you have any others you can try? I might have some more of those particular LEDs left, so I could always drop a couple in the mail to you.

I picked mine up at a local Radio Shack and they work fine in my pedal. Here they are:
http://www.radioshack.com/product/index.jsp?productId=3060980&filterName=Brand&filterValue=RadioShack


musovern

Thanks for the help guys,
I have tryed again. This time not with a battery but a 9v power supply. And now the LED's light up, Not very much change in sound so it is a Led problem.

do you think this led would be ok.?
5mm 20,000mcd WHITE LED 3.4V

My current one is a 5mm RED CLR 12,000mcd 2.3v.

Kind regards

Vernon

pryde

Best thing to do is try them out. The 3.4 voltage is similar to the radio-shack ones I use so they may work for you.

I will say that the difference in clipping sound in my build is by no means "dramatic" so I don't know how much should be expected between stock and LEDs? To me I actually prefer the stock clipping anyway.

mgwhit

#9
Quote from: musovern on March 05, 2012, 10:22:55 PM
do you think this led would be ok.?
5mm 20,000mcd WHITE LED 3.4V

My current one is a 5mm RED CLR 12,000mcd 2.3v.

If you're having trouble getting a 2.3v LED to clip, I would think that the 3.4v would just be even less likely to work.  (Edit: I just read Bean's post saying he used 3.2v LEDs -- go figure....)  Still, socket and test!  I gotta admit that since these LED's are connected to VB instead of ground there may be things going on that I don't understand.