Friday 16 June 2017

Electro-Harmonix Signal Pad

With 1000 verified layouts in site, I figured I'd throw in something small, simple, and usable.

From the Source:

The Signal Pad is a passive attenuator that allows you to instantly switch to a different preset volume. It's like your guitar's volume knob, with a fully-passive and color-free circuit. Leave your amp's volume set high for overdrive, and use the Signal Pad to lower your level for a clean sound -- then switch it off to kick in your amp's natural overdrive. You can also experiment with the Signal Pad anywhere in your effects chain -- you'll bring out new tonal combinations from your favorite old pedals.

Basically a simple switchable volume pedal.



31 comments:

  1. I think the volume 3 connection to ground should be volume 1, no?

    Also is there an advantage to this as opposed to just wiring the pot by itself as a passive attenuator? I've been trying to figure this out for awhile and the circuit just looks like it's for power filtering, the LED and treble bleed.

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    1. yea, i guess i forgot to save after i changed it. the advantage is that it also has some treble roll off, as opposed to just a pot, which i think is nice.

      i just had to do it. i mean i love all things EHX. typically they're the kings of bargain priced amazing pedals, but $45 for this is insane. there's maybe $7 in parts and the enclosure.

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    2. also, just updated the layout.

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  2. I've been thinking of using an attenuator pedal again so I'll have to give it a shot. I was wondering if a booster behind it or a volume cut pot in front of a booster would be a better idea to compensate for volume loss.

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  3. That would be a nifty circuit to put in a guitar on a toggle / extra POT... I just don't have the heart to butcher my guitar up LOL

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  4. A pedal I always wanted to know what was inside but couldn't bring myself to pay for. Best pedal I have for this application is the MP evolution orange underdrive.

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    1. I read somewhere that it used an L-pad pot, guess not.

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    2. Leo, there's an answer: New Guitar Day!

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  5. What I use for that is the deep blue delay with added volume pot from this blog. Boosting for solos I crank the volume and put some delay, deboosting for rythm sections with singer i lower the volume and put the mix at 0. This is of course limited to one setup per song but it works great and saves a lot of place on my small pedalboard

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  6. 1000 verified layouts! Wow! I haven't build vero in a while, but have built quite a few of these in the past. Thanks for all the hard work guys.

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  7. what´s the value of CLR? thanks

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    1. CLR stands for current limiting resistor. it's the resistor for the LED so it doesn't burn out and explode.

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    2. ok thanks! so 1k should be ok???

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    3. depends on how bright you want the LED. anything between 1k-10k is used, the lower it it the brighter the LED will be. a lot of people use 4.7k, while i like mine brighter and use 2.2k

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    4. I use 15k with ultra bright leds

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    6. I've found with a series of LED's I got from mammoth that I needed to up my resistor to 47k for blue and 51k for red else I'd get blinded. I had 4.7k in there forever and i would see spots after gazing at my pedals for too long...

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  9. hi, i want to know if is possible to get 0 treble roll off?

    Thanks

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    1. Just take out the cap. The higher value pot you use the less treble roll off there will be.

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    2. How would you modify this to use a treble bleed? Replace the cap with a higher value cap and resistor in parallel?

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  10. Replies
    1. Whatever value you need for your LED. It prevents it from burning out or being too bright - it's a current limiting resistor. Try anything between 4.7K to 22K. The higher the value the dimmer the led.

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  11. I was looking at doing this as a pseudo Master Volume in the amp effects loop. Does it still require power if you don't add the LED? This will be my first build, so I'm still learning how to read the diagrams.

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  12. Verified. Works great with my OR15 with low to mid gain tones. It will clean up your tone as well as your guitars volume pot will, so it’s a nice addition to your board if you hate playing with your guitar volume. I doubt you are going from super saturated amp gain to nice clean with this, if you’re hoping for that, prepare to be disappointed. It’ll work in that application for a lower gain tone but cleans, no. Thanks for the layout Zach.

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    1. +1 to using this with guitar amp FX loop. I have a single channel GenzBenz BP30, using it with low to mid volumes, so majority of drive is coming from preamp, and fx loop is usually coming between preamp and power amp (in this case just before phase splitter). After all Master Volume on the old Marshall JCM800 is exactly the same thing in the same position.

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  13. I am looking at the layout. With 220p capacitor wired like this this is not treble bleed circuit (capacitor comes between input and output leads), but treble cut (similar to guitar tone control - capacitor between input and ground). Does it need to work as treble bleed (preserve treble, while rolling off the pot, thus maintain the original guitar tone as close as it can) or as a treble cut(this is like additional passive EQ that otherwise is not present in the circuit)?

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  14. Hi! Thanks for Your work! but so if I wanted to do without the LED, just the 1M pot and the 220pf cap are enough? the power is only for the LED?
    Thanks

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    1. without the led theres no need to build the board. the only component besides the pot is the 220pF cap from volume 3 to ground.

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