Uproar: Alternate Switch Wiring

[madbean]

In the Uproar wiring diagram, the switch wiring was simplified to use an On/Off/On SPDT which is easily obtainable (as opposed to an On/On/On). In the wiring set-up in the Uproar document, the two back to back LEDs are always in the signal path to ground. This is pretty much a hack, because when another diode pair of lesser forward voltage is in parallel, the resulting signal will clip mostly through that pair, and only a little through the LEDs.

This alternate wiring uses a DPDT On/On/On and is probably what the actual Riot uses. In this case, each position on the switch results in only a single pair of diodes to ground rather than a mix of pairs in parallel. Note that this is untested!

You will need to wire the two LEDs off board and also R13 and R14 as pictured. It looks a little messy, but it is actually quite easy!

[Mark_McQ]

I'll give this a try soon.
Found the perfect accompaniment to it too:
http://www.guitarpcb.com/apps/forums/topics/show/4363315-dpdt-wiring-boards-endless-mod-options-

[Ang3lus]

thanks brian !
you are the man

[Ang3lus]

Tried it now, difference between positions is much more noticeable, is there any effect to using white leds that change color or using just colored leds ?

i'm using white leds that change color

[madbean]

There could be a difference if those LEDs have a higher or lower forward voltage.

[Mark_McQ]

I gave this a try, as the stock setup with the SPDT didn't do anything for me. Still can't hear any difference though.
Noticed my tone pot doesn't really do much either, pedal sounds good but very 'dark'. I'm using the 10kC from the build doc, but I recall you had mentioned, on the v1.5 build, that you had used another pot (100k B?). I have one here, would it be worth me trying it?

[Ang3lus]

yeah, noticed that too, very very dark sounding pedal

[bigmufffuzzwizz]

I'm using the 10kC from the build doc, but I recall you had mentioned, on the v1.5 build, that you had used another pot (100k B?). I have one here, would it be worth me trying it?

Did you give it a try??

[Mark_McQ]

I just tried the 100k B pot. Makes a difference to the range, the pot has a noticable effect now. Although as you roll it back, it seems to remove a little gain too.

[yomanfree]

Hello
just to come back on this interesting discussion on LEDs and connection. I'm going to start soon this pedal and try to understand (not sure it is the case at all).
A typicall Vf for a RED/BLUE LED (not low current) is typ = 1.7/1.9 to max 2.1/2.5 when 20mA (can change depending on manufacturer for sure). If current is much lesser than 20mA, the Vf could be more around 1.3 to 1.9V, correct?
For 1N34A // 1N914, respectivelly: Vf max is 1V (5mA), Vf max is 1V (10mA). I guess here that these diodes should work more around 0.8V in case of low current, correct ?
(Additionnaly I guess that we should have some voltage drop in R13/R14).
Comparing these values (typ / max), how could we predict which diodes will have the major effects ?
One more question: why a blue LED in parallel of D5/D6, and not 2 1N914 like for the 1N34A ?
Additionally, some Blue LEDs have higher foward voltage than red led: is it the reason of the color choice ?
thanks


PS: 2 links for ON/ON/ON (for europeen guys :-) ):

http://www.musikding.de/product_info.php/info/p2060_Toggleswitch-DP3T-ON-Z-ON.html
http://uk-electronic.de/onlineshop/product_info.php/cPath/39_41/products_id/1243?osCsid=40e34f170b3983b5ba9410874c6c0273

[sgmezei]

Back to the tone pot.

I built my uproar and I notice no difference with the clipping switch. The pedal is so dark it still sounds muddy when its wide open.

I am going to try this new wiring diagram. I just wanted to know what you folks did to change the darkness. What pot value do you recommend? or is it the case of socketing a cap and trying bigger or smaller values.

Just wanted to make sure it wasnt an error in my build.

[yomanfree]

Hello sgmezei,
I dont know how much is dark your pedal (and if it is normal), my pedal is effectivelly "relativelly" dark when the gain is low - medium. When you increase the distortion, highs increase (in my mind this pedal is not for low gain). At the beginning, I had found that the gain of my pedal was a bit lower compared to gain in internet videos (therefore probably more darkness a large part of the gain range). therefore I have replaced the 100K pot (gain) by a 250K. I dont know exactly the differences between 100 vs 250K (I've not done some test), but it works for me. No darkness at all when high gain.
For the tone itself I've replaced the 10K by 100K (10K was not really efficient) as advised in this thread. The 100K works perfectly but with the disagreement that the volume (and partially the gain in the same way) decreases when you turn the tone pot in the counterclockwise. But no problem because the volume pot is efficient to correct this problem. Therefore even when you decrease the gain (means more darkness), you can play with the tone pot.
It works for me quite well.
For the ON/ON/ON and madbean scheme, it works. It doesn't change drastically the sound, but you can ear the difference (and even some tonal differences depending on the switch position). For me this mod is necessary if you want to be sure to ear some differences.

Ah just forgotten: "Suggested substitutes are 10n for C9 and 33n for C8", this is the values I used.

Thanks
A bientot

[sgmezei]

Hey thanks Yomanfree! I will try that out and see how it sounds.

[ben_allison]

What would be the easiest to simply hard wire the diodes used in the middle position?

[irmcdermott]

Any one have this alternate switch wiring diagram, since this was deleted?