DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: Govmnt_Lacky on November 27, 2010, 08:28:26 PM

Title: Am I crazy??
Post by: Govmnt_Lacky on November 27, 2010, 08:28:26 PM
I am getting ready to wire up a Tonebender based off of the GGG layout and I noticed something that just did not look right and I want to confirm it.

http://www.generalguitargadgets.com/diagrams/tonebender_m2p_lo_pp.gif?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

Correct me if I am wrong but, according to the above layout isn't the LED getting V+ on both the anode AND cathode  ???

Shouldn't the resistor side of the LED (anode) be hooked up to the same spot as the V- from the DC jack/Battery snap?
Title: Re: Am I crazy??
Post by: ACS on November 27, 2010, 08:37:50 PM
Yep, you're going crazy....

Nah, just kidding - I read it the same way as you.  When pole one of the switch is in the 'on' position for the LED, you got a nice loop from 'ground' (+ve), through the resistor, through the LED, through the switch and back to 'ground'.  Needs to go the a -ve somewhere...

Title: Re: Am I crazy??
Post by: Govmnt_Lacky on November 27, 2010, 08:43:36 PM
Quote from: ACS on November 27, 2010, 08:37:50 PM
Yep, you're going crazy....

Nah, just kidding - I read it the same way as you.  When pole one of the switch is in the 'on' position for the LED, you got a nice loop from 'ground' (+ve), through the resistor, through the LED, through the switch and back to 'ground'.  Needs to go the a -ve somewhere...



So... should the anode/resistor side be removed and connected along with the battery/DC jack V- or is this a PNP positive ground kind-of-weird wiring thing?  ???
Title: Re: Am I crazy??
Post by: John Lyons on November 27, 2010, 09:26:19 PM
The end of the resistor goes to -9v (black battery lead) and not to ground.
You just look at it being the black and red wires from the battery are swapped.
Red is ground now and black is "power" or -9v since it's a positive ground circuit.
Title: Re: Am I crazy??
Post by: Govmnt_Lacky on November 27, 2010, 09:32:06 PM
Quote from: John Lyons on November 27, 2010, 09:26:19 PM
The end of the resistor goes to -9v (black battery lead) and not to ground.

Actually, according to the layout, when the input jack is inserted the sleeve and ring are shorted thus connecting the resistor-end of the LED to the batteries RED wire.

Quote from: John Lyons on November 27, 2010, 09:26:19 PM
You just look at it being the black and red wires from the battery are swapped.
Red is ground now and black is "power" or -9v since it's a positive ground circuit.

I get what you are saying John however, in the diagram above, both leads from the LED are connected to the same potential (V-/-9V) when the switch is engaged. Am I wrong?
Title: Re: Am I crazy??
Post by: BadIdeas on November 27, 2010, 09:38:54 PM
I haven't seen the layout, I just know that the current should flow from anode to cathode. In a positive ground circuit, the round side goes to (positive) ground, the flat side goes to the (negative) power supply. If the layout is wrong, just "customize" it.
Title: Re: Am I crazy??
Post by: PRR on November 27, 2010, 10:42:00 PM
> Am I crazy??

Insufficient data.

However you ARE short memory:

QuoteAm I crazy??
on: Today at 09:28:26 PM
I am getting ready to wire up a Tonebender based off of the GGG layout and I noticed...

QuoteAm I crazy or is this layout wrong??
on: September 24, 2010, 12:28:08 PM
I was looking at this Tonebender layout on JDs site and something looks....

http://www.diystompboxes.com/smfforum/index.php?topic=87199.msg732488#msg732488

Title: Re: Am I crazy??
Post by: John Lyons on November 27, 2010, 11:09:50 PM
The layout is wrong. The end of the resistor going to +9v on the layout (via the ring/sleeve connection
when the jack is inserted) should go to the -9v on the DC jack instead.
As it is now you are not getting any power to the LED (both ends are being grounded).
Title: Re: Am I crazy??
Post by: DiscoVlad on November 28, 2010, 04:01:48 AM
It should be like this:

(http://cabbages.orconhosting.net.nz/graphics/joes_rubbish/fx/tonebender_m2p_lo_pp-fixed.gif)

To be fair though, there are 4 different versions of this circuit on GGG so some errors between pos and neg ground versions are bound to slip through.  ;)
Title: Re: Am I crazy??
Post by: Govmnt_Lacky on November 28, 2010, 02:35:14 PM
Thanks Vlad and everyone else. Your revision is exactly what I had in my head as the "correct version."
Title: Re: Am I crazy??
Post by: Telvis on September 16, 2013, 12:38:54 PM
I'm riding this same circuit and had observed the same error, I used the same solution given by DiscoVlad, when I turn the effect the LED turns on, but the audio is muted. Someone noticed another error in this circuit?
Title: Re: Am I crazy??
Post by: armdnrdy on September 16, 2013, 04:29:29 PM
Quote from: Telvis on September 16, 2013, 12:38:54 PM
I'm riding this same circuit and had observed the same error, I used the same solution given by DiscoVlad, when I turn the effect the LED turns on, but the audio is muted. Someone noticed another error in this circuit?

Your first post!
Let me be the first to say welcome!

TELVIS is in the building!  ;D