GGG A/B switch Pop.

solarplexus · September 15, 2013, 02:48:41 PM

Hi guys,

trying to get rid of the Switch pop on my GGG A/B build. I have added 2 input buffers for my guitars, added the AMZ LED pop solution and a 2.2M resistor to ground on the output. It still pops. What can I do? Am I right to think that adding pulldown resistor on the input jacks will suck the tone out of the guitars or since I added input buffers, it won't matter?

Please help!

Thanks!

senko · September 15, 2013, 07:03:12 PM

I'd suggest removing the extra buffers/LED from your circuit and testing where exactly the pop is coming from.

Could you post the schematic here?

The LED has always been an issue with my true-bypass builds. Start here before anything else.

solarplexus · September 15, 2013, 09:22:20 PM

Thanks for the tip! I have fixed the popping issue with this layout:

BUT, I cannot make the LED's light up with a battery. I hooked up the battery as I always did before (the GGG method). How should I wire it with this layout?

MrStab · September 15, 2013, 10:31:09 PM

the diagram seems to check out. the ground connections on LED 2 and the DC jack aren't coloured black like the rest of ground - a small point, but worth checking to see if you mixed something up. assuming you're only using a battery (and you don't mean the lights work on an adaptor but not on a battery), you're probably getting no popping because the LEDs aren't working!

just ideas: have you triple-checked connections? is the current-limiting resistor definitely the right size? as you've changed the switch wiring and i don't know how your de/soldering skills are (probably better than mine), i have to ask: do the switch and LEDs still work? switches can be prone to heat damage if you leave the iron on them too long.

once you do get it working, i'd reconsider using the same value of resistor for both LEDs, if they're different colours, otherwise one might be brighter than the other.

i wonder if "coloured black" is an oxymoron. hmm...

solarplexus · September 16, 2013, 02:35:02 PM

The LED work with the DC jack and everything switches as it should. I am wondering if it has to do with the ground of the DC jack being on the switch itself? I'd really like to use it with a battery since I'll only use the A/B live to switch guitars. When it was wired as in the GGG diagram, the 9V battery worked. I just can't figure out where to solder the battery clip on the Beavis Audio diagram.

Hemmel · September 16, 2013, 02:51:32 PM

Quote from: MrStab on September 15, 2013, 10:31:09 PM
i wonder if "coloured black" is an oxymoron. hmm...

If black is defined as "the absence of color", than yes

solarplexus · September 17, 2013, 09:36:18 AM

so.... any idea where to connect the 9V clip?

Kipper4 · September 17, 2013, 11:04:11 AM

Wire the battery snap in the place of the dc jack.
you could also wire it to the dc jack so that when the dc jack is in use it eliminates the battery power (switched dc jacks) only.
I hope this helps

solarplexus · September 17, 2013, 12:15:50 PM

I tried to connect it to the DC jack and it's a no go, the LED's won't light up with the battery.

Hooking the battery in place of the DC jack... would it drain the battery when not in use?

Kipper4 · September 17, 2013, 01:57:57 PM

it will not drain the battery if you replace the input jack with a stereo (Tip, ring, sleeve) and put one ground wire from the battery snap to the ring.
Then hook up two wires from the input sleeve to the A and B output sleeves.
This way the Input (T,R,S) jack is acting as a switch for the battery on.
So the battery only makes a connection to ground when the mono (T,S) guitar cable is plugged into the input (making the switch connection form input sleeve to ring)
I hope i'm making myself clear.
That way as soon as you remove the input jack plug, it wont drain the battery.

MrStab · September 17, 2013, 03:19:27 PM

i think wiring the battery in place of the DC jack is the best temporary debugging approach - you can change it to the ring of the input jack later.

apologies if i'm stating the obvious (i always overlook the obvious), but some more food for thought:
you've tried a few different batteries, right..? are you definitely using the right value of resistor (maybe a really high one would light with an adapter's current but not with the limited battery current)? can you light the LEDs from the battery with just the resistor and the LEDs themselves? there's not much to this circuit - i have a feeling it's one of those "annoyed grunt" mistakes. or "D'oh!" for non-Simpsons fanatics.

one time i dropped a 9V battery onto metal and it happened in such a way that the battery just plain stopped working, but came on after a few minutes' use. that was one of the rarer anomalies.

solarplexus · September 17, 2013, 04:17:45 PM

I tried all your suggestions, nothing works. The only way to make the LED's light up is if I replace the DC jack with the 9V with the same wiring, and then, the LED's are always lit up.

There is something in this diagram that I don't get, or it is not possible to have a battery with this.

?

MrStab · September 17, 2013, 04:25:16 PM

Quote from: solarplexus on September 17, 2013, 04:17:45 PM
The only way to make the LED's light up is if I replace the DC jack with the 9V with the same wiring, and then, the LED's are always lit up.

^ that's good news kinda, you're narrowing it down! my immediate assumption based on that is that the battery ground isn't following exactly the same path as the ground to the DC jack did. it sounds like the battery ground is always connected when it shouldn't be, via the switch. by the sounds of it, the DC jack isn't wired right either.in any case, i'm really leaning towards a ground connection somewhere.

if it's nothing to do with the ground-battery connection on the 3PDT switch, quintuple-check that connection on the jacks and whether the ground is touching anything metal. trace the path from battery negative like a hawk. if that's an appropriate analogy. lol

MrStab · September 17, 2013, 04:33:19 PM

imagine a checklist of sorts, one ground connection to each, doesnt matter which order, and trace it:

Input jack > output A > output B > buffer board(s) > LEDs > 3PDT > battery negative

solarplexus · September 17, 2013, 04:38:48 PM

GOT IT.

The ground of the DC jack went to the input jacks' ground. The ground of the battery went to the ring of the input jack. There is a slight pop, but it is minimal, so I think it's working ok.

Thanks for all the help!!

MrStab · September 17, 2013, 04:54:37 PM

congrats! time for a well-earned jam. crank up to 11 and make enemies with the neighbours. lol

you may notice that popping is more intense the first time you use the switch after powering up, but less-so afterwards.

solarplexus · September 17, 2013, 05:05:59 PM

I know that putting resistors to ground on the input and output would help for the slight popping... but... would I be degrading the guitar tone if I used a 680K to ground?

Kipper4 · September 17, 2013, 05:07:32 PM

Have fun

MrStab · September 17, 2013, 06:02:48 PM

Quote from: solarplexus on September 17, 2013, 05:05:59 PM
would I be degrading the guitar tone if I used a 680K to ground?

i honestly cant remember if higher or lower resistance to ground is preferred (in so far as avoiding tone loss), but all the info i recall is that ~1M seems to be preferred. i'd imagine that you'd want a higher value to prevent signal loss, so that less gets disposed of to ground. given tolerance & all that, 2x 680K to make 1.36M could probably be a good compromise, if that's all you have. maybe someone who knows more can step in.

you could have the resistor to ground loose, with your guitar/amp plugged in, and manually touch it to the switch (or wherever you're putting it) to see if it affects the signal negatively

solarplexus · September 18, 2013, 09:17:24 AM

That's good info! I'd like to know if someone can confirm which one is better? Higher or lower resistor value for pulldown resistor? How does it affect the pickup load/impedance/guitar tone?

News:

GGG A/B switch Pop.