'SPITFIRE' Metal 'n' Blues Pedal...

[347sixtyseven]

Thanks Luke, ill give it a try

[347sixtyseven]

Unfortunately shielded wiring hasn't helped.

I might be missing something obvious but I can't understand how it can make noise when bypassed.

The noise is there constantly unless the gain pot is turned below half. The classic/modern switch has an effect on the noise as well.

I am using a stereo input jack for power switching and have found that if I remove it from the enclosure the noise stops. The noise starts again as soon as I touch the jack on the enclosure. When I move it away from the enclosure the noise stops by fading off over a second or two, makes me think a cap is draining.

[ggedamed]

If it's true-bypass, try switching the input to ground when bypassed.

[midwayfair]

Hi guys,

I just completed a build using the layout the Ozsi posted.

With basic ancilliary wiring it worked beautifully but i have just boxed it up and am having problems.

When a battery is connected the pedal produces a squealing noise even when the effect is bypassed. (standard 3pdt,led,9vdc socket wiring)

I have triple checked everything and cant see anything that would be causing a problem. Please note that the 3 position switch and the gain pot cause variation of the sound. Also if the board is lifted from the enclosure and moved around the noise varies (sounds like a theremin almost).

Any suggestions or direction to obvious problems would be greatly appreciated

Cheers

Gary

Is your circuit input grounded in bypass? What bypass scheme are you using?

[347sixtyseven]

I don't have it grounding input on bypass. I used the following wiring

[deadastronaut]

Top centre lug should have 9v from board > led > 4.7k ...to top centre lug...

and central/middle lug of 3pdt to ground....

shield the input from top left lug...

to input on pcb....should be fine.

[347sixtyseven]

Thanks for all the help guys.

Deadastronaut, I will try your changes

[347sixtyseven]

Modified wiring and still have the noise.

only if the gain pot is higher than about two thirds.

this is all while bypassed, there is no problem when active regardless of gain pot position.

However, with these wiring mods, the effect does not pass any sound when activated

I have shielded wire on input and output between the board and switch, as well as between the switch and jacks. all shields are connected to ground.

[Luke51411]

The effect was working when engaged before you made the changes on the 3pdt? It might help if you posted a pic of your wiring. I wire all of my 3pdt switches like this http://www.generalguitargadgets.com/pdf/ggg_sw_3pdt_tb_gi_dcj.pdf I've always grounded the circuit input when bypassed in this manner. It's probably not necessary to change over to this wiring scheme though. You probably just have something shorting to ground, a solder bridge or cold joint. How does the 3pdt switch look? It's possible to mess up the contacts with too much heat.

[347sixtyseven]

Yes Luke, it was working,

I had however noticed a strange noise when I switched to my neck pickup. Hard to describe. Didn't notice it on my bridge pickup. (Both humbuckers) when I plugged in another guitar the odd noise was noticeable on all pickups (single coils)

I will try to get a pic tomorrow, the one I have doesn't show the wiring very well. I might try retwiring it anyway as the neat wiring I had is getting messed up with all the troubleshooting.

[347sixtyseven]

Here is a pic I took earlier after making the changes Deadastronaut suggested. As I mentioned its a bit hard to see what's going on in the pic. The grey wires are the shielded input and outputs. All of the grounding is being done via the ring of the jacks.

By now the soldering looks like crap but the joints are solid. Switch is in good condition, no excess heat.

[duck_arse]

do you have the shields connected to ground at both ends? you only want to ground at one end, you can fold the braid back over the outer and heatshrink at the other end.

try testing continuity between inner and outer conductors on your shielded, see if any shortings.

[347sixtyseven]

I have earthed both ends of the shield.
I will disconnect one end of each in the morning when I get another chance to play with it.

The shielded wire was added after the problem noise appeared and hasn't seemed to have made any difference that I can tell

Cheers

Gary

[J0K3RX]

I've had something like this before... Ended up being a cap

You should make an audio probe and use it to pin point where the noise originates from. Very useful tool!

http://www.diystompboxes.com/pedals/debug.html

There are a lot of videos on youtube on how to make and use them...

[347sixtyseven]

Thanks J0K3RX,  I will make one when I find my old damaged lead.

Gave myself some time away from this but just had a play, I now have it grounding the input and the noise is gone when bypassed.

Effect is working beautifully, like it was before boxing it up.

However, if the gain knob is turned past half or so and you unplug your guitar (at the guitar) there is a horrible squealing noise. It can be stopped by dropping the gain and made nastier by increasing it. The noise is not present with an instrument connected.

[axemurderforhire]

Just a few questions, Its been a hell of a long time since i built something so im rusty as hell

I had to substitute some parts and im just looking for some advice from you guys/gals

R3 560k i used a 680k

C11 6.7 nf  i used a 10nf

Tone 47k lin i had to use a 100k lin

Im just wondering if they (in particularly the tone pot) are going to effect the pedal that much.

Also i'm getting squeeling when ever i stop playing. I haven't boxed it up yet

[deadastronaut]

for the tone pot, i would go smaller 22k for example, rather than 100k...


sheild the input when boxing up and it'll be fine...


other issues you'll get away with. 

[axemurderforhire]

Thanks Rob your a gentleman

[fastbreak78]

I'm looking for a bit of input. Would this be a decent pedal for a 2nd build? I'd rather not jump in over my head. Too much at least.  

[deadastronaut]

Yep, you'll be fine, easy build man...