Still getting buzz with D'Lite build on OD setting. Ideas?

[Ed de Jager]

Well,i`m not sure if i like it more then an ecc83 but i liked the growl i heard, very meaty.Haven`t had much use for very high gain settings on this amp so far.Will let you know more after band practice.

[dobbhill]

Is the relay energized in clean or OD mode? I had hum when I energized the coil in OD mode, so I switched the leads around so that the relay coil was energized in clean mode.
Hum gone...
D

[markmalin]

Is the relay energized in clean or OD mode? I had hum when I energized the coil in OD mode, so I switched the leads around so that the relay coil was energized in clean mode.
Hum gone...
D

Cool idea! I may try that.

Mark.

[Ed de Jager]

Dobhill,please forgive me this maybe stupid question but, do you mean reversing the leads to the NO and NC on the relays?

Thanks,Ed

[dobbhill]

Exactly..Not stupid.
D

[greiswig]

Interesting...after my last set of tweaks, I noticed a hum that I hadn't before with the OD switch on. It's not too loud, but I didn't notice it before, and it goes away when the PAB switch is engaged.

One of the tweaks was with the caps on the far left, which affect the mid voicing. I wanted something between the .05 and .01uF caps, so I put a pair of .068 caps that I had in series. I made a judgment call that the inside foil on both caps is what should be connected together, so that the eyelets both hooked up to outside foil for shielding. Was I wrong about that?

[markmalin]

I made a judgment call that the inside foil on both caps is what should be connected together, so that the eyelets both hooked up to outside foil for shielding. Was I wrong about that?

I should probably know this but... does the direction of the inside foil effect things like buzz? I know they say it's better for audio when you have them in the correct orientation, but I always thought on amps that was overrated. Can someone expound on this?

Mark.

[Structo]

This may help:
https://tubeamparchive.com/viewtopic.ph ... light=foil

[markmalin]

This may help:
https://tubeamparchive.com/viewtopic.ph ... light=foil

Thanks for the link, Structo.

So if outer foil goes to low impedence, which side of the circuit is low impedence? Is the low impedence side of the circuit always toward ground? I guess I'm not clear on that.

Also, will incorrect orientation cause more noise? I've pretty much narrowed the buzz down to the input of the circuit. Here's how I've characterized it:

1.) It starts in the first gain stage (V1)
2.) It's WAY louder with single coil pickups (strat in position 1, 3 or 5) and all but goes away when I have humbuckers (strat in 2 or 4, or using a Gibson).
3.) If I turn different directions, it goes away
4.) If I touch either the bright cap or the 500 pf cap on V1, it gets REALLY loud (presumably because I become the antenna).

Last night I started thinking I should pull all the caps and check the outer foil orientation, but stopped myself because I thought, "I need a systematic way to debug this, not just start pulling parts and swapping things out without knowing whether what I'm doing even effects noise".

Mark.
Mark

[Structo]

Hmmm, what you are describing sounds a lot like singe coil noise.
Two of my strats have noiseless systems on them and one doesn't.
I experience much of what you describe with that one strat with the single coils. Like you say if I turn my body and guitar in certain directions in relation to the amp, I can get from a heavy buzz/ hum to virtually none.
My new tele is about the same.
With any high gain amp I think you are going to get that buzz with single coils, unless I am wrong about the type of noise you are experiencing.

[mlp-mx6]

1.) It starts in the first gain stage (V1)
2.) It's WAY louder with single coil pickups (strat in position 1, 3 or 5) and all but goes away when I have humbuckers (strat in 2 or 4, or using a Gibson).
3.) If I turn different directions, it goes away
4.) If I touch either the bright cap or the 500 pf cap on V1, it gets REALLY loud (presumably because I become the antenna).

Why do you think this represents any kind of problem in the amp?

[greiswig]

Mark,

Try this: unplug everything from the input. Do you still get this noise? The hum that I have is there even with nothing plugged in.

It sounds to me like your guitars are causing the noise: humbuckers buck hum, single coils generate it.

[phsyconoodler]

'goes away with humbuckers' That pretty much sums it up Mark.

[Ed de Jager]

well mine does`t go away with humbuckers:-)
I guess i have to follow up Dobbhill`s advice.
I tried everything else i could think of.
Pity because i have to completely dismantle the entire relay section.
My chassis is a bit smaller;i even had to saw off most of the sides from the relayboard to make it fit between the turretboard and the front switches.But if most of the hum goes away this way it will be worth it.

[markmalin]

4.) If I touch either the bright cap or the 500 pf cap on V1, it gets REALLY loud (presumably because I become the antenna).

Why do you think this represents any kind of problem in the amp?

I guess the fact that if I touch either cap the thing buzzes. Yah, it sure points to the Strat. I'm just having a hard time reconciling having to deal with so much noise. I thought if there was some way I could shield things better I could keep the single coils from buzzing so much, but you're right... it points to the guitar / high gain amp combination.

But why doesn't my 5E3 with an overdrive pedal do this? Is that because it's high gain input, rather than high gain w/in the amp? Isn't both scenarios amplifying a 60hz hum?

Mark