power filter hum

[Gene]

I replaced one 33uf 450v power filter cap in a pair. These are wired in series.

Now, there is a slight hum but you can stop the hum by pushing the 2 caps away from each other.

What might be the theory here? Before I replace the other cap, I thought I'd try to figure out why the hum stops by pushing the caps away from each other.

[Nolatone Ampworks]

I replaced one 33uf 450v power filter cap in a pair. These are wired in series.

Now, there is a slight hum but you can stop the hum by pushing the 2 caps away from each other.

What might be the theory here? Before I replace the other cap, I thought I'd try to figure out why the hum stops by pushing the caps away from each other.

You sure you don't have a bad/cold solder joint? Maybe it's not the moving them away from each other, but just the moving them that's allowing a better connection.

Just a guess.

[Gene]

Yup, I was going to check the soldering and remelt it. I can't think of any other reason why this might be.

[Gene]

Nope, it wasn't the soldering or the cap. I tried another new cap as well and still the same. It hums but if you push away the 2 radial caps slightly away from each other, it stops.

I have a feeling it is the cheap looking pcb. This is a Duncan 84-40 amp.

[TheAmpNerd]

Well if that is the case, figure out which one you can move fartherst
then when you go to solder it in, glue it down in that farther position.

You'll have longer leads...but that shouldnt be a problem.

You wont' have any hum.

Care full with that board too, they are typically only good
for desoldering maybe 2 if you are lucky.

Good luck.

[Gene]

I don't think I was lucky. The board now hums and I can't get it to stop. I did desolder more than a couple of times. Just about all the pots failed on this board plus the power filter caps went south.

I replaced all the electrolytics and still hums...

[Nolatone Ampworks]

I don't think I was lucky. The board now hums and I can't get it to stop. I did desolder more than a couple of times. Just about all the pots failed on this board plus the power filter caps went south.

I replaced all the electrolytics and still hums...

Maybe the board has just had the lick.

One of those "wow, I coulda had a V8 (or turret board)" moments.

[Gene]

This amp just never was reliable... Always had issues one way or another. I might just get a tag board and wire it myself...

What a waste of time. This pcb is so flimsy, it looks like it'll break just by looking at it.

[Trout]

This amp just never was reliable... Always had issues one way or another. I might just get a tag board and wire it myself...

What a waste of time. This pcb is so flimsy, it looks like it'll break just by looking at it.

Don't Feel bad about it Gene,

I have a Seymour Duncan Convertible 100W in my basement that was purchased new the week they came in at a local shop in the 80's.

It developed the ole snap crackle pop syndrome at about a year old, then chronic rectifier arc at about 2 years old, I have had to work on that thing at least once every other year to fix stupid things that should never fail.

If I could figure out an easy way to put in a turret board and still have the modules line up right, I might actually fix it again.
Last time it started making noise, it went in the closet, and it has been there for nearly 2 years now.

I got a lot of help with mine via emails with Paul Marossy over at DIYguitarist.com (http://www.diyguitarist.com/)
He seems to have a good bit of insight on Seymour Duncans.

Trout

[TheAmpNerd]

Maybe the board has just had the lick.

One of those "wow, I coulda had a V8 (or turret board)" moments.

What a dick!

I can just see it now with some F***ed up POS amp
that works and they ask you how you did it.......




...but I did stay at a Holiday Inn Express last night. :dude:dude

[Nolatone Ampworks]

What a dick!

I can just see it now with some F***ed up POS amp
that works and they ask you how you did it.......




...but I did stay at a Holiday Inn Express last night. :dude:dude

I don't get it. :crazy