As I understood, the buzz is louder when outerfoil is connected with the tip. Follow the video. I hope I understood it right.
In this video the differenc is so gravity that I ecpected it with ervery cap. Not at all! There is a big different between producers - looks like.
BTW I think the exploration is bigger with a box because all the stuff is shielded. Somehow. So the nois can concentrate on the cap. Right?
That's how I assumed it would be, but looking at close-ups of the box, it looked as though it was wired so that the opposite was true! Admittedly it was late, which didn't help.
The outter foil is more likely to pick up noise from stray EMF, and so it will be connected to ground when the lowest noise is heard (or seen on a 'scope) because that allows the noise voltage to drain away.
Similarly, in the amp circuit, if the cap doesn't have either end connected directly to ground it is connected so that the outer foil has the lowest impedance to ground.
OK, I built a tester the other day.
I was messing around with it and found that most of the 6PS orange drops I have are fairly consistent.
That is, if you hold it with the printing on the left side, the lead towards you is the foil.
But there were a couple that were opposite....
I even have a few that have a factory line on the end of the logo and those checked out as marked.
Today I tried to test the caps in my 100w ODS.
When I built this amp I oriented the caps so the logo is facing the power supply.
I pulled the tubes and then tried to test them but it just doesn't work good enough for me to tell with them installed.
Just too much hum either way to tell exactly which is which.
The amp is pretty quiet so I'm not going to sweat that one but in the future I am armed with this tester and I will check them.
Structo wrote:When I built this amp I oriented the caps so the logo is facing the power supply.
Interestingly enough, that is how I positoned all of mine. And if your finding holds true in this case, only two caps are not positioned correctly.
Do you concur?
I was about to tackle this issue in a few days, but now I'm not sure whether it's worth it.
Hi,
my conclusion is that a scope is neccessary for correct indication.
Bigger caps than 0,01 (orange drops) you cant select by noise. smaller yes. The orange drops, I guess, have a thick coating.
All my Xicons and Mallorys I could check.
As written above: my amp is fairly quiet too. But for next builds I will take care on this too. It makes you sleep better, btw.
yeah, I noticed the larger orange drops like the .1uf are a little harder to detect but if you turn the amp up enough you can differentiate between the foil and tip.
I really didn't feel like unsoldering all those caps so I will let sleeping dogs lie.
I debated whether to bother with this on my new build but I came up with a "poor man's" version of the tester. The yellow wire is to tip of the jack. Totally worth my 2 minutes to build it. I definitely noticed the hum difference on all the orange drops that I tested. Just remember to turn down your amp volume in between clipping on the capacitors.
sonicmojo wrote:I debated whether to bother with this on my new build but I came up with a "poor man's" version of the tester. The yellow wire is to tip of the jack. Totally worth my 2 minutes to build it. I definitely noticed the hum difference on all the orange drops that I tested. Just remember to turn down your amp volume in between clipping on the capacitors.
On some caps it represents the outer foil. On other caps it doesn't mean anything, which is why it's better to test them yourself unless you specifically know that the caps you are using are marked properly with the outer foil direction.
