Shielding a cap

[kagliostro]

Old remedy to noise capture 

Look to the wrapped capacitor




K

[HotBluePlates]

Usually not needed, especially if you orient the outside foil towards the lowest impedance to ground (because then it acts as its own shield).

The rules sometimes change with radio, so if this is a radio chassis, all bets are off.

[kagliostro]

Ciao HotBluePlates

No, no radio, old unknown guitar amp

Usually not needed, especially if you orient the outside foil towards the lowest impedance to ground

yes, I agree, but want to put in comparison with such a note of folklore 


Franco

[shooter]

I found the same setup but on a resistor, but it was from a radio chassis, I figured it was either noise or a hand-wound choke in parallel with the resistor.  I like looking back in time, so much more artisan than a sterile pcb
 

[kagliostro]

That was an inductor for sure

I've seen such a thing also in audio amp

as you say, in RF, it was common to wrap a small number of turn of wire around a non inductive resistor to obtain an inductor





K

[jazbo8]

Ciao HotBluePlates

No, no radio, old unknown guitar amp
Franco

Yup, the origin of this amp (posted over at TAG) is driving me crazy  , who made it? The tubes selection is a bit odd as well - 2 EF86s in the preamp (probably one per channel)?! But it's definitely not a "Tweed"...

[kagliostro]

Yup, the origin of this amp (posted over at TAG) is driving me crazy   , who made it?

for that reason I like very much TIMBO's idea


http://el34world.com/Forum/index.php?topic=16986.msg169082#msg169082


K

[Ed_Chambley]

Been looking all over for it as well.  I have encyclopedias of amp books and origins.  I have no idea as I have found nothing.  I am beginning to wonder if it was a build of some kind.  I noticed the speakers are very low in the cabinet, not really like a production amp would be IMO.


And yes, shielding can be done in this way.  I restored an old Flot-a-Tone amp with a crazy tremolo.  Sounded awful, but it had a .0022 cap wrapped.  Why, I do not know.  I replaced it and wrapped the new one.  Probably did not need it, but I am used to it.  I love my old radios and it is a great way to get noise down.

[terminalgs]

Ciao HotBluePlates

No, no radio, old unknown guitar amp
Franco

Yup, the origin of this amp (posted over at TAG) is driving me crazy  , who made it?

I see a pinex cap.  That's euro (West Germany?)... Rules out North America and Asia?

[tubenit]

Thanks for sharing that!  I think that is an interesting idea and perhaps could be useful in some situations where orienting a cap or location of a cap is a challenge?

With respect, Tubenit