What the heck is this electrical component?

[HolyGhostFire20]

This is part of the audio board of my teac a-l700p amp. I know what resistors and caps look like, but I have no idea what the long slinder gray component is. Is it a resistor in disguise or something else? The board labels it as BD86 or BD85. Thanks for your time in this matter, Kevin.

 

[Mr Evil]

They look rather like ferrite beads to me, used to create a small inductance to filter RF.

 

[beerguy0]

Mr. Evil has it right...

They look rather like ferrite beads to me, used to create a small inductance to filter RF.

We use these a lot in the products I work on, as RF filters. We mostly use SMT versions, though.

 

[Leolabs]

Definitely a ferrite bead.

 

[HolyGhostFire20]

Do ferrite beads affect the sound in a good way or bad way? I am just curious since tripath never mentions it in their spreadsheet.

 

[Mr Evil]

No components are inherently good or bad for the sound; it depends how they are used. They will look pretty much like a plain piece of wire at audio frequencies, so they shouldn't do any harm, but applied appropriately they will keep high frequency nasties out (or stop them escaping, if they are internally generated), which is of particular importance for switching amps.

 

[Jocko Homo]

Yes, they are ferrite beads, but they do not create a small inductance to filter RF. Some of you guys need to read up on the basics................

Jocko

 

[jan.didden]

My vote: 0.1uF 63V film caps...

Jan Didden

 

[blr-amp]

ferrite beads

Yes, they are ferrite beads, but they do not create a small inductance to filter RF.

What else are they doing? A short explanation would be very kind.

 

[jan.didden]

My vote: 0.1uF 63V film caps...

Jan Didden

Oops, I looked at the wrong components...


Jan Didden

 

[phase_accurate]

I'd say some of them would indeed build a small inductor but that is depending on the ferrite materials used.

Most work by introducing magnetic losses at RF.

Regards

Charles