R/E/P Community

R/E/P => R/E/P Archives => Oliver Archut => Topic started by: Radd 47 on January 08, 2005, 07:44:49 PM

Title: 76 Input
Post by: Radd 47 on January 08, 2005, 07:44:49 PM
Oliver, what is this strange piece of foam on the V76 input?
Just curious.
Thanks!

http://vacuumbrain.com/The_Lab/TA/Telefunken/v76_iron.jpg
Title: Re: 76 Input
Post by: Level on January 10, 2005, 11:51:29 AM
That is a vibration damper. Coil tensioner. Chokes, x formers and coils will resonante when voltage is passed through them. This is to keep the resonances away from the chassis and to provide a tidy and snug tension on the coils. Notice, it is touching the bottom windings. The coils will move ever so slightly..this simply keeps an even tension.

The other thing, if one winding (stack) is removed, this is a novel way of plugging the gap!
Title: Re: 76 Input
Post by: Oliver Archut on January 10, 2005, 01:38:11 PM
Hello Radd47,

looks like that you are a huge 76 fan, to answer your question in a general term (without giving too much away).
Level is going in the right direction  some sort of damping device.
Every Nickel core x-former grows by the amount of energy that is put into it, a linear sheet of 1 meter can grow as much as 1 cm while exposed to a magnetic field. If you cast the x-former in an epoxy you end up with a solid mass, that will try to move but can't, so mechanical distortion emerge and are transformed into electrical ones.
Most plastics/epoxy interfere with either the magnetic,- electrical field (reducing or amplifying it) or become some sort of conductors that shorting out the turns ,  so specialty material is needed.
If you loosely suspend the coils, they will grow and retract by the given room, so you end up with no or the smallest amount of mechanical distortion.


Best regards,