[Patrick Turner]

choobs wrote:

Pulled the amp from an old phono player. It was intended to be mounted
with the tubes horizontally. I want to situate it vertically. When I
do so I get a lot of hum. If I turn it upright, the way they intended,
it's much quieter. Can someone explain why this might be? Can I unbolt
the power transformer and rotate it 90 degrees? Thanks to all.

I am not sure exactly what you have done but phono amps
can be very prone to stray magnetic fields from nearby mains transformers
and
cabling.

This is because the mains hum is at 50/60Hz and the LF gain of phono amps
is huge and the smallest amount of induced hum can perhaps cause hum.
Makers try to locate their mains transformers in such a way to cause the
least
hum, and any change you make can mean a hum increase.

Unbolting the mains tranny and rotating it 90 degrees may or may not work.

Sometimes what you suspect what may be the cause of hum just isn't the
cause at all.

Patrick Turner.

[[email protected]]

Patrick Turner wrote:

Sometimes what you suspect what may be the cause of hum just isn't the
cause at all.

Patrick Turner.

Hi RATs!

OK, hum is caused by the last thing you suspect

Please consider moving the power transformer to a separate chassis. The
mfgr was trying to be sensible. We are trying to improve what we hear.
Not the same thing

Happy Ears!
Al