View Single Post
  #12   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Op Amp Labs Transformers

wrote:


--------------------------



I'm particularly interested in how badly they ring.
What causes an audio
transformer to ring?


60Hz transformers hum,


** A lot of force comes from the 60Hz supply acting on anything
magnetic with a bunch of wire wound around it. This is single,
low frequency, forced vibration, not resonance.



You know, in AC solenoids a shorting ring is beneficial to keep
60 Hz buzzing to a minimum, as the shorting ring provides a CEMF!!!!


** However, solenoids and relays have moving parts - transformers do not, so are normally bolted up tight and run silent.

Had a Chinese made guitar amp here that would suddenly made a loud hum if laid over on its back, standing upright it was OK.

The four bolts holding the power transformer laminations together were barely finger tight. Soon fixed.


..... Phil