new ht5rh - transformator hum !!! ???

[lenylenyleny]

Hi,
can anybody please confirm that transformator on that amp make audible hum?
just bought yesterday and i am really unhappy.

can it be replaced with some with better quality? what will be a cost?
i´m sorry for my english and thanks for an answer

[thephantum]

Tube amps will always have some level of hum. In other words, they will never be dead quiet. Assuming that the hum is overbearing, then there is something wrong with the amp, but it's most likely NOT one of the transformers. If it's brand new, take it back and get another. If it's a few months old, take (or send) it to a authorized repair center. If it's no longer under warranty, take it to a reputable tech.

[lenylenyleny]

this hum is traight from head, not from speakers
https://www.youtube.com/watch?v=e9jU_ecZvGY

i have also marshall jtm and orange th. none of them buzzing like that.
amp is new, so i will probably return it.

[zone]

I have this also with an Ht Metal 5 Head.
But is very quiet. You cant hear it while playing, also i noticed that it is gone after a couple of minutes while playing.

[lenylenyleny]

mine not gone after any minutes.
my friend, electrician, told me, taht it is unquality output transformer, so i returned head yesterday.

[thephantum]

Hum is typically caused by either AC or DC ripple current being induced into the audio circuit someplace. It was most likely as simple as a bad tube. It could have also been a bad diode or capacitor in one of the rectifiers or even a bad choke resistor.

The output transformer is actually one of the least likely culprits. It's actually more likely to be the power transformer, and even that's really rare. In that case the lamination's on the power transformer oscillate as current flows through the primary winding. As they oscillate, they smack into each other at the same frequency of your AC power (60hz here in the US) causing a hum. Again, that's extremely rare...

About the only way it could be the OT is if it's somehow gotten magnetically coupled to the PT. That would be a design flaw, where either the transformers are too close together and/or the lamination's of both transformers are physically aligned in parallel, causing them to magnetically couple together and produce a hum. However, the OT and PT are far enough away from each other and mounted perpendicular to each other.

Again, my guess is you got one with a bad tube. Regardless, the amp was new, so when you returned it, you should have made them give you another one.

Every HT-5 I've heard is pretty quiet, including my own, with only a little hiss at high volumes.