acceptable level of hum at full volume

[roggae]

so i am noticing a faint hum when i set my amp to full volume. not sure if it's been there all along but i was tinkering around and noticed it. here is my setup: rega p3-24 w/ttpsu and herbie mat into jolida jd 9 into decware mini torii. if i switch the mini torii to the second input via the switch i get no hum, but when i switch back to the phono i can hear it. mind you this is at FULL VOLUME. my question is, is there an acceptable level of hum at these outrageous volumes. it's not present in the music at normal or even loud listening levels it's just something i noticed while dickering around. i've tried all the usual solutions to eliminating hum like cheater plugs and moving components and swapping cables. i even have a line conditioner. what say you enthusiasts?

[JaS]

Yes, it's normal to have low level hum/hiss/noise from the phono input when the amplifier is turned up full (ie beyond normal listening levels or sitting closer to the speakers than normal listening distance). Check out specs for any amplifier with a phono stage and you will see they have worse signal to noise ratios than the line inputs.

Regards,
JaS

[denti alligator]

Yep, unavoidable, as far as I can tell. I've had two Regas with the same hum. My guess is I could reduce some of it by moving my preamp further from my amp, and some more by doing a rewire. But I doubt the hum would be eliminated completely.

[tomytoons]

You will get some hum with tube equipment always.

[denti alligator]

You will get some hum with tube equipment always.

Not true. My Bottlehead S.E.X. tube amp is dead quiet. I can turn the volume all the way up with a CD or digital input and I hear nothing.

Now the tube phono stage adds a little hum, and I think in my case that has more to do with its placement close to the other amp's transformer.

[denisnelson]

Do you even listen at full volume?

Just enjoy your music and stop worrying!

[tomytoons]

Maybe I was too general speaking. There could be lots of factors involved, tube equipment, individual tube type in Phono or amp,wires, wall electrical AC quality, speaker sensitivity, Isolation device used, hell even the wall outlet itself. Who listens at full volume anyway? As mentioned I wouldn't worry unless you hear a lot of hum in between music selections.
Forgetaboutit!