How much hum is normal for a new tube integrated amp?

[TommyC]

As per title, I've got some transformer hum from the Phasemation SA-1500 integrate amp. Clearly audible at 4 feet, but barely audible from my seating position of 8 feet. Speaker driver hum is less, but still audible within 4 feet.

I've tried some trouble shooting steps:
- Swapping back to the Accuphase is dead silent. No hum from the transformer or speakers. I cannot tell whether the unit is on or not. Completely silent
- Disconnecting the RCA input, no change
- Tried another outlet with supplied 2-prong power cord, no change
- Hum loudness stays the same regardless of volume or input selected

Hoping to get some feedback from tube experts here.

Thanks!

 

[mep]

As per title, I've got some transformer hum from the Phasemation SA-1500 integrate amp. Clearly audible at 4 feet, but barely audible from my seating position of 8 feet. Speaker driver hum is less, but still audible within 4 feet.

I've tried some trouble shooting steps:
- Swapping back to the Accuphase is dead silent. No hum from the transformer or speakers. I cannot tell whether the unit is on or not. Completely silent
- Disconnecting the RCA input, no change
- Tried another outlet with a different power cord, no change
- Hum loudness stays the same regardless of volume or input selected

Dealer is away for 2 weeks, hoping to get some feedback from tube experts here.

Thanks!

There should be zero hum. I would return it. Go back to your Accuphase.

 

[Bones13]

Check your grounding, and tubes, before getting crazy. Consider trying to power it at someone else’s house.

I think “acceptable” hum is the kind you can just perceive with your ear right at the speaker. Worse with high efficiency speakers.

Consult the manufacturer.

 

[puroagave]

this may not be related but half of Japan gets their power over 50hz lines the other half is 60hz. I was told depending on the manufacturer the xmfrs windings are optimized for 50 or 60hz depending on where the mfr resides. That said, Manley told us on a tour that winding power xmfrs for countries using 220-240v over a 50hz line freq often excerbate hum, ie. grounding issues.

I havent owned too many tube integrateds but have plently of tube separates where its hit and miss with xfmr hum., regardless of what grounding scheme i've tried. balanced lines help mitgate it.

 

[Porsche]

there should be no hum

 

[TommyC]

Many thanks for the responses. Tried a few more things without success. I’m investigating further with the dealer/distributor/manufacturer.

Good to know tube amps do not always hum and can be silent like SS gears.