SMSL T1 DAC/Tube Amp

From personal experience, I can confirm that the T1 does not drive the HE4XX headphones well; it only gets them loud. The 4XX is eating up every bit of power the amp gives them. Once you hear the headphones on an amp with upwards of 1W per channel, you'll immediately notice what you've been missing: bigger soundstage, more bass, greater dynamics, and smoother mids and treble.

I have 2 of these and both exhibit the same noise issues even with premium NOS tubes. It is an intermittent problem and I suspect it originates in the power supply design. It works well otherwise, but I am very unsatisfied with these amps now. This is clearly a design issue and should never have passed developmental QC testing. They should have eliminated this problem before producing amps for sale, IMO. Us tube amp customers are seeking quality sound, and this issue is unacceptable to true Audiophiles! Has your replacement shown this issue yet?

That's the rumor