[Terja]

Also try lower gain tubes with this amp -- 5751 (70% gain), 12AT7 (60% gain), 12AY7 (45% gain), 12AV7 (41% gain), 12AU7 (19% gain). The Bellari is very sensitive to tube swaps and will likely let you know when you have found just the right tube for the SQ you're looking for. My sweet spot was a Tung-Sol 12AT7 at 60% gain. Just the right everything for my Hifiman HE-500. Loads of juice, detail, and warmth.

 

[derbigpr]

Anyone experiencing channel imbalance with the HA540? I use it in stock form with the Ruby tube, and is seems like left channel is slightly louder than the right one.  It is more pronounced at low volumes, and as i turn the knob up it sort of equalizes at around 12 o'clock.  But its annoying because my listening level is at 9-10 o'clock, and at that point imbalance is quite obvious when paying attention to the sound.  Can it be because of the tube, or is the volume pot bad?