Xenithon,
Sorry things didn't turn out well on the Havana.
I should give you another thing to think about on the 840C. I ordered some new power cords including one for the 840C. Last night, while I was installing the PC's, I temperarily took my Audio Magic Mini Digital power supply out of service and plugged the 840C directly into the wall. Oh my, the difference was not subtle, and not good! It may be that the 840C is especially sensitive to AC line noise. Based on what I heard last night, I would not be at all satisfied with my 840C without the power supplied through the mini-digital. You might want to start there before you start tube rolling.
Also, I use balanced silver IC's to my pre-amp. I've wondered if some high quality coppers might be a better choice.
Sorry things didn't turn out well on the Havana.
I should give you another thing to think about on the 840C. I ordered some new power cords including one for the 840C. Last night, while I was installing the PC's, I temperarily took my Audio Magic Mini Digital power supply out of service and plugged the 840C directly into the wall. Oh my, the difference was not subtle, and not good! It may be that the 840C is especially sensitive to AC line noise. Based on what I heard last night, I would not be at all satisfied with my 840C without the power supplied through the mini-digital. You might want to start there before you start tube rolling.
Also, I use balanced silver IC's to my pre-amp. I've wondered if some high quality coppers might be a better choice.