They both sound nearly identical. The original one prob doesnt have as much high end. Also, if you modify(increase) the power supply voltage and/or tweak the trimpots you can get subtle variations in tone. Just mark the trimpots before you tweak :0)
Yes, I think its just to illuminate the tubes (which looks cool). so, im starting to think that the one that doesnt have the tubes lit just has a bad bulb.
Is it possible EH made 2 versions of the BF? (one lit, one not)
So, does anyone know if this lamp is replaceable (ie whats the voltage?)