Adrian, That's a very good question about the biasing of the D70..
Frankly, this is perhaps the only real drawback to the amp. The procedure is NOT for the faint of heart..:0(
I just re-tubed my D70 with rolled in tubes and there was NO way I was going to do the biasing myself. According to the ARC manual it is a procedure that any 'phile can do....BS!! Who ever wrote and thought that at ARC back then,must have been smoking something!! Nonetheless, once my tech had the amp biased, it hasn't wavered since and the sound is to die for. Luckily, i have a couple of very good tech's near me; if that isn't the case for you, then perhaps an auto-biasing ARC amp would be more appropriate. (Although, I think that the sound of these is inferior)
Frankly, this is perhaps the only real drawback to the amp. The procedure is NOT for the faint of heart..:0(
I just re-tubed my D70 with rolled in tubes and there was NO way I was going to do the biasing myself. According to the ARC manual it is a procedure that any 'phile can do....BS!! Who ever wrote and thought that at ARC back then,must have been smoking something!! Nonetheless, once my tech had the amp biased, it hasn't wavered since and the sound is to die for. Luckily, i have a couple of very good tech's near me; if that isn't the case for you, then perhaps an auto-biasing ARC amp would be more appropriate. (Although, I think that the sound of these is inferior)