Many tube amps used a self-biasing tube circuit (not the same thing as auto-bias). A self-biasing tube circuit has no means of adjusting bias. This eliminates the need for a bias voltage power supply. Eico offered one amp kit in both self-biasing and set bias versions. The self biasing amp was less expensive and delivered less power. Otherwize the specs were similar.
To bias or not to bias
After making the switch from solid state to tubes and now having three tube systems, I spend a fair amount of time biasing my amps to obtain peak performance as recommended by many enthusiasts.
As I was doing this one day I thought back to my youth when many people had tube equipment (Yes, I am that old) and it dawned on me that I don't remember anyone biasing their equipment back then. I had a college roommate that had McIntosh tube equipment and he never biased his rig. It always sounded fantastic. I remember my Dad having Scott tube amps and tube radios, playing them for years and other than replacing a bad tube every now and then, never biasing his gear. Again, they sounded great.
So that led me to thinking, why do we pay so much attention to biasing today? Is it because the equipment requires it or is it audiophile tweaking run amok?
Your thoughts on the matter would be much appreciated.
As I was doing this one day I thought back to my youth when many people had tube equipment (Yes, I am that old) and it dawned on me that I don't remember anyone biasing their equipment back then. I had a college roommate that had McIntosh tube equipment and he never biased his rig. It always sounded fantastic. I remember my Dad having Scott tube amps and tube radios, playing them for years and other than replacing a bad tube every now and then, never biasing his gear. Again, they sounded great.
So that led me to thinking, why do we pay so much attention to biasing today? Is it because the equipment requires it or is it audiophile tweaking run amok?
Your thoughts on the matter would be much appreciated.