biasing an amp by ear

[thinskin57]

curious as to what the consensus is on this. fire away.

 

[94Tremoverb]

As long as you're also measuring to check that the tubes are within the safe operating range, it's the best way - since there is no "right" bias for all tones and tastes with any amp, there's just a range of settings where the amp will run OK and the tubes will last a decent amount of time. As long as you're not exceeding the point where tube life is drastically shortened to the point of risking failure, even that may be flexible if you're willing to accept the slightly shorter life.

You may also find that if you go by ear first and current second, the setting that sounds best is *not* at the hottest safe bias, despite the popular myth that hotter is always better.

Just don't rely on visible red-plating at idle as the sign of when they're too hot - with many amps you're well into the danger zone by then. You need to measure the current and voltage as well, especially with higher powered amps - you've got less margin for error when they're being pushed harder.

 

[espboogie123]

I guess its kinda like moving the distributor and timing it by hand/ear. The more timing, the more gas/power up to a point. The less timing, the less gas/power. There's always gonna be a sweet spot.

 

[fishyfishfish]

You can do it by ear, but personally I would always be wondering at show time. If it sounds good at a reasonable volume and you get to play really loud for a set, it would sound mushy without definition. I always use a meter or a bias rite and go on the low side of things just for peace of mind. That way I "Almost" don't have to worry if I get rail at a big gig.

 

[212Mavguy]

Depends on the size of the room...in small rooms where you don't turn up all that loud you can run a bit hotter than at that big outdoor gig. I like a slightly cooler setting for cranking the god out of it. That's why I had my Maverick modded for a bias knob. I call it the "depends" mod, the setting depends on my mood, the guitar, and the room... and when it is in that wonderful sweet spot I might need to put on a pair...!

Sounds better than the "one setting for all situations" thang it came with.