Get Your Amp Biased

[Dr.Mavashi]

Re: Get Your Amp Biased

Gear Moron here again, Can anybody recomend somebody in San Francisco, who knows how to do bias right with other maintnance when changing tubes on Laney AOR 50??? THank you.

 

[J Moose]

Re: Get Your Amp Biased

My amp's already biased. It spends all day watching Fox News and reading Ann Coulter books.

ba-da-bomp!


Sirjack - The Pro & Blues Jr amps have a fixed bias...most EL84 amps do including Vox's.

Anyway, is there anyway to bias an amp at home without taking it to a shop? I've got a multimeter and I've been poking around audio gear all my life so it's not like I'm about to stick a screwdriver across a 60,000pfu cap 'cause I have no idea what I'm doing!

:smokin:

 

[jerryjg]

Re: Get Your Amp Biased

absolute balderdash! No need to ever rebias. The factory biases the amp for the proprer tube. I have run my amps for 320 years with the factory setings. Just get mil-spec tubes.Forget about biasing.

 

[shredaholic]

Re: Get Your Amp Biased

He tried to tell me something about "back in the day" they used "built-like-a-tank" Phillips tubes, and that they were ten times stronger (inconstruction i assume) than the "pansy" new stuff of today !???

He's probably right in that respect - tubes made in the heyday of tube manufacture would be far more rugged than those made today, new production right now just can't compete. That's why with most modern production output tubes, you can't have much more than 500v on the screens, and they don't last anywhere near as much as their modern counterparts. A guy called Terry Kilgore over on the Metroamp forum who used to hang around with Eddie Van Halen back in the day said that when a power tube blew, they used to just go to the store, buy one of them and pop it in, no biasing whastsoever.

However, having tubes that are far out of spec with each other would be more of a concern for the OT's lifespan than the lifespan of the output tubes. It could be likely though that decades ago tube tolerances were made to a certain standard in terms of current draw to avoid people needing to rebias - you just buy the same brand of tube and it will have a current draw of within 10mA of your other tubes. If that was the case, that could be why he got away without rebiasing.

 

[SirJackdeFuzz]

Re: Get Your Amp Biased

. . . i hear what you say !

Thanx "shedaholic" !