Got my half stack!

NicDots · Post by **NicDots** » Sun Feb 24, 2008 6:58 pm

Does it not matter if the tubes I'm getting aren't Groove Tubes?

Tommy · Post by **Tommy** » Sun Feb 24, 2008 9:20 pm

Preamp tubes are self-biased. Plug and play. But preamp tubes can last for decades, aswell... The only tube getting any wear, I'd say is the one in V1 pos. As for biasing yourself, get a bias tool of some sort. Like the Groove Tube Bias tool. I'm getting a Weber Bias Rite myself...

Now, unless your 5150 has the bias mod done to it, you have to open her up, and adjust the potmeter for the bias with a screw-driver, afaik. The only amps to come with external bias points (afaik), is the Diezels. And no, you do not need Groove Tube tubes, to use the Groove Tube biasing tool. EL34's are EL34's, no matter which brand. 5150's have 6l6 powertubes, I think...

Oh and yeah, the 12AX7's are the preamp tubes. When you bias, you adjust the idling current that goes through the powertubes (6l6's in your case)

NicDots · Post by **NicDots** » Sun Feb 24, 2008 9:51 pm

I did some googling and I asked my amp-head frienda bout biasing. He said that 5150 heads already have set biases so I wouldn't have to do it myself...

Tommy · Post by **Tommy** » Mon Feb 25, 2008 7:50 pm

NicDots wrote:I did some googling and I asked my amp-head frienda bout biasing. He said that 5150 heads already have set biases so I wouldn't have to do it myself...

You sure about that? Sounds weird that the 5150 auto-bias is already set!

NicDots · Post by **NicDots** » Tue Feb 26, 2008 5:02 am

Well, I googled it and my amp-head friend said that was the case...