Where can i get a good bias tool?

I didn't check first, but if you go to accessories on Ebay and type in bias tool, something should come up.

I bought mine on there for $15-$20. I bought the mA version
and use it with my volt/ohm meter.

I make sure 6L6's are around 32mA
and El-34's are around 36-42mA
I make sure the tubes stay around those numbers, but
go by ear till the amp sounds it's healthiest.
 
HolyDirt said:


To bias an amp with that tool, you...

Have the chassis on a bench with books or something to support it. Have a guitar plugged in, and a speaker cab plugged in.

Put the new power tubes in, with the bias tool in between one of them,and the chassis.

Plug the bias tool into your volt/ohm meter, set on mA

Turn the amp on, and make sure 6L6's read around 32mA
and EL-34's around 38mA.

Start strumming the guitar with one hand, with your right hand on a mini screwdriver, to adjust the bias pot inside your amp's chassis. Turn it very sparingly, making sure to keep the number close to the numbers I listed.

When the amp sounds boldest, most articulate and healthiest on both of your amp's channels, AND is pretty close to those numbers, try moving the bias tool to another tube, just to make sure all 2 or 4 are running at the same mA.

This process can take about 1/2 an hour, till your amp sounds it's best. MAKE SURE you don't touch anything inside the chassis while you're doing this. The Current is LETHAL in a tube amp.

If you end up looking like Yosemite Sam, DON'T sue me!:D
 
You'll have to excuse me guys, but I'm new to this biasing thing. Do you just bias power tubes, or do you bias pre-amp tubes as well?

Also, I'm prepared to spend a decent amount of money for a good bias tool, but I really don't know what to look for in one. I'm confused by the bias rite things on the weber vst website.
 
On Ebay, some guys are selling that two sided tube socket with a wire dangling off it. They go for around $20, but you'll also need a volt/ohm meter. You can get those at radio shack or Sears.

I have a mA version. The Voltage version is good too, but I like to know the current, so I don't turn the plates red accidentally by
turning the bias pot too far in one direction.

Only power tubes need biasing. Pre tubes all sound a little different, so you buy those by brand, but don't need to adjust anything.
 
the_Chris said:
You'll have to excuse me guys, but I'm new to this biasing thing. Do you just bias power tubes, or do you bias pre-amp tubes as well?

Also, I'm prepared to spend a decent amount of money for a good bias tool, but I really don't know what to look for in one. I'm confused by the bias rite things on the weber vst website.

I wouldn't blow too much on those shunt sockets that go between the tube and socket. They're even fairly simple to make yourself. Now, the Bias King is a different story...
 
Yeah, I'd like to have one of those Bias Kings!

If you figure that buying those tools and learning to do it yourself will cost about the same as paying a tech, you'll save money,
not to mention learning more about tubes.
 
I was checking on eBay and the BiasTool looks really simple to me. Does anyone have one and would care to comment on their experience with it?

I'm gonna be ordering some new tubes very soon so this would be very useful.

As always, thanks for helping me out : )
 
the_Chris said:
I was checking on eBay and the BiasTool looks really simple to me. Does anyone have one and would care to comment on their experience with it?

I'm gonna be ordering some new tubes very soon so this would be very useful.

As always, thanks for helping me out : )

The SRS Bias Tool is simple and effective. I just plug it into my Fluke and it works. No complaints, except that the cable comes out of the socket right where the tube retainer clips are, but it's just a minor issue.
 
I have a prehistoric "Accu-bias" that I got from some long-forgotten place called the Tube Farm back around '93.

If you are strapped for cash, or just prefer DIY, Hoffman amps has instructions on making a bias probe, and sells the parts. You'll need a $2 socket, shielded cable at $.30 a foot, and a banana plug.

bias probe instructions
 
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