Bias Question

[PUCKBOY99]

I bought a Weber Bias Rite 2+2 (2 octal + 2 9-pin sockets) & a Copper Cap rectifier.

I wanna try EL34s & a SS rec in the Edana(KT66s & GZ34) to see what the difference is.

The question is: Do I need to bias the rectifier & if so, to what setting?


AND....For Scott or the other Edana owners: Have you done this or are any of you runnings EL34s?

 

[kmcguitars]

Re: Bias Question

NO! Please don't attemp to bias your rectifer.:no1: :no1:
BTW, I think you may have bought the wrong Bias rite? KT66,EL34 and 6L6's have 8 pin outs.I think only EL84's have 9 pinout? Check it out.

 

[PUCKBOY99]

Re: Bias Question

Octal = 8 pin

I also have an EL84 amp, so I got the one that allows you to do both 8 pin & 9 pin.

In reading the Bias Rite FAQs, it says the Copper Cap is a direct replacement, but makes no mention of biasing.

By your reaction, I assume there's no need to bias the rectifier???!!!

 

[kmcguitars]

Re: Bias Question

Octal = 8 pin

I also have an EL84 amp, so I got the one that allows you to do both 8 pin & 9 pin.

In reading the Bias Rite FAQs, it says the Copper Cap is a direct replacement, but makes no mention of biasing.

By your reaction, I assume there's no need to bias the rectifier???!!!

YUP! your right about the weber.:smack: (That Ole' paying attention thing)
When you bias your tubes, Your mainly checking the cathode current. Rec. tubes don't require any adjustment.

 

[Scott_F]

Re: Bias Question

For the record, when switching to EL34's, you'll have to change out the bias resistor so that you can get a decent range of adjustment out of the 10KL bias pot. That is a slight drawback. But, it's a very easy substitution. On the Weber replacement rectifiers. They do not have the "solid state rectifier" voltage boost you are probably after. They actually try to emulate a real rectifier tube in terms of sag and ramp up and such.

On the other hand, several companies sell a small solid state plug that goes into your rectifier slot. That will give you more voltage to the power tubes.

To do this right, you really ought to check the voltage to those power tubes after you install the new rectifier plug. There is a handy bias calculator on the Weber Forums, under the tube section. From there, you can select Class AB, then EL34 and then put in the voltage going to the tubes. Hit the button and you'll get your max setting. Then you can use the biasrite to do the trick. I usually back off that max (70%) a few milliamps.

 

[PUCKBOY99]

Re: Bias Question

For the record, when switching to EL34's, you'll have to change out the bias resistor so that you can get a decent range of adjustment out of the 10KL bias pot. That is a slight drawback. But, it's a very easy substitution. On the Weber replacement rectifiers. They do not have the "solid state rectifier" voltage boost you are probably after. They actually try to emulate a real rectifier tube in terms of sag and ramp up and such.

On the other hand, several companies sell a small solid state plug that goes into your rectifier slot. That will give you more voltage to the power tubes.

To do this right, you really ought to check the voltage to those power tubes after you install the new rectifier plug. There is a handy bias calculator on the Weber Forums, under the tube section. From there, you can select Class AB, then EL34 and then put in the voltage going to the tubes. Hit the button and you'll get your max setting. Then you can use the biasrite to do the trick. I usually back off that max (70%) a few milliamps.

RE: THE BIAS RESISTOR.....isn't that what the inside toggle in the Edana does?

RE: THE SS REC.....is there one you would or could recommend other than the Copper Cap ?

Something like this?: http://www.vintone.com/rectifier.html

That calculator on the Weber site is pretty sweet:bigthumb: