Anyone Know How to do Baising?

[rick_bravotino]

Dear All,

I am Rick from Spore. New bie in HiFi World. Need some help and guide line.

1) how can I do and check baising?
2) what is the value? and how do I find out?
3) where is the control for adjustment?

Really appreciate for all attention and feed back

Cheers!

[analog_sa]

Originally posted by rick_bravotino
New bie in HiFi World.

You work for the magazine?

If you mean "biasing" and it's not a journalistic secret, could you share what do you intend to bias?

[Iain McNeill]

Do you have a schematic? You'll need one.
Google will find it for you, perhaps for a small fee.

[h_a]

Hi Rick,

You really work for the magazine?

The answers of all your questions depend entirely on the amp you're working on, there do not exist any general answers.

By the way, if you didn't already know this, then you shouldn't fiddle with the bias.

Have fun, Hannes

[AndrewT]

Hi,
there is a general answer for an EF output stage.
Bias at 15mV to 25mV across each output emitter resistor.
Set the output bias with the DC offset near zero mV and with the input shorted and no load connected.

Do apply apply this rule to FET output stages nor to CFP output stages.

[h_a]

Hi Andrew, you really think the original poster knows what an EF is

Bias at 15mV to 25mV across each output emitter resistor.

Good observation indeed...Emitter resistors in designs are generally ranging from 0.1 up to 0.47 R? The bias currents would equally range from 40mA all the way up to 200mA...

All the best, Hannes

<Post edited>

[AndrewT]

Originally posted by h_a
Hi Andrew, you really think the original poster knows what an EF is

no,
but if he's interested at all he will start researching.

[rick_bravotino]

I have just finished changing all Cap on both L%R driver board. Now the Right side is hotter than the Left side. My friend said need to do baising to balance.

The driver board have 2 tiny control...but not sure how to do it...?

[Bigred]

Well why don't you TELL US the amp your trying to set the bias current on or is it a secret?

[rick_bravotino]

I have no ideal how to do baising...my friend told me send it to Krell in S'pore, which I think is expensive. Not sure where sure I put the multi-meter + & - points to monitor the reading, and what value should I look for?

I read some DIY project talking about current n voltage. But how to do it? and what value to adjust?

Thanks for the attention