| Bias Measuring points, pros cons - Click HERE for Original Thread |
| Zero Cool |
I am curious about the Pro's and cons of various Bias measuring methods.
I am finally finishing the rebuild of an amplifier and i need to set the final bias once it is all done. It appears that the factory method of setting bias is by measuring across the emitter resistors. This is how i set initial bias. But noticed that if i was not very careful, that the amp would oscillate due to my meter leads.
So i am curious how i can better my method. I have a very good Fluke 189 multimeter that i have been using. Would shielded leads be better then the stock leads for the meter?
And what about measuring Bias by putting the meter inline with one of the power supply leads? the amp would be less prone to oscillation that way, but is that a better method? it is definitly harder to set up as this amp does not have B+/- fuses. and using this method i understand i need to add the total of all the devices for the bias measurement. but am i adding ALL devices. for example if i have 4 pairs (8 devices 4N & 4P) and they need to be set to sat 50ma each, would i then be looking for 200ma, or 400ma? I would assume 400 ma correct?
advice please.
Zc |
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