how sensitive should the bias-pot be?

  • Thread starter Thread starter petereanima
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petereanima

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i've changed a pair of power tubes for the first time, and as this was my first-time-ever biasing, i first turned it real gently, and it changed (as i suggested) slowly by 0,01 mA, but then from one REAL REAL gently move to another there was a drop down to ~15mA, and by turning back (AGAIN: the move was as smooth as the first ones) up to 60...was a tuff one then getting it to 65 haha...

just wanted to know if this is normal.

aif yes i will smoke an extra cigarette in the future before biasing to get my hand not shaking :lol: :LOL:
 
Its very sensitive i have noticed that too. Also make sure that you first remove the screwdriver and then check that the multimeter reading stays where you want it to be.

Once i did it other way and accidentally turned the bias pot while removing the screwdriver, it went something like -10mA wrong!

yep have fun ;)
 
yeah, thats how i found out too. i pulled out the scredriver, and then saw "47,35 mA" :confused: -> damn, i had to re-adjust it 3 times until i got the screwdriver out perfect. :aww:

<-- noobie. :doh:


but i have to say: its over the top noob-friendly, i was almost surprised like "o.k...so thats it?"

and then i thought "wow, and the shop wants 100,- without tubes for that?" :doh:
 
Please don´t care to much about a few milliamps.
Your main voltage change every minute.

:thumbsup:
 
What do you need to bias amps? Like tools.....other than a screwdriver.
 
petereanima":fqkq822x said:
Szar":fqkq822x said:
What do you need to bias amps? Like tools.....other than a screwdriver.
Click to expand...

a digital multimeter. :)
Click to expand...
Thats it? Need to pick one up and do the biasing myself, saves time and I don't need to leave home. :D
 
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