nad 3020b idle current

[Chrisr3521]

hi, i would like to be able to adjust the idle current in my nad 3020b by using a pot, however my knowledge is very limited so im asking if anyone would point me in the right direction? heres the schematic for the 3020b

http://homepage.mac.com/planet10/manuals/3020b_schematic.gif

thanks
chris

 

[jaycee]

If you mean, you are looking for a pot to tweak in the circuit, there isn't one.

If you mean you want to add one, then you would replace R645/646 with pots. You might also want to check if RX1 and RX2 are actually fitted and if so, what their values are.

 

[Chrisr3521]

sorry yes i want to add a pot any ideas on resistance? are those resistors the only parts i need to remove?

thanks

 

[YFW]

The spirit of NAD3020 is zero-adjustment and easy to maintain/manufacture.So I think it's not required to modify it.
If you insist to do this,you need to add a adjust bias circuit and emmiter resistors which will change the structure a lot.

 

[Chrisr3521]

yes its easy to maintain and adjust apart from the idle current which is fixed bias, so if this drifts the procedure to rectify this is tough to do for amutures like me, so adding a pot to adjust this current to recomended values would be great.

thanks