N-Channel no bias problem

B.I.G · 18th October 2004, 06:21 PM

I`ve built Holton`s N-Channel and the bias pot doesn`t work i have 0V across the drain/source resistors !!

the pot is multiturn 4.7K and it is ok!

The amp plays sound and hass severe crossover distorsion !

B.I.G · 18th October 2004, 06:58 PM

i`ve solved the problem but now have another one ... the previous one was that the lm317 regulator wasn`t mounted correctly

but now i have Bias and it starts from a low value and increasses to about ... i really don`t know .... the most i`ve seen 150mv on my 0.22R resistors ... it should be about 18mv

it doesn`t matter how i turn the bias pot it still increasses

B.I.G · 18th October 2004, 06:59 PM

PS: it increasses very fast in about 10sec it getts to about 150mv

18th October 2004, 06:21 PM	#1
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	N-Channel no bias problem I`ve built Holton`s N-Channel and the bias pot doesn`t work i have 0V across the drain/source resistors !! the pot is multiturn 4.7K and it is ok! The amp plays sound and hass severe crossover distorsion ! __________________ B.I.G

18th October 2004, 06:58 PM	#2
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	i`ve solved the problem but now have another one ... the previous one was that the lm317 regulator wasn`t mounted correctly but now i have Bias and it starts from a low value and increasses to about ... i really don`t know .... the most i`ve seen 150mv on my 0.22R resistors ... it should be about 18mv it doesn`t matter how i turn the bias pot it still increasses __________________ B.I.G

18th October 2004, 06:59 PM	#3
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	PS: it increasses very fast in about 10sec it getts to about 150mv __________________ B.I.G

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