I have aquired 2 Phonic MAX1500 amps for nix.....one is working and one has a few gremlins that need sorting. Anyhoo I downloaded the schematic from Phonic but am a bit concerned about some component values which seem out of place. I thought peeps like those who have read this far could take a look and see if my cheese has slid off the cracker or am I on the track.
Components concerned is in the protection circuit for the output transistors. Specifically resistors R327, R328 and R323, R324.
Everything looks nice and symmetrical except for these few resistors on the bases and emitters of Q308 & Q307. Is this ok???
Also while I'm here and have your attention.....is it odd that Q303 is a darlington??
Components concerned is in the protection circuit for the output transistors. Specifically resistors R327, R328 and R323, R324.
Everything looks nice and symmetrical except for these few resistors on the bases and emitters of Q308 & Q307. Is this ok???
Also while I'm here and have your attention.....is it odd that Q303 is a darlington??
Can't help with the blurry protection values. I agree it seems strange.
Q303 should give 4 Vbe but only has a 1:1 divider. So Q303 must be 2Vbe, a Darlington.
Q303 should give 4 Vbe but only has a 1:1 divider. So Q303 must be 2Vbe, a Darlington.
Thanks “PRR”. I’m no guru but I e haven’t seen a Darlington used in this way. I am now a tiny bit wiser thanks🙂🙂🙂