04-03-2017, 07:46 PM
Hi.
Thanks for the info. Seeing the cartridge load impedance is 47K that makes more sense, some of the older crystal types were far higher.
I also remember the old Philips Electronic Engineer kits with the AF116 & AC126, these used direct collector to base biassing with either a 680K or 330K resistor. Once I did my C&G and got more theory I understood the reason they did it that way rather than having two resistors between supply and ground to give a pre-determined bias point.
Snag for me is it's a long time since I did all the learning, involved with servicing and some health issues a lot has gone out of the window. At least it seems to be coming back....... well a little bit.
Thanks for the info. Seeing the cartridge load impedance is 47K that makes more sense, some of the older crystal types were far higher.
I also remember the old Philips Electronic Engineer kits with the AF116 & AC126, these used direct collector to base biassing with either a 680K or 330K resistor. Once I did my C&G and got more theory I understood the reason they did it that way rather than having two resistors between supply and ground to give a pre-determined bias point.
Snag for me is it's a long time since I did all the learning, involved with servicing and some health issues a lot has gone out of the window. At least it seems to be coming back....... well a little bit.
