Hi to all,
I’m andrea, and i just wanna know how to (and if it is necessary) bias the tubes if i want to put another pair..i know how to measure but i don’t know how to regulate it..
Thank you
Have a good day!
Biasing m15mk1
-
-
Hi and welcome to the forum!
The M15 is cathode biased meaning you don't have to set a negative bias voltage when replacing tube, just put in new EL84 and measure the voltage across the cathode resistor (R28 in parallel to R29). If the voltage is in the region of 9,7V (+/- 20%) everything is fine, if the voltage is too far away from that, one or both tubes are broken or at least not adhering to EL84 specs.
Regards,
Martin -
Thank you so much, just another question, using a probe what is correct range of mA i need to stay?
-
Using Ohm's law you get 9,7V divided by 135 Ohm = 72mA for both EL84 => 36mA per tube
Regards,
Martin -
Thank you sooooo much, i will try!
Jetzt mitmachen!
Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!