Hello ,
if the Mosfet is ok , across R4 should measure something like 1,6 or 1,8 Volt depending on the values of Vdd and the light bulb .
To test the mosfet , measure the resistance between gate and source , and viceversa , if it is something like infinite or Megaohm , it is ok .
Also , do not insert the lightbulb when the amp power supply is turned on .
Check also R4
perhaps a counterpart of this amp:Chances are likely that iPapa will be entertaining himself with a monaural setup in 20 years and 2 months from now, using a single light bulb, fully biased of course.
http://www.diyaudio.com/forums/soli...ke-pure-classa-se-despite-low-idle-power.html
Just to clarify, the resistance between G & S is taken with the power off.
"do not insert lightbulb", you mean R2 or lightbulb safety lead?
Thanks
Rob.
Not relevant to this thread, but i wonder what the average sustained bias level of the Momentum would be, with a non-interrupted music signal entering.
Zero output stage bias isn't very relevant if it's zero only when you're visiting the Johns.
(the d'A sorta makes me think of hybrid cars with start/stop technology)
Who knows, in twenty years from now, a SOTA energy-saving light bulb may turn off when you stop reading the book.
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Who knows, in twenty years from now, a SOTA energy-saving light bulb may turn off when you stop reading the book.
Yeah, and your tablet will turn off as soon as you stop reading the forum. It will have a special sensor that would track your eyes movement, and it will also turn off as soon s you start reading, or writing Off-Topic. Welcome to 1984
Also OT But, I think he mentions the static power consumption, along with some other crumbs, during the Geek interview
To test the the Mosfet , at least the Gate must be disconnected from the circuit .
For the second q ,I mean R2 . Still I don't know what the lighbulb safety lead really is ... or what is its use in this contest .
OK. So waht do you think I should do next?
Check R4 ( use the big heatsinked one ) , rebuild the circuit from scratch . Since the mosfets are ok , there is not reason it'll not work . Check for currents in the actual circuit , also in the mains . Something should be wrong , and preventing the turn on of the amp.
s