My Aleph 30 is almost finished. I tryed to turn it on and mosfets become warm.
Could you suggest me some test before I connect Aleph to loudspeakers?
Could you suggest me some test before I connect Aleph to loudspeakers?
Assuming you've checked and verified the bias current, you should also
measure the DC offset (between +/- output terminals). You want it to
be low, say less than 50mV.
If DC offset is fine, then you can try hooking up some test speakers.
Cheers,
Dennis
measure the DC offset (between +/- output terminals). You want it to
be low, say less than 50mV.
If DC offset is fine, then you can try hooking up some test speakers.
Cheers,
Dennis
No, I didn't check bias current. I'm using BrianGT boards. Where can I measure it? Across some resistor?
What resistance value did you use for the source resistors? The Aleph 30 calls for 0.47R and the manual says each resistor should have 0.25V across it, as Dennis pointed out. This translates into about 0.5A through each vertical pair of MOSFETs, or 1.5A total bias per channel.
Of course, if you used a different value for the source resistors, then you will see different numbers.
I'm using Brian GT boards that I bought on Chipamp (expired???) and I'm using the parts that are in the partlist... Nothing I changed
Question: how may I check If mosfets are no brocken? I have measured Vgs that is the same for each mosfet. More or less 4.4 V. Does Vgs is 0 If mosfet is damaged?
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I remember reading some of his parts designations were different from the
original schematics. I did manage to find the original here:
http://www.dianzitx.com/uploadfile/2010/0815/20100815101057521.gif
Perhaps you can check if it matches what you used?
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