Im working on a 10K amp The amp has 32 outputs The driverboard has 4 driver IC'S on it so 1 Driver IC controls 8 outputs the next driver IC controls 8 more and so onWondering on these class D amps do the dates codes need to match in the same bank of outputs or doesnt it matter ?I know class A/B amps the date codes need to match wondering if the same applies to the class D amps
I agree. All in a bank of parallel FET must (at least) have matching date codes.
I don't know if it makes a difference but I've been checking the capacitance of the FET (even if they have matching date codes). Gate to drain/source in parallel. They plug right into my capacitance meter.
Most FETs from reputable distributors are relatively close. Some that were sent (by the owner) with an amp to be repaired were all over the place. They were marked Fairchild but were from ebay. I didn't use them. When selecting FETs for a bank of parallel FETs, I pick the one with the closest capacitance readings.
I don't know if it makes a difference but I've been checking the capacitance of the FET (even if they have matching date codes). Gate to drain/source in parallel. They plug right into my capacitance meter.
Most FETs from reputable distributors are relatively close. Some that were sent (by the owner) with an amp to be repaired were all over the place. They were marked Fairchild but were from ebay. I didn't use them. When selecting FETs for a bank of parallel FETs, I pick the one with the closest capacitance readings.
Someone (it may have been Troy or his partner Ethan) posted up a video of new fets installed in a board, all were the same except for one which had a different date code (not generic, just a different batch) and he was pointing the IR gun @ each one. The temps were all the same until he got to the one fet that was different, and it was noticeably hotter.
In amps that have multiple transformers, I feel comfortable using one batch of fets in front of one transformer, and another batch of fets in front of another - but I wouldn't want to mix them on the same transformer.
That's my personal preference anyways.. it's always interesting to hear how others do it - or what they do and don't consider acceptable
In amps that have multiple transformers, I feel comfortable using one batch of fets in front of one transformer, and another batch of fets in front of another - but I wouldn't want to mix them on the same transformer.
That's my personal preference anyways.. it's always interesting to hear how others do it - or what they do and don't consider acceptable
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