Nakamichi PA1004

[Dr Zeus]

I've got this amp needing new output fets in one of it's four channels; which are IRFZ34N. Would I be able to sub something in close range to it like an IRF530, IRF540 or IRFZ44N? IRF530 and IRF540 seem very close.

The amp is using 22ohm 1/8w gate resistors and 0.1 ohm resistors. Whats kind of strange about this amp is that is appears to be manufactured with some of the source resistors removed by design such as R230. its like this on all channels but the other channels are working OK.

[MOER]

Dr. Zeus,

I designed these amps. Use IRF540N or similar and they will work fine BUT you must replace all FETs in a channel if you change.

Used parallel FETs with common source resistors

Careful on setting the bias, FETs go up in smoke if you over bias them

Steve Mantz
Zed Audio

[ppia600]

Originally Posted by Dr Zeus

Whats kind of strange about this amp is that is appears to be manufactured with some of the source resistors removed by design such as R230. its like this on all channels but the other channels are working OK.

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[Dr Zeus]

I designed these amps

[ppia600]

What was the reasoning behind the random resistor and jumper setup, did he ever tell you? (why I reposted the pic)