Ok I am working on a 1th gen Fosgate Punch 75 I am replacing the output transistors 2N6487 & 2N6490 Mouser has them in stock with a G on the end of the number but I can not find the drivers 2N6728 & 2N5716 in TO-237-3 package. Is there a substitute I can use in their place?
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TO-237 is an old package.
You can replace with other package type with same key parameters and pinout.
if you are willing to reverse pins 2 and 3, you can easily use a pair of bd139 and bd140 (which have a slightly different pinout)
You can replace with other package type with same key parameters and pinout.
if you are willing to reverse pins 2 and 3, you can easily use a pair of bd139 and bd140 (which have a slightly different pinout)
Use IRF540 and IRF9540. Do not use the "N" version.
I have used these in many of these amps as a sub with high success.
I have used these in many of these amps as a sub with high success.
He mentioned non-mosfet 2n6487 and 2n6490 as outputs. I thought the first gen 75 had non mosfet outputs? What would the 540 and 9540 be for?
I did read his post, but thanks for looking out.
I have used IRF540 and IRF9540 in these amps many times with no problems. The IRF540 is "N" channel used in the "NPN" location and IRF9540 are "P" channel used in the "PNP" location.
Example: IRF540 "N" channel will be used for 2N6487 "NPN"
Example: IRF9540 "P" channel will be used for 2N6490 "PNP"
I have used IRF540 and IRF9540 in these amps many times with no problems. The IRF540 is "N" channel used in the "NPN" location and IRF9540 are "P" channel used in the "PNP" location.
Example: IRF540 "N" channel will be used for 2N6487 "NPN"
Example: IRF9540 "P" channel will be used for 2N6490 "PNP"
That's pretty badass, didn't realize they would interchange. Does that help the amp run cooler and/or improve sq?
How would an amp like a ppi with the same outputs react with 540 and 9540 in their places react?
How would an amp like a ppi with the same outputs react with 540 and 9540 in their places react?
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I must add the ones I subbed were for MTP3055A and MTP12P05. You may be right on this one PPIA600.
I'm almost positive I have done it with the other ones as well. I have did it on many power 650 and power 300 amps too. Let me check my notes.
I did not know that a mosfet could be installed in place of a bjt without problems.
Are 2 types of different devices, will it work normally?
There are one or two amp topologies where swapping out bipolar outputs for mosfets without circuit adjustment is possible. Amp in question is probably using CFP 's - for low voltage drop when the outputs clip. It will run the driver transistors at a higher quiescent current compared to BJT outputs, but require less of them at full drive. This trick only really works for modest size amps - if you try to scale it up to something big it will have problems. Those old RF amps aren't that big by today's standards.
Thats good to know but what I need is a sub for the 2N6728 & 2N5716 they are no longer available / obsolete. I think I found a sub for the 2N6728 that is a MPS751 in TO-92 package but I stiil need a sub for 2N5716.😕
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I misread your first post. I thought you were looking for outputs not drivers, my apologies.
The later models used D41D8 and D40D8. I stock those. If the pin out is right maybe they will work.
The later models used D41D8 and D40D8. I stock those. If the pin out is right maybe they will work.
I thought D40D series TO-202's were just as much unobtainum as those funny looking TO 92-ish things. Even the tall 1 watt To92 is pretty well gone. Could use KSA1120/KSC2690.... while you can still get 'em.
It's odd that all of the drivers would fail. Are you sure that you need to replace them? Sometimes subs can cause problems.
I just pick up the Punch 75 tested it distorted outputs opened it up and found the fuses wrapped in tinfoil 😱I guess they thought it would work better that way 🙁
2N6491+6488 Genuine ON Semi PNP+NPN 80V 15A Transistors
5 Pair 2N6491+6488 Genuine ON Semi PNP+NPN 80V 15A Transistors | eBay
5 Pair 2N6491+6488 Genuine ON Semi PNP+NPN 80V 15A Transistors | eBay
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