I have a Rockford Fosgate 150a2 that I would like to upgrade the power supply in. I am wanting to use IRF3205 in place of the IRFZ44N in the power supply.
1) If I use the 3205's, should I use 47ohm resistors or another value for R19 and R20, which are the gate resistors.
2) R29 and R30 on the board right next to the gate resistors are also 100ohm and tied to the emitter (third leg). Should those be replaced with a different value if using 3205's?
3) The original driver transistors feeding the FET's are MMBT3904 and MMBT3906. Should those be upgraded as well? If so, what would be a nice upgraded replacement that would work?
Thanks in advance for any help!
1) If I use the 3205's, should I use 47ohm resistors or another value for R19 and R20, which are the gate resistors.
2) R29 and R30 on the board right next to the gate resistors are also 100ohm and tied to the emitter (third leg). Should those be replaced with a different value if using 3205's?
3) The original driver transistors feeding the FET's are MMBT3904 and MMBT3906. Should those be upgraded as well? If so, what would be a nice upgraded replacement that would work?
Thanks in advance for any help!
I just looked at the schematic again and R29 and R30 are tied to ground so I assume they will stay the same. I glanced over it when I was writing the thread.
I have a Rockford Fosgate 150a2 that I would like to upgrade the power supply in. I am wanting to use IRF3205 in place of the IRFZ44N in the power supply.
1) If I use the 3205's, should I use 47ohm resistors or another value for R19 and R20, which are the gate resistors.
2) R29 and R30 on the board right next to the gate resistors are also 100ohm and tied to the emitter (third leg). Should those be replaced with a different value if using 3205's?
3) The original driver transistors feeding the FET's are MMBT3904 and MMBT3906. Should those be upgraded as well? If so, what would be a nice upgraded replacement that would work?
Thanks in advance for any help!
There is no emitter, these are MOSFETS. They have a gate, drain, and source.
Install the IRF3205 FETs, change the gate resistors to 47 ohm for the power supply FETs.
You can replace the original driver transistors MMBT3904 and MMBT3906 or use MMBTA06 and MMBTA56.
You can replace R29 and R30 that are attached to the "source " leg of the power supply FETs. They may have been damaged, you can check them with your meter. Leave them the same resistance as they are now 100 ohm.
Only change the gate resistors R20 and R19 to 47 ohm.
Thanks for the quick reply. I was in a hurry writing this post and I guess writing as if they were BJT's and not FET's came out for some reason lol.
So the original driver transistors are sufficient enough to power the FET's without failing under normal use due to the 3205's?
So the original driver transistors are sufficient enough to power the FET's without failing under normal use due to the 3205's?
I replaced both gate resistors with 47ohm and dropped in the IRF3205's and saw that one channel had blown transistors so I just replaced both channel's outputs anyways. The amp powers up and works great! Thanks.
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