heatsink very hot
Hi, I'm very happy with the SQ of this amp, but some times when put my fingers on the heatsink, it makes me a little nervous. The main heatsink was about 50-60 C, and the L sharp heatsink attached power MOSFETs to main heatsink was even higher, about 70-80C, can't hold finger for more than 2 seconds. Although the amp seems functioning OK
Is it normal, or should I use a larger heatsink?
Hi, I'm very happy with the SQ of this amp, but some times when put my fingers on the heatsink, it makes me a little nervous. The main heatsink was about 50-60 C, and the L sharp heatsink attached power MOSFETs to main heatsink was even higher, about 70-80C, can't hold finger for more than 2 seconds. Although the amp seems functioning OK
Is it normal, or should I use a larger heatsink?
Yes, that is far too hot. A finger pressed against the heatsink with comfort for less than 10 seconds is too hot. The junction is typically 20C higher than the case, so this semi will not last very long.
HD
HD
Albrerta, can you give more details such as the bias current you use and heatsink size. I know that this amp is also prone to oscillation depending on several factors.
Fab
Fab
Thanks AKSA, fab
My heatsink is about 270 mm long, 75 mm high, about 10mm solid base then 25 mm fins. 130-140 ma bias, +/-50V main PS, my speaker is magnepan MG12, not a easy one
The amp is fine if use lightly, but after intense playing (like a might Mahler's symphony) , the heatsink is too hot to hold a finger, I tried to let it idle for a while, the heatsink then back to normal temperature
My heatsink is about 270 mm long, 75 mm high, about 10mm solid base then 25 mm fins. 130-140 ma bias, +/-50V main PS, my speaker is magnepan MG12, not a easy one
The amp is fine if use lightly, but after intense playing (like a might Mahler's symphony) , the heatsink is too hot to hold a finger, I tried to let it idle for a while, the heatsink then back to normal temperature
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Joined 2009
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It sounds like it's working find, heavy use will certainly generate a lot more heat. Only worry would be if you're driving to some unstable oscillations. For regular heavy use the easiest option might be to increase air flow over the heatsink - maybe it's a case of orientation and positioning - or add a super quiet fan controlled by a temperature sensor.
Bigun beat me to it!
I use GB150D's and also like full throttle Mahler!
In my case I added a whisper-quiet 5" 12V DC fan (Desk-top PC market) and ran it a 7V using a series resistor to make it certainly quieter that a Mahler brass section!
Cooling problem totally solved.
I use GB150D's and also like full throttle Mahler!
In my case I added a whisper-quiet 5" 12V DC fan (Desk-top PC market) and ran it a 7V using a series resistor to make it certainly quieter that a Mahler brass section!
Cooling problem totally solved.
it depends ....
As long as there is an entry in the case for fresh air, and an exit for warm air, positioning it anywhere that encourages the flow will do.
If the case s big enough by all means put a fan on each heatsink, but that is not necessary. But replacing the warm air generated is what is important, not just blowing it around in a sealed box!
Post a photo of the assembly?
As long as there is an entry in the case for fresh air, and an exit for warm air, positioning it anywhere that encourages the flow will do.
If the case s big enough by all means put a fan on each heatsink, but that is not necessary. But replacing the warm air generated is what is important, not just blowing it around in a sealed box!
Post a photo of the assembly?
Can someone please make a recommendation for Q1 and 2 and Q3 and 4 that reflects currently available parts?
Cheers Wayne
Cheers Wayne
Can you just try a ctl-shift-R in your browser and check again please? I'm getting a placeholder page.
I would like to build one as bass amp for my LX521. Therefore, I would like to ask if GB150D can work well with 4 Ohm load? And how much power it consumes in on idle?
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Joined 2009
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Jim's Audio 150W MOSFET servo amp
Has anyone tried this other 150W MOSFET board with servo from Jim's Audio:
Fully complementary MOSFET power amplifier w/servo control DC offset PCB 1 pc ! | eBay
Looks very similar to the GB150D with some difference in details. Added servo.
Has anyone tried this other 150W MOSFET board with servo from Jim's Audio:
Fully complementary MOSFET power amplifier w/servo control DC offset PCB 1 pc ! | eBay
Looks very similar to the GB150D with some difference in details. Added servo.