Nikolai Petrenko
Member
But TO-247 and TO-3P has no difference in pinout or pin spacing.Just check that the pin spacing of the transistors that you are using are the same as the TIP3055/TIP2955. Some output transistors are TO247 etc.
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But TO-247 and TO-3P has no difference in pinout or pin spacing.Just check that the pin spacing of the transistors that you are using are the same as the TIP3055/TIP2955. Some output transistors are TO247 etc.
I did say check. Also TO220. There is also another bigger plastic pak (can't remember and too lazy to look it up) too. No big deal- just a thoughtBut TO-247 and TO-3P has no difference in pinout or pin spacing.
But there is too much space between 2 output transistors as your can see, even enough space for fat guy like 2SC2922/2SA1216.I did say check. Also TO220. There is also another bigger plastic pak (can't remember and too lazy to look it up) too. No big deal- just a thought
'Fat Guys' I am learning some new phrases from youBut there is too much space between 2 output transistors as your can see, even enough space for fat guy like 2SC2922/2SA1216.
Not bad, but much better to have heatsink vertical, as shown in the case design on the Transistor Equivalent thread.Mounting board and transistor in this way, well?View attachment 100037
That will be OK, and what you have shown will be fine for an audio amplifier, but to get the optimum performance, it is best to mount the transistor in the middle of the heat sink and to have a free flow of air around the heatsink, both sides.It is just the mounting method, of course the heatsink will be raise up vertically for best air flow.
PCCT???PCCT
If I mount like the shown, I cannot access the board without unscrewing the output transistors?It is also better to mount the transistor in the center of the heatsink rather than the edge. If you do need to mount the transistors on the edge of the heatsink they should be mounted on the bottom of the vertical heat sink.
As a general rule, always allow access to all parts of your circuitry. With your present layout you cannot access the bottom of the PCCT board.
There is a saying in electronics: 'Any part of a circuit, never mind how simple, that cannot be accessed will always be the most troublesome'. God has his little jokes.
you did ask
Heatsink should have vertical fins and long for best convection air flow, otherwise use a quiet 35 mm fan to get a plenum of air moving at least 1m/s , volume of air like 10 CFM can be small and quiet if low RPM.Mounting board and transistor in this way, well?View attachment 100037
View attachment 100042
This excellent Nakamichi design, above, which I Just found on web using your transistor part numbers, does what I just wrote.
Sorry, I am a poor man, my money still for speakers, not only can concern on output transistors.This is another reason your design is less capable than the Leach Design which uses two parallel output stages. I recall the Crown DC200 used 8 parallel output Q's. So heat spreading to multiple devices is critical for cooler operation.
Yes, I am going to make a thermal controlled fan speed for better thermal protection, it is also available to control speed by hand. If the fan can't cold down heatsink in some condictions, the mission is for thermal fuse..........Heatsink should have vertical fins and long for best convection air flow, otherwise use a quiet 35 mm fan to get a plenum of air moving at least 1m/s , volume of air like 10 CFM can be small and quiet if low RPM.
BUT air Speed is most important, so for convection , heat rises , make use of free air rising to cut thermal resistance in half and with ducted tiny fan , 10x better.
The pic I have shown only tell the mounting method, of course I never fool enough to turn my amp into a toast.If heatsink is under board and horizontal , you just made it at least 2x hotter temp rise on Transistor Case.
I have known about this way since I have learn about thermal and airflow. This way is much more benefit than using more output transistors in parallel.Study commercial Power Amp layouts for heatsink. Fan can be avoided to prevent dust, but requires understanding of how heat rises and airspeed, with vortex and vents below and above to create chimney effect. Otherwise, use more parallel devices to spread heat.
PCCT???
If I mount like the shown, I cannot access the board without unscrewing the output transistors?
Tony Stewart have said.No understand: can you explain?
It is my way.(Definity Power over ethernet) I learn how to make a spoiler air intake to create turbulence then attach thermistor to transformer hotspot with epoxy and use LM317 + Q + pot + RC network to make automatic temperature speed control.