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PeeCeeBee V4H GB

Good to know. :up:🙂

Mosfet bias brought back to 215mV
But it's heatsink is really hot after 15mn !!

My workbench's mess attached, no shame !

JM
 

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Thanks for the pic. With heatsinks lying flat it should get hotter than usual as airflow is restricted. All looks normal. :up:

I'm going to have 1 fan on top of each of my smps in my enclosure,
as I'm living in a hot place, and as this amplifier is located in a not so well ventilated shelf. Otherwise it's going to get much too hot in my enclosure,
not so good for electronics.

What is the minimum bias I should have to keep it stable ?
Is 150 mV still OK ?

JM
 
I'm going to have 1 fan on top of each of my smps in my enclosure,
as I'm living in a hot place, and as this amplifier is located in a not so well ventilated shelf. Otherwise it's going to get much too hot in my enclosure,
not so good for electronics.

What is the minimum bias I should have to keep it stable ?
Is 150 mV still OK ?

JM

It can be stabilised at any bias. But that bias has a direct relationship with cooling required. So one has to find it out in a given cooling situation.

If it is acceptably warm then 150mA is just fine. If it still gets too hot, then try 100mA.
 
It can be stabilised at any bias. But that bias has a direct relationship with cooling required. So one has to find it out in a given cooling situation.

If it is acceptably warm then 150mA is just fine. If it still gets too hot, then try 100mA.

OK, I'll take care of this later when my enclosure will be ready.
Next step for me is to fix my other (damaged) pcb, will take time as I'll have to order some parts .......

JM
 
MORE SMOKE !!

R26 fried, as I was into starting some measurements with my scope and low freq generator.
:lickface:
I had a 8ohm power resistor - exploded 😕- (on heatsink) as load on the output.
I guess I had a bit too much voltage on the input.
LEDs still lighting up. Looks like the BJTs are OK and no other obvious damage.
Should I check anything else in particular before starting again for more fun ?
Thanks again ......

JM
 
Last edited:
MORE SMOKE !!

R26 fried, as I was into starting some measurements with my scope and low freq generator.
:lickface:
I had a 8ohm power resistor - exploded 😕- (on heatsink) as load on the output.
I guess I had a bit too much voltage on the input.
LEDs still lighting up. Looks like the BJTs are OK and no other obvious damage.
Should I check anything else in particular before starting again for more fun ?
Thanks again ......

JM

Check Q3, Q4, Q9, Q10.
I hope this kind of fun doesn't happen to you again.
 
Don't worry about the temperature. My heatsinks have about 48° C after 2 hours, while Exicons direct contacted have 78° C.
Temperature feeling is hotter then it is in real. F.e.g. You do a bathing at home and water does have 38° some will think/feel it's too hot to go in.

Good Luck
Jo