I made my quick "calculation" based on simple logic. The circuit has a physical layout that almost "symetrical": 1/4W resistor - Vds - Vds - 1/4W resistor.
Whatever the DC rail, the input should have only a few mV above ground, right? With Vgs around 3 to 4V, the Drain of current source should at most 5V above ground. Then how do you share a 25V between Vds and a 1/4W resistor? (assumming a 30V rail)
I'm not good at electronics, so would you look at it for me once more, please?
Whatever the DC rail, the input should have only a few mV above ground, right? With Vgs around 3 to 4V, the Drain of current source should at most 5V above ground. Then how do you share a 25V between Vds and a 1/4W resistor? (assumming a 30V rail)
I'm not good at electronics, so would you look at it for me once more, please?
Agree with JoeD. You don't need a heatsink.
In my case, I use a 40V-0-40V transformer. Originally, I didn't use any heatsink, and I used a resistor to offset the DC in the current source. Later, I removed the resistor and put a heatsink on the ccs MOSFET.
What is the specified rail for Aleph2? 30V? 35V? If 35V, I believe there is a considerable amount of heat. You can do the math if you think it is worth to do
In my case, I use a 40V-0-40V transformer. Originally, I didn't use any heatsink, and I used a resistor to offset the DC in the current source. Later, I removed the resistor and put a heatsink on the ccs MOSFET.
What is the specified rail for Aleph2? 30V? 35V? If 35V, I believe there is a considerable amount of heat. You can do the math if you think it is worth to do
Hi,
Regarding in this old thread, I have a question.
After powering up my aleph 60, it starts just right up.
The sound is audible, but after a few minutes, one of the diff pair become very hot, Q2. Q1 doesn't get even hot, but they are matched pairs.. Q3 also gets hot, but thats logical.
When powering it down with the variac, the sound is very long audible, but there is 140.000mF p/ch.
By the way, I left out the resistor R0 out, wich is 3@3W.
Is this the reason for the heat differential?
I'm not using heatsinks for these pairs.
Thank you,
Remco
Regarding in this old thread, I have a question.
After powering up my aleph 60, it starts just right up.
The sound is audible, but after a few minutes, one of the diff pair become very hot, Q2. Q1 doesn't get even hot, but they are matched pairs.. Q3 also gets hot, but thats logical.
When powering it down with the variac, the sound is very long audible, but there is 140.000mF p/ch.
By the way, I left out the resistor R0 out, wich is 3@3W.
Is this the reason for the heat differential?
I'm not using heatsinks for these pairs.
Thank you,
Remco
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