Hello friends
I'm building my Aleph3 clone based on an ebay PCB, and I noticed a strange behaviour at power on.
For testing I'm using two bench power supplies to provide +/-23Vdc. The maximum current is limited to 2.5A, and only one channel is powered. No load is connected to the amplifier output.
All power devices are matched, and the the pairs of the differential input stage are matched and thermally coupled via a little copper bar.
When I turn on the first module, all seems to be ok. Output offset is something like 80mV, and after warming up it reduces to about 50mV. the heatsink temperature goes to about 55 celsius degree.
When I turn the second module, the positive rail goes in current limit at 2.5A for about 2 seconds. During this period of time the voltage rail goes down to 11Volt. After those 2 seconds, the overcurrent on the positive rail goes out, the voltage rises to 23Volt and the current is equal to 1.6A.
Is it acceptable this startup or I have to find somenthing wrong in the circuit?
Attached two snapshots of the module and the test bench.
I'm building my Aleph3 clone based on an ebay PCB, and I noticed a strange behaviour at power on.
For testing I'm using two bench power supplies to provide +/-23Vdc. The maximum current is limited to 2.5A, and only one channel is powered. No load is connected to the amplifier output.
All power devices are matched, and the the pairs of the differential input stage are matched and thermally coupled via a little copper bar.
When I turn on the first module, all seems to be ok. Output offset is something like 80mV, and after warming up it reduces to about 50mV. the heatsink temperature goes to about 55 celsius degree.
When I turn the second module, the positive rail goes in current limit at 2.5A for about 2 seconds. During this period of time the voltage rail goes down to 11Volt. After those 2 seconds, the overcurrent on the positive rail goes out, the voltage rises to 23Volt and the current is equal to 1.6A.
Is it acceptable this startup or I have to find somenthing wrong in the circuit?
Attached two snapshots of the module and the test bench.
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