Does anyone know why these 2250's draw such high current (8-10 amp range) while idling ?
I've just rebuilt this one, all new PS and output mosfets. It sounds great, but wow , does it draw some hefty current with little or no signal applied. (and this is with 8 ohm test speakers)As you give it more signal, the current draw drops a bit maybe 25%.
I have noticed this before with another 2250's I've repaired.
I've got a 2100 HCCA that I have just restored also, but it doesn't have this idle power hungry characteristic. I know it's a different amp but the 2250 and 2100 don't look all that different.
TIA
I've just rebuilt this one, all new PS and output mosfets. It sounds great, but wow , does it draw some hefty current with little or no signal applied. (and this is with 8 ohm test speakers)As you give it more signal, the current draw drops a bit maybe 25%.
I have noticed this before with another 2250's I've repaired.
I've got a 2100 HCCA that I have just restored also, but it doesn't have this idle power hungry characteristic. I know it's a different amp but the 2250 and 2100 don't look all that different.
TIA
I don't think that's normal. I have one that I'll be testing later today. I'll check the idle current.
In the mean time, you can measure the voltage across the emitter resistors to see if one channel has too much bias current. If I'm not mistaken, there should be 0.000v across the emitter resistors. I'll check that also.
What is the rail voltage with signal (where the idle current drops) and without signal?
In the mean time, you can measure the voltage across the emitter resistors to see if one channel has too much bias current. If I'm not mistaken, there should be 0.000v across the emitter resistors. I'll check that also.
What is the rail voltage with signal (where the idle current drops) and without signal?
1-1.5A at idle.
108v across the rails (13.5v DC input).
Can you confirm that the large resistor between the two power transformers is 120 ohms. I have one here and the resistor was burned beyond recognition.
108v across the rails (13.5v DC input).
Can you confirm that the large resistor between the two power transformers is 120 ohms. I have one here and the resistor was burned beyond recognition.
Hi guys;
Perry; The rail-rail volt on this thing was 103.4 idling and went up 1/10 of a volt with signal.
The resistor between the toroids measures 178 ohms.
It looks like its marked as a 2.9K but it's discolored and that could be wrong.
Also, I noticed it was the power supply fet's that were dissapating the heat under idle. So, just for the hell of it I started taking out all the mounting screws one by one and checking current. Nothing chnged until I pulled the board right out of the case.
Now, it's idling at 2 amps. I must have some leakage somewhere in the mounting process.
Perry; The rail-rail volt on this thing was 103.4 idling and went up 1/10 of a volt with signal.
The resistor between the toroids measures 178 ohms.
It looks like its marked as a 2.9K but it's discolored and that could be wrong.
Also, I noticed it was the power supply fet's that were dissapating the heat under idle. So, just for the hell of it I started taking out all the mounting screws one by one and checking current. Nothing chnged until I pulled the board right out of the case.
Now, it's idling at 2 amps. I must have some leakage somewhere in the mounting process.
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