HI, i've a RF T5002 AMP.
The amp work perfectly, both channel produce clean audio, but one channel get warm, the other no!
Probably i need to adjust the bias current!
How can i set the bias current in this amp?
thank to all.
The amp work perfectly, both channel produce clean audio, but one channel get warm, the other no!
Probably i need to adjust the bias current!
How can i set the bias current in this amp?
thank to all.
I haven't an amperometer on main supply, so, i can't make this type of bias regulation.
looking at the wiring diagram of this amplifier, I noticed that beside RV1000 (the trimmer regulating the BIAS) there is written "BIAS 1.8mV - 2.2mV at 25 ° C".
I would like to know if that statement refers to the voltage at the heads of R1064, R1070, R1065, and R1071 (SHUNT RESISTORS), because in that case, I can follow that procedure very well.
looking at the wiring diagram of this amplifier, I noticed that beside RV1000 (the trimmer regulating the BIAS) there is written "BIAS 1.8mV - 2.2mV at 25 ° C".
I would like to know if that statement refers to the voltage at the heads of R1064, R1070, R1065, and R1071 (SHUNT RESISTORS), because in that case, I can follow that procedure very well.
Do you have a multimeter with reading function of amps up to 10A?
If so, you can connect it in series on the B + of the amplifier to observe the consumption of the amplifier.
Once this is done, you can act with care on the potentiometer of the bias, keep in mind that if you increase it excessively you will get an excessive heating on the FETS of audio output, being able to reach its destruction in a few seconds.
In your case, I think you'll have to lower it a bit.
The option you mention, I have never tried it, I would not know to tell you ..
If so, you can connect it in series on the B + of the amplifier to observe the consumption of the amplifier.
Once this is done, you can act with care on the potentiometer of the bias, keep in mind that if you increase it excessively you will get an excessive heating on the FETS of audio output, being able to reach its destruction in a few seconds.
In your case, I think you'll have to lower it a bit.
The option you mention, I have never tried it, I would not know to tell you ..
unfortunely no! i don't have it.
Tipically, with this method yuo can see a current flow inside SHUNT resistor. This current flow must be observesd as voltages that not exced 1.8-2.2mV (as schematic). I don't know if this method is correct with all class AB amps.
This amp use mosfets as output stage, no transistor...
There are no emitter resistor here but only shunt resistors.
The 0.1ohm resistor connecting to the source leg measure across it.You could also compare it to the other channel.
I just used this method, it works perfectly.
Rotate the trimmers completely counterclockwise, with the mV multimeter to measure the voltage at the head of a resistor coming from source fet; turn clockwise, slowly, until you get a voltage of about 2mv.
repeat the same operation with the other channel.
I did this, now the amplifier does not heat up abnormally and works really well!
Thank you all for the help.
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