Hi,
Just wondering has anyone got the service manual for the luxman SQ 503X
I would like the part about setting the DC offset and the Bias.
I presume the DC offset should be as close as possible to 0V measured at the speaker terminals (with volume down), but what should the bias voltage be, I see the output resistors are going to location pins / wires 5L & 10L and then to emitters for the left channel and 5R and 10R for the right channel, I presume I measure across these with DM set to mV.
Thanks in advance.
Regards,
Jer.
Just wondering has anyone got the service manual for the luxman SQ 503X
I would like the part about setting the DC offset and the Bias.
I presume the DC offset should be as close as possible to 0V measured at the speaker terminals (with volume down), but what should the bias voltage be, I see the output resistors are going to location pins / wires 5L & 10L and then to emitters for the left channel and 5R and 10R for the right channel, I presume I measure across these with DM set to mV.
Thanks in advance.
Regards,
Jer.
Yes I see that, even though there are 2 adjustment pots for each side / channel, one seems to adjust the dc off set, which I have set to as close as possible to 0mv at the speaker terminals, and the other one adjusts the bias, the one shown on the diagram, so really was hoping someone would have the service manual for this amp, so I know what to set the bias to, I will set it to 20mV across the output transistors for now, I read somewhere that some luxmans need to be set to 29mV, I suppose I can try it and see if it gets hot or not
Yeah, the service manual is lacking... Currently working on a SQ-505X, decided to go for about 8mV across 1 emitter resistor (0.33ohms) giving about 25mA. I read a few posts online, suggestions from 3mV to 50mV so careful what you read/believe. If you have a working scope (both mine need a psu recap...) maybe gradually increase while checking the crossover distortion...