Quiescent Current Luxman M-03
I have to adjust the quiescent current of my Luxman M-03 Amplifier. In my downloaded Schematic (I found it in this Forum - thanks) there ist no hint where i have to measure the current and what value i have to adjust.
Could someone help me?
On left channel you measure between pin 1 and 3 at CB104 and on the right you measure at CB204.
Original the amplifier runs 3.5+/-0.5mV.
You should set the attenuators at minimum when doing this measurement recording to the servicemanual...
I have replaced the trimpots VR101 and VR201 with 20turn ones (easier to adjust and stays at selected value) and turned the current up a bit so that the amplifier now is quite hot (ca50C) when on.
I can`t really remember how much current I run my M-03 at, but I will see if I can measure it again some day.
I also replaced C121, C122, C221 and C222 with 1uF Wima MKP, and I removed the level potmeters and connected the input terminals directly to the amplifier pcb.
All this resulted in a "new" amplifier, it sounds much bigger and more relaxed.
thanks a lot for this info :)
Thanx for the info , just made the modifications and checked the idle setting , because one channel was a bit cooler . Now it's running on 4,19 mV . Jou are right about those trimpot's . They are not quite the most stable components for such a nice amp... I purchased myself a nice set of Spendor bc3's , my amp now sounds more relaxed indeed !
Can you let me know what idle setting you use ? , just curious ..
be aware ...there various articles in the forum talking about situations of the M03 mostly regarding soldering problems on the amplifier boards .
I presume you already been there if not you are actually in danger you have to look at this ASAP
Sakis , thanx for the warning . I had some soldering problems before with this amp . It was so strange , it got microfonic ... So I took it apart and did every soldering joint again . ( quite a work ) . Also I had an issue before , Powered it up but no click from the outputrelais . After a while I found a transistor which had un soldered itself ( located in the back , in the amp protection cirquit ) Also made a heatsink on this one .... But for me the Luxman M-03 is still a very nice amp , this machine has tremendous power reserves and a clean , precise sound .
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