Perform Biasing on B&K ST-140 - diyAudio
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Old 31st January 2010, 05:17 AM   #1
Falcon is offline Falcon  United States
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Default Perform Biasing on B&K ST-140

Hi Forum Members:
I have just replaced the pre-drivers and output drivers on both channels of my B&K ST-140 ( early version with only one pair of output transistors per channel ). I would like to know what is the procedure(s) to check and setup the bias on both channels correctly. Also anything else I need to check and adjust to make sure that everything is fine and within specification? I contact B&K but no response so far. Thanks.


Mike
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Old 31st January 2010, 07:50 AM   #2
djk is offline djk
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Pull one fuse on one channel, adjust the bias to about 125mA (100mA per output plus 25mA for the front end). Repeat for the other channel.
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Old 6th February 2010, 05:59 AM   #3
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Default Bias

do you know the steps to bias the newer style with 4 outputs per channel
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Old 7th January 2013, 12:55 PM   #4
djk is offline djk
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Same way, 100mA per output P&N output pair, plus 25mA for the front end
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Old 8th January 2013, 06:26 AM   #5
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I had a couple problems trying to bias the amp. My readings were all over the map. 1st I was using a cheap multimeter to try and measure ma and 2nd was my 4 100uf 100v caps had a lot of leakage. So I put new caps in and I got a real test meter for measuring ma and now it works like a charm. Thanks djk
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Old 4th March 2013, 06:48 PM   #6
tony Ma is offline tony Ma  United States
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Here what I got from the factory
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File Type: pdf Amplifier Bias and DC.pdf (73.5 KB, 71 views)
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