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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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8th Feb 2023, 2:41 pm | #1 |
Diode
Join Date: Feb 2023
Location: Coalville, Leicestershire, UK.
Posts: 1
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Nytech CA252 Amplifier. Bias settings?
Hi,I'm new to this site and not totally sure how it all works but I was wondering if anyone could advise me on biasing a Nytech ca252 amplifier. It would be gratefully accepted.
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8th Feb 2023, 8:05 pm | #2 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
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Re: Bias settings.
HiFi Engine has the power module schematic.
Looks like one pot for midpoint voltage (RV101) and another for bias current setting (RV102). Don't know the recommended value for bias but around 5mA or so (about 2mV across each output emitter resistor) would probably be a starting point. Twiddle at your own risk!
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9th Feb 2023, 7:25 am | #3 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,636
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Re: Bias settings.
There's a manual available here - https://www.hifiengine.com/manual_li...io/ca252.shtml that might have the info you need.
Andy.
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9th Feb 2023, 12:40 pm | #4 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
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Re: Bias settings.
That link seems to go to the same page I found the schematics downloads on. I didn't see any useful manual listed there
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....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |
9th Feb 2023, 4:28 pm | #5 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,636
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Re: Bias settings.
Good point Chris, brain malfunction.
Andy.
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Curiosity hasn't killed this cat...so far. |
9th Feb 2023, 4:50 pm | #6 |
Heptode
Join Date: Jul 2014
Location: Boston, Lincolnshire, UK.
Posts: 992
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Re: Bias settings.
Try this one - the first schematic image shows the bias as 10mA (note written on the LHS)
https://www.diyaudio.com/community/t.../#post-5493117 |