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| Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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26th Nov 2018, 2:48 pm
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#21 |
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Dekatron
Join Date: Oct 2003
Location: Southport Lancashire, UK.
Posts: 3,236
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Re: Another Dansette Major - hum this time!
The only issue with using a bridge rectifier is that a big ballast resistor is needed. 1k in the case of the Decca
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Paul |
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26th Nov 2018, 5:48 pm
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#22 | |
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Rest in Peace
Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
Posts: 1,378
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Re: Another Dansette Major - hum this time!
Quote:
The reservoir capacitor will charge to the peak AC voltage in both cases. The capacitor will discharge somewhat less with a bridge rectifier but not a lot with the large capacity. Any resistance will reduce the heating in the transformer which is a good thing and getting rid of the DC component will also help, maybe reduce lamination hum. |
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26th Nov 2018, 6:00 pm
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#23 |
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Dekatron
Join Date: Oct 2003
Location: Southport Lancashire, UK.
Posts: 3,236
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Re: Another Dansette Major - hum this time!
The HT was far too high for the ECL82 - over 300v on the pentode anode with no resistor.
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Paul |
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