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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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Thread Tools |
19th Jun 2019, 1:31 pm | #21 | |
Triode
Join Date: Dec 2015
Location: Les Salles Lavauguyon, France
Posts: 43
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Re: GZ32 rectifiers for a quad amp
Quote:
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20th Jun 2019, 3:37 am | #22 |
Heptode
Join Date: Oct 2009
Location: Melbourne Australia
Posts: 901
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Re: GZ32 rectifiers for a quad amp
I'd side with Lucien's view of the small deposits on the top of the glass being tungsten from the heater at the top hair-pin. The heater would sit at hundreds of volts relative to glass, and would be the hottest metal.
They may have purposefully not coated that top bend region. If uncoated, that small section of heater may be visible at power on from 'heater flash', as there is no coating thermal mass to slow the dynamic temperature rise from in-rush current. The sections of exposed heater wire at the base would be cooler due to the connecting tabs. |