Advice on replacing EL34 valve on Audio Innovations S500 amp

voyduser

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Hoping someone can advise.

The valve on the very left of my AI S500 (as you look at it from the front) is hardly glowing at all. It still sounds normal but I've ordered a matched pair of EL34s in any case.

Assuming I have to replace the non-glowing valve, which other valve should I replace ?

 

JezR

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Swap the inner left valve over with it, if that valve also glows dim it would be the heater supply, if not it's a duff valve.

Assuming it's the heater supply, I had this happen on my Second Audios, I got it serviced by Mike Pointer at Audio Note, he replaced the rectifiers to a metal clad ones, no problems since. 

 

voyduser

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Nov 2, 2011
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Swap the inner left valve over with it, if that valve also glows dim it would be the heater supply, if not it's a duff valve.

Assuming it's the heater supply, I had this happen on my Second Audios, I got it serviced by Mike Pointer at Audio Note, he replaced the rectifiers to a metal clad ones, no problems since. 
Thanks For that Jez - just swapped the inner left over as per your suggestion and it is indeed the valve not the heater supply.

I've got a matched pair arriving tomorrow - do I swap both the inner and outer left valves with the new matched pair?

 

Juancho

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David
Swap the inner left valve over with it, if that valve also glows dim it would be the heater supply, if not it's a duff valve.

Assuming it's the heater supply, I had this happen on my Second Audios, I got it serviced by Mike Pointer at Audio Note, he replaced the rectifiers to a metal clad ones, no problems since. 
Hi,

You now know it's a faulty valve but just to say the heater supply on the EL34s in these amps (and the ECC88 phase splitters) is ac direct from the transformer. There is a DC heater supply for the line and phono ECC83s and yes the rectifier occasionally fails

David 

 
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