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Old 7th May 2009, 5:37 am   #11
dominicbeesley
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Join Date: Nov 2004
Location: Hebden Bridge, West Yorkshire, UK.
Posts: 1,885
Default Re: How much hum is normal? and valve change DAC90A

I'd also be interested to hear from anyone who has the back off their set in the future as to an actual measurement of hum from their set, i.e. taken in volts RMS (or peak to peak if easier) across the field coil of the set or anode of the output valve. When I get back from my hols I intend to have a quick service of my set.

My set also hums a little (messing with filtering components exhausted but not tried the UL41 tag dodge). The trouble is I've no idea what is a 'little hum' having only heard any one elses DAC90A playing in a crowded auction hall where the hum is completely masked by background noises.

Cheers

Dom

PS: As to the expensive valve pip breaking excercise - some idiots take more than one go to work out why all their valves are going gassy - three ECH42s in a Pye P76F before I clocked!
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