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Originally posted by Mr_bibbles
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But using an ear should do as well.
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As an OT can't transfer DCV, there is no DC offset at the output. You might use an AC milliamp-meter though.
But using an ear should do as well.- Own Opinions Only - -
In the manual, it states: (paraphrased since I can't copy / paste)Originally posted by Helmholtz View Post
"To adjust hum, allow the amplifier to warm up for a few minutes, attach a DMM to the speaker terminals and measure for lowest possible DC offset..."
So if our transofrmer cannot pass DC, how would the hum reach the speaker terminals? Offset is probably the wrong word here, I'm just trying to understand the hum-balance instructions as they seem strange.Comment
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That instruction is plain nonsense, I thought that was obvious.Originally posted by Mr_bibbles View Post
Hum reaches the speaker terminals because it's ACV.So if our transofrmer cannot pass DC, how would the hum reach the speaker terminals? Offset is probably the wrong word here, I'm just trying to understand the hum-balance instructions as they seem strange.- Own Opinions Only -Comment
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Sounds like someone had a brain fart and wrote DMM but then put in some verbage that would be appropriate with a D'arsonval movement meter, in which you would have to rectify the AC hum to be a DC voltage (which is not an offset, of course).Comment
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360-0-360V secondary is marginal for a single 1N4007 per arm, given mains variation and no load initial start and some margin on a 1kV PIV, and especially if you use a UF4007 (which start to conduct above about 1.2kV under test). I'd recommend 2x 1N4007 in series (or UF4007 in series) to replace each 5AR4 diode side.
The use of back-to-back 1N5408 in the first filter cap neg legs is interesting.Comment
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