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In Reply to: RE: Yes, three 12AX7's ... posted by drlowmu on June 24, 2012 at 08:25:05
So you're talking about an application for rectifiers that has nothing to do with this thread?
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Follow Ups:
No, not at all, I never once mentioned rectifiers.
A regulator is different from a rectifier TK.
I was making a comment on Eli Duttman's suggestion about using a low drop regulator for an Ef supply.
Jeff Medwin
So, you're saying the regulator used to power the filament of an indirectly heated cathode affects the sound?
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Sure, everything, every part, every wire, every solder connection effects the sound TK.
Very elementary, no high school degree needed to know that.
Jeff Medwin
No, not every part affects the sound. Are you saying you never graduated high school?
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Buy Chinese. Bury freedom.
No, I am saying YOU need to forget whatever you learned after grade 12, go back to elementary and high school, and learn that every part inside the amp effects the sound.Cheers,
Jeff Medwin
Edits: 06/25/12
Every part inside the amp does NOT affect the sound. As for education, ignorant people generally make poor design choices.
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Buy Chinese. Bury freedom.
With all the bickering.....(give each other a big hug, please) the point of regulator was lost.
IF I understand correctly, when using one of the 78xx regulators you need voltage a couple volts ABOVE the intended regulated voltage before regulation. Maybe, expressed as a %age, 25% or 20% would do.....some help here would be nice....or perhaps a rule of thumb I could remember later.
But, that, as near as I can tell, was the point of the regulator. So, to get 6v to the heaters, you'd need maybe 8 or 9v INTO the regulator.....and apparently a different, non-CT transformer.
And while it is OT for a phono preamp, my CMOY headphone amp taught me this. I have a 24vdc wall wart which I regulated to 18v. Very stable, though no longer 'portable'. Straightforward following a drawing with no improv.
Too much is never enough
You'll need more than a couple volts headroom with the 78XX series regulators. Google "7812 datasheet" for more info. Also, the ground terminal of a three-pin regulator can be raised above ground to increase its output voltage. For example, one could use a 7805 with two silicon diodes forward biased in series at the ground terminal to achieve approximately 6.3VDC. OTOH, if you're concerned about accuracy, the LM317 only requires two resistors to set its output voltage to an exact value. It can also be configured as a current regulator, which will eliminate the startup flash of tubes like the 12AX7.
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Buy Chinese. Bury freedom.
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