John Curl's Blowtorch preamplifier part II - Page 3215 - diyAudio
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Old 2nd January 2013, 06:34 PM   #32141
gpapag is offline gpapag  Greece
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Quote:
Originally Posted by bcarso View Post
Yes, that is a time-honored technique that I've used as well, despite the extra diode drops.

I guess I was just puzzled that you introduced (or re-introduced) the subject at this point. But as you say, the concept of a thread topic is long gone.

ThorstenL, (Kuei Yang Wang) advocated this in the long past.
There is also a dedicated thread. Pay attention to Fred Dickmann contribution (post #38)
2 Rectifier bridges : Why ?

Of course, apart from more balanced loading of the separated secondary windings, it all boils down to better defined return paths (hello jneutron ! )

George
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Last edited by gpapag; 2nd January 2013 at 06:37 PM.
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Old 2nd January 2013, 07:05 PM   #32142
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Thanks for the input, Ed, Brad, and others. Yes, I use the dual bridge in the CTC Blowtorch.
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Old 2nd January 2013, 07:05 PM   #32143
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Advantages of 2 bridges have been known for a long, long, long time.
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Old 2nd January 2013, 07:20 PM   #32144
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Advantages of 2 bridges have been known for a long, long, long time.
Pavel,

Would you care to start the list of all the advantages?

ES
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Old 2nd January 2013, 07:28 PM   #32145
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Much better rejection of interference voltages, you can easily measure it and compare to center-tapped bridge. You are capable enough to do it yourself, Ed. Ground contamination of center-tapped bridge is MUCH higher.
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Old 2nd January 2013, 07:45 PM   #32146
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Much better rejection of interference voltages, you can easily measure it and compare to center-tapped bridge. You are capable enough to do it yourself, Ed. Ground contamination of center-tapped bridge is MUCH higher.
You mean like this?
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Old 2nd January 2013, 08:24 PM   #32147
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Originally Posted by RNMarsh View Post
yes. My sediments, exactly :-)
Are you a stone, or you did mean sentiments, Ryan?
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Old 2nd January 2013, 08:26 PM   #32148
jcx is offline jcx  United States
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being able to use the better performance positive linear regulators for both polarities is a handy split sec/dual bridge feature

but in a preamp avoiding most of the single bridge-CT common impedance noise isn't that hard with intelligent layout, routing, choice of gnd points - in power amps the currents are a little large for doing it right with just pcb trace - but still can be largely attenuated compared to naive implementations

but treating it as a pro level audio amp design secret when the issue is shown in Self, Cordell books is a little behind the times - either nih syndrome or once again propping up a strawman version of what "conventional enigeering" knows, even modestly well read interested audio amp designers should have seen

Last edited by jcx; 2nd January 2013 at 08:38 PM.
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Old 2nd January 2013, 08:40 PM   #32149
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As we know:
1. It is impossible
2. It is possible but not important
3. We invented it. '-)
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Old 2nd January 2013, 08:47 PM   #32150
jcx is offline jcx  United States
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who cares about ancient history, exact path to best practice, it all has to come form somewhere - and some local "audio" designers seem to be reluctant to credit EE as having more sophistication, many sub fields, think they don't have to look in any other specialty for design principles, insights

but now its in audio power amplifier design "textbooks", hard to deny that == "what conventional (audio) engineering knows"
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