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WAD Problems For questions and answers re older World Audio Design Projects |
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#1
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Phono II i/p resistor to earth
I've varied the resistor to earth on the Phono II in a range from 2.4K to 4.2K. Using a Dynavector needing 30R (which through the step-up txs means 3K).
I hear virtually no difference. Indeed, mounting all the pairs of Rs on a separate baord, connected via crocodile clips, if I remove the croc clips so that there is no connection to earth, nothing changes. Is this normal or must I have made a mistake somewhere? Thanks Adrian |
#2
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Re: Phono II i/p resistor to earth
What stepups are you using?
It may just be the case the dynavector isn't very sensitive to load.
__________________
Just about everything I say has been in public use since the 1940's so no one owns the copyright on that. If by any chance its not prior art, then the copyright is retained by me. |
#3
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Re: Phono II i/p resistor to earth
Standard WAD D8749. Know anything about them?
I also wondered about sensitivity. Perhaps you recall how at the first Withamfest my phono II sounded awful with Gerry's SP10 + 103, which IIRC needs a 4K load. Part of the reason for making this off-board load resistor 'switch' is to test a 103 Gerry's lent me. Actually, just read an old thread where you pointed out difference between source resistance and load, which for a 103 is 20-25K. Any opinions anyone on why no difference if I disconnect the link to earth of R13/14? Cheers Adrian Last edited by buddam; 11th February 2007 at 04:21 PM. |
#4
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Re: Phono II i/p resistor to earth
Assuming the step-ups ate 1:10, then a 103 will need something more like 10k-15k.
You have varied the dynavector load from 24R to 42R, I can believe that a low impedance output cart wouldn't produce that much change over that range.
__________________
Just about everything I say has been in public use since the 1940's so no one owns the copyright on that. If by any chance its not prior art, then the copyright is retained by me. |
#5
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Re: Phono II i/p resistor to earth
Yes 1:10. The 103 specs leaflet recommends 100R (x 100 = 10K), but I see others use up to 25K. Maplins tomorrow for some higher value resistors
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