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In the Forum: Analog Playback
In the Thread: About EAR 834P Modifications
Post Subject: More about my 834P corrector.Posted by Romy the Cat on: 12/29/2004

I have seen some people built 834P with alternative input and output tubes but I never heard them. I personally tried all imaginable 12AX7-type tubes (AZ, AT, AU, 6N2P and many others) in 834P. Some other triodes were king of better “here and there” but I very much like the result that I got with my present settings and I keep using it.

In my corrector the input and output tubes is a smooth plate 12AX7 Telefunken (selected for better sound as the all different). As the middle tubes I use a broken pair of 7025 Sylvania. This is kind of a mystery story. I bought this pair for $1 at MIT fleamarket juts because I did not used the Sylvania’s 12AX7 and wanted to try them. When I placed them into my ML2 then they were not impressive not to say that they were bad, very bad. That Sylvania pair did something bizarre on tube tester. On my tube tester the 12AX7 and 7025 use the same settings and the normal “full charge” transconductance of new 12AX7 usually around 1700. I never saw before any 12AX7-family tubes that measured more then 1950. However, those Sylvanias pushed 3750…

Anyhow, when I placed those Sylvanias into the second stage of my 2834PT then my love to this corrector started to grow immensely and I really do not remember how my 834P sounded with other tubes. I believe I put those Sylvanias into use in 2000-2001 (The corrector still produces a flat response with 112pf and 330pf). I really hate to see what happen when this pair will die. However, because I heat juts opposite half of tube I will flip them from right to left channel… I think I’m all set to rest of my live with this pair of 7025 and I really have no motivations to try anything else with this corrector.


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