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Re: 7591 JJ Tesla or EH in Scott 299c.

Posted by smollett (A) on January 17, 2005 at 18:53:43

In Reply to: Re: 7591 JJ Tesla or EH in Scott 299c. posted by Jim McShane on January 17, 2005 at 07:58:40:

Jim,

I make no pretensions to being a tech, trained or otherwise, merely a person who enjoys good music reproduction, and who can follow rudimentary instructions.

How can the difference in performance between the EH 7591As and the NOS GE/Sylvania/Westinghouse/ and other branded tubes, such as Fisher, Hammond, RCA and Amperex, be explained? Let us put aside the sonic differences that a number of people, including me and my tech, a tube afficionado, heard, all of which favored the NOS. He changed all the resistors so that all would be within Fisher's original design specs. All the capacitors were checked, as well as every diode. He could not find a problem with the amp which would have caused the EH tubes to glow cherry-red.

The amp works fine with every version of NOS 7591A. Biases and balances perfectly - and keeps the adjustments after hundreds of hours of play. Not even new out of the box EH tubes did this.

Of course, I would prefer to be able to use the EH tubes at $70/quad. Jeezo, that's 25% of the price of an NOS quad. But I really began to detest having to listen for the telltale sound of a tube melting down so I could shut the amp off before other expensive components failed. Every few minutes I found myself getting up from work to see if one or more EH tubes was having a "Chernobyl" event.

$250+ for NOS quads is expensive, but it is the price I have found I have to pay for sonic excellence and peace of mind.

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

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