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7591's for Fisher 500B


oldmako

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Greetings. Long time no post.

 

I finally got around to having my 500B serviced and the guy mentioned that it would benefit from some new tubes. Specifically 4 new output tubes, the 7591's.  He said that I'd probably not notice that these are toast except when I had it wound up loud.

 

At any rate, while it sounds great now and I'd like to begin the search for new tubes.   Do you smart guys have any good recommendations for sourcing these?   He said that I either needed a matched set of 4, or two sets of 2.   

 

I'm using it in my bedroom with a pair of Forte II's.

 

I should add that the guy said that some replacement tubes from Eastern EU have "oversized" pins and that once you jam them in, you're stuck with them as the correct tube (smaller pins) won't fit properly into the stretched pin sockets.   Obviously I'd like to avoid that dilemma.  

 

Thanks for reading and any replies.

 

 

 

 

Edited by oldmako
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The service technician is confusing the 7868 tubes the Fisher 400 uses for the 7591. None of the modern production 7591 made today have a pin size issue like the 7868. There is one modern 7591 that has a really large glass bottle size both tall and fat. You have 3 modern production 7591 to choose from the EH 7591(really fat and tall), JJ 7591 (1/2" tall), Tung-Sol Reissue 7591 (1/4" tall). I personally prefer them is this order

1)Tung-sol

2)JJ 

3)EH

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On 9/9/2017 at 10:16 AM, NOSValves said:

The service technician is confusing the 7868 tubes the Fisher 400 uses for the 7591. None of the modern production 7591 made today have a pin size issue like the 7868. There is one modern 7591 that has a really large glass bottle size both tall and fat. You have 3 modern production 7591 to choose from the EH 7591(really fat and tall), JJ 7591 (1/2" tall), Tung-Sol Reissue 7591 (1/4" tall). I personally prefer them is this order

1)Tung-sol

2)JJ 

3)EH

 

Interesting you list the Electro Harmonix last... is that based solely on the sound or because they are a little oversized?  I haven't rolled through power tubes on my 500C but I've really liked the EH tubes. Actually, I never bought anything else because of all the happy EH owners that I've read about.  One warning about the EH is that the wood cabinet will hit the top of the tubes if you try to remove the cabinet with the power tubes installed.  You have to install and remove the tubes with the cabinet ON.  There is just enough room to install them.

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