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? Tube Replacement Question ?

As a novice in the world of vacuum tubes, I have a couple of basic questions. I have a Audio Research SP16 tube preamp I purchased new in January 2008 & use on a daily basis. The tubes have never been replaced.

(1) When is it prudent to replace the tubes?

(2) Will sound quality deteriorate with age?

(3) Are there advantages of replacing the tubes with aftermarket alternatives vs. OEM tubes?

Thank you kindly for your help.
kitjv
mapman's avatar
mapman
22,601 posts
 
Kit,

If it still sounds good to you other than the hiss in teh one channel, try rearranging the tubes in the sp16 in different orders first before replacing.

SP 16 uses 6 tubes. Tubes age at different rates. Location of the tubes in the sp16 slots help determine resulting background noise levels I found. As tubes age differently, moving a "better" tube into a different location can make a difference and buy you time before you are inclined to replace.
samujohn's avatar
samujohn
291 posts
 
Never base tube purchases on the name brand of the manufacturer.
Only an expert reseller can tell who actually made a tube, or its condition.
Fraud and misunderstandings abound in the NOS business, not to mention
the buying and selling of brand names and the relocation of factories in China and Russia etc.
The reliable reseller earns his fee and stands behind his performance rating.
kitjv OP
69 posts
 
Mapman,

Thanks for the suggestion. I spoke with Calvin at ARC a few minutes ago. He claims that the useful tube life in the SP16 preamp is 3K - 4K hours. I realize that this is just a rule-of-thumb, but that puts my OEM tubes over the top. Although rearranging the tubes might very well decrease the audible hiss, I am equally concerned about the deterioration of sound quality that I might have become accustomed to over the years. So, I think replacement is in order. Rather than "rolling the dice" with NOS, I will likely order directly from ARC.

BTW, one other question: Is it money well-spent to replace all of the tubes with low-noise types or just replace the input tube with a low-noise (& regular tubes for the others)? I realize that the answer can be quite subjective. But, is any audible benefit worth the extra cost? Thanks you, all.
samujohn's avatar
samujohn
291 posts
 
Some years back a friend who was not a "tinkerer" bought a used Hybrid ARC line preamp. Not being sure how old "the" tubes was he contacted ARC and purchased the correct replacement from them directly. It took me some weeks to convince him to let me take the cover off and try one of my old RAM tubes. When we finally did his jaw dropped. No question that immediately it was quieter.
rodman99999
6,206 posts
 
You will find it WELL WORTH the cost, to replace all the tubes with certified, "Low Noise" tubes. If you use the phono stage; they are a must, in that position. The higher the gain of the stage, the lower the noise necessary. If you are not using the phono stage, you won't notice any noise with older or noisy tubes, in that stage.
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