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Manufacturers' warning not to change tubes

I want to discuss what I believe is a very important matter.

Some tube amplifier manufacturers (e.g., Italian ones) strongly discourage customers from changing tubes in their amplifiers implying that their products are best optimized for the stock tubes.
I believe that "tube rolling" is a great fun and the benefit of owning/using a tube amplifier.

When the manufacturer discourages its customers from "tube rolling", this demonstrates the weakness rather than an advantage of its products.

It especially goes for automaticlly biased amplifiers.

I will appreciate azny comments
transl
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
It is possible that the tube gear in question could be tough on tubes. I've seen companies, like Audible Illusions, recommend NOT to use NOS tubes because their design is tough for older tubes. They don't like folks spending hundreds of dollars and having tubes die within a couple of months. Many new tubes may sound a tad grainier, but are built more ruggedly. So it's possible that the tube designer is just trying to warn folks the their designs may be more treacherous on tubes.
hifigeek1
770 posts
 
I totally agree with Jmcgrogan2. Let me also add that manufacturers like ARC 'voice' their products with a particular type or types of tubes that are not NOS. They do this so that their products sounds consistently good from unit to unit. This is also true of output tubes where specs can vary widely with NOS tubes. Sometimes using NOS tubes creates more problems then it solves.
arh
366 posts
 
Many companies sell replacement tubes at a very elevated price. They want to sell you these rather than you buying tubes elsewhere. I do see the warrenty issue if you put in some bad tubes that cause the failure of the amp they should not have to honor their warrenty.
Alan
atmasphere's avatar
atmasphere
11,784 posts
 
We have no problem with customers installing output tubes that they got from elsewhere.

People often ask us which 6SN7s sound best in our amps and we tell them what information we have from the field as well.

However, people want to roll tubes in our preamps too. In the line stage we have no problem with that, but in the phono section its common that that NOS tubes will simply not meet our specs for noise. That results in a noisy phono stage, so we recommend that customers get low noise tubes from us so the noise floor will meet spec. I'd have no problem with them getting the tubes elsewhere if we thought that they would have a chance of getting quiet tubes! If you have an all-tube phono section capable of LOMC operation, you have to have hand-picked tubes, and most of the NOS tubes that were quiet enough were sold off the shelves a good 30-40 years ago.
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