AudioAficionado.org - How often should you replace tubes?

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Quote:

Originally Posted by 2fastdriving (Post 1023687)

George, small correction: the larger tube is a 6550. The smaller tubes are the 6h30.

Thanks.

Quote:

Originally Posted by 2fastdriving (Post 1023740)

Another fun fact about the 6h30 is that if you want to do "tube rolling", then avoid a preamp that uses this tube. There are only 2 tubes you can get for this, and my understanding is that they are essentially the same. There's the sovtek version and the electroharmonix. The EH version is the same as the sovtek, except it has gold pins.

That's correct, Marc. I used Sovtek 6N30P-DRs in my CJ CT-5, which I just sold, BTW. I would classify them as a very neutral tube. but they are not Amperex Bugle Boy 6922s, either.

Quote:

Originally Posted by 2fastdriving (Post 1023740)

Same with the bigger 6550 tube. However there are NOS versions of this tube that are in high demand.

This is why you don't hear many people talking about tube rolling with Audio Research. There's not much you can do.

With respect to the 6550s, I would agree. It's not...um, my favorite power tube. Luckily, with C-J's blessing, I was able to substitute the specified 6550's in my LP-70S with Tung-Sol KT120s, which are not only a much better-sounding tube, but more durable as well.

Quote:

Originally Posted by Puma Cat (Post 1023727)

The 6H30 (aka known as 6N30, as the actual Cyrillic letter resembles both an "N" and an "H") are a Soviet military avionics tube and are extremely durable. They should be good for at least 10,000 hours or so.

This is generally true for most all small signal tubes (12AX7, 6SN7, etc.).
The 'rule of thumb' for power tubes (EL34, 6550, KT88, etc.) is 2000hr.
Power tube life varies depending on the amp, as some are harder on the power tubes than others, being run at higher plate voltage, etc. I owned a pair of Cary monoblock SET amps that used a Russian military tube that would literally break (either the internals or the glass envelope would crack) after ~1000hr. At $150/per, they were expensive to keep running.
And, we all hear what we hear. For me, in McIntosh MC275 & MC75s the 'Winged C' 6550 was a terrific sounding tube. Sad they shut down the plant that made all 'Winged C' tubes.