Replace tubes yearly?

I have been using tubes for 56 years so you would think that might make me an authority but I will make no such claim. Just my experiences, these are what they are:

I used a Dyna Stereo 70 and the Dyna MK IIIs for 17 years. The tubes tended to last for 2-5 years. I think for the Stereo 70 those are the 7199 and the 5AR4 and one or two others, for the MK IIIs those are 6550 and a 6AN8A, and there’s maybe another? I am having difficulty remembering.

I switched to the NYAL Futterman OTL3s in 1985. For 10 years, they were a little unstable. One meltdown was my fault: I experimented with a pair of Duntec speakers that caused the caps to liquify, 😂.

But for the last 30 years, I have gotten 15 years (not a typo) out of the 6LF6 tubes. I just refreshed them last year with a completely NOS set of GEs. The tubes that got replaced still had 65% of their juice in them. The little tubes in the back have been replaced maybe once the entire 40 years that I have relied on the amps. I asked Jon Specter if I should replace them along with the 6LF6 tubes that got replaced last year, he said not necessary.

I replaced the tubes in the DYNA PAS preamp maybe twice during those 17 years. I have replaced the tubes in the Beard P505 preamp 3 times over 40 years. This last time, last year, the Beard got serious NOS Telefunkens, Mullards etc from the late 1950s / early 1960s.

The caps in the Futtermans got replaced in the mid 1990s, as stated, and again, when I replaced them just last year (along with the tubes), after 30 years of use, they were quite dried out and almost at the point of failing. I switched from the photoflood caps to three big mofos, I don’t know what they are but they are faster than the photoflood (the photofloods were the fastest back in the day, so I’m told), and more robust, especially in the bass.

As for on/off: the Futtermans get turned off at the end of the day. They are rarely running for more than 6 hours at a time, ever.

The Beard is left running 24/7 unless I am away for several days.

The Project phono stage is also left running 24/7 unless I am away.

As for tube-rolling: some tubes will sound different but not better. Some old tubes can sound better than new tubes. Some cheap tubes can sound better than pricy ones. I just had a situation where a cheap $50 Raytheon sounded better than a $350 Mullard. It’s system dependent. Trial and error.

@brianlucey

”…if you didn’t notice, then everything is fine.”

This is not true.

Parts slowly deteriorate. Some of that deterioration can cause a slow moving degradation in sound over a number of years. You don’t really notice. Then one day a part fails, you replace everything and then you notice what you’ve been missing.

It’s sorta like the frog in boiling water.

I’m not an electronics guy. I’ve learned a bit along the way (how to change a tube, for example, and which tubes are for power, input, output, feedback, etc.) out of necessity. I have had a number of tubed pieces over the years, mostly ARC. I had an ARC PH-3 with three 6922 tubes and they never blew. I changed them because I wanted to find out about rolling tubes. I had a CJ Premier-14 preamp for a number of years and don’t remember changing the tubes.

So, what gave the most trouble were ARC Reference 2 Mk.2 and ARC reference 3 preamps. Often tubes didn’t last more than a few months. (I think there are bad tubes or faulty tubes that come out of manuacturing.) On both ARC preamps pretty much every type of tube blew. Output, input, power, etc. As I’ve gotten older, changing tubes especially in a preamp has become a giant pain in the ass. So, I sold the Reference 3 and bought a Pass XP-30 solid state which I love as much as the Ref. 3. Both great preamps.

I still own an ARC PH-7 phono preamp because I can’t find anything within my price range that I liked better. I bought the PH-7 used for $3500. I called every dealer in the U.S. looking for a used one and finally found a dealer in Canada who had just gotten one on a trade in. The tubes have been pretty stable in that one. It uses four 6922 tubes in a striaght line that power both channels. Supposedly they last for 2,000 hours, and the preamp counts hours, so I’m waiting for it to hit about 2,000 before retubing. I have used spares in a drawer in case an odd one blows. It also has a 6l6G power tube which has blown once. I’m not counting huors on that. I’ll just replace it when it blows.

Truthfully, ghdprentice, I hope I have your luck in the future. Because isolating bad tubes and changing them is a pain.

@audio-b-dog

Thanks for your reply. Really sorry to hear of your experiences.

Ok, you are unlucky in purchasing some malfunctioning preamps. I am assuming they were used... and they needed to be repaired. I know folks that have used tubed preamps for decades without blowing a tube... changing them or not. I have owned tubed equipment for more than a decade without failure.