I don’t think the 6922s even belong in the M1200s nor BHK. They are equivalent to the 12AX7s if I’m not mistaken. The BHK250 and BHK300 use 'em.
12AX7 are high gain tubes, and could potentially distort the sound if used in place of 12AU7. The latter is the standard in BHK preamp and M1200 mono blocks.
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Guess I’ll just stash the 6922s…I have a couple of phono tube pre-amps that might like them someday.
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Another vote for Gold Lions. Smoother and quieter than the stock PSVanes. Particularly a good mate with Pass Labs pre-amplification.
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Hi all. I’m coming up on 1 year of ownership of the M1200s. Absolutely no regrets. These are my first experience with tube equipment of any kind. I’ve read that over time the tubes will start to degrade causing the amps to sound “dull and lifeless”. I can’t say I’ve noticed that but again, I’m new to this tube world.
I’ve read a number of posts talking about tube rolling. I’m not talking about that. If you simply want to know when it’s time to replace the tubes with stock equivalents, how do you know it’s time? Is it obvious or is it one of those gradual things that’s obvious after the replacement? My amps will be a year old next month. I would guess they are on 2-3 hours a day, 4-5 days a week. Any help would be appreciated.
Hi @davidnapo
All those who bought the M1200 are happy, and that says it. Tubes in input stages and preamps are known to last fairly well. I would think 2500 hours and above. Some users reported 5000 hours and tubes still delivered quality. So, unless you hear a clear sign of deterioration, the tubes are still intact.
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My method has been to keep a spare set on hand and once per year, swap them. If it sounds better, leave the new ones in. If not, put the originals back.
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Thanks. Based on my estimated use, about 800 hours, I probably have plenty of life left. I like the idea of having spares so I think I’ll order a spare set along with Paul’s book, 99% true. Based on his posts and his writings that I’ve read, he can probably pick up a secondary job as a writer. I find him pretty entertaining.
Good strategy 
I changed mine after 500 hours. The cost of the tubes $120 Kevin’s stash Gold Lion’s was one of the best cheap upgrades I made to the M1200’s. I have read on the forum (and it may of been @jamesh) said the tubes could go up to 10000 hours because of the class D efficiency. IMO the Gold Lions are superior to the stock Psvanes. I also tried the Brimar’s but preferred the sound of the Gold Lions. The Brimar’s are better than the Psvanes IMO.
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Small input tubes can last up to10,000 hours because they are driven gently, as opposed to power output tubes which are doing a good deal of work.
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I revised right away to over 500 hours. I used my BHK preamp to give me the hours and it was around 575 after doing the math. But yes I also agree with Elk. Tho I’m way to impatient to wait 10000 hours. Good luck @davidnapo with what ever you decide!
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Exactly. Because they’re input tubes, they aren’t driven as hard and don’t get as relatively hot.
Crazy the 1200s have already been on the market for over a year! Unless you’re like someone I aspire to be and have music going all day everyday, I fully expect the tubes to last closer to 2 maybe even 3 years in these amps. RonP’s strategy is my favorite, always have a spare pair around and you can test every few months or so.
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Paul, can you say what it was about the Gold Lion’s you preferred? They had to sound different somehow for you to have a preference. If you can put that into words your experience would be helpful to me.
For me on my system. The Gold Lions had better vocal accuracy and musical instruments had better clarity and it was noticeable as soon as the music was playing. I think IMO with your Maggie’s you will experience the same! @stuartmc has a great review on the M1200’s and helped push me toward the Gold Lions. I’m also using the Herbie’s RX-9 ring on each tube. IMO this brings the M1200’s up a notch or 2 in performance. Visit @stuartmc review, it’s spot on what you get with the M1200 upgrades.
One last question for folks who have pulled the tubes out of the M1200s. Do you need the tube puller from PSA or will careful fingers win the day? It seems like having a spare pair would be a good idea. The RX-9 rings look like a reasonable upgrade with a lot of bang for the buck. Getting to the backs of the amps in my system means pulling everything out of the rack. I may as well be ready to try everything at once.
Thanks for humoring me!
I have the tube puller. I’ll admit I have fat fingers so I thought the tube puller would be necessary. I don’t think it’s necessary tho it can help. I found using a light (or flashlight) on the side vents helps with positioning the tubes seating properly on the board.
If using the Herbies follow @stuartmc directions on getting the most effective fit being more on the loose side because crazy enough it does make a difference on the tightness of the rings.
I wouldn’t sat the puller is a necessity but certainly helps. I don’t have any problem without one.
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I have the Gold Lion in M1200 for three months, but I just switched back to PSVANE 12AU7-S and the overall sound is fuller and the high has better extension. Yes, the voices are not as clean as the Gold Lion, but now I am happy with the S sound. I guess that’s why we do tube rolling.
Yes, the tube puller definitely makes it easier to remove the tubes from M1200.
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I’m sure it’s different for all system setups but the Psvanes will not be going back in my system. The GL’s beat them in every way on my system. I also currently use them in my BHK preamp and the results have been superb!