I played about with this a bit on my CJ Premier 11a. Found the GL KT88s to be by far the best. Don't know whether or not your amp allows individual tube biasing but if it does, it sure saves on not having to but matched tubes.
Re-tubing a McIntosh power amp
I have a McIntosh 275 VI tube amp that I am considering changing out the tubes. Not interested in rolling, just upgrading from the stock tubes that it shipped with. Don’t want to go exotic ($$$) just trying to replace them with some upgraded, reliable tubes. Have any if you done this recently? Looking for suggestions on brands and reliable, fairly priced tube sources. Thanks!
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re-reading your initial post, it seems like you, after reading, are concerned about ’probable failure’, and don’t want to ’wait and see’. I get that, I always want a spare set handy, and I understand staying with KT88’s, seems wise. So, what ’non-exotic’ RELIABLE KT88’s? It’s a simple question really. I went JJ KT88 Blue Glass. Blue glass is just a different colored glass, just for looks, (mine are very visible), identical to their regular KT88. I’ve never had issues with JJ. My Electro harmonix 6550eh’s now my spares, maybe I’ll need them, after say 5,000 hrs playing time, for me 15 hrs/week that’s 6-1/2 years. Professional use in a guitar amp is a whole different thing. But, like anyone, anywhere, you can find ..., i.e. from ghosthouse, a member here posted in 2007 had nothing but trouble with JJ https://forum.audiogon.com/discussions/expected-hours-for-jj-tesla-kt88 I did buy some Gold Lion Cryo Tubes once. Loose with birthday money, the difference is only .... WTH. I wouldn’t do that again. They are in an amp or the mono amps downstairs, I forget. https://www.worthpoint.com/worthopedia/gold-lion-kt88-cryo-treated-matched-24909629 |
Heavy - your post seemed heavy on buying in bulk and sifting thru the crapshoot of grading tubes. You should get to know Andy and his ears and test gear. I am sure he would enjoy a conversation with you. Mac in the golden age designed for tube longevity, my 1960 MC240 ran hard for most of it’s life has all original small signal tubes, ditto the 1965 MX110z save one ! tube replacement about 6 years ago. power output tubes a different story but still relatively long lived in a Mac…. Remember the performance clinics run by factory techs at the dealers ???? Fun |
I found this 'state of the tube industry 2016' https://theartofsound.net/forum/showthread.php?44432-State-of-the-Vacuum-Tube-Industry-2016 is there an updated version somewhere? |
^^^^^^^^^^^^^^^^^^^^^^^ Good Post ^^^^^^^^^^^^^^^^^^^^^^ ” I'm listening to a MC225 and a C20 right now.. Looking at them, you would swear they were brand new out of the box Macs.. 60 + years old now.. ALL factory VALVES, I've never changed a single one in that pair..“ Now *Thats* what I call value for money! |
There is no crap shoot with GL KT88s or anything tested and burnt in.. I know of two vendors that recommend JJs, because THEY don't have failures.. ANY valve that is tested and then burnt in, very seldom does fail. But recommend them because they don't FAIL. I'll pass, they are a so so valve at best as far a SQ. Just about anything sounds as good and many many other valves sound a LOT better.. I'd take a Valve Art over JJs.. I have piles of the little critters here.. ALL questionable as far as SQ but they test just fine. Tap the glass with a pencil, LOL everything changes.. Underwater they go.. or echo chamber effects.. I use a lot of mill spec surplus from Russia. 1/3 are bad BUT after testing and burn in, better than ANY JJ I've ever used. 1.25 each in bulk.. Golden Lyon OP you'll be very happy.. so we are clear, I'm not huge GL fan, I just happen to know Macs and what they like pretty well after 50 years of fixing and using them.... I'm listening to a MC225 and a C20 right now.. Looking at them, you would swear they were brand new out of the box Macs.. 60 + years old now.. ALL factory VALVES, I've never changed a single one in that pair.. Caps and resistors YES.. That's it.. Heaven will have that pair of Macs in it.. :-) Regards |
Golden Lyon KT88s. 4-6000 hours 12AX7, 12AZ7, very close. Golden Lyons, Tellies, RCAs (if you can afford and find them) or if you want a sharper edgy valve, PSVANE all over 5000 up to 7-8000 hours. They last a LONG time in a new Mac for sure. I have a GG with 15000 hours, I did lose an original power valve within the first 1000 hours.. It was a made in China valve. It said Mcintosh on the side.. LOL it was probably a JJ. I have Solvex in there now, wonderful valve for the money. I paid about 75-80 per quad in bulk. 15% failure, no kidding out of the box or within 50 hours.. After they were burned in (and didn't BLOW up).. Just like any other valve.. 5-10000 hours A quad of Solvex is 125-175.00 close Regards |
not rolling but upgraded from stock, oh baby what a quest. stock tubes from whom, OEM tubes or you bought used? I imagine OEM's put what they believe is best, then people replace/roll. The difference to the OEM of 'stock' tube cost is insignificant to the cost of the amp. You will get into the issue of Bias, I started a thread about that 1-1/2 yrs ago, after ton's of advice, then Covid, all kinda other new stuff all over the house, did nothing about bias. https://forum.audiogon.com/discussions/tube-bias-socket-to-me?highlight=bias%2Bsocket%2Bto%2Bme Since 1973 I have messed with these power tubes: EL37's; EL34's, 6L6; 7581, 5881; 6550, KT88. weak, shorts, got hold of some money, .... a variety of amps and reasons. Most recent, my Cayin A88T came with used 6550's. I like having spares, got some b'day $, bought some new KT88's. I loved the 6550's, I love the KT88's more. Convinced myself with my own expectation bias? Source: Brent Jesse, http://www.audiotubes.com/ |
Thing is tho, by your intent you will in fact be tube rolling! Are you looking to replace a whole set of signal and OPT’s or a combination of same? If you are considering replacing valves ( Mainly the KT’s) that you feel. may be a little tired my first inclination would be Mac factory tested and approved via a Mac dealer. |
GL KT88s are about 210-230.00 per quad. I'd stick with KT88s not 6550, and yes there is BIG difference. GL are a good sounding valve for one. A 6550 in the older 1961-67 275s that's a different story. The amp is made differently. Actually I like a GE6550 better than even the old GLs. BOTH are wonderful valves though.. PSVANE is just a no no too. I tried a few times.. The signal valves not too bad, but the power valves.. YIKES! I know I have used some Solvex that were REALLY good. The problem I had was the failure rate out of the box and for about the first 50 hours or so.. SUPER high.. I bought in bulk, and didn't lose my shirt, BUT I was burning in quads for a while.. 15% failure rate, THEN they were fine.. Over 30 valves out of 200, three different times.. Some put on quite the fireworks display in a tube.. Scare the heck out of you the first few times.. :-) OP rolling valves is swapping, but normally we roll small valves for the final tweak. Some have fewer to roll than others.. That's all. LOL |