[cminer]

As the happy owner of a new Ultra EC and Ultra 350, I have a few questions about the tubes.

1. How long should I expect the tubes to last?  I realize they usually decline gradually rather than outright die, but give me a rough idea.  6 months?  A year?  Two?  I usually listen about 10-15 hours a week with the volume set between 9 and 10 O'clock.

2. In looking at tube websites I see a lot of 12AT7's but very few 12AT7A's.  Are they interchangeable?

Thanks,

Curt

[martyo]

Tubes last for thousands of hours. I would say you'll be fine for several years. I just got a spare set for my 550 from Frank, $30. And I got a spare matched set of 6N1P's for my preamp for $13.90 from a local tube vendor. Frank will have to answer the interchangeability question.

Happy listening!

Marty

[mark funk]

Hey, I have had my 550 EXR6 for over two years. When I first got it I rolled some tubes in it and it did not take very long, and the JJ were back in! JJ are all I run in my 550, as for how long they last, I changed them after two years and that may have been too soon. I would say for the last 1 3/4 years my set ran for maybe 35-40 hours a week and 9:30/10 o'clock would be just warming things up! As for the Ultra Pre with the 6NIP tube Oh no that's 6N1P tube I could not say I only have a T5-SLR with the old 12AT7 tube. But don't change the brand of tube in the Ultra 550 amp. Just sit back and listen and when its time the tubes well tell you, change me. What kind of speaker are you using with this new AVA stuff?

[cminer]

Thanks, gentlemen.

Here's my system, start to finish -

Homebuilt PC running Foobar 9.4.3 with an iTunes interface (thanks to Localhost's great multi-plugin) -> Empirical Audio USB offramp -> Turbomodded Perpetual Technologies P-3A -> AVA Ultra EC -> AVA Ultra 350 -> Ohm Walsh 2 speaker cabinets with Mk-II drivers.

I'm obviously brand new to tubes, but I've been reading very good things about Mullards.  Mark, would you say the stock tubes are better?

Curt

[tonyptony]

Curt, can't speak to the 6N1Ps, but the way Frank uses the 12AT7s in the FetValve puts very little stress on them. That, coupled with many examples of this type being known to last for many thousands of hours (up to 10,000 for the ECC801S and other well regarded NOS varieties), suggests that you'll get a lot of years out of the amp at least.

[warnerwh]

I personally prefer the Mullards over the stock tubes.  The military version from the early eighties you  can find for 40 a pair. According to Upscale Audio the Mullard is the most robust tube they sell in this tube type, also the favorite. I've had mine in there for a couple of years and my system spends a good 30 hours a week on. I can hear no degradation.

Bnb tubes is a good place to get these Mullards. They are also called the Mullard CV4024, exact same 12at7 tube however. I think CV4024 is just a number the military gave them.

[cminer]

I was able to get ahold of some highly regarded tubes (cryo treated, too) to do a tube shoot out.

I spent a couple of hours swapping tubes in and out and in and out until I almost forgot which was which.

The amp was easy - I figured out real quick I liked the stock tubes better than the Mullard 'upgrades.'

Then the preamp.  This was a closer call.  The new tubes may have sounded a little sweeter than the stock ones, but the stock sounded a little clearer and crisper.  But not much.  I finally decided I liked the stock ones just a little better, and that's all that matters.

So, I ended up right back where I started.  That's my story.

[martyo]

Thanks for the update. There may be times when your in the mood for sweeter.

I have 2 tube stories I've been waiting to post somewhere......

My brother and I spent a Saturday rolling tubes last year in his preamp. All NOS with the exception of a set of Ei's. He has alot of NOS tubes. I think we started with a couple different Siemens, Tung-Sol, Neuhaus, some French ones. Anyway as the day went on we finally just started going for "killer mid-range" only. Brimar, Valvo, others I can't remember,and finally with the Mullards. It was real serious fun. Anyway, I have found for myself that I need to live with something for awhile rather than A-Bing. It takes me longer to hear all the suttle differences and often my final choice is different than my first impression.

So after listening to ALOT of NOS tubes with my brother, I really liked these 60's Valvo's from the Hamburg plant. Every so often a few show up. I ordered a T8 and made a promise to myself of one set of NOS's. Before I get my T8 the Valvos show up, I order a set($120) but even before they are delivered Frank announces the 6N1P upgrade and my preamp will have those tubes in it. No problem, my brother gladly took them but Frank probably saved me alot of money when he switched to the 6N1P's.

[tonyptony]

I haven't tried the Valvos, but I have tried the Mullards, Eis, Sylvanias, and RCAs in my FetValve. I hate to say it, but that all stopped when I got a pair of NOS Telefunken ECC801s. To me they turned out to be as good as they say. I hope they're the only pair I'll ever have to buy. 

[martyo]

Tonyptony, am I understanding you that you have the ECC801s in the 550? Did they require a different bias than the JJ's?

I've only heard the 550 with the stock JJ's. But in the T5 and DAC, the Telefunken's are THE TUBE. Price and availability was the reason I got the Valvo's. They are "sweet" and pretty linear, but not as sweet or linear as the Telefunken's. And personally, Mullards have a "Killer midrange" but they ain't linear at all, again, IMO.

I posted it earlier, Frank's upgrade to the 6N1P probably saved my alot of money on tubes. But I am spending alot on new music since I got his equipment.

[tonyptony]

Marty, I got the Teles when my amp was still a FetValve EXR5. I plugged them in without re-biasing (Frank advises against owners playing around in there). They still sounded great; my guess is that the tube stage of the FetValve operates in such a small linear range that it can accommodate tube changes pretty well, even given that a re-bias would certainly optimize them. In any event I thought they sounded just fine, to my ears the best I had heard. When I sent my amp in for the Ultra upgrade the Teles went with it, and at that point the amp was biased with these tubes.

[mark funk]

Well, I must say I did go on quite the tube binge for a time. I have tubes for six life times, and it was fun rolling all those tubes, you sure can change the way things sound, but when you start rolling tubes like using tone controls you are asking for trouble! I broke my T-5 playing with really old tubes, the tubes that did it are one of the ones Martyo was talking about ( 1957 Mullard, Mitcham plant not Blackburn) they have quite the midrange I mean talk about liquid. But be carfull, Frank fixed my T-5 out of the goodness of his hart he did not have to fix it but that's way I go to Frank, really evey thing ever sad by Frank that I tried has worked and made things sound better I could go on but that's is for that other thread. As for tubes I think Telefunken are the top of the list and the ECC801s, that is the tube and they are hard to get and make sure they have a <> on the bottom. This is how I would place them Telefunken ECC801s, Valvo Hamberg 6201, Siemens E81CC. I would not put them in the amp I tried that and to me the JJ worked and sounded just fine to me, but I wound how it would sound biased for the 801s?