Power tubes as drivers -- Line Magnetic

I just purchased a LM 518 IA, which is a 22 watt SET integrated using 845 tubes. The amp uses 2 6L6 as drivers and 12ax7 for input.

I'm picking up the amp this week, and although I haven't seen the user manual yet, From what I can gather, virtually any power tetrode or pentode, including EL-34, KT-88, 6L6 and 6V6 can be used as a driver in this amp. Of course that means I'm getting ready to try a buncha tubes.

My current thought is to pick up decent, but not expensive, current production samples of the various tubes (probably all made by the same manufacturer to maintain some control) so I can get a handle on which sound I prefer most, then move on to more expensive and probably NOS versions of those tubes I like best. Just checking in with the community for reality check on if this makes sense to anyone else.

Also, I've seen on various tube sellers sites reference to "this (noisy/micro phonic) tube is only suitable for use in a driver stage . . . ." Can I infer from this that I can get away with slightly dodgy driver tubes and thus buy really fancy schmancy tubes in low grade and still achieve good results?

Will appreciate your thoughts.

Good post! I had also suggested taking the speakers to the dealer. Tboooe has some reservations about the LM amplifier's ability to drive the Sonus Faber, well this would address that concern. Steve Huff found the 518 to be "very close" to the 219 amp and said both drove his SF speakers effortlessly. For 3000.00 dollars less the 518 seems a terrific buy.
I have the 518IA and have experimented with the various power tubes and to my ears the vintage KT66 tubes sound the best. Sweeter and smoother than the 6l6 or EL 34. My second favorite is the 6V6. This amp requires extended break in time before it blossoms.
I own the Line Magnetic 518IA. I have reviewed it on www.wallofsound.ca

First, the stock power tubes are great. They are the Psvane HiFi Series. Good to see that LM didn't just put cheap entry level Shuguangs in. I just bought a pair of HiFi Series from PartsConnexion. They are identical to the stock tubes.

The most important tube to roll is the 12ax7. I have some Psvane Treasure mk2's in right now. These are remarkable tubes--brilliant from top to bottom.
My favorite, though, is the TJ Full Music 12ax7. So warm! The new production Genalex Gold Lions work very well too.

Second, in order of importance, I think, is the rectifier. I would remove the stock Shuguang and replace it with NOS or with a current production Mullard, Genalex or Tung-Sol. I have the current production Mullard. This, plus the Psvane 12ax7s, has eliminated all hum. Plus consider an Emotiva CMX-2 to get rid of hum produced by your line.

Third, the driver tubes. I am a 6L6 freak. I have over a dozen pairs than I use in single ended amps. After rolling all sorts of 6L6s and EL34s, I settled on... wait for it... Shuguang Treasure black bottles. The ones sold about 2 to 3 years ago. They impart a muscular tone and rhythmic drive to the amp that I find compelling.

This amp really is incredible. It is so fast, but so smooth. It has unlimited reserves of power with most dynamic speakers. You won't use it for Maggies, but virtually everything else will work.
I've read your review Tim and have shared a lot of your observations. Kudos on a well written review that really captures the soul of this amp!

Although you and my dealer both suggested the preamp tubes would make a lot of difference, I've found them to make a more subtle difference, although I haven't done a proper shoot out with all my tubes on hand. I'm liking a pair of 1960's Mullard CV4004 best so far. Agree the rectifier is very important. I'm using a '60s Mullard there too, and it widened the soundstage considerably. I haven't experimented with many 6L6 or 5881 types, but looking for a nice pair of KT66 to try. So far, my favorite drivers have been a pair of 1950s RCA Greyglass 6V6 tubes I pulled out of a non-working RCA console radio I bought at a consignment shop, and an original pair of Genelex Gold Lion KT88 I happened upon on another tube hunting excursion. I must say I think the drivers are important too. It's probably more a case of making sure it's not a bad fit-- the good ones all work well, but a pair of EL-34s (and they we're pretty good ones) made the amp sound almost broken to my ears.

Agreed its a fantastic amp. Looking forward to adding an analog source quite soon!