Hmmmm...I think the Chinese 12AX7's sound really awful. But maybe I am spoiled.

Go for the GE 5751 - these sound very good and are relatively affordable for a 5751. I agree the JAN-Philips can be a little crisp.

Skylab, what would you recommend to roll for the JJ Tesla EL84?

My favorite, and what I use in mine, are REAL (not re-issue) Mullard EL84's. But I also used Sylvania black-plate 6BQ5's which sounded terrific.

Thanks.

Is this OPT or OTL ?

I'm going to be getting this amp for Christmas, and I'm quite excited, I must say!
I've been reading and looking around a bit, and trying to determine what tubes for sure it uses, I think I have it all sorted out that it uses 2x 6BQ5/EL84 Tubes, 2x 5751/12AX7 Tubes, and a single 6EZ? tube in the center. Is this correct? And also, is there any rolling option for this center tube? That's the one that I've been most confused about I guess. Any info available on that?

Thanks,
Victor

The rectifier tube(center) can be replaced with an EM87 tube. Replacing this tube with an nos does make a difference. Maybe not as much as the driver tubes, but you can hear an improvement.

Pacific Valve incorrectly lists the type of "cat's eye" tube that the MC 84C07 uses - it is a 6E2, not 6EZ. There is no 6EZ. The 6E2 = EM87 = 6HU6. I have 6HU6/EM87's from Sylvania, Mullard, GE, Siemens, Telefunken, and Amperes, although all were either made in England or Germany.

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Great Christmas gift! You're gonna love this amp.

This is a great Christmas present. One under reported attribute of this amp is that it does have speaker jacks. If you have a television in the same room where you are using this amp then try running "efficient" speakers on both sides of the television.

My impression is that regular music from the speakers powered by this amp is not that great. Not nearly as nice as it is from the headphones. But the television sounds wonderful.

My guess is that most of what comes across from shows is not music but dialogue and environmental sounds (footsteps, blowing leaves, doors openning, aircraft sounds, fist fights, etc.). The amp does a fantastic job of bringing me into the video presentation. "Fringe" "Dexter" "Crash" "Bored to Death" and movies are awesome. Just 2D sound, no 5.1. or 2.1.

At present I have JAN Philips 12AX7 (sounding better as they burn in). Mullards EL84s on order on Skylabs suggestion.

P.S. The tubes do not get that hot but the transformer is a roaster. Make sure that this is on a desktop and not in an enclosure.

I mostly use this amp for speakers and I like the sound alot but I'm only using vintage Marantz speakers which happen to be efficient. It doesn't sound as detailed as the headphones. I do plan on getting some higher quality speakers in the future which will certainly make a difference.

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Well actually the speaker outs have been reported on several times in this thread. For me the speaker outs are at least on par with the headphone out. If ,like you said, you have effcient speakers. This amp sounds really nice with my psb bookshelves. It just throws images all over my bedroom. I was able the trick my wife into thinking the center channel and surrounds were playing. But even without the speaker outs, the headphone out is very, very good.

These days I also use mine mostly with speakers - it powers some small B&W speakers in my office.

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what speakers are you using with the Ming Da?

I am definitely not pushing these speakers as the ones to get but they work for me. I had a wonderful set of Thiels but our new place could not handle giant floor standing speakers.

I got the Infinity Model Three V only because they were small enough and look cool.

Infinity - Home Audio

If you are serious then there is no reason why you could not put the Ming Da (already burned in on headphones, remember it is all class A (I think) so it is always on full power regardless of load), an ipod, 3.5 mm cable and speaker wire with spade lugs on the ends in the box the Ming Da came in and take it down to your hi-fi store and plug it into some speakers. Regardless of the outcome it would be fun and also maybe blow the minds of the salespeople.