[UTF]

Can you tell is this long plate or short plate?

(1) Mullard 12AU7 ECC82 Tube, Blackburn England - eBay (item 250378710259 end time Feb-23-09 17:48:05 PST)

And what is the difference between 12Au7A and 12AU7?

 

[somestranger26]

Quote:

Originally Posted by UTF /img/forum/go_quote.gif Can you tell is this long plate or short plate? (1) Mullard 12AU7 ECC82 Tube, Blackburn England - eBay (item 250378710259 end time Feb-23-09 17:48:05 PST) And what is the difference between 12Au7A and 12AU7?

It's definitely not a long plate. (There's other types besides "short" and "long" plate so I wouldn't know for sure) For long plates you're looking for a "K61" in the date code or, assuming the auctioneer is being honest, a 1950's Mullard.
Regarding your question about the "A" suffix, it means the tube has a higher gain according to a quick google search.

Edit: The long plate ones aren't necessarily Mullard, some are rebranded under brands like Amperex (Bugle Boy) and will be marked made in England/Great Britain but you'll still need to make sure it's a long plate, 1950's and not one of the other types.

 

[UTF]

Thanks!

Quote:

Originally Posted by somestranger26 /img/forum/go_quote.gif It's definitely not a long plate. (There's other types besides "short" and "long" plate so I wouldn't know for sure) For long plates you're looking for a "K61" in the date code or, assuming the auctioneer is being honest, a 1950's Mullard. Regarding your question about the "A" suffix, it means the tube has a higher gain according to a quick google search.

 

[UTF]

Yesterday I was still wondering if the burn-in made any difference. Tonight, I happened to try a Sarah Brightman CD and the difference turns out to be "huge". With the amp, the highs are extended to a completely new level. Without the amp, it just doesn't sound right. Then I say let me try Pavarotti, again, the amped sound is definely better, not stunning though. I guess now I understand what amp means and what I should expect for (not a different sound signature, like sweet and warm vocals I hope for on HD600).

Next I will definitely try a Mullard, hopefully to have that sweet mids. I tried an Amprexed already, which impresses me for a surrounding sound effect, though not very impressive for my classical listening. But tube rolling is interesting.

Quote:

Originally Posted by UTF /img/forum/go_quote.gif I have done about 40 hours burn-in on the amp, but not felt there is a significant change of the sound. To my ears, the amped sound is only a subtle improvement over unamped from the HP output of my Marantz CD player. Basically, the amp brings out more bass (but not punchy) and a kind of smooth (less fatiging) sound. I am not sure if that is what I could expect from the amp or it still needs more break-in time or other treatments.

 

[olblueyez]

One easy way to tell them apart is to look at the boxes on the anode. If it is a short plate then the boxes will be wider than they are tall. If it is a long plate then the boxes will be taller than they are wide. The Mullard is really an ECC82. ECC82 is the European counterpart to the American 12AU7/A, im not sure what the "A" versions are, it may just be a ruggedized version for the military or for computer use.

Short

Long

Unfortunatly the auction you linked too shows the side of the tube but based on the distance between the top mica and the flash I would think it is a short plate. Also because the logo is modern and the long plates were replaced by the short plates and the short plates continued long after the demise of the long plate version.

 

[UTF]

Thanks, olblueyez!
Btw, the Amperex i got sounds clear but distant. Is any tube giving a closer and clear sound? Also, for symphony, Amperex sounds not powerful and dynamic enough. Any other recommendations? Thanks all!

 

[Wenglish]

Just got my EF1 yesterday, Luminette said there were about 80 hours on it IIRC. Swapped the RCA cleartop with an IEC Mullard and have about, oh, an hour and a half on it? Too busy to listen to music = worst days.

Anyway, so far so good. Vocal presentation is quite nice. I'm interested in the burn in for the tube, and will definitely withhold judgment until it's got quite a few more hours under it's belt.

 

[UTF]

I think I am done here, after my Mullard arrived today. That is the sound I am looking for, close, clear, and musical. Not only vocals are great now but even symphony sounds more dynamic. No more doubt, right tube is the key.

Quote:

Originally Posted by UTF /img/forum/go_quote.gif Btw, the Amperex i got sounds clear but distant. Is any tube giving a closer and clear sound? Also, for symphony, Amperex sounds not powerful and dynamic enough. Any other recommendations? Thanks all!

 

[somestranger26]

I'll go ahead and cross-post my early impressions along with some tube rolling impressions from the "Head-Direct EF-1" thread since we're discussing tuberolling here.

Quote:

Originally Posted by somestranger26 /img/forum/go_quote.gif All impressions done with my Ultrasone Pro 900, sourced by an Auzentech X-Fi Prelude soundcard with OPA2134 Op-amp (not LM4562), BJC MSA-1 cable, NO BURN-IN ON THE AMP. I received my amp today (took 3 weeks from ordering, that was a trying wait) and right out of the box with the stock tube I noticed: HUGE soundstage Increase in detail Sparkling highs Much improved instrument separation Cleaned up bass Upon rolling the tube to my Mullard 'Short Plate:' Further increased detail, especially in the bass Improved mids, vocals seem more natural Slightly more engaging and musical Slightly reduced soundstage compared to stock And finally, with my Mullard 'Long Plate:' The highs of the stock Sylvania tube, taken to the next level. The level of detail is impeccable. It's hard to describe how huge of a difference this tube + amp (not just the tube, the combination) made in this area. The mids of the short plate, with some refinements and added liquidity. Well controlled bass, that extends quite with great detail. Impressive soundstage similar to the stock Sylvania Can't wait to see what burn-in does with this amp, too bad I don't think anything improves with burn-in as much as ultrasone's headphones . So far very happy with the amp and think it was completely worth the $320.

 

[olblueyez]

Quote:

Originally Posted by somestranger26 /img/forum/go_quote.gif I'll go ahead and cross-post my early impressions along with some tube rolling impressions from the "Head-Direct EF-1" thread since we're discussing tuberolling here.

Makes you realize how funny it is when people talk about sonic signatures for tube amps, each one has many. Some people call my Raptor Solid State sounding, cracks me up.

 

[somestranger26]

Quote:

Originally Posted by olblueyez /img/forum/go_quote.gif Makes you realize how funny it is when people talk about sonic signatures for tube amps, each one has many. Some people call my Raptor Solid State sounding, cracks me up.

Oh, for sure! The tubes all have their own unique sound. Switching from the LM4562 to the OPA2134 (a "downgrade" to many, but the 4562 sounds too sterile to me) on my sound card made a larger difference than I expected. (Probably getting an spdif-accepting dac soon... sorry about my wallet) And now I know the tubes are the same, so I'm definitely a believer in opamp/tube rolling. I'm not sure about cables though, I went for the BJC because they look nice, are well built, and the radio shack cables I had lying around are probably bad enough to actually affect the sound. I don't think one could convince me to do the same with a power cable or to spend triple digits

.

Edit: Retroactive thanks to you, olblueyez, for the tube recommendations earlier in the thread. I'm quite happy with the Mullards. Also, I noticed the inclusion of an obobskivich quote in your signature, every thread I read where he posts we seem to agree on everything, it's quite eery, with this quote being no exception.

 

[theBigD]

Got a tung-sol black glass yesterday. After 24hr burn in I really like it. Has a tighter sound stage than sylvania. And the mids are really defined and clear. the highs are still present but not as bright as rca cleartop. Bass seems tight and defined. I am using with the moon which I still like very much. I have been using my akg 701s with this combo and like it alot. Cant wait to try with d7000 whenever they get here, it seems like it would do the trick for the recessed mids that are about the only issue i have with denon. I could also check the bass extension of this tube when the d7000 gets here, cant really tell much bass wise with 701.

 

[HeadphoneAddict]

I have both a Mullard short plate and long plate 12AU7 coming in next week. Should be interesting.

 

[Skylab]

I will be interested in your comments, Larry. I do prefer the long-plate.

 

[somestranger26]

Something interesting I've noticed is that the amp barely even gets luke warm with the Mullard tubes, while the stock Conn/Sylvania tube heats up considerably more.