Tubes Asylum: REVIEW: Telefunken 12AT7/ECC81 Tubes by Luminator

Model:	12AT7/ECC81
Category:	Tubes
Suggested Retail Price:	$85
Description:	small signal vacuum tube
Manufacturer URL:	Not Available
Manufacturer URL:	Not Available

Review by Luminator on June 17, 2002 at 12:26:36
IP Address: 66.47.253.250

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for the 12AT7/ECC81

In terms of audio popularity, the 12AX7 is probably second only to the ubiquitous 6922. Thus, much has been said and written about Telefunken's 12AX7. Hardly anything or anyone uses 12AT7s, so very little has been said about Telefunken's ECC81/12AT7. Indeed, even though I have been using 12AT7-based equipment since the mid-90s, until now, I have not been able to gather enough Telefunken 12AT7s (1) to assemble matched quads, (2) to determine what they truly sound like, and (3) to write up a review. You can quite easily find singles here and there, but what if you need matched pairs or quads? If you want a pair tested for low noise and microphonics, be prepared to pay through the nose.
The AudioPrism Debut II power amplifier is an excellent tool in determining what a 12AT7 sounds like. The Debut II uses a total of four 12AT7s. Its sound is heavily dependent upon which 12AT7s you use. The Debut II's basic character is one of neutrality, so tube colorations have nowhere to hide. Since I own an AudioPrism Debut II, it is my main reference for evaluating 12AT7s. I also used several other pieces that use 12AT7s, just to confirm my findings. I will note differences between components later on.
When I did acquire NOS Telefunken 12AT7s, they burned in relatively quickly. A 24-hour cycle with the Purist Audio Enhancer CD does the trick. If you use your system on and off, a week of such activity should be enough to burn in the Telefunken 12AT7s. The ones I used did not give off large amounts of hum or hiss. In the 15 or so I came across, none was microphonic. That is, they resisted feedback and, when lightly tapped, did not ring or make any thumps. I forgot to check the ones I used a few years ago, but the ones I have now have gray plates and a circular getter hoop. Two have an x-shaped seam at the top of the glass. I do not know if these are the ones sourced from East Germany, which bought old Telefunken equipment. They sounded the same as the others, so who knows?
Regardless of what the Telefunken 12AT7s went into, they sounded consistent. The first thing people notice is that treble instruments are placed far back in the soundstage. In several rooms and systems, the hi hat on Peter Gabriel's "Red Rain" and cymbals from Megadeth's "Disconnect" were placed behind the plane of the speakers. Your initial reaction is to say that the treble is rolled off. But if you listen longer and more carefully, you start to notice that the detail is there, but placed farther back in the soundstage. Metal Church's "Blessing In Disguise" and Kingdom Come's "In Your Face" have a reduced treble amount. If your equipment does roll off the top end, you will know it on these two albums. With the Telefunken 12AT7s, these two albums' top ends sound distant, but if you listen carefully, the detail is still there.
Regardless of system, the Telefunken 12AT7 does not reproduce soundstage width as well as other tubes. In this regard, it is on par with the likes of the Mullard gold pin 6201 and Sylvania Gold Brand 6201. The CBS 7728, RCA black plate 12AT7, Telefunken ECC801S, and Tung-Sol 12AT7 do a better job of placing instruments further to the outside of the speakers [assuming that those instruments actually were recorded that far to the left or right].
In the majority of systems that used 12AT7s, the Telefunken would place instruments just in front of the loudspeaker plane. From there, the soundstage potentially could stretch into the next room. Put it this way. If (1) such info is on the recording and (2) your system and room are able or recreating it, the Telefunken 12AT7 will do nothing to diminish soundstage depth. With the wrong tube, Overkill's "Horrorscope" can have as much depth as a piece of paper. But with the Telefunken in place, the small amount of depth and space between the planes of the guitars and drums are easily perceived. Also, the instruments themselves retain their fleshed out depth. This allows the listener to anticipate the kick drum action, before it actually happens. The way the air moves down low allows you to hear these nuances. In turn, these little depth cues draw you into the music, even if you are still watching from the tenth row, as opposed to being up onstage or in the studio hanging out with the band.
Even when using equipment and cables that yield razor-sharp image outlines, the Telefunken 12AT7 would round off those edges. This tube, tonally, emphasizes the lower midrange, giving a warmer, more romantic view of the music. At all frequencies, the music did not start and accelerate the way it should. Add these three characteristics up, and the overall sound takes on a sway-your-head-left-and-right feel. This was true whether playing some slow Hawaiian music, or some spastic thrash metal. Stuart Hamm's fingering on "Who Do You Want Me To Be Today" is a little slurred. Yet the feel and personality of his Kubicki bass is there. The horn section does not attack as it should, so the end result is a lazier, more relaxed vibe.
But you know what? If this sounds like "classic tube," I could not argue with that assessment. I normally detest this sort of sound, but the Telefunken 12AT7 does it the right way. It makes you feel the music first, and think about the detail second. In this regard, the Telefunken 12AT7 parallels the sound of Conrad Johnson's classic MV-55. If this is your sonic cup of tea, you will find lots to like in the Telefunken 12AT7. Hoarding these tubes for your system is like locking the bathroom door and stepping into a nice warm bath. Aahâ€¦
All things considered, the Mullard gold pin 6201 ($40 each) is the worst 12AT7. It is slow, fuzzy, artificially warm, and lacks resolution at the frequency extremes. I know it was voiced this way to fall in line with that sound of yore, but this is ridiculous. On the other hand, the Telefunken 12AT7 is voiced in a similar fashion, yet, it holds the music together. With the Mullard gold pin 6201, you think "colorations." With the Telefunken 12AT7, you marvel at the beauty of the music.
If you cannot afford the Telefunken 12AT7, the cheapest alternative would be the current production JJ (about $8 each). However, the JJ does not have the resolution, involvement, ambiance, or beauty of the Telefunken. Otherwise, the RCA black plate 12AT7 has a soft top end, bigger images, a wider soundstage, and somewhat better pace & rhythm. Maybe it is due to the 12AT7's solid state-like distortion, but most 12AT7s I have tried do not do the "classic tube sound" well [some Inmates have told me that the 12AT7 is a "loser tube," that it is "not suitable for quality audio"]. In modern day equipment, most brands of 12AT7s are neither "romantic" nor "sharp 'n' detailed." They fall in the middle. So if your needs or tastes run to the romantic side, you do not have much choice. You can achieve this type of sound if you hold your nose and pony up for the Telefunkens. The alternative is to spend even more on cables and tuning devices. It amazes me that people will spend $50 each on cones or footers, yet, they balk at a set of vacuum tubes. Here is a suggestion. Since you are just going to use your 12AT7s, why bother looking for NOS specimens? These tubes are rated for 5000+ hours. Take the time to find good used pieces, and save significant amounts of money, versus going with NOS.
Okay, so now you want to know more about the 12AT7-based equipment I used.
I have tried two versions of the VTL Tiny Triode monoblocks. The old TT-25 had rosewood-colored side panels. The newer version has a silver faceplate. Both versions use one 12AT7 per channel. The TT-25 needs all the speed and treble emphasis it can get. Thus, the Telefunken 12AT7 is a poor choice.
The VTL ST-85, like the AudioPrism Debut II, uses four 12AT7s. In stock ultralinear form, the ST-85 does not sound romantic like the CJ MV-55, nor does it sound tight like the solid state McCormack DNA-125. Also, like the Debut II, the ST-85 will never win popularity contests. Solid state fans go with their favorite brands, and tube groupies go for more colorful and exotic models. But to me, the ST-85 is a model of convergence, giving a nice, middle-of-the-road solidity. I know, I know, other Inmates tell me that that description is a euphemism for "boring," "compromised," and "mediocre." Whether or not you like the ST-85 is up to you. But I can tell you that, like the Debut II, it comes in handy when evaluating 12AT7s.
Personally, I strongly prefer the ST-85's ultralinear mode. Triode mode just does not give me the speed, neutrality, and accuracy needed to get off on the music. If you want some of that "triode magic," without having to flip the ST-85 into triode mode, why not use Telefunken 12AT7s, and leave the amp in ultralinear mode? Once you optimize the 12AT7s, you can then choose your favorite flavor by tube rolling the EL-34s.
The Conrad Johnson PV-10A uses one 12AT7 in the phonostage. In this preamp, be sure to optimize the two 12AU7s in the linestage. Once you do, then you can see how the three phonostage tubes influence the sound of LP playback. I did not get any more or less hiss with the Telefunken 12AT7 in the phonostage, than I did with other 12AT7s. Keeping everything else the same, and only rolling the 12AT7, the more neutral 12AT7s work better. However, with a reedy, squawky, warbly turntable, the Telefunken 12AT7â€™s recessed treble will go a long way towards making vinyl more listenable.
The Sonic Frontiers SFL-1 is a hybrid line stage preamp which uses one 12AT7. Even with 12AT7s tested for low noise, the SFL-1s I have tried are noisy (they pass some hiss on to the amp and speakers). Be that as it may, the choice of 12AT7 in this unit is critical. The G.E. 5-star 6201 did not have enough transparency. The Mullard gold pin 6201 was godawful, sounding like I stuffed too much fruit into the blender. The JAN Philips 12AT7 had a jiggly edge to the mid-treble that put off some listeners. The current production EI 12AT7 is not bad, though it squashes image depth. The RCA black plate 12AT7 could sound too bottom heavy. I actually liked the Tung-Sol 12AT7 for its balance. The Sylvania black plate 12AT7 was way too lean, mean, and nasty. But the Sylvania Gold Brand 6201 just slew, tightening the images, and not interfering with the start and stop of the music. If you find the SFL-1 too forward, too brash, then the Telefunken 12AT7 works okay. It did not seem to scale dynamic peaks with enthusiasm, though, so check to see if this bothers you.
I find the stock Earmax headphone amp to be a little too smooth and pleasant for my tastes. However, when I have borrowed the Earmax, I almost always use it with top-notch digital sources and the Sennheiser HD-600. Assuming your Earmax has low-noise 6GM8s, if you use it with hashy front end and headphones, the Telefunken 12AT7 can be a godsend. It is like using Softlips on dry and cracked lips, rubbing aloe on sunburn, or spreading cool papaya on a jellyfish sting. Playing regular redbook CDs on a Sony SCD-333ES can be too much to take. Run that to an Earmax, use nasty-sounding earbuds, and you'll be reaching for the Telefunken 12AT7. Look. Let's say you do have a nice front end and good cans like the HD-600. And let's say you want MORE of that classic tube sound. Spending $85 on a tested NOS Telefunken 12AT7 is cheaper than the Clou Cable 212 Red Jaspis ($120), Tara Labs Air AC ($695), and Wattgate 381 ($156), all of which I use when borrowing the Earmax.
If you have non-neutral tubes like the Telefunken 12AT7 in your preamp or amp, it is fun to see how speakers react downstream. Even with forward-sounding gear, the Totem Arro does not project images too far in front of the plane of the speakers. Replacing the Sylvania Gold Brand 6201s with Telefunken 12AT7s made the soundstage go waaaaaaaay back behind the Arros. The Sonus Faber Concerto Home was not a good match, the chocolatey mids and soft highs not having enough bite. The ProAc Response One SC tells it like it is. The B&W Nautilus 805 is a mixed bag. The treble was all about quality, but the midbass could be too much like a soft and rubbery squid. But the N805's cleanliness in the mids, coupled with the Telefunken's beauty made some alluring sounds. If you like singing to yourself at low levels, this combo will keep you going all day. But the real surprise was that kicking out my ProAcs, and subbing in an old pair of NHT SuperZeroes made for some giggly-happy listening sessions. Here, the Telefunken 12AT7's pushed-back treble complimented the NHT's sometimes crunchy and harsh tweeter. In the mids, the Telefunken/NHT combo was fun, fun, fun. I even replaced my Fanfare FM tuner with the tuner section of an Onkyo receiver, and my friends and I had a ball, listening to Top 40 radio stations. Here, the Monkees' "I'm A Believer," with its rubbery but bouncy bassline, was much more enjoyable than Smashmouth's cover. Bonnie Tyler has no rhythmic talent, so Nikki French's version of "Total Eclipse Of The Heart," was infinitely better. Articulation on Amber's "This Is Your Night" was so good, we put down the clipboards, and just boogied. Max Weinberg's cymbals had more height on Bruce Springsteen's "Born In The USA." And Survivor's really thin-sounding "High On You" now was easier to take. Furthermore, we just could not stop belting out "I Canâ€™t Hold Back." Everybody knows that the NHT SuperZero is excellent in the technical sense. But I did not know how intensely enjoyable these little speakers could be, until I stuck Telefunken 12AT7s in my AudioPrism Debut II amp.
Upscale Audio's Kevin Deal has said that, while people strive for neutrality, tube rolling is like adding flavor to soup. It thus becomes a matter of taste. I constantly strive for neutral components. But even I have to admit that Mr. Deal is right. The Telefunken 12AT7 is far from neutral, but its "flavor" is rather tasty. If you are looking for such a flavor in a 12AT7, go for it. True, $85 (or more) for a vacuum tube seems ridiculous. But we audiophiles can think of many other ways to waste money. If you want or need the "classic tube sound," the Telefunken 12AT7 is it. I generally hate this type of sound, but while using this tube in various equipment, I actually saw why the other side likes it. And yes, I did have some rather enjoyable moments with this tube in the system. If your equipment uses 12AT7s, try out the Telefunken. If you do not like it, no big deal. Just take the money you would have spent on them, and apply it towards some other tube.
If I were Enjoy The Music, here is how I would grade the Telefunken 12AT7. Please note that I consider 60 to be "typical high-end audio" standards. On my scale, most mass market types would rate in the 30s.
Tonality: 64
Sub-bass: 50
Mid-bass: 55
Midrange: 75
High-frequencies: 58
Attack: 44
Decay: 72
Inner resolution: 70
Soundscape width front: 59
Soundscape width rear: 60
Soundscape depth behind speakers: 80
Soundscape extension into the room: 25
Imaging: 60
Fit and finish: 65
Self noise: 75
Value for the money: 50

Product Weakness: difficult to find in quantity; can be rather pricey; not a neutral sound
Product Strengths: consistent performer; classic tube sound

Associated Equipment for this Review:
Amplifier:	AudioPrism Debut II
Preamplifier (or None if Integrated):	Mark Levinson No. 380
Sources (CDP/Turntable):	Rega Planar 3/Grado Platinum; Fanfare FM FT-1; Theta Jade and Mark Levinson No. 360
Speakers:	ProAc Response One SC
Cables/Interconnects:	Tara Labs The One, The Two, and RSC Reference Bi-Wire
Music Used (Genre/Selections):	Rock, pop, oldies, thrash, hi-nrg, Hawaiian, some classical and Broadway
Room Size (LxWxH):	16 x 15 x 8
Room Comments/Treatments:	ASC 9" round Tube Traps
Time Period/Length of Audition:	3 years
Other (Power Conditioner etc.):	Tara Labs AD/10B, AD/6C, The One AC, Air AC
Type of Audition/Review:	Product Owner

Product Weakness:	difficult to find in quantity; can be rather pricey; not a neutral sound
Product Strengths:	consistent performer; classic tube sound