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Tên mặt hàng: bóng 12ax7 telefonken
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Thông tin thêm:chào cả nhà . em xin hỏi về bóng 12ax7 telefonken - phiến 17 gân chất âm hay hơn . hay phiến 17 trơn chất âm hay hơn.
và có 2 loại logo lớn logo nhỏ in trên bóng . xin anh em có kinh nghiệm chỉ giáo và chia sẽ . tks

 

Tai mình không đủ tinh để đánh giá các loại tube, nhưng có lúc tìm hiều về tube thấy có bài viết này bạn tham khảo. Nếu bóng phiến gân là bóng ribble plates tong bài thì ông này đánh cao loại này (chỗ mình bị đậm)


Joe's Tube Lore



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Joe's Tube Lore

Life with 12AU7s....
Posted by Joe S on March 04, 1999 at 16:04:14:

Here's an edited version of an e-mail I sent EDP regarding 12AU7 experiences in his time of need. I make no representation as to how any of these tubes might sound in your system, but it might help narrow down to a few choices for an evaluation of your own.

Without further ado, here we go....

Now, regarding tubes, yes those 12AU7s in your amp are indeed drivers, and no, if you change them it will not effect the bias of the output tubes so experiment as much as you want. I've posted on AR a few times on this tube type, but I'll go into a bit more depth here. I've been through the mill on this tube type over the past year and tried the following tube types:

· RCA 1960s top getters gray plates

· RCA 50's top getters black plates

· RCA '60s clear tops

· RCA black plate 5814As

· GE grey plates

· Sylvania grey plates

· Sylvania '50s black plates

· Sylvania '50s limited production black plates

· RFT (German)

· Valvo

· Mullard ribbed plate

· Mullard box plate CV4003

· Brimar

· Amperex Holland Orange globe logos

· Amperex Holland Bugleboys

· Amperex Holland 7316 (instrument grade)

· Tesla

· Telefunken smooth plate

· Phillips

· Tung Sol 6189 / 12AU7WA

· Raytheon

Now frankly, most of these are competent at best and not really anything special - in fact I would say this is a fairly unexceptional tube family with just a few high points. In my system the only tubes of merit broke out something like this:

Best of the lot

· Amperex Bugleboy 12AU7 Holland

· Amperex 12AU7 Holland (no bugleboy logo, later production)

· RCA Clear top (side getter) 12AU7

· RFT 12AU7

Best of the rest:

· Mullard CV4003 box plate

That's it. The rest, amazingly enough, weren't worth the waste of time in my rig - but the risk of course is that one of those might ideally match your rig, 'cause with tubes you never know what's going to lock-in in any given system. Given that, the 3 tubes I identified as the winners do have fairly broad followings among audiophiles while most of the others do not, though a few do like the Mullard box plate.

When it comes to sonics general comments go something like this:

RFTs - linear, clean but just a bit clinical and hard sounding. Good transparency and detail.

RCA - A bit fuller, richer and a bit more vibrant than the RFTs, not clinical, but still good detail. A more traditional NOS sound.

Amperex - I think the bugleboys are a bit better,but I might be fooling myself, so these comments apply to any Holland made Amperex 12AU7. Full range, nice extension on top with a great sense of vibrancy, transparency and life with very good focus. This tube sounds warm, vibrant, exciting, extended & clean on top, yet smooth and fatigue free all at the same time. Clear winner in my system.

Oh yeah, the Mullard Box plate - Nice extension on top, tends to emphasize air and ambience at the expense of just a bit of focus, but still nice overall. Just not quite as good as the three above.

Now of course the above might not translate to your system but if I were going to do some experimentation I think I'd chase down a pair of RCA clear tops first. These things are common as can be, cheap (if you pay over $12 a piece you're paying too much) and sound ridiculously good for the money. You will see these at a lot of hamfests and amateur radio shows, often for as little as $5 - $8 each. If those didn't work out and I needed a more controlled and solid state kind of character I'd then go hunt down some RFTs. You wont find these at the average hamfest - more likely, you will have to mail order them from an NOS dealer. Typical price is around $15 to $18 each. I've seen them at Triode Electronics in Chicago, and a few other dealers sell 'em too. The Tech Talk (now that dates this e-mail doesn't it? - Sorry!!)crowd could help there. If, on the other hand, after the RCA experiment I liked what I heard then I might then spring for the Amperexes. They take the basic RCA clear top sound to another level entirely, thought the degree to which they sound better is a bit system dependent. At least one TT poster thinks they are better, but not worth the extra scratch - I find them indispensable and a rather dramatic improvement. Then again my system is very transparent & I'm pretty anal when it comes to the sound I like. Problem with these guys for some is cost. If $35 to $40 a tube doesn't phase you then it's no big deal, but if you don't like the idea of spending that much then there is you're rate limiter, because they are desirable and priced accordingly. You wont see these too often at hamfests even though there were a ton of them made - audiophiles have been snapping 'em em for years and they are getting scarce & expensive. Oh, and by the way, stick with Holland made tubes for these - Amperexes are labeled by country of manufacture and the Hollands are clearly the best.

So, hopefully that gives you a few pointers and some ideas. Oh, well that's about it for now, so good luck and be sure and let me know what you find!

Joe+++++++

Now shifting back to the present, the only other comments I might add relate to the obvious "what about the Mullard rib plates & legendary Telefunkens?" question. Well frankly there wasn't much to say. IMHO these are two of the most overrated brands in the NOS universe. generally speaking all the Telefunken 12A family tubes I've heard ('X7s, 'T7s, 'U7s) are a bit bright, thin and airy sounding. I've talked to Charlie Kittleson at Vacuum Tube Valley about this and he basically agreed, observing that these guys more or less built their reputation on their use by the old gear crowd. Why? Well his comment was that the caps, resistors & transformers in old gear were dark sounding sludge and the Teles offered a useful brightening of the sound to a more natural balance. The issue, of course, is that when you put them in a contemporary design with much wider bandwidth and a more neutral '90s kind of balance things can go over the top.

Now before any Tele lovers who find them ideal in their new gear freak out and tell me how wonderful they sound - I believe it. There is a system out there somewhere that's the ideal match for any tube. This is just a comment on a general tendency. Now Mullards are another matter. I have found a few that sound quite nice and they generally are warmer than Teles, but in my rig they never quite make it to the top of the heap.

· Life with 12AX7s - Part 1
Posted by Joe S on March 17, 1999 at 19:05:44:

Well, here's the promised second installment of my tube odyssey into the world of small signal NOS tubes. Just to get the formalities out of the way here first - Yes NOS tubes do sound different from current production tubes. Yes they will have real impact on the sound of your system. And yes, they all sound different. Which will sound best in your rig? Who knows. There are significant differences in the way in which individual components, systems and tastes interact with individual tubes so my experience may not predict yours, in other words - "Your mileage may vary" - but hopefully this may help separate some of the gems from the dregs for your own personal evaluation short list....

Well, first things first. This is the ubiquitous small signal triode, they are probably about as commonly used as 6DJ8/6922s and in my humble opinion they are widely misunderstood. Why? Because the hype surrounding a few specific supposedly invincible NOS brands is way out of proportion to their true quality and their likelihood to mesh with any given system - but more on that later. My opinions are based on using this type in my system in 4 different preamps over the years - most recently in the output stage of the Thor.

Now on to the tubes themselves. Brands and versions I have on hand include:

· Sovtek 12AX7 WXTP(premium, supposedly modeled after the classic Telefunken)

· Telefunken 12AX7 ribbed plates

· Mullard 12AX7

· Mullard CV 4004 box plate

· Sylvania (Phillips) JAN 12AX7WA

· Brimar CV 4004

· RCA 12AX7A grey ribbed plate

· Amperex 12AX7 Bugle Boy Holland

I've also owned and heard the GEs in the past but thankfully don't have a pair on hand at the moment ;-) Now, regarding nomenclature - the CV numbered tubes are British military tubes labeled according to the British Military numbering system - they are still just 12AX7s. The WA on the Phillips denotes a premium or select version.

Now when it comes to sound quality where do I begin? Well, to my ears - they ALL suck. There, I said it. Even (particularly?) the legendary Telefunkens. How can this be? Well, every 12AX7 I've ever heard has a common sonic character that's drives me to distraction. Specifically, they all sound a bit fuzzy, unfocused and hazy with a subtle sense of a soft sonic haze permeating a soundstage populated with large unfocused images. Added to this are other sonic artifacts unique to each tube. To hit a few of the highlights, here goes:

Telefunken 12AX7 ribbed plates - a typical soft, unfocused 12AX7 sound with big, soft, images allied with a bright bass shy character. I was shocked when I heard these guys first hand, but the more I talked to people who knew these tubes the better I understood them. I generally associate NOS tubes with a warmer, more harmonically complex & rich sound than current production, but light and airy is the order of the day here - to the pint of brightness. The secret is that these guys are a favorite for use in a lot of old classic gear from the '50s & '60s where the transformers, wire and caps used were thick, dull sounding sonic sludge. The bright balance of this tube is great complement for this kind of gear, but drop it into current broad bandwidth tube gear (like the Thor) and you might just get sonic hell - all for just $50 to $65 a tube!

Mullard 12AX7 ribbed plate - a warmer and fuller sound than the Tele, but it still suffers from the typical 12AX7 softness and lack of focus. A bit rolled at the extremes in my rig and more forgiving than the Tele. All in all a better choice for contemporary gear in most circumstances IMO than that tube - but I'm still not getting any shin burns from my sox rolling up and down in excitement at the prospect...

Mullard CV4004 box plate - very extended at the extremes, great frequency response overall in fact, but maybe even more fuzzy than the usual 12AX7.

Amperex 12AX7 - now this one is a bit more interesting. The typically vibrant yet rich and transparent Amperex sound with less of the typical 12AX7 softness and lack of focus. If I lived in a world in which I had to use a 12AX7 this would be the one I would use. But I don't & neither do you, but more on that later...

The rest of the pack - the Sylvania/ Phillips, GE, RCAs, etc.. are even worse. In fact, added to the usual (to my ears) 12AX7 sins add lack of refinement, microphonics and huge sample to sample variability. Not a pretty sight, trust me. And, oh yeah - the Sovtek? Its a cool harmonically bleached and basically disappointing beast that I wouldn't use under any circumstance - but hey, that's just my opinion.

Well I've just run roughshod over some of the most revered tubes in the NOS universe and basically damned them with faint praise at best. So what do you do if your gear has a couple of sockets that expect to see a 12AX7? Well I would propose that you cast an eye toward the 12AX7s more refined and altogether superior offspring - the cheap, lowly 5751. In its day (it was introduced in the mid '50s) the 5751 was created as premium 12AX7 designed by US manufacturers to overcome the well known limitations of American made 12AX7s, specifically: huge sample to sample variability, microphonics and noise. The fact is this tube had considerable care exercised in its design that is evidenced in its physical construction: Rigid metal rods linking the mica spacers for a more rigid less microphonic tube, a third mica spacer to brace the getter halo (again to combat microphonics), careful testing to assure consistency tube to tube and lower mu (apparently to combat noise) which results in an altogether more focused & palpable sound.

But then a funny thing happened. This tube was made in massive quantities by companies like Sylvania, RCA, GE and Raytheon and was supplied to the US military resulting in massive JAN stocks of NOS tubes lying about. Just not the sort of exclusive limited availability tube that exclusive NOS tube dealers could charge $ 50 a pop for - like those rare & exclusive Tele & Mullard 12AX7s...So a premium tube with great performance and a genuinely careful design has knocked about as a common $8 NOS plug in for 12AX7s while its less capable but better known 12AX7 competitors have achieved legend status. Now all may not be well in audio land here so I'll warn you now. The 5751 has a lower mu than a 12AX7 and some circuits purportedly don't abide by that but I've tried them in 4 preamps with no problems and this guy has found pride of place in a lot of tube preamps over the years CJ used them in their line stages for years and Joule Elektra ran them in the LA 100 / 200 series of preamps until very recently - so there are other people have heard the merit in these guys too.

So if the 5751 is the direction to look, where do you start? Well there are several choices and vintages (most of which are ridiculously cheap) that will put a Tele or Mullard 12AX7 to shame - but its late & that's a story for part 2 of the 12AX7 story....

 

Telefunken logo đáy . Để phân biệt dc tiếng 2 em này . Cần phải có amly chuẩn và đôi tai biết thẩm ...
Logo nhỏ dưới thì là bóng cổ nhất . A e vn thích cổ thì tìm nó thôi ... chứ bản thân bọn tele này chả khác nhiều ... còn mullard . Thì lại khác xa giữa các dòng bóng ...

 

tks anh em đã chia sẽ .