Vintage Tannoy
Vintage Tannoy
  • Видео 13
  • Просмотров 9 629

Видео

McIntosh VU Meters with Marantz Receiver
Просмотров 1,1 тыс.21 день назад
Marantz Model 2010 Receiver with McIntosh MPM4000 VU Meters. 00:00 - Intro 01:31 - Model 2010 02:40 - Setup & Connections 07:56 - Meters in Action
McIntosh VU Meters with Eico HF-81 Amplifier
Просмотров 1,3 тыс.Месяц назад
McIntosh MPM4000 - Car VU meters with Eico HF-81 tube amplifier 00:00 - Intro & Background 03:00 - User Manual 07:44 - Impedance 09:51 - Rant 11:08 - Trial & Error 13:17 - Results
NOS Tung-Sol 6550 Tubes - All versions of vintage 6550 tube for McIntosh MC275, Aegis tube amp
Просмотров 5659 месяцев назад
I have tried to capture all the different versions, iterations and the chronology of the vintage Tung-sol 6550 tube to the best of my knowledge. Please add your inputs in the comments section if you have any additional context or information. Thanks! 00:00 - Intro 01:42 - Ver 1.1 04:21 - Ver 1.2 06:04 - Ver 1.3 07:21 - Ver 2.1 09:45 - Ver 2.2 10:07 - Version Details 10:59 - Sound Differences
NOS GE 6650A Tube Iterations and Sylvania 6550 for McIntosh MC275, Aegis tube amp
Просмотров 3149 месяцев назад
I have tried to capture the history and the chronology of the the straight-bottle GE 6550A and Sylvania 6550 tubes to the best of my knowledge. Please add your inputs in the comments section if you have any additional context or information. Thanks! 00:00 - Introduction 00:19 - GE 6550A History 01:49 - GE 6550A Ver.1 02:01 - Sylvania 6550 03:06 - GE 6550A Ver.2 04:15 - Sound Differences
NOS 6550 & KT88 Tubes - TungSol, GEC, GE, Sylvania for McIntosh MC275, Aegis tube amp
Просмотров 8519 месяцев назад
I have tried to capture the history and the chronology of the vintage 6550/KT88 tubes to the best of my knowledge. Please add your inputs in the comments section if you have any additional context or information. Thanks! 00:00 - Introduction 00:50 - Labels vs Manufacturers 04:08 - 6550 History 05:24 - Tungsol 6550 08:20 - GEC KT88 10:34 - GE 6550A 12:21 - Sylvania 6550 12:53 - Summary
McIntosh MX110 Z Vintage Tuner Preamp - Tubes, Streamer & DAC - Wiim ADI RME
Просмотров 1,7 тыс.9 месяцев назад
00:00 - Intro 01:15 - MX110 Versions 02:30 - Early vs Late Z 05:22 - Streamer & DAC 10:25 - Tubes 14:56 - Tuner 15:30 - Streaming
NOS Telefunken EL34 Tubes
Просмотров 431Год назад
Comparison of some original Telefunken El34's from the 1950'-60's and the RFT Telefunken from the 70's. 0:00 Intro 1:42 Telefunken EL34s 2:35 Telefunken Labels 4:45 Tube 1 Late 50's West German Tele EL34 6:00 Telefunken Date Code 8:36 Late 50's Tele Structure 10:53 Tube 2 Early 60's West German Tele EL34 11:17 Telefunken Date Code 12:05 Early 60's Tele Structure 13:05 Tube 3 70's East German RF...

Комментарии

  • @jerrywatt6813
    @jerrywatt6813 11 дней назад

    Wish i could still get these telefunken el34's my marshalls sounded so mutch better with these they were loud crunchy and lasted about 6 months of brutal cranked marshall nite after nite the nos are expensive and you dont know if they are any good so ive stayed away thanks cheers !

    • @vintagetannoy
      @vintagetannoy 10 дней назад

      Are you referring to the RFT Telefunkens? Those are some real nice tubes. I have been listening to them in my Marantz 8B for a couple of months now and they deliver a great sound. Best bang for the buck for less than half the price of NOS Telefunkens.

    • @jerrywatt6813
      @jerrywatt6813 10 дней назад

      Well i did'nt even know about them are yhey as good as the ones i got in the 70's and 80's ? Thanks ! ​@vintagetannoy

    • @vintagetannoy
      @vintagetannoy 9 дней назад

      ​@@jerrywatt6813 just to clarify there are two types of "NOS" Teles.. the original ones from the West Germany factories and the RFT ones from East Germany. The West German Teles are unobtanium or they are prohibitively expensive. The RFT Teles are from the 70's and are also expensive but still less than half the cost of the West German tubes. I'm referring to these RFT Teles.. they are a great value in terms of sound and cost. I would stay away from current/new TFK El34s.

  • @PiotrWoryma
    @PiotrWoryma 16 дней назад

    Thank you! I was wondering if you also tried the JAN version of the GE 6550 and could comment if there is any difference in sound from the regular GEs.

    • @vintagetannoy
      @vintagetannoy 16 дней назад

      There is no sound difference with the JAN tubes. From my understanding, at some point GE/TungSol stopped manufacturing the tubes for consumers but still manufactured some batches for the military in the form of JAN tubes. Eventually these showed up as military surplus. They are the same exact tubes sound wise.

    • @PiotrWoryma
      @PiotrWoryma 16 дней назад

      @@vintagetannoy Thank you!

  • @PiotrWoryma
    @PiotrWoryma 16 дней назад

    Thank you! So useful!

  • @sofabaton
    @sofabaton 17 дней назад

    Very nice video, we appreciate your home theater, are you interested in using a universal remote?

  • @farooqashraf9672
    @farooqashraf9672 19 дней назад

    I have a 150 watt McIntosh amp. Do you think this will be ok since the VU meter is rated for 100watts?

    • @vintagetannoy
      @vintagetannoy 19 дней назад

      It's actually rated for 200 watts so you are good👍. You can see the "200" in tiny print at the right end of the meter scale.

  • @farooqashraf9672
    @farooqashraf9672 19 дней назад

    Excellent. I just purchased the VU meter recently and am going on the same journey as you. Thanks for the video

  • @farooqashraf9672
    @farooqashraf9672 19 дней назад

    Great video. You left out the most important aspect of the video. How did you connect each wire to get it to work?

    • @vintagetannoy
      @vintagetannoy 19 дней назад

      Yes, I was not completely sure if it would work so I was recording intermittently on a phone without a tripod. I have just uploaded another video detailing how I connected everything including the power supply. Here it is: ruclips.net/video/gNjrLIpb6VI/видео.html

  • @phonebackup8132
    @phonebackup8132 21 день назад

    I am building an amplifier using the output transformers from a ma230 using the 6550. I have the Russian Tunsol 6550. Have you noticed any difference within the Russian versions of tubes or are they all the same. I will try to get a set of black plate 1.1 or 1.2 versions but they aren't easy to obtain. How much difference do you note in your amps between these groups, ie the 1.1-1.2 versus the Russian tubes. Also i since I'm building the amps I can change the idle current and negative voltage on the screen grid. I don't know if you can or have messed with these parameters but if so what were your findings? Thanks in advance for your input.

    • @vintagetannoy
      @vintagetannoy 20 дней назад

      The current Russian TungSols are not the same as the vintage American made TungSols. I have heard the Russian tube and they sound good for the price but the problem with current generation tubes I have encountered is that they are not consistent, both sound wise and quality/longevity wise. Keep your Russian tubes and try the most affordable vintage TungSol 6550 - v2.2 - grey plate with 3 holes. If you notice the difference there then you can upgrade to the more expensive and rare vintage solid plates. If your system is resolving enough and you can hear the difference then it makes all the sense to try to obtain older more expensive tubes. In my experience 1.1 and 1.2 are exceptional in their sound and they are best sounding 6550 tubes followed by 1.3 and 2.1. Followed by the TungSol 2.2, Sylvania 6550 straight bottle and GE 6550A. These vintage tubes sound better than any current production Russian or Chinese tubes. Regarding the amp current/voltage, I haven't messed around with it since I use the McIntosh MI-75s, you can look up the specs of that amp but when I checked last I read 430V at the plate with at average plate current of around 26mA.

    • @phonebackup8132
      @phonebackup8132 19 дней назад

      @vintagetannoy Thanks for the info help. I'm putting around 830v on the plates and a very regulated 320v on the screen grid. The idle current is close to 38 ma. The test circuit is extremely resolving playing through an Altec 515 woofer, Altec 311-90 with a 290E giant voice compression driver and a Electrovoice T350 super tweeter. I will endeavor to obtain several sets to roll. I can confirm tube parameters with my calibrated Hicock tester.

  • @ЛевЗагорский-ц6к
    @ЛевЗагорский-ц6к 21 день назад

    В рековой стойке устройство смотрелось совсем неплохо. Мне кажется, вы зря отказались от этой идеи.))

  • @josedominguez6088
    @josedominguez6088 21 день назад

    Cool thanks 😊 😎

  • @lizard_girl_
    @lizard_girl_ 23 дня назад

    woah this is so cool! thank you for sharing!!

  • @mauriceprudhomme5296
    @mauriceprudhomme5296 Месяц назад

    Don't melt that VU on that amp, I have one they get mucho hot lol. pretty cool!

    • @vintagetannoy
      @vintagetannoy Месяц назад

      👍 Yep, it was only for testing purposes. That Eico gets pretty hot with those EL84 tubes.

  • @AudioGuyBrian
    @AudioGuyBrian Месяц назад

    Looks like a fun project. Not for me though. I cannot stand VU meters with bouncing needles. Give me a spectrum display or Flourescent Display VU or Power meter any day. At least you can see non-analog meters from a distance. I have one amp with old timey analog VU meters and I hate having to walk right up to it to see if the channels are balanced and both working correctly. With a digital meter I can tell from across the room.

    • @vintagetannoy
      @vintagetannoy Месяц назад

      Agree, the needles can get distracting sometimes. If I do implement some sort of vu meters in my rack setup I would add a power switch to the meters to turn them off if I need to.

    • @MikeGilbert-zm9lb
      @MikeGilbert-zm9lb Месяц назад

      Blessfamy

    • @AudioGuyBrian
      @AudioGuyBrian Месяц назад

      @@MikeGilbert-zm9lb I learned a new word today. "Blessfamy". Not even in the Urban Dictionary. You should enter it and give a description on whatever it means.

    • @AudioGuyBrian
      @AudioGuyBrian Месяц назад

      @@vintagetannoy I don't even see them unless I am 2 feet away from the device. They are so thin like hairs for obvious reasons. That is a good reason why audio gear moved away from that nonsense and went to the LEDs or Fluorescent meters like the beautiful Pioneer Blue Flouroscan ones. Except for McIntosh which has millions of fans for the blue meters only. They could care less about anything but the McIntosh meters. Silly.

    • @MikeGilbert-zm9lb
      @MikeGilbert-zm9lb Месяц назад

      I absolutely love VU meters my sound room is small so I got 6 of them I watch montering any input signal I throw at it sorry I spelled the word wrong it's Blasphemy meaning irreverence towards something considered sacred or inviolable.

  • @shenmisheshou7002
    @shenmisheshou7002 Месяц назад

    There are quite nice, but given the very high price of these units even on the used market, something like the Fosi Audio LC30 or the Douk Audio VU2 would probably be a much better choice. These are aimed at the home system, and has the necessary hookups. I suspect that you could change the LEDs to a different color if that was desired. There is also a European company that makes beautiful custom meters but I am to lazy to look for their sight. I think they sell a component kit as well. There is al

    • @vintagetannoy
      @vintagetannoy Месяц назад

      Thanks for your input. I will look into Fosi Audio and Douk Audio vu meters but I would really need a 19" rack mountable unit and I was hoping to maintain the authentic McIntosh look on the rack but McIntosh doesn't make it easy. Oh well.

    • @shenmisheshou7002
      @shenmisheshou7002 Месяц назад

      @@vintagetannoy ruclips.net/video/TjbcQe_4swQ/видео.html

    • @shenmisheshou7002
      @shenmisheshou7002 Месяц назад

      @@vintagetannoy There is also a custom maker in Europe that makes custom VU meters. This has a very Mc looking vibe. ruclips.net/video/TjbcQe_4swQ/видео.html They have many videos on YT of different designs. I was looking at having them make me something and the price was reasonable. I did not do the project in the end, but they were someone that seemed promising.

  • @YourfriendNextDoor2
    @YourfriendNextDoor2 Месяц назад

    Starting with ge6550A to use in ZMF Aegis headphone amp.

  • @mikeg2491
    @mikeg2491 Месяц назад

    IMO if you’re in the market for a McIntosh tuner these combo tuners/preamps are the best value because you’ll find you will use the tuner function less than you think but the preamp is worth its weight in gold for other devices.

  • @michaelangelo1955
    @michaelangelo1955 Месяц назад

    I use MC 240 eith Tannoy Ardens and dknetimes Harbeth 40th.

  • @michaelangelo1955
    @michaelangelo1955 Месяц назад

    I have 2 mx110's abd they are awesome. Sound is delicious! 1:54

  • @miranjisaab
    @miranjisaab 2 месяца назад

    Vintage audio tubes evoke a nostalgic sense of the past, thanks for sharing!

  • @vintagetannoy
    @vintagetannoy 4 месяца назад

    Needless to say this is an exercise in futility as the youtube video/sound will not do justice to the real sound in person. Sigh.

  • @stevesentanoe6730
    @stevesentanoe6730 4 месяца назад

    Between version 2.1 and 2.2 is that the big sound quality diffrent? Im planning to buy 1 set of those, but the 2.1 is more expensive than the 2.2 version, can you tell me what the diffrent between version 2.1 and 2.2? By the way right now im using 6550 svetlana B2, on my audio research I/50. Thank you in advance

    • @vintagetannoy
      @vintagetannoy 4 месяца назад

      Audio Research I/50 looks like a nice amp. As far as the tubes are concerned, I would broadly categorize them into three based on how closely they sound to each other: 1. Black plates with D getters (1.1 & 1.2) 2. Solid plates with halo getters (1.3 & 2.1) 3. Three hole with halo getters (2.2) You can't go wrong with any version of these tubes, the sound gets more refined as you move up the chain with older tubes. 2.1 is closer in sound to 1.3. I believer the reason why the solid plate tubes are expensive is because: 1. Fewer of these were manufactured when compared with the 2.2's. Tung sol went through 4 different iterations from 1.1 to 2.1 in a span of 8 years which averages to about 2 years of production for each iteration from 1.1 thru 2.1. Whereas, the last version 2.2 was in production for well over a decade. 2. The 3-hole grey plate is a great tube but the solid plates and D getters do have an edge on sound that is discernible on a system that is resolving enough. I would start with the tubes I could afford and then try the next older version of the tubes when time and wallet permits to see if the sound difference is noticeable and then keep the tubes I like based on sound and value. I also have some tubes to sell that I usually list on USAM. You can contact me at vinttannoy@gmail.com if you have any further questions.

  • @benitomaldonado7381
    @benitomaldonado7381 5 месяцев назад

    Beautifull

  • @cdbeen123
    @cdbeen123 5 месяцев назад

    Cheers for that , great info . In % terms, how much better is your favourite version from the version 2 grey plate ?

    • @vintagetannoy
      @vintagetannoy 5 месяцев назад

      Needless to say, it's all going to be subjective but there is a discernable difference between the tubes as the gap gets wider. As far as percentage goes, it's hard to tell. I had a methodical way to A/B the tubes. Keeping everything else constant, I kept swapping out the tubes and critically listened to the same music on each set of tubes for at least two weeks before I swapped them out with a different set of tubes. I went from a set of current gen tubes to 70's tubes to 60's tubes to 50's tubes. I personally prefer the earlier tubes only because I'm able to hear the difference. As we all know it's very difficult to describe sound in words, it just has to be heard and experienced. The 1.1's were simply the best sound I have ever heard. It's like veils were lifted and I was in a studio listening to music being performed/recorded. Vocals and instruments just sounded so organic and real.. it felt like the 1.1's held the note a split second longer, the reverberations on the strings and wind instruments lasted split second longer, the noise floor dropped and the blacks were darker if that's even a thing.. the music on 1.1's either brought a smile to my face or tears to eyes. Speakers, amp, gear, equipment just disappeared and I was in a private concert. I'm sure the Tannoys had a a lot to do with it as well, along with the MI-75s, MX110z and the Tele 12ax7 in there. So, I just happened to have found my bliss in the coming together of all the equipment in the chain and I'm keeping it. :) The other revelation I have had through this process is that the- tube. is. the. amp! The amplifier with the transformers and the design allows for the tube to do it's job and a well designed amplifier will keep the distortion at a minimum and be functional for long periods of time without causing undue stress to the various components of the amp. That's why some of the best amps from the 60's - the Macs and the Marantz have stood the test of time with their impeccable design. Once you get the design of the amp out of the way.. the actual amplification happens within the tube. Think of the tube as a lens for the DSLR, the DSLR will define the limits for the camera.. the megapixel, the features etc.. the amp is the camera body but ultimately the lens will have the most impact on the quality of the image. Similarly, as you change the tube and the sound changes. It's as if various brands of tubes and tubes from different periods are EQ'ed differently. Some bring vocals forward while others sparkle at the top while some render the bass differently. So finding the right tube for you will require some A/B'ing and will also depend on your preferences for sound. Having said that, 1.2 is closer to 1.1, 1.3 is closer to 1.2 and so on. I don't know why the tubes from the 50's sound best on my system but they do. However, it's hard to justify the price of these tubes these days. I only got into tubes a couple of years ago so I have paid premium price for these tubes. I would say, start with the later tubes from 70's or 60's and then- IF your system, your ears, your wallet allow for it.. upgrade to older set of tubes and see if you can hear a difference. I definitely do not want to promote the 1.1's as the best but that has been my experience on my system and who knows - maybe someone will like the the 2.2's best or the current gen tubes best. To each his own.. everyone's journey is going to be unique. As long as you are enjoying the music, the system you have is the best system. Cheers!

  • @cptsobczak
    @cptsobczak 7 месяцев назад

    Thanks for the video. Def interested in the mx110 for purchase

  • @Haramain-j8v
    @Haramain-j8v 9 месяцев назад

    Thanks for making amazing information videos.. Can you Please send me your contact number. If you ok...

  • @Maquis1943
    @Maquis1943 9 месяцев назад

    This is great. I'd love to hear those MI-75s though the Tannoys!

  • @vintagetannoy
    @vintagetannoy 9 месяцев назад

    I have tried to capture all the different version, iterations and the chronology of the vintage Tung-sol 6550 tube to the best of my knowledge. The coke-bottle 6550 was manufactured by Tungsol and was re-labeled for many other manufacturers. I have personally come across RCA, GE, Sylvania, Stromberg-Calrson and Raytheon labeled Tung-sol 6550 tubes. I have come up with a versioning system to better understand and document all the different variations and iterations of this tube, you can find the versioning in this video. Tung-sol manufactured these 6550 tubes from ~1955-1976*. *Dates are approximate. Please add your inputs in the comments section if you have any additional context or information. Thanks!

  • @vintagetannoy
    @vintagetannoy 9 месяцев назад

    I have tried to capture the history and the chronology of the straight-bottle GE 6550A and the Sylvania 6550 tubes to the best of my knowledge: 1. The straight-bottle 6550A was manufactured by GE. I have seen GE 6550A also re-labeled as Philips. GE manufactured the 6550A tubes from ~1971-1991*. There were at least two iterations of the GE 6550A tube. First version had welded plates and three circular holes in the plate. Ver.1 was in production from approximately ~1971-1979*. Second version had stamped/stapled plates and had two circular holes and one rectangular hole in the plate. Ver.2 was in production from approximately ~1980-1991*. 2. Straight-bottle 6550 was manufactured by Sylvania. I have personally come across RCA labeled Sylvania 6550 tube. Sylvania manufactured the 6550 tubes from ~ 1971-1979* *Dates are approximate. Please add your inputs in the comments section if you have any additional context or information. Thanks!

  • @vintagetannoy
    @vintagetannoy 9 месяцев назад

    I have tried to capture the history and the chronology of the the 6550/KT88 tube to the best of my knowledge: 1. The coke-bottle 6550 was manufactured by Tungsol and was re-labeled for many other manufacturers. I have personally come across RCA, GE, Sylvania, Stromberg-Calrson and Raytheon labeled Tung-sol 6550 tubes. Tung-sol manufactured the 6550 tubes from ~ 1955-1975* 2. GEC KT88 was manufactured by MOV for GEC. There are Genalex and Gold Lion versions of the GEC tubes as well. These were manufactured from ~ 1957 - 1980s* 3. Straight-bottle 6550A was manufactured by GE. I have seen GE 6550A re-labeled as Philips. GE manufactured the 6550A tubes from ~ 1971-1991* 4. Straight-bottle 6550 was manufactured by Sylvania. I have personally come across RCA labeled Sylvania 6550 tube. Sylvania manufactured the 6550 tubes from ~ 1971-1979* *Dates are approximate. Please add your inputs in the comments section if you have any additional context or information. Thanks!

  • @kdl46ex723
    @kdl46ex723 9 месяцев назад

    Wow. Good amount of information and great presentation. Thank you! It would be great to listen to each of these tubes in an amp and get an impression of the sound differences. What's your opinion of each of these in terms of sound? Not everyday that someone is able to get their hands on all of these vintage tubes.. that too with original boxes. What a treat.

    • @vintagetannoy
      @vintagetannoy 9 месяцев назад

      They all sound different to each other. Some are drastically different, others are slightly different. At the end it really comes down to personal taste and preference. :)

  • @vaughnallen2066
    @vaughnallen2066 9 месяцев назад

    Thank you. Amazing once again. I will watch a few times.

  • @kdl46ex723
    @kdl46ex723 9 месяцев назад

    How does the MX110 sound with the Marantz 8B?

    • @vintagetannoy
      @vintagetannoy 9 месяцев назад

      Delicious! MX110+8B is one of the best preamp/amp pairing I have ever heard. It's my new favorite. 🙂

  • @elvisisalive2716
    @elvisisalive2716 9 месяцев назад

    good stuff. I have a Yamaha S2100 and it has no DAC either so it took me a bit to figure out the best combination I enjoyed since I wanted to use the balanced inputs on the unit. I went with the Cambridge streamer, its pretty good but I hate the controls on it so on the hunt for a new one now.

    • @vintagetannoy
      @vintagetannoy 9 месяцев назад

      If you don't mind separates you can consider the RME ADI 2 DAC seen here in my video. It has a balanced out, parametric EQ, a remote and tons of other features I don't even use but I like it for its ease of use, flexibility and a clean neutral sound.

    • @elvisisalive2716
      @elvisisalive2716 9 месяцев назад

      @@vintagetannoy I'll check it out, I love separates so all good there, just need a decent streamer to match as well. Thanks for the info

  • @vintagetannoy
    @vintagetannoy 9 месяцев назад

    Apologies about the shaky handheld video. It was supposed to be a really short video that ended up being quite lengthy. I may do a re-do with a tripod later.

  • @sevestan
    @sevestan 9 месяцев назад

    The look of vintage analog Mcintosh tuners is bar none the most exquisite.

  • @vaughnallen2066
    @vaughnallen2066 10 месяцев назад

    Thank you. What do you think about next the Telefunken 12AX7!

  • @Seaghost08
    @Seaghost08 10 месяцев назад

    Tell me about the streamer and the dac. Looking to to run digital through my MX110

    • @vintagetannoy
      @vintagetannoy 10 месяцев назад

      As mentioned in the description, in this video I'm running the Wiim Pro streamer into the RME ADI 2 DAC. Wiim Pro is great as a standalone streamer and can be paired with any decent external DAC. I'm using RME ADI 2 DAC because of all the studio level features and adjustments it has but any decent, lower priced DAC will also sound great on the MX110. My other DAC is the ifi Zen One Signature and that DAC sounds fabulous with the MX110.

  • @miranjisaab
    @miranjisaab 11 месяцев назад

    Thank you for the exceptionally thorough research and the wealth of knowledge you've shared regarding identifying and distinguishing vintage Telefunkin NOS EL34s. Your detailed analysis and insightful tips have been incredibly helpful for audio enthusiasts like myself who cherish the rich sound and history of these classic once in a lifetime components. Your dedication to preserving and sharing this knowledge is a true service to the audiofile community and generations to come. Great Reference video! 👍🏼

  • @vintagetannoy
    @vintagetannoy Год назад

    More on the Philips & Siemens: They were produced in the same year and month. Although the xf1, xf2, xf3, xf4 is usually associated with Mullards. These xf codes were used by Philips, Mullards, Siemens, Valvo, Brimar. Mullards usually have an xf code a 'B' code representing Blackburn plant. What's also interesting that xf4 code on my Philips/Siemens is much older than the xf4 codes that appears on Mullards. Philips xf4=~1957-1962 whereas Mullards xf4=~1976-1980 My tubes with code xf4 L0L were produced in the same factory, year and month: xf4 = EL34 tube L= Sittard/Holland 0= 1960 L= December