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!
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!
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
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.
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!
Starting with ge6550A to use in ZMF Aegis headphone amp.
Cheers for that , great info . In % terms, how much better is your favourite version from the version 2 grey plate ?
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!
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
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.