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I found two matched octet KT88 original Svetlana St. Petersburg tubes in my stash, less than ten hours on them, probably the last in the world. I had a buddy that bought a pair of VTL enormous monos that used EIGHT per side, he decided he wanted to use 6550's instead and sold them to me for next to nothing more than twenty years ago. I had totally forgotten about them until I came across them a year ago.
That 6550 you showed with the round holes and the 45 degree getters is also a REAL st Petersburg tube, that was constructed before the C version, it is the B version and some of thpse had issues with thermal runaway and then they purchased new grid alignment tools and moved to the rectangular holes. If you see a 6550 with the getters in an angle and the half moon holes in the mica you have the real deal as well and they will sound the same as the C, I am running a quad of those as we speak in my r8, and I even prefer their mid range sweetness over the 6550C
Thanks, I always thought the "B" version was labelled 6550B, you learn something new everyday! I remember picking up a post from a company that was trying to make use of what must have been a large surplus inventory of the B version, and they said not to worry, they rigorously tested the tubes and had thrown away the 80% that were defective!
We did some research (we have a lot of miscellaneous 6550 tubes both St.Petersburg and Saratov production) and it looks like that tube I showed was a first generation St,Petersburg 6550C (we have a number of them with 6550c labels). As far as I can see the 6550B's all had side getters and the tube in question doesn't. But all of this is mute, because no one has enough inventory to make up matches of these early types and no one wants to run the earlier problematic 6550B.
I have a quad of those, they are somewhat crooked in the base, but sound just excellent, have a mid range smoothness normally not associated with KT style tubes. I switch back and forth between xf2 and these and honestly even prefer the 6550 in rhe r8, The xf2 have more upper end detail and "emotion" perhaps, but the 6550 have some flair about them that really speaks to me. There are many variations, there is also one with a "pill getter" on the side and clear glass , and then there is the side getter version you mentioned. The way to identify st Petersburg tubes is not the holes in the plates, but rather the ufo getters in a 45 degree angle and the crecent moon mica's ... the 6550 I have are rock solid, I can even run them in my SE diy amp @120% plate dissipation without red plating, or any other issues , However I did not run them for more then a few hours like that. The cathode bias was set for kt90 at the time. There are sadly no current production KT tubes I enjoy listening to... maybe the super expensive KR , but that's over my budget , the Sophia Electric KT88 are also nice, but I wouldn't buy those if I could get Svetlana's in stead, I own xf2, rft, and those 6550, sold all the rest, I also run Adzam Brussels 6sn7gt from 1952 which meassure over 9ma, which is a first for the 6sn7s.i measured, I have 3 of them and they even go over 10ma on some triodes. Then I run ww2 vt229 Sylvania, after a extensive search I found non microphonic ones that sit snug in the glas balloon 🙂 you can tap them all day, and won't hear a single thing through the speakers, and then I have a set of your USA gold, "Roger's 6sn7, " and tall boy 6sl7, and the Russian VR, while they are not terrible , the tubes I have in the r8 now are from another world... ps like your channel
How important is it to use matched quads (or octets) for amps like Primaluna with active autobiasing? What are the potential cons of using non-matched tubes in a Primaluna Integrated amp?
Other than in guitar amps (in which you actively make distortion) you want the same manufacturer, same tube type, with matched plate current (mA) for your best sound. Think of the auto bias or fixed bias as a fine tuning or trimmer circuit. Now will a bunch of mismatched tubes work? Yes of course they will, however sound quality will suffer. The ultimate power amp has one gain/driver stage and one power tube or a pair of close matched power tubes running in parallel. That will be pure Class A and once you hear it, you'll never sacrifice sonics for power again.
Svetlana 6P1P-EV, the Chinese made their own version, I think also called the 6P1P. The -EV is the Soviet designation for a rugged tube. In the West a comparable equivalent would be a true "mil spec" tube.
Got it. Similar to a 6AQ5 but 9 pin. Documentation is scarce. I found one data sheet partially translated from Russian, but it’s difficult to decipher anything more than the pin diagram. I’ll keep looking. Thanks for letting us know about this tube!
@@CountyLineMike a google search should turn up the full translated data sheet. However don't expect to find much in the way of circuit designs, almost no one is working with this amazing tube. As soon as we finalize the Kit Headphone Amp, we'll publish a full schematic.
So glad digital finally caught up to tube amps. Just in time. I ditched tube amps 10 years ago, and I never looked back. Tube amps have gotten so expensive now, it's literally a luxury item for rich people. Like a Rolex watch. Or a Porsche. Total waste of money.
We have both a high quality digital system and our own custom tube gear, last night I was listening to both and the all analogue tube system blew away the digital side, using the same tube preamp and power amp. Now I agree with you quality vintage tubes are expensive, and yes solid state gear has improved substantially, but when comparing just the sonics of each, the tubes blow away digital solid state.
@@tubelab194 I don't hear that big of a difference. Especially with cleans and high gain. The lower gain "edge of breakup" stuff is where the difference is more noticeable for me. A tube amp can sound a little better, but at what cost. AxeFX-III with the new Cygnus-3 firmware is so close, it's not even worth it. But then again, the Fractal unit is just as expensive as a decent 100watt tube amp. Even if you get an FM9, you still need a power amp and a cab. Preferably a 4x12 cab. Speakers make a big difference with the tone. With all these plug-ins, IR's, and DAW's... people don't need to mic-up a big tube amp like they did back in the "old days". The Tone-X is really good, especially for the money. The debate over "tube vs digital/SS" will probably never end. For me, i'm just sick of what is going on with tube amps these days. Super expensive. Made in China or Mexico. They run hot. They are inconsistent. They will have problems. Tube shortage now, due to the "Russia situation".
That's a VERY foolish claim that in another 1000 years people will be listening to audio through tube gear. The format is barely over a 124 years old now. Technology will be so different , that we have no way to predict how music will be listened to.
Haha it was hyperbole! Just meant to reassure tube lovers that the world of tubes won't end any time soon! The World we live in is filled with stress, worry and concerns about the future and the last thing anyone needs to hear is that they'll be one of the last generations to hear great sounding music through vacuum tubes.
Thanks guys for another very good dive into vintage tubes
Whew!
I found two matched octet KT88 original Svetlana St. Petersburg tubes in my stash, less than ten hours on them, probably the last in the world. I had a buddy that bought a pair of VTL enormous monos that used EIGHT per side, he decided he wanted to use 6550's instead and sold them to me for next to nothing more than twenty years ago. I had totally forgotten about them until I came across them a year ago.
Ahhh found Treasure, look after them, they'll be one of the first power tubes to truly go extinct.
That 6550 you showed with the round holes and the 45 degree getters is also a REAL st Petersburg tube, that was constructed before the C version, it is the B version and some of thpse had issues with thermal runaway and then they purchased new grid alignment tools and moved to the rectangular holes. If you see a 6550 with the getters in an angle and the half moon holes in the mica you have the real deal as well and they will sound the same as the C, I am running a quad of those as we speak in my r8, and I even prefer their mid range sweetness over the 6550C
Thanks, I always thought the "B" version was labelled 6550B, you learn something new everyday! I remember picking up a post from a company that was trying to make use of what must have been a large surplus inventory of the B version, and they said not to worry, they rigorously tested the tubes and had thrown away the 80% that were defective!
We did some research (we have a lot of miscellaneous 6550 tubes both St.Petersburg and Saratov production) and it looks like that tube I showed was a first generation St,Petersburg 6550C (we have a number of them with 6550c labels). As far as I can see the 6550B's all had side getters and the tube in question doesn't. But all of this is mute, because no one has enough inventory to make up matches of these early types and no one wants to run the earlier problematic 6550B.
I have a quad of those, they are somewhat crooked in the base, but sound just excellent, have a mid range smoothness normally not associated with KT style tubes. I switch back and forth between xf2 and these and honestly even prefer the 6550 in rhe r8, The xf2 have more upper end detail and "emotion" perhaps, but the 6550 have some flair about them that really speaks to me. There are many variations, there is also one with a "pill getter" on the side and clear glass , and then there is the side getter version you mentioned. The way to identify st Petersburg tubes is not the holes in the plates, but rather the ufo getters in a 45 degree angle and the crecent moon mica's ... the 6550 I have are rock solid, I can even run them in my SE diy amp @120% plate dissipation without red plating, or any other issues , However I did not run them for more then a few hours like that. The cathode bias was set for kt90 at the time. There are sadly no current production KT tubes I enjoy listening to... maybe the super expensive KR , but that's over my budget , the Sophia Electric KT88 are also nice, but I wouldn't buy those if I could get Svetlana's in stead, I own xf2, rft, and those 6550, sold all the rest, I also run Adzam Brussels 6sn7gt from 1952 which meassure over 9ma, which is a first for the 6sn7s.i measured, I have 3 of them and they even go over 10ma on some triodes. Then I run ww2 vt229 Sylvania, after a extensive search I found non microphonic ones that sit snug in the glas balloon 🙂 you can tap them all day, and won't hear a single thing through the speakers, and then I have a set of your USA gold, "Roger's 6sn7, " and tall boy 6sl7, and the Russian VR, while they are not terrible , the tubes I have in the r8 now are from another world... ps like your channel
How important is it to use matched quads (or octets) for amps like Primaluna with active autobiasing? What are the potential cons of using non-matched tubes in a Primaluna Integrated amp?
Other than in guitar amps (in which you actively make distortion) you want the same manufacturer, same tube type, with matched plate current (mA) for your best sound. Think of the auto bias or fixed bias as a fine tuning or trimmer circuit. Now will a bunch of mismatched tubes work? Yes of course they will, however sound quality will suffer. The ultimate power amp has one gain/driver stage and one power tube or a pair of close matched power tubes running in parallel. That will be pure Class A and once you hear it, you'll never sacrifice sonics for power again.
Thanks for this excellent endangered species report! You mentioned a Svetlana 9 pin equivalent to the 6v6. What tube is that? Thanks again.
Svetlana 6P1P-EV, the Chinese made their own version, I think also called the 6P1P. The -EV is the Soviet designation for a rugged tube. In the West a comparable equivalent would be a true "mil spec" tube.
Got it. Similar to a 6AQ5 but 9 pin. Documentation is scarce. I found one data sheet partially translated from Russian, but it’s difficult to decipher anything more than the pin diagram. I’ll keep looking. Thanks for letting us know about this tube!
@@CountyLineMike a google search should turn up the full translated data sheet. However don't expect to find much in the way of circuit designs, almost no one is working with this amazing tube. As soon as we finalize the Kit Headphone Amp, we'll publish a full schematic.
@@tubelab194 Great! I’m looking forward to seeing the schematic.
So glad digital finally caught up to tube amps. Just in time. I ditched tube amps 10 years ago, and I never looked back.
Tube amps have gotten so expensive now, it's literally a luxury item for rich people. Like a Rolex watch. Or a Porsche.
Total waste of money.
We have both a high quality digital system and our own custom tube gear, last night I was listening to both and the all analogue tube system blew away the digital side, using the same tube preamp and power amp. Now I agree with you quality vintage tubes are expensive, and yes solid state gear has improved substantially, but when comparing just the sonics of each, the tubes blow away digital solid state.
@@tubelab194 I don't hear that big of a difference. Especially with cleans and high gain. The lower gain "edge of breakup" stuff is where the difference is more noticeable for me. A tube amp can sound a little better, but at what cost. AxeFX-III with the new Cygnus-3 firmware is so close, it's not even worth it. But then again, the Fractal unit is just as expensive as a decent 100watt tube amp. Even if you get an FM9, you still need a power amp and a cab. Preferably a 4x12 cab. Speakers make a big difference with the tone. With all these plug-ins, IR's, and DAW's... people don't need to mic-up a big tube amp like they did back in the "old days". The Tone-X is really good, especially for the money. The debate over "tube vs digital/SS" will probably never end. For me, i'm just sick of what is going on with tube amps these days. Super expensive. Made in China or Mexico. They run hot. They are inconsistent. They will have problems. Tube shortage now, due to the "Russia situation".
That's not true.
That's a VERY foolish claim that in another 1000 years people will be listening to audio through tube gear. The format is barely over a 124 years old now. Technology will be so different , that we have no way to predict how music will be listened to.
Haha it was hyperbole! Just meant to reassure tube lovers that the world of tubes won't end any time soon! The World we live in is filled with stress, worry and concerns about the future and the last thing anyone needs to hear is that they'll be one of the last generations to hear great sounding music through vacuum tubes.