The reason they haven't must be because it's umentionable
I saw some hint of needing to find the best operating point of the 12AU7. However, its non-linear behaviour wasn't clearly mentioned. When you consider that any job the 12AU7 can do can be done better by the 6FQ7 (or 12AT7, depending on the application), it's difficult to see why the 12AU7 still gets chosen by so many designers.
I saw some hint of needing to find the best operating point of the 12AU7. However, its non-linear behaviour wasn't clearly mentioned. When you consider that any job the 12AU7 can do can be done better by the 6FQ7 (or 12AT7, depending on the application), it's difficult to see why the 12AU7 still gets chosen by so many designers.
Kegger,
As SY said, the 12AU7 will make a lot more distortion than a 6SN7 under similar conditions. The "emotion" you hear in the 12AU7 may be the rich sound of second harmonics. If you like it, then enjoy it. However, the "unemotional" sound of the 6SN7 is probably more neutral and real, at least to my ears.
As SY said, the 12AU7 will make a lot more distortion than a 6SN7 under similar conditions. The "emotion" you hear in the 12AU7 may be the rich sound of second harmonics. If you like it, then enjoy it. However, the "unemotional" sound of the 6SN7 is probably more neutral and real, at least to my ears.
I have tried them all except........
the Mullard CV4003. Diffierent circuits respond differently to each tube. I never like RCA 5693 or RCA 12AU7 cleartop, but others like them. From your list, best in my amps best were in this order:
Raytheon 6CG7 USA blackplate (other brands were not good as next 3 tubes, Raytheon Japan are poor, 6FQ7 label tubes missing center shield- stay away)
Amperex PQ 6085 USA (Super in 12AU7 circuits, 2x fil current, beats all 6CG7s except the Raytheon USA)
Brimar 13D5 (drop-in replacement for 12AU7 but 6.3 volt only)
CBS/Hytron 12AU7 (chrome plate retainer clips + square getter)
CBS/Hytron 5814A (same internal details, equal to above)
RCA 12BH7 (grey plate- equal to above in some circuits)
Additional comments- My findings are in my DIY circuits, performance varies in different circuits. The least bit hazy sonics from a tube makes me move on to another tube. I do not like a warm tube as I believe warm can mean hazy. However, if warm means smooth & clear without edge or grain, that is great.
I never found a 12AT7 I liked in an audio circuit except a guitar reverb driver. Not mentioned, but best tube out of many others I tried in my DIY line-stage is TungSol 6P5GT. Great tube for preamp type service, but not for a driver or phase splitter due to the plate resistance is too high.
My 2 cents
the Mullard CV4003. Diffierent circuits respond differently to each tube. I never like RCA 5693 or RCA 12AU7 cleartop, but others like them. From your list, best in my amps best were in this order:
Raytheon 6CG7 USA blackplate (other brands were not good as next 3 tubes, Raytheon Japan are poor, 6FQ7 label tubes missing center shield- stay away)
Amperex PQ 6085 USA (Super in 12AU7 circuits, 2x fil current, beats all 6CG7s except the Raytheon USA)
Brimar 13D5 (drop-in replacement for 12AU7 but 6.3 volt only)
CBS/Hytron 12AU7 (chrome plate retainer clips + square getter)
CBS/Hytron 5814A (same internal details, equal to above)
RCA 12BH7 (grey plate- equal to above in some circuits)
Additional comments- My findings are in my DIY circuits, performance varies in different circuits. The least bit hazy sonics from a tube makes me move on to another tube. I do not like a warm tube as I believe warm can mean hazy. However, if warm means smooth & clear without edge or grain, that is great.
I never found a 12AT7 I liked in an audio circuit except a guitar reverb driver. Not mentioned, but best tube out of many others I tried in my DIY line-stage is TungSol 6P5GT. Great tube for preamp type service, but not for a driver or phase splitter due to the plate resistance is too high.
My 2 cents
As I said guy's I didn't say I do not like the 6SN7 or the 6CG7, in fact I use them in an amp and pre.
But I also don't need nor want a system that is totally neutrel and "PERFECT", I find it sterile and lifeless.
I want a little color/charactor in my system, not to much but a little goes a long way with me. Personal taste.
I find the 12BH7 is usually the better tube for me in these regards, fairly clean but a little tube flair to boot.
But I also don't need nor want a system that is totally neutrel and "PERFECT", I find it sterile and lifeless.
I want a little color/charactor in my system, not to much but a little goes a long way with me. Personal taste.
I find the 12BH7 is usually the better tube for me in these regards, fairly clean but a little tube flair to boot.
I wonder about the 12AX7. My first impressions of this were that it is a little hazy. I understand that this could have to do with the particular implementation I was using. It's my second impression (when I tried it again much later) that appeals.
It have found in the past, that some days a 6SN7 based amp can sound a little boring. Too many variables here for me to be sure of how and why. I feel that based on this thread, you understand where I'm coming from.
I have found that using the 12AX7 I'm talking about has restored some of what I've felt was lacking. I have seen it as a temporary measure and don't use it normally. Sometimes I wish I had a 12AX7 line stage on standby for those days I just don't know what to do.
Guessing, I feel that this is why I prefer single ended circuitry. I am not suggesting I like an excess of 2nd order HD, I just like to have it present in its natural quantities (I hope that came out right). I have developed the feeling that, if I have an amp that is producing some odd order HD around the output stage for example, changing the early stages to be ultra clean doesn't always sound like an improvement.
Push-pull amps tend to cancel even order harmonics, however, too many people are satisfied with push-pull amps for them to be the problem. So, a logical assumption I might suggest is that we could search our amps for traces of odd/high order HD first, then if we eliminate these and are still dissatisfied, it may then be that we do like an excess of even order HD.
Just to add, it's not inconcievable that sources and speakers can contribute to the sound which we may ultimately attempt to fix by way of our amp. Using a good 6SN7 based amp can be like 'peeling back the layers', and if the core is bad, it will be revealed. I also found this when I started using ScanSpeak 9500 tweeters. If I didn't tweak the crossover carefully, or use quality components, it wouldn't sound good. These tweeters can sound very good. Also, do you listen to tape and vinyl?
Anyway, <off soapbox>
"Present in natural quantities" would imply that the amp and the rest of the recording/playback chain should have added ZERO additional (or subtractional) 2nd harmonic to what was originally in the sound picked up by the microphone. I suspect that what you meant was that if some distortion must be present, it may as well be a bit of the second since there is almost always some 2nd harmonic structure already present in the sound of natural (and unnatural) instruments. And I'd agree.
I've tried some different combinations in my Aikido. Each tube change required changing the cathode resistors to adjust the bias current. Since the Aikido uses active loads (top valve of V1 and bottom valve of V2), there's no plate resistors to change.
Most of these valves in this discussion thread have similar gain, although totally different plate currents, drive characteristics, and plate impedance. The beauty of the Aikido is the drive stage (V1) drives an easy load (V2) and can be adjusted with two resistors (at the cathodes of the V1 valves). This itself may be a "tainted" test, because you're making sonic judgments about V1 using a ridiculously easy load. You can't use your observations to compare with, say, what the tube will sound like when driving a KT88.
What I'm trying to say is the tube can only be evaluated for the intended application. It's no good for me to say "The 6FQ7 blew away the 12BH7 in my Aikido", and for you to assume it'll also blow away a 12BH7 for driving an interstage transformer (and also which interstage transformer, and how it's loaded!).
For 12V heaters, you can compare 12AU7, 12FQ7, or 12BH7 and get the same overall system transfer characteristics, although you'll need to install carefully calculated cathode resistors between each listening session for each tube's optimized performance (DC operating point, output voltage swing, etc). If you're willing to operate slightly non-optimized bias currents, there may be a single "compromise" cathode resistor value that will "work" for all three. But non-optimized bias currents in order to make the test easier will taint the results, IMHO.
Old thread, same problems, different prices. If you can't directly drop in a tube into a circuit you can't really compare it. By the time you got through doing the changes your audio memory is going to have colored the results so they are no longer of any real use.
If you can run the after components into a disc burner/tape recorder or something like that you will get the coloration of the recording and playback but at least it will be a constant in the process and you should be able to say that in this system with the only difference being the resistors in getting the cathode biased (use a stepped attenuator with good resistors or a top notch pot man!) and the results using the same recording and the same source, wires, etc is that this one made my nipples hard, so the emotional content of the music got through, and on the other ones not even the hair stood up on my arms.
Choose music that has an emotional content to it (all does or should but pick one where it really stands out for you. The recording comes through your system and the singer or the piano or something really stands out for you and it does it so well that you get a physical reaction caused by emotions. It is what we are seeking, isn't it? The soundstage opens up and becomes a place, the players are there and you haven't been smoking anything. Yes, we had a way to make crappy recordings turn into emotional masterpieces in the 70s with a big Pioneer SS receiver and Bose 901s, zip cord and a Dual TT. Clean the bong water man!
So what are we chasing? It isn't perfect distortion free sound that lacks the emotion of the musician, no matter what the recording tech did to it on what ever they write it on out there, so we go trudging mile after mile to St Alphonso's Pancake Breakfast where she abused the sausage patty and said "Why don't you treat me mean?"
At St Alphonsos Pancake Breakfast
Where I stole the margarine.
Now if you saw that concert you are seeking to re create the thing in your living room. What were you doing the 1st time you heard Dark Side Of The Moon, did the soundtrack of Clockwork Orange turn you on to Beethoven and Rossini? The Moog get you ready for Emerson Lake and Palmer? Yes? No? Probably if you are old enough and saw that but were ignorant of the 9th before.
Oh yea, this is about tubes and how if you bring flowers and candy you don't get a sterile soundscape that can easily be achieved with lots of money, some really big Krell and a pair of B&W Nautilus, where you can hear it all but miss what is happening.
What wine did Steve Martin have in the bubblers next to the tennis court in the Jerk? It is called nuance. Are you getting enough?
When I went to see The Girl With The Pearl Earring I cried at the end because when I saw for the first time that the painting was also in the pearl it added something I never knew was there after all these years since studying the masters in school, THAT was never shown, and it made it perfect, so I cried.
Emotionality is what we seek with the music and if it doesn't touch your soul, no matter how perfect it is then move on and find what does.
Music that hits that sweet spot, where I open up to the emotional content, because that day in the studio they got the pearl painted and the system is working perferfect, the humidity is perfect for the paper in the cones, for what ever and Ella Fitzgerald recorded by Verve sings a love song written by Jerome Kern and the whole crowd is there, they are painting the Pearl in a way that Steely Dan never could because the artists never worked together, you guys know where I am going with this. Somewhere, sometime that whole thing was together in a way that had it moving like a perfectly tuned for that track racecar. There are so many things to keep that from happening in your living room. Compression so tight that when they let it loose it got the bends and never recovered, like that Aerosmith blues album 10 or so years back. Somebody screwed that thing up so that it was fit for fart cars only, to blow out the eardrums of kids who couldn't walk or weren't even a sperm when Arosmith was playing The Barn in New Hampshire. Why was that album composed of great tunes, some from as far back as 78RPM on wind up clockwork players that used horns as the only amplifier, given the bends?
Off Topic, but not really. We search for the emotional quality of a live performance where you are inside the cone of the PA system DJ monster who is trying to turn the music hall into a fart car and take the emotion out of it.
Have any of you gotten a real emotional moment with a sand amp turned way up, gotten an endorphin high from the music and not been influenced by chemicals? A few times, I bet yea. I have, but here I sit an old fart, looking for the subtle, wanting the hair to stand up on my arms, the back of my neck, for my nipples to get hard because I got something out of the music besides coordinated sound.
Which tube does it? Well, I think different tubes for different music. Typically it is middle gain so I can push it without blowing my ears out of my butt. I find that very unpleasant. I don't like bright so no RCA clear top 12AU7s unless I get a BB gun too.
Does it happen all the time. No. That is good because then it would become normal, like the Beatles not releasing music that had anything below 80 Hz so it would always sound like a single speaker car radio. That was a great idea.
Rolling tubes is fun, so if you want to listen to 6CG7s make sure that is what they are and there is nothing about a Q in there. They are not the same tubes There is a very important piece in a 6CG7 that is not in a 6FQ7. It is a plate that separates the sides stopping crosstalk and is a tube made for Audio with a capitol A. Not many of them around.
Never buy one that has 6FQ7 on it. It is a 6FQ7 completely, there is no 6CG7 about it, because without the separation plate it has gone from special to extremely ordinary.
Do a bit of research and you can find the octal half of a 6SN7 and use 2, or if you are using half as a cathode follower use something cheaper that has a good cathode.
1st cup of coffee in a week. Should I go for cup number 2? Maybe some Ribose and Royal Jelly. Tyrosine? Yes, I think so, then some Zappa Valley Girls, Oh I am sure!
Thatch
If you can run the after components into a disc burner/tape recorder or something like that you will get the coloration of the recording and playback but at least it will be a constant in the process and you should be able to say that in this system with the only difference being the resistors in getting the cathode biased (use a stepped attenuator with good resistors or a top notch pot man!) and the results using the same recording and the same source, wires, etc is that this one made my nipples hard, so the emotional content of the music got through, and on the other ones not even the hair stood up on my arms.
Choose music that has an emotional content to it (all does or should but pick one where it really stands out for you. The recording comes through your system and the singer or the piano or something really stands out for you and it does it so well that you get a physical reaction caused by emotions. It is what we are seeking, isn't it? The soundstage opens up and becomes a place, the players are there and you haven't been smoking anything. Yes, we had a way to make crappy recordings turn into emotional masterpieces in the 70s with a big Pioneer SS receiver and Bose 901s, zip cord and a Dual TT. Clean the bong water man!
So what are we chasing? It isn't perfect distortion free sound that lacks the emotion of the musician, no matter what the recording tech did to it on what ever they write it on out there, so we go trudging mile after mile to St Alphonso's Pancake Breakfast where she abused the sausage patty and said "Why don't you treat me mean?"
At St Alphonsos Pancake Breakfast
Where I stole the margarine.
Now if you saw that concert you are seeking to re create the thing in your living room. What were you doing the 1st time you heard Dark Side Of The Moon, did the soundtrack of Clockwork Orange turn you on to Beethoven and Rossini? The Moog get you ready for Emerson Lake and Palmer? Yes? No? Probably if you are old enough and saw that but were ignorant of the 9th before.
Oh yea, this is about tubes and how if you bring flowers and candy you don't get a sterile soundscape that can easily be achieved with lots of money, some really big Krell and a pair of B&W Nautilus, where you can hear it all but miss what is happening.
What wine did Steve Martin have in the bubblers next to the tennis court in the Jerk? It is called nuance. Are you getting enough?
When I went to see The Girl With The Pearl Earring I cried at the end because when I saw for the first time that the painting was also in the pearl it added something I never knew was there after all these years since studying the masters in school, THAT was never shown, and it made it perfect, so I cried.
Emotionality is what we seek with the music and if it doesn't touch your soul, no matter how perfect it is then move on and find what does.
Music that hits that sweet spot, where I open up to the emotional content, because that day in the studio they got the pearl painted and the system is working perferfect, the humidity is perfect for the paper in the cones, for what ever and Ella Fitzgerald recorded by Verve sings a love song written by Jerome Kern and the whole crowd is there, they are painting the Pearl in a way that Steely Dan never could because the artists never worked together, you guys know where I am going with this. Somewhere, sometime that whole thing was together in a way that had it moving like a perfectly tuned for that track racecar. There are so many things to keep that from happening in your living room. Compression so tight that when they let it loose it got the bends and never recovered, like that Aerosmith blues album 10 or so years back. Somebody screwed that thing up so that it was fit for fart cars only, to blow out the eardrums of kids who couldn't walk or weren't even a sperm when Arosmith was playing The Barn in New Hampshire. Why was that album composed of great tunes, some from as far back as 78RPM on wind up clockwork players that used horns as the only amplifier, given the bends?
Off Topic, but not really. We search for the emotional quality of a live performance where you are inside the cone of the PA system DJ monster who is trying to turn the music hall into a fart car and take the emotion out of it.
Have any of you gotten a real emotional moment with a sand amp turned way up, gotten an endorphin high from the music and not been influenced by chemicals? A few times, I bet yea. I have, but here I sit an old fart, looking for the subtle, wanting the hair to stand up on my arms, the back of my neck, for my nipples to get hard because I got something out of the music besides coordinated sound.
Which tube does it? Well, I think different tubes for different music. Typically it is middle gain so I can push it without blowing my ears out of my butt. I find that very unpleasant. I don't like bright so no RCA clear top 12AU7s unless I get a BB gun too.
Does it happen all the time. No. That is good because then it would become normal, like the Beatles not releasing music that had anything below 80 Hz so it would always sound like a single speaker car radio. That was a great idea.
Rolling tubes is fun, so if you want to listen to 6CG7s make sure that is what they are and there is nothing about a Q in there. They are not the same tubes There is a very important piece in a 6CG7 that is not in a 6FQ7. It is a plate that separates the sides stopping crosstalk and is a tube made for Audio with a capitol A. Not many of them around.
Never buy one that has 6FQ7 on it. It is a 6FQ7 completely, there is no 6CG7 about it, because without the separation plate it has gone from special to extremely ordinary.
Do a bit of research and you can find the octal half of a 6SN7 and use 2, or if you are using half as a cathode follower use something cheaper that has a good cathode.
1st cup of coffee in a week. Should I go for cup number 2? Maybe some Ribose and Royal Jelly. Tyrosine? Yes, I think so, then some Zappa Valley Girls, Oh I am sure!
Thatch
Hi,
You must be into some sport or other?
It's a crying shame so few of all those so called "equivalent" references weren't measured for distortion properly.
Lots of so called "equivalents" in datasheets are not equivalent at all.
Tube rolling might have been fun so many years ago, nowadays I find it rather depressing.....
Ciao,
You must be into some sport or other?
It's a crying shame so few of all those so called "equivalent" references weren't measured for distortion properly.
Lots of so called "equivalents" in datasheets are not equivalent at all.
Tube rolling might have been fun so many years ago, nowadays I find it rather depressing.....
Ciao,
I guess I'm still learning but I always thought the makings of a good audio system was the ability to amplify the signal without adding something to it that isn't there. You talk about the lifeless of a 6SN7 for example. I'm confused... so a tube is supposed to alter and inject something into the mix that just isn't there? I had always thought that a recording of a performace should sound just like the performace did. Boy was I wrong
So, my Aikido (6sn7/6sn7) and my Frank's 6sn7/5692 line stages are incorrect because they are more true to life sounding? My Quicksilvers with 12BH7 should have the 12BH7's pulled in favor of the 12Au7?
Oh, I almost forgot about the 6fq7/6cg7. The 6cg7 is better because its got a magical screen in it but yet when I have tried a one lb coffee can of assorted tube I can tell no difference in my 6FQ7/5687 Aikido. Still confused
Granted what I have is minimal compared to some of the systems and equipment that some here own but for accuracy against the real thing I'll go with what I have.
So, my Aikido (6sn7/6sn7) and my Frank's 6sn7/5692 line stages are incorrect because they are more true to life sounding? My Quicksilvers with 12BH7 should have the 12BH7's pulled in favor of the 12Au7?
Oh, I almost forgot about the 6fq7/6cg7. The 6cg7 is better because its got a magical screen in it but yet when I have tried a one lb coffee can of assorted tube I can tell no difference in my 6FQ7/5687 Aikido. Still confused
Granted what I have is minimal compared to some of the systems and equipment that some here own but for accuracy against the real thing I'll go with what I have.