Hi,
Have 7 E88CC’s (with the gold clad pins) in my spare box. 2 are brand new and the other 5 are bought from a surplus store for almost nothing and have had various service life as can be seen from the various degrees of “blackening’ on the glass. All are from Philips and are looking optically the same. But measured Gm differs more than 30%. They also sound different. Although I must admit I have to listen carefully to hear a difference. Except one is sounding a bit dull and is probably near its life end. No doubt when I hook up a spectrum analyser the harmonic content will also differ slightly.
But what is it telling? Probably not much, only that those same looking tubes sound somewhat different and for sure will measure different. Oh what a surprise. When carefully measured (with a curve tracer) same tubes from different brands, no doubt you will find also different curves. Unfortunately I don’t have an automated curve tracer at hand to show you.
No magic, no religion, just engineering. Tubes are funny things.
Cheers
Have 7 E88CC’s (with the gold clad pins) in my spare box. 2 are brand new and the other 5 are bought from a surplus store for almost nothing and have had various service life as can be seen from the various degrees of “blackening’ on the glass. All are from Philips and are looking optically the same. But measured Gm differs more than 30%. They also sound different. Although I must admit I have to listen carefully to hear a difference. Except one is sounding a bit dull and is probably near its life end. No doubt when I hook up a spectrum analyser the harmonic content will also differ slightly.
But what is it telling? Probably not much, only that those same looking tubes sound somewhat different and for sure will measure different. Oh what a surprise. When carefully measured (with a curve tracer) same tubes from different brands, no doubt you will find also different curves. Unfortunately I don’t have an automated curve tracer at hand to show you.
No magic, no religion, just engineering. Tubes are funny things.
Cheers
Yes, my bad. The frequency spectrum of the harmonics is very important. And different curves will generate different harmonics. Does this happen for the same model tube? I guess the answer is, it depends on the specific type of tube and how critical the tolerances are to its operation.
Yes, I believe this and other effects like it.
A very fair criticism. I actually do have some listening experience and I am working on some hardware that hopefully will enhance that. But, I haven't done the kinds of A/B comparisons where others are hearing differences from swapping out components.
Is that true 'objectivists'? Is the only claim that these effects are too small to hear?
Audio nirvana would be great. I'm not really trying to get there, I'm just trying to understand what this is all about. So far, there have been some very good answers. I can say, however, that often very good theory precedes the experiments that verify the effect. So, things are not always predictable.
Although it really doesn't make sense to swap these particular tubes, does it? Since the operating points, Zo, etc. will differ?
Skip, skip, skip . . . good stuff actually. But I think the moderators will kick me off the list if we go too far afield, even if it worthy of discussion.
Hadn't though of that one. Surely someone has tried it.
Regarding contact potential, I am surprised that the contact potential variations are big enough to affect the tube's behavior. But, I guess it's true.
But, if they have different curves, then they are different resistors to the circuit and they may sound different. My original thought was that if the curves are identical, the tubes must sound the same.
.
I have a hard time with this too. How does it happen?
Thanks very much for everyone's replies. I have learned much
It was always there...
I have rolled tubes in old Quad II amps. I have rolled tubes in old Mac amps. Same stuff like modern tube amps. The differences are audible and huge between tube makes. Every brand a general aural signature. Every type a more specific one.
Well it seems that in the 50s and 60s very few people had put such things under the aural microscope. In those days valves were a commodity. Remember how enthusiastically they have adopted the transistor? Bloody hell, they were living for years with excellent tube gear and they got tricked by crude solid state amps of the time! Same with CD. Remember? In the start they said all players are sounding the same and that are inherently perfect...ha! ha! ha!
I just believe that audiophilia just now is getting digested as a culture that done its first cycle. We are wiser as a hobby society now. Most of all we can communicate through forums. Imagine if Peter Walker could air his views to the people like Nelson Pass does today....
And another thing..its amazing how such obvious things that we listen to are masked by our mental prejudice... In a psychoacoustic seminar I have been told that hearing is the most complex and elusive sense because 80% of it is processed by the brain.... Just imagine....What G.Bush would prefer for his audio gear and what...Noam Chomsky!
I have rolled tubes in old Quad II amps. I have rolled tubes in old Mac amps. Same stuff like modern tube amps. The differences are audible and huge between tube makes. Every brand a general aural signature. Every type a more specific one.
Well it seems that in the 50s and 60s very few people had put such things under the aural microscope. In those days valves were a commodity. Remember how enthusiastically they have adopted the transistor? Bloody hell, they were living for years with excellent tube gear and they got tricked by crude solid state amps of the time! Same with CD. Remember? In the start they said all players are sounding the same and that are inherently perfect...ha! ha! ha!
I just believe that audiophilia just now is getting digested as a culture that done its first cycle. We are wiser as a hobby society now. Most of all we can communicate through forums. Imagine if Peter Walker could air his views to the people like Nelson Pass does today....
And another thing..its amazing how such obvious things that we listen to are masked by our mental prejudice... In a psychoacoustic seminar I have been told that hearing is the most complex and elusive sense because 80% of it is processed by the brain.... Just imagine....What G.Bush would prefer for his audio gear and what...Noam Chomsky!
Hi,
That is quite true really.
To understand why tube rolling is so popular amongst die hard audiophiles you have to know tube history, economic history on a continent to continent basis.
Brand reputation is a major factor too and sometimes,with some particular tube types, not so well reputed brands can surprise you.
As an example:
In Europe it was not uncommon for instance that RFT East-Germany would manufacture some tube types for Telefunken ( diamond cast logo included).
Those EF86s weren't bad but the homemade TFKs were better still...
The ECC range from RFT is often a load of crap and it WILL show on the curve tracer too.
How many people don't think Tungsram is a Eastern-European brand and therefore think those tubes are inferior?
Well it isn't and alot of their tubes are absolutely great.
Let's not forget either that those tubes we're handmade and that some manufacturers concentrated precision on particular parameters that could be more relaxed with others and vice versa.
Having a variable bias will help to some extent, surely. In reality people don't have variable bias and go by their ears.
I never had good curves from a bad sounding tube but had often very good sound from a well tracing tube, so, to my mind there must be a correlation.
Certainly, materials used, cnstruction methods and measures against susceptability to microphony all add to good quality.
The worst and oddest sounds I ever heard were from the early Chinese tubes...phasey imagery with all the musical emphasis in the wrong places.
Absolutely weird, almost as if a recording engineer had the whole thing panned the wrong way around.
Did they measure like crap? Yes, sir!
So much so that you could just as well have invented new names for them; 12AX7S(hit) for example.
Enough ranting for the day/
Cheers,
That is quite true really.
To understand why tube rolling is so popular amongst die hard audiophiles you have to know tube history, economic history on a continent to continent basis.
Brand reputation is a major factor too and sometimes,with some particular tube types, not so well reputed brands can surprise you.
As an example:
In Europe it was not uncommon for instance that RFT East-Germany would manufacture some tube types for Telefunken ( diamond cast logo included).
Those EF86s weren't bad but the homemade TFKs were better still...
The ECC range from RFT is often a load of crap and it WILL show on the curve tracer too.
How many people don't think Tungsram is a Eastern-European brand and therefore think those tubes are inferior?
Well it isn't and alot of their tubes are absolutely great.
Let's not forget either that those tubes we're handmade and that some manufacturers concentrated precision on particular parameters that could be more relaxed with others and vice versa.
Having a variable bias will help to some extent, surely. In reality people don't have variable bias and go by their ears.
I never had good curves from a bad sounding tube but had often very good sound from a well tracing tube, so, to my mind there must be a correlation.
Certainly, materials used, cnstruction methods and measures against susceptability to microphony all add to good quality.
The worst and oddest sounds I ever heard were from the early Chinese tubes...phasey imagery with all the musical emphasis in the wrong places.
Absolutely weird, almost as if a recording engineer had the whole thing panned the wrong way around.
Did they measure like crap? Yes, sir!
So much so that you could just as well have invented new names for them; 12AX7S(hit) for example.
Enough ranting for the day/
Cheers,
> My original thought was that if the curves are identical, the tubes must sound the same.
If you mean: the curve plotted with exact (or at least semi-quantum) precision, that may be most of the sound.
Practical curve tracers are 1% accurate at best. Actually when you slap a tube to its limits, as often done in tracers, you run into hysteresis and other effects that cause the trace to be different going up than going down. Tracers are handy for quick checks, and to estimate max power and approx THD near that power.
The ear is sensitive to errors smaller than 1%, smaller than most tracers try to measure. We could propose a "close-up" tracer that would (say) sweep the grid from 1.000 to 1.010 volts and measure current-change with similar accuracy. This type of test would show kinked-grid and cathode hot-spot small nonlinearities, which may be what people are hearing. However I suspect it would be simpler to drop the tube in a basic amplifier and do tests (instrument and listening) than to fancy-up a curve tracer.
Vacuum Tube Valley magazine does a lot of "Tube Shoot-Outs", comparing different brands and years of the same tube. They often do both curve-trace tests and listening tests. The gross measurements do show differences between "same type" tubes, sometimes 10:1 difference between NOS TungSol and New-China in THD at reasonable levels. (I wish they would show the spectrum.) In the listening test, they do sometimes re-bias each tube (though it may be the same bias for all tubes, rather than an "optimum" bias for the specific tube in the socket).
And just to be a grump:
> they were living for years with excellent tube gear and they got tricked by crude solid state amps
No, we mostly had crappy tube stuff. Yes, there were the Quads and the Macs, and a few Eicos that didn't suck too bad (volume pots always scratched, and tin jacks never got good connection). Bogen made (probably by mistake) a pretty decent 150W tube PA amplifier; a trio of these earned me pizza-money for several years, because it did sound better (and take abuse more gracefully) than many of the transistor amps of the day.
But there was a lot of pretty-bad and some really awful tube gear. I had two low-power (2 watt) stereo amps, one a pair of 60FX5 and one with five transistors per channel. While the sand amp rasped a bit at soft level, it gave much flatter response and better speaker damping than the no-feedback pentode. (Remember: from 1935 to 1985 no commercial design and essentially no hobbyist designs used power triodes.) I had some very early and very inoffensive HH Scott transistor amps in service until recently.
Most tube gear sucked, more or less. The stuff that has survived isn't typical: we trash-binned a lot of it.
If you mean: the curve plotted with exact (or at least semi-quantum) precision, that may be most of the sound.
Practical curve tracers are 1% accurate at best. Actually when you slap a tube to its limits, as often done in tracers, you run into hysteresis and other effects that cause the trace to be different going up than going down. Tracers are handy for quick checks, and to estimate max power and approx THD near that power.
The ear is sensitive to errors smaller than 1%, smaller than most tracers try to measure. We could propose a "close-up" tracer that would (say) sweep the grid from 1.000 to 1.010 volts and measure current-change with similar accuracy. This type of test would show kinked-grid and cathode hot-spot small nonlinearities, which may be what people are hearing. However I suspect it would be simpler to drop the tube in a basic amplifier and do tests (instrument and listening) than to fancy-up a curve tracer.
Vacuum Tube Valley magazine does a lot of "Tube Shoot-Outs", comparing different brands and years of the same tube. They often do both curve-trace tests and listening tests. The gross measurements do show differences between "same type" tubes, sometimes 10:1 difference between NOS TungSol and New-China in THD at reasonable levels. (I wish they would show the spectrum.) In the listening test, they do sometimes re-bias each tube (though it may be the same bias for all tubes, rather than an "optimum" bias for the specific tube in the socket).
And just to be a grump:
> they were living for years with excellent tube gear and they got tricked by crude solid state amps
No, we mostly had crappy tube stuff. Yes, there were the Quads and the Macs, and a few Eicos that didn't suck too bad (volume pots always scratched, and tin jacks never got good connection). Bogen made (probably by mistake) a pretty decent 150W tube PA amplifier; a trio of these earned me pizza-money for several years, because it did sound better (and take abuse more gracefully) than many of the transistor amps of the day.
But there was a lot of pretty-bad and some really awful tube gear. I had two low-power (2 watt) stereo amps, one a pair of 60FX5 and one with five transistors per channel. While the sand amp rasped a bit at soft level, it gave much flatter response and better speaker damping than the no-feedback pentode. (Remember: from 1935 to 1985 no commercial design and essentially no hobbyist designs used power triodes.) I had some very early and very inoffensive HH Scott transistor amps in service until recently.
Most tube gear sucked, more or less. The stuff that has survived isn't typical: we trash-binned a lot of it.
runeight said:
It does to me. The circuit was designed for AU, but that doesn't have enough gain; AX has enough but too high a Zo distorts the frequency response and doesn't sound good. AT just happens to have a nice low Rp. By a happy coincidence, if I were to calculate good operating points for each of the tubes, the bias resistors would come out about the same, so bias is not an issue.
Guess I'll have to go unspool some of that stainless steel lockwire and run my speakers off it for a few days...
That reminds me, I was going to build an amp using resistive wire such as that some day. Too bad it tins like crap.
Tim
Well, let's see . . .
I don't think there is any question about this. Everyone should know that often what he/she hears is whatever he/she is willing to process.
Which is at least part of what I'm trying to pin down, that bad tubes are also measurably bad.
All makes sense to me. I truly do believe that tubes with the same label (and not re-labelled) have a wide variation and can sound different for all of these reasons.
I know you're right on this one.
Oh no, I believe this because you're talking about fairly long lengths where the properties of stainless will matter. It is hard for me to see, though, that this will matter much for very short lengths. For example, I don't recall what the connecting strips in tubes are made of, but whatever they are they have to be resistive because they are spot welded. Yet, I don't think we talk about the resistance of these wires as having an impact (at least in audio) because they probably don't.
Well, now I never thought we'd get here, but it is relevant. Actually, about 10e-39 seconds after the ignition of the big bang, the universe was approximately a sphere about the size of a nickel. Now, you can't think of this as a small ball of matter inside a very large empty space that got filled up. Everything we know as time and space was actually inside the ball. So, what was outside of it or before it? No matter what the answer is, tuberolling is a direct consequence of the big bang or whatever surrounded it and preceded it.
Furthermore, as I understand the current inflation theory (and I am definitely rusty) the universe sprang from absolutely nothing. Not only that, if you add up all of the matter in the universe and all of the gravity (which amounts more or less to negative matter) it all still adds up to . . . zero, nada, nothing.
So, folks, when you make posts to this forum and your juices get going about someone's stupid post, remember that you are basically . . . . . . nothing.
Thanks for being so generous with your time and comments.
I don't think there is any question about this. Everyone should know that often what he/she hears is whatever he/she is willing to process.
Which is at least part of what I'm trying to pin down, that bad tubes are also measurably bad.
All makes sense to me. I truly do believe that tubes with the same label (and not re-labelled) have a wide variation and can sound different for all of these reasons.
I know you're right on this one.
Oh no, I believe this because you're talking about fairly long lengths where the properties of stainless will matter. It is hard for me to see, though, that this will matter much for very short lengths. For example, I don't recall what the connecting strips in tubes are made of, but whatever they are they have to be resistive because they are spot welded. Yet, I don't think we talk about the resistance of these wires as having an impact (at least in audio) because they probably don't.
Well, now I never thought we'd get here, but it is relevant. Actually, about 10e-39 seconds after the ignition of the big bang, the universe was approximately a sphere about the size of a nickel. Now, you can't think of this as a small ball of matter inside a very large empty space that got filled up. Everything we know as time and space was actually inside the ball. So, what was outside of it or before it? No matter what the answer is, tuberolling is a direct consequence of the big bang or whatever surrounded it and preceded it.
Furthermore, as I understand the current inflation theory (and I am definitely rusty) the universe sprang from absolutely nothing. Not only that, if you add up all of the matter in the universe and all of the gravity (which amounts more or less to negative matter) it all still adds up to . . . zero, nada, nothing.
So, folks, when you make posts to this forum and your juices get going about someone's stupid post, remember that you are basically . . . . . . nothing.
Thanks for being so generous with your time and comments.
something about nothing!
Sorry, I couldn't resist! Its not that we are all nothing, the big kabosh produced equal amounts of somethings and anti-somethings. Thats why we are always having all these arguments. Only when one considers all points of view even handedly does one end up with truly nothing!
Maybe we should start concentrating our energies on how to make a time machine, then we can all go back and buy up those rare tubes we all want.
regards,
Don
Sorry, I couldn't resist! Its not that we are all nothing, the big kabosh produced equal amounts of somethings and anti-somethings. Thats why we are always having all these arguments. Only when one considers all points of view even handedly does one end up with truly nothing!
Maybe we should start concentrating our energies on how to make a time machine, then we can all go back and buy up those rare tubes we all want.
regards,
Don
So..
"Furthermore, as I understand the current inflation theory (and I am definitely rusty) the universe sprang from absolutely nothing. Not only that, if you add up all of the matter in the universe and all of the gravity (which amounts more or less to negative matter) it all still adds up to . . . zero, nada, nothing.
So, folks, when you make posts to this forum and your juices get going about someone's stupid post, remember that you are basically . . . . . . nothing.
Thanks for being so generous with your time and comments."
So who made matter and ant-imatter? By what laws, and all the universe is governed by laws of some sort, did "nothing" become something? Or did laws just come into being by themselves?
"Nothing" becoming matter and anti-matter is a little far fetched to me, and only a guess anyway. I believe Einstein definitely believed in a supreme being.
"Furthermore, as I understand the current inflation theory (and I am definitely rusty) the universe sprang from absolutely nothing. Not only that, if you add up all of the matter in the universe and all of the gravity (which amounts more or less to negative matter) it all still adds up to . . . zero, nada, nothing.
So, folks, when you make posts to this forum and your juices get going about someone's stupid post, remember that you are basically . . . . . . nothing.
Thanks for being so generous with your time and comments."
So who made matter and ant-imatter? By what laws, and all the universe is governed by laws of some sort, did "nothing" become something? Or did laws just come into being by themselves?
"Nothing" becoming matter and anti-matter is a little far fetched to me, and only a guess anyway. I believe Einstein definitely believed in a supreme being.
"Valves could then go missing - mid song - from peoples equipment"
We just take the old tubes back and swap them when were done with them, no one will notice. Thats why tubes are always burning out, Time Bandits, they know whats worth stealing!
"By what laws, and all the universe is governed by laws of some sort, did "nothing" become something? Or did laws just come into being by themselves?"
You have a point here, its truly Spooky how mathematics seems to work so well. Especially considering where present math/physics is leading. As far as the do unto others thing goes, I always liked the Chinese proverb about the man who wakes up and can't decide whether he has awoken from a dream or is currently dreaming. Ever wonder why everyone has to sleep regularly? What if we all just wake up as someone different every day, but with the monotonous memories of always being that person. Puts a new light on being sympathetic to others, you might be having an argument with yourself if you aren't careful about thread posting times on the net!
Guess we should apologize for threadjacking runeight's thread, but maybe he's still sleeping!
We just take the old tubes back and swap them when were done with them, no one will notice. Thats why tubes are always burning out, Time Bandits, they know whats worth stealing!
"By what laws, and all the universe is governed by laws of some sort, did "nothing" become something? Or did laws just come into being by themselves?"
You have a point here, its truly Spooky how mathematics seems to work so well. Especially considering where present math/physics is leading. As far as the do unto others thing goes, I always liked the Chinese proverb about the man who wakes up and can't decide whether he has awoken from a dream or is currently dreaming. Ever wonder why everyone has to sleep regularly? What if we all just wake up as someone different every day, but with the monotonous memories of always being that person. Puts a new light on being sympathetic to others, you might be having an argument with yourself if you aren't careful about thread posting times on the net!
Guess we should apologize for threadjacking runeight's thread, but maybe he's still sleeping!
I got a totaly diffrent picture from this post about tube rolling.
(or am i just paranoid)
Tuberolling:buying cheap valves ,removing printing and "rolling"
cheap valve over a screenprint making it a exspencive vale
eg (mullard)
cheap valve £2.00
Mullard NOS sold on Ebay £35-XXX depending on valve.
If i am wrong about this please forgive me, but I do know
it goes on so beware.
stormy
(or am i just paranoid)
Tuberolling:buying cheap valves ,removing printing and "rolling"
cheap valve over a screenprint making it a exspencive vale
eg (mullard)
cheap valve £2.00
Mullard NOS sold on Ebay £35-XXX depending on valve.
If i am wrong about this please forgive me, but I do know
it goes on so beware.
stormy
Of course tube rolling is 'real' and has significant effects on equipments' sound in many cases, just as different types of capacitors, resistors, transformers and variations in circuit topology affect sound.
I still recall when I built my phono preamp, merely dialing up the supply voltage from 325VDC to 375VDC made a perceptible improvement in the sound at the line level output. Same components and everything - just a slightly different bias and a minor change in harmonic distortion spectrum, I imagine.
You should use some Spice program like Beige Bag which is very easy to use.
You can see very easily how the distortion levels and the spectrum change with changes in the operating point . In spite of the speed of the computer it still takes time to try out all the combinations you want.
IMHO the spectrum that drops with increasing frequency probably sounds better than lower distortion with odd order harmonics coming up higher than even order harmonics. I think the sound will be harder if the higher order harmonics do not drop rapidly .
And with all simulations they are just indications of circuit performance, as the models are never perfect. So you will eventually have to build your final circuit to see if it really is the best.
Cheers.
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