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Tube Rolling: Does it Make a Difference?

Doodski

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Did you bring enough to share?
If you are OK with cans here's a crispy brew. :D
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SMJ

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If you can, try doing a measurement where the glass envelope is exposed to acoustic energy or mechanical shock. Poor mechanical integrity of the parts inside the bottle will show up in the measurements. As well as increasing the susceptibility to unstable feedback, the slightest knock will increase distortion too. A lot of high-end preamps and tape recorders in the valve era had the bottles mounted in rubber for both mechanical and acoustic isolation. Some wise old timers have said at least it keeps the glass in one place when you break the tube!

SMJ
 

SIY

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Billy Budapest

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Tks

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Personally even if I signed up for a tube product, I would not waste time "rolling tubes." You are likely to suffer more from "rolling placebo" by your brain than any variation in such tubes.

Heavy subjectivists be like: See there's SOME difference even by looking at the measurements, how could you ever assume there aren't people out there like me that hears these differences?

Also heavy subjectivists: Dude, you honestly believe you can hear a difference between a 100dB DAC and a 120dB DAC?
 

Nango

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Personally even if I signed up for a tube product, I would not waste time "rolling tubes." You are likely to suffer more from "rolling placebo" by your brain than any variation in such tubes.
Tubes audiophiles won't call it suffering, they enjoy the placebo. Kind of paradigm shift we usually don't fulfill.
 
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Hipster Doofus

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Buy the quick and numerous reply’s to this topic I am guessing there are many opinions…

Just a thought…
I know very little of why I roll tubes , but that is true of most of what I do in audio. All the numbers make my head spin to be honest, but I have had a noticeable difference with gold lion 12ax7s. This was in amps and preamps. My question is …do tubes make more difference in this world then the dac world…would anyone else be interested in Amirm doing a baseline on how tubes rolling does or does not work on amps and preamps…because it is so much fun to put some of these myths to rest.
 

AdamG

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New ASR Product Launch notification: Coming Soon…

ASR Panther Head Tubes…..Make your Amp purr…
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Aperiodic

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I recently reviewed the Mhdt Pagoda tube DAC. Owner was kind enough to send me three other tubes to test with it. Here are the set of tubes I received:

View attachment 168967


Channel 1 is the same but channel 2 has 6 dB lower distortion. Is half the tube better or is there some asymmetry in the design?

That's all I have for you. :)

Conclusions
It is clear that by far the source of distortion is the design and not choice of tube. In three cases the difference is negligible and inaudible. In the forth example, the WE 396A, there is reduction of distortion in one channel. In the larger picture, there is so much distortion here that reducing it with this tube is not going to make a difference one way or the other.

Notice the level of instrumentation it takes to see the impact of the tube. You need to measure to see if there is a difference and not just assume there is.

Personally even if I signed up for a tube product, I would not waste time "rolling tubes." You are likely to suffer more from "rolling placebo" by your brain than any variation in such tubes.

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Either a poor-quality tube to begin with or an old and tired sample (or both). One unknown variable here seems to be how much time the samples have on them which definitely affects performance although probably not by enough to rescue a broken design, If it's a twin type like a 'dual triode' it should be a close match (both channels should suck equally).

Another botched decision by the designers to use these oddball tubes instead of something readily available like the 12AX7 but they may have just been catering to the subset of tube fetishists hobbyists that believes that the more obscure / esoteric the tube is (directly heated triodes for example), the 'better' it must be.
 
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ta240

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I never understand why it's called "rolling tubes" as opposed to "changing tubes". It seems to imply some inherent skill involved in the process.

Because, everything has to have a cute name now.
 

ta240

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Either a poor-quality tube to begin with or an old and tired sample (or both). One unknown variable here seems to be how much time the samples have on them which definitely affects performance although probably not by enough to rescue a broken design, If it's a 'dual triode' it should match closely.

Another botched decision by the designers to use these oddball tubes instead of something readily available like the 12AX7 but they may have just been catering to the subset of tube fetishists hobbyists that believes that the more obscure / esoteric the tube is (directly heated triodes for example), the 'better' it must be.

If the tubes aren't bought from a really reputable vendor that verifies they are NOS or a seller like Jim McShane that thoroughly tests them, then their condition is questionable at best.
 

Aperiodic

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Buy the quick and numerous reply’s to this topic I am guessing there are many opinions…

Just a thought…
I know very little of why I roll tubes , but that is true of most of what I do in audio. All the numbers make my head spin to be honest, but I have had a noticeable difference with gold lion 12ax7s. This was in amps and preamps. My question is …do tubes make more difference in this world then the dac world…would anyone else be interested in Amirm doing a baseline on how tubes rolling does or does not work on amps and preamps…because it is so much fun to put some of these myths to rest.
Frank van Alstine, whose company makes SS, all-tube, and hybrid gear, has hypothesized that many of the differences people hear in tubes has to do with how hard the tube is being driven in the circuit (bias, operating voltages etc) and that some tubes behave differently at or close to their operating extremes, and that equipment in which tubes are operated more conservatively tend to show smaller differences between different tubes as a result. In a word, implementation. Where have we heard that before.

Hard to draw many conclusions about the tubes when their history (are they brand new or have 1500 hours on them etc) is unknown. Mr. van Alstine reports that one measurable side effect of careful implementation is longer tube life.
 

Larry B. Larabee

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I googled that Kootenay 120 amp. It's a top shelf tube amp from what I gathered. My pic shows it off better. :D
2352852-cd030b10-don-sachs-kootenay-120-this-may-be-the-best-amplifier-ive-ever-heard.jpg

I was wondering what everyone did with their useless turntables. Turns out the plinth makes a nice tube amp enclosure.
Even though I'm not a tube fan it's still tough not getting a boner whenever I see a KT88/6550 aglow.

L
 

phoenixdogfan

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People would be better experimenting with putting different electric guitar pedals into their system if they like all their music to sound like it's being played by Edge from U2
My Octo-Purifi system lacks a wah-wah pedal. :(
 

MakeMineVinyl

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As shown by a recent post where I outlined selecting two of the lowest distortion 12AX7 tubes out of a lot of a dozen, using the preamp where the tubes would be operating, there was a range of 0.3 to 0.9% THD. I would call this significant, and certainly audible in certain circumstances!

If a product was tested here and there was that wide of a range of distortion between channels, it would be declared 'broken', yet the conclusion for this test was that the differences were not that big a deal. The range of a couple tenths of a percent distortion absolutely is significant - maybe not at 2 volts, but possibly at lower levels and depending on the program material.

I know there is a baked-in bias against vacuum tubes in parts of this forum, but glossing over and dumbing down tests results because of these biases is not a good look. Better to simply not do these kinds of tests in the first place if they cannot be performed with the rigor afforded to more mainstream components.
 

pseudoid

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Wutz a 'tube'?
 
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