Tube Rolling: Does it Make a Difference?

[Angsty]

The decapitated panther head - I love it!

 

[Xyrium]

The name comes from the circular rolling motion used to slide the tube's connection pins out from their sockets in the amp.

Indeed, though it's more like twisting. It never even requires a 1/4 rotation to replace one.

I'll admit replacing preamp tubes in guitar amp heads for those that would break up sooner to get a grittier tone. I never actually heard a difference, but whether it was psychoacoustic or not, it "felt" different while playing.

 

[deprogrammed]

Rolling something else makes a big improvement....

 

[MattHooper]

Wow, excellent thread and very timely for me.

Though I've owned tube amps for many years I never tried "tube rolling" except to simply replace a tired (distorting) tube with whatever the manufacturer suggested.

But when I had to replace a whole lot of tubes not too long ago I decided what the heck and tried some different tubes for my Conrad Johnson Premier 12 monoblocks, including replacing the 6550 output tubes with KT120s, and a variety of small driver tubes.

Subjectively...holy cow, I was shocked by what seemed to be obvious differences. The regular 6550 power tubes in the amps seemed to produce really tight, punchy, up front sound that I'm used to, but the KT120s seemed to be more relaxed, everything sounded bigger, from images to soundstage to a deepening of bass (perceptually). And with the driver tubes, going between my normal GE tubes and some different RCA/NOS tubes, the RCA tubes seem to produce a lush, relaxed spacious rolled off sound and the GE tubes seem to produce an obviously brighter, tighter, more neutral sound.

Now, as always, this could be imagination, but wowza is it ever a strong impression!

I was even thinking of recording the output (mic at seating position) of the different tubes and using this to blind test:

Audio Blindtest

nyxl.de

(Just to add: much of my recent experience trying different tubes started with receiving a new pair of Premier 12 amps. I was able to grab a newer pair, more recently serviced, in better condition than mine, at a price that would allow me to sell mine without losing any money. But the new 12s came with KT120 power tubes installed, about which I knew nothing in terms of sonic expectations, and when I compared my old amps which had the regular 6550 tubes to the new ones with the KT120s it sounded to me like my speakers had suddenly grown in size and I was wondering "what the hell is going on here?"

Wasn't expecting that at all. So I started swapping tubes to try to trace down what seemed to be causing the main difference and when I put the KT120 tubes in to my original CJs, then a similar change in sound seemed to occur, now soudning like the new amps. Hence I became intrigued by the tube rolling thing. Again, not pushing any of this as actual evidence of course).

 

[ThoFi]

A very interesting topic!
I read all posts to get some more information. After more than 120 posts unfortunately I didn’t found any further more technical, scientific (measurements) information….
To me it would be very interesting to see FR measurements of the system.

 

[Spkrdctr]

Wow, excellent thread and very timely for me.

Though I've owned tube amps for many years I never tried "tube rolling" except to simply replace a tired (distorting) tube with whatever the manufacturer suggested.

But when I had to replace a whole lot of tubes not too long ago I decided what the heck and tried some different tubes for my Conrad Johnson Premier 12 monoblocks, including replacing the 6550 output tubes with KT120s, and a variety of small driver tubes.

Subjectively...holy cow, I was shocked by what seemed to be obvious differences. The regular 6550 power tubes in the amps seemed to produce really tight, punchy, up front sound that I'm used to, but the KT120s seemed to be more relaxed, everything sounded bigger, from images to soundstage to a deepening of bass (perceptually). And with the driver tubes, going between my normal GE tubes and some different RCA/NOS tubes, the RCA tubes seem to produce a lush, relaxed spacious rolled off sound and the GE tubes seem to produce an obviously brighter, tighter, more neutral sound.

Now, as always, this could be imagination, but wowza is it ever a strong impression!

I was even thinking of recording the output (mic at seating position) of the different tubes and using this to blind test:

Audio Blindtest

nyxl.de

(Just to add: much of my recent experience trying different tubes started with receiving a new pair of Premier 12 amps. I was able to grab a newer pair, more recently serviced, in better condition than mine, at a price that would allow me to sell mine without losing any money. But the new 12s came with KT120 power tubes installed, about which I knew nothing in terms of sonic expectations, and when I compared my old amps which had the regular 6550 tubes to the new ones with the KT120s it sounded to me like my speakers had suddenly grown in size and I was wondering "what the hell is going on here?"

Wasn't expecting that at all. So I started swapping tubes to try to trace down what seemed to be causing the main difference and when I put the KT120 tubes in to my original CJs, then a similar change in sound seemed to occur, now soudning like the new amps. Hence I became intrigued by the tube rolling thing. Again, not pushing any of this as actual evidence of course).

Matt, you have just had a real first hand experience with your ear/brain fooling you into thinking it had a huge change in performance. You would swear on a stack of Bibles that the change was real, very large and anyone could hear it. But, when tested, it would not be noticeable. That is how over powering and amazing the effect is. This is why subjectivists have fits about measurements. To them and your own experience it is real. Your brain is saying this is real and huge. That is why it is so tricky. Even Amir is NOT immune to the effect. It affects everyone. There is no way to out think it.

It is amazing isn't it? When you really get to wrap your head around the idea, it is an eye opener to discount so much of the audio worlds marketing mumbo jumbo crap. Until it happens to you it is hard to believe. Heck, I was tuning in an EQ for my sub awhile back and made a bunch of big changes to really dial it in perfectly. Then when I had "arrived" and was all set to call it a day, I checked the sub and found out it WAS TURNED OFF. I had turned it off a few hours before and forgot to turn it on again. That was yet another slap in my face at how strong the brain is in fooling us. It really is amazing when you think about it. Thanks for a great post!

 

[MattHooper]

Matt, you have just had a real first hand experience with your ear/brain fooling you into thinking it had a huge change in performance. You would swear on a stack of Bibles that the change was real, very large and anyone could hear it. But, when tested, it would not be noticeable. That is how over powering and amazing the effect is. This is why subjectivists have fits about measurements. To them and your own experience it is real. Your brain is saying this is real and huge. That is why it is so tricky. Even Amir is NOT immune to the effect. It affects everyone. There is no way to out think it.

It is amazing isn't it? When you really get to wrap your head around the idea, it is an eye opener to discount so much of the audio worlds marketing mumbo jumbo crap. Until it happens to you it is hard to believe. Heck, I was tuning in an EQ for my sub awhile back and made a bunch of big changes to really dial it in perfectly. Then when I had "arrived" and was all set to call it a day, I checked the sub and found out it WAS TURNED OFF. I had turned it off a few hours before and forgot to turn it on again. That was yet another slap in my face at how strong the brain is in fooling us. It really is amazing when you think about it. Thanks for a great post!

Actually it's not my first experience. I've done blind tests off and on since the 90's and I'm quite familiar with how my mind can fool me
Sometimes in the blind tests I could reliably identify what I thought I heard in the sighted tests, sometimes not. So for me my imagining a difference - because anyone can imagine a difference! - is ALWAYS a live option. In fact if I have a reputation in the "other" audio forums its for continually pushing the relevance of blind testing. (I'm an evil objectivist on Audiogon forums, Steve Hoffman and others. I even set up a blind test of video cables over on the AVSForum)

One thing though: You seem to have leapt to the conclusion that there were in fact no sonic differences occuring between the tubes in my amps. I think the skepticism is warranted, but that fact isn't yet demonstrated. (It also seems a bit of a leap to me to go from Amir's test here to "therefore tube rolling never makes a difference." That would be a pretty incautious leap of inference without a lot more justification it seems to me).

Anyway, hopefully I can test this, so I'll see.

 

[ThoFi]

Actually it's not my first experience. I've done blind tests off and on since the 90's and I'm quite familiar with how my mind can fool me
Sometimes in the blind tests I could reliably identify what I thought I heard in the sighted tests, sometimes not. So for me my imagining a difference - because anyone can imagine a difference! - is ALWAYS a live option. In fact if I have a reputation in the "other" audio forums its for continually pushing the relevance of blind testing. (I'm an evil objectivist on Audiogon forums, Steve Hoffman and others. I even set up a blind test of video cables over on the AVSForum)

One thing though: You seem to have leapt to the conclusion that there were in fact no sonic differences occuring between the tubes in my amps. I think the skepticism is warranted, but that fact isn't yet demonstrated. (It also seems a bit of a leap to me to go from Amir's test here to "therefore tube rolling never makes a difference." That would be a pretty incautious leap of inference without a lot more justification it seems to me).

Anyway, hopefully I can test this, so I'll see.

You are calling yourself a objectivist and do blind tests.
Why don’t you do measurements?
Maybe you did and can share them.
cheers

 

[watchnerd]

You are calling yourself a objectivist and do blind tests.
Why don’t you do measurements?
Maybe you did and can share them.
cheers

Double blind ABX tests are a valid objectivist methodology.

 

[audio2design]

That depends. I've seen a LOT of incompetent high distortion cathode follower circuits. Two common mistakes: assuming low output impedance means low loads are driveable (so yeah, let's use a 12AX7!), and biasing (with the grid at 0V, just take the signal off the 1k cathode resistor!).

Take a look at the photos in the DAC review. Do you see any clearance anywhere for the plate voltage? Let's hope those output caps never develop a short. Looks like the ground on the AC is just floating anyway.

Then again, maybe the plate voltage is really low so that it is not totally unsafe, and hence there is almost no linear region.

I lean towards both things being true. Dangerous and a bad design.

 

[ThoFi]

Double blind ABX tests are a valid objectivist methodology.

but not very accurate. Matthooper said that he sometimes hear a difference and sometimes not.
so why not measure?

 

[watchnerd]

but not very accurate. Matthooper said that he sometimes hear a difference and sometimes not.
so why not measure?

As a methodology ABX testing can be perfectly valid with enough sample sizes to provide statistical signficance.

From a statistics POV, I don't know what "sometimes" means when @MattHooper says that.

But if you can pass an ABX test 70 out of 100 times (i.e. "sometimes"), that's a high degree of confidence.

Since we're debating if tube rolling is "audible", a double blind listening test is entirely appropriate and objectivist.

After all, we already know tubes can measure differently -- if they didn't, we wouldn't need to test and grade them.

 

[daniboun]

Hi Amir,

Many thanks for the review.
I am going to send you a private message check it out please.

 

[LTig]

Actually it's not my first experience. I've done blind tests off and on since the 90's and I'm quite familiar with how my mind can fool me
Sometimes in the blind tests I could reliably identify what I thought I heard in the sighted tests, sometimes not. So for me my imagining a difference - because anyone can imagine a difference! - is ALWAYS a live option. In fact if I have a reputation in the "other" audio forums its for continually pushing the relevance of blind testing. (I'm an evil objectivist on Audiogon forums, Steve Hoffman and others. I even set up a blind test of video cables over on the AVSForum)

One thing though: You seem to have leapt to the conclusion that there were in fact no sonic differences occuring between the tubes in my amps. I think the skepticism is warranted, but that fact isn't yet demonstrated. (It also seems a bit of a leap to me to go from Amir's test here to "therefore tube rolling never makes a difference." That would be a pretty incautious leap of inference without a lot more justification it seems to me).

Anyway, hopefully I can test this, so I'll see.

Why not invest in a RME ADI-2 PRO fs? It's probably the next best analyzer short of an AP. And you can use it as SOTA DAC, headphone amp and preamp including EQ.

 

[watchnerd]

Why not invest in a RME ADI-2 PRO fs? It's probably the next best analyzer short of an AP. And you can use it as SOTA DAC, headphone amp and preamp including EQ.

I have an RME ADI-2 Pro (pre-FS) but I'm not understanding how you are suggesting using it as an analyzer for tubes.

The RTA display isn't very granular.

 

[LTig]

I have an RME ADI-2 Pro (pre-FS) but I'm not understanding how you are suggesting using it as an analyzer for tubes.

You can measure all line level signals. For higher voltages you need an attenuator.

The RTA display isn't very granular.

REW is your friend. See an example here ( scroll down to Dashboard).

 

[watchnerd]

You can measure all line level signals. For higher voltages you need an attenuator.

REW is your friend. See an example here ( scroll down to Dashboard).

But you don't need the RME to use REW.

Any decent ADC will do.

 

[amirm]

For folks asking about op-amp rolling, I have done that twice:

Rolling Op-amps in Gustard H20 Headphone Amplifier

I reviewed the Gustard H20 which is a high-end headphone amplifier yesterday. Its owner kindly sent me some high-end op-amps to "roll" in there to see what difference it makes. The task was pretty easy. The top screws come out of the H20 and if you tilt the unit, the lid falls out exposing...

www.audiosciencereview.com

Rolling (replacing) Op-amps in Topping D10 DAC

This is a study of whether changing op-amps in a DAC makes a measurable difference. Taking a lead form "rolling" tubes in tube products, a trend has started in replacing op-amps -- sometimes with much difficulty -- to improve performance of solid state products like DACs. A few months ago I...

www.audiosciencereview.com

 

[LTig]

But you don't need the RME to use REW.

Any decent ADC will do.

In the price range of the RME I had not found a better ADC. I've read somewhere that RME did design it for measurements, to be used in their own production lines. The manual has a short section how to use it for measurements.

If you intend to measure only devices with high distortion (like in this thread) I agree; you could use almost any ADC.

 

[watchnerd]

In the price range of the RME I had not found a better ADC. I've read somewhere that RME did design it for measurements, to be used in their own production lines. The manual has a short section how to use it for measurements.

If you intend to measure only devices with high distortion (like in this thread) I agree; you could use almost any ADC.

Over Christmas break, I might try tube-rolling in my Mjolnir 2 and capturing that via the RME.

I have to decide whether the pre-out or the headphone out is the better scenario to use.