Tube Rolling: Does it Make a Difference?

[don'ttrustauthority]

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.

Not it doesn't. It implies tubes roll around on your desk when you put them down because they are circular. Why do you people always go for the cheap insult?

 

[Pugsly]

@amirm
I think we should name the head 'skeptical panther (is skeptical)'
His little head/eyes made me lol.

 

[dfuller]

So my thinking is that it could be audible, depending on the circuit and the tube in question.

No doubt, it is much more audible when you intentionally cause grid clipping (see: guitar amps).

 

[elvisizer]

By good, I mean pleasant, like barely picking up an overseas station on long wave radio that happens to be playing a song you like.

whaaaaaaaaat the heck?

It implies tubes roll around on your desk when you put them down because they are circular.

lol i've always wondered where this term came from, if it's actually this then I'm still never using it

 

[watchnerd]

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 of the rolling motion you use to get the tubes out of the socket.

You don't just pull straight up.

 

[watchnerd]

My use case / experiences with tube rolling.

Schiit Mjolnir 2 headphone amp:

Tube gain stage
SS output stage

In "high gain" mode, there is no feedback.

Out of my 40 different 6922 family tubes (6DJ8, 6922, 7DJ8, 7308), both NOS and new production, there are probably 15 pairs (30 tubes) that I doubt I could tell apart in a blind test. It certainly wouldn't be easy.

The remaining 10 tubes (5 pairs) are pretty easy, because they're either noisier, more microphonic, or have noticeably less gain.

I can just put on headphones with nothing playing, crank up the volume, and listen for noise and microphonics

 

[Ra1zel]

Why tubes sound different despite similar frequency response was not made clear

It would become very clear to you after conducting a test with controls

 

[mightygrey]

I was eager to read an in-depth article about whether changing tubes affects many aspects of audio, including frequency response. Alas, this is hardly a 'case closed' that changing tubes does not affect sound in any way. I'd be keen to see a more robust review using more than one piece of equipment (perhaps one that is less badly implemented, for starters), and measuring distortion, SINAD, dynamic range, frequency response, channel separation etc.

 

[paulraphael]

I was eager to read an in-depth article about whether changing tubes affects many aspects of audio, including frequency response.

I asked this question once on ASR and was given an emphatic "no!" ... but I'd like to have some confirmation on this.

I used to have a tube stereo preamp and a tube preamp for electric bass, and played around with tube rolling a bit. With the bass preamp, I never heard any difference at all, even though it was a pure tube design with no solid state anything in the signal path.

With the stereo preamp, I thought I heard some frequency response differences, including a tube that was supposed to sound "warm and mellow" but sounded bright and harsh to me. This could just be listener fatigue and hallucination, who knows. They were not blind tests.

Interestingly, I did not notice ANY differences in noise and distortion, which is where the actual measurable differences probably would have turned up. But the world is a noisy place, and I know from some real blind tests that I'm not especially adept at hearing low levels of distortion.

 

[amirm]

I was eager to read an in-depth article about whether changing tubes affects many aspects of audio, including frequency response. Alas, this is hardly a 'case closed' that changing tubes does not affect sound in any way.

It is not just this case. I have done this type of testing I think two other times with same outcome.

 

[paulraphael]

It is not just this case. I have done this type of testing I think two other times with same outcome.

Are you saying that that you've never seen a change in frequency response?

Based on your engineering knowledge, could you imagine a design that would have its frequency response altered by different tube characteristics?

 

[amirm]

I don't think frequency response impact was brought up. In general, I don't see that impacted by tube change in audible band but maybe someone more knowledgeable about tube circuits can comment.

Here is one of the other tube rolling experiments: https://www.audiosciencereview.com/...rtuga-tpb-v1-tube-preamp-buffer-review.24897/

 

[watchnerd]

I agree. As an example, ECC82 x ECC802 in the same circuit, same test conditions. Hopefully I have put it into my archive. Please note almost 2 : 1 distortion. Please note 10dB difference in 50Hz mains line. No topology change except for tube exchange. Please note slight difference in gain (peak level).

View attachment 169099

View attachment 169100

And as another bit of data....

Here are graphs of a Schiit Mjolnir 2 hybrid tube headphone amp (not mine) in high gain (no feedback) vs low gain (with feedback).

The change in noise floor and distortion is visible.

The general community commentary is that tube differences are more audible in high gain mode.

vs

 

[mhardy6647]

My days of paying near $400 for a quad-matched set of KT88s/6550s are long over!
Back then, we would 'roll' other items!
I see that the GoldLions KT88s (quad-matched) are now only fetching under $200.
View attachment 169115
Maybe I should have never sold my MC275 [not].

Yes, but not real Gold Lions, of course -- just a brand name for some modern Russian- (or perhaps Chinese-)* sourced "Kinkless Tetrodes". I guess 50 a pop isn't bad, though, as they should be perfectly OK output tubes.

* I had it right the first time

 

[mhardy6647]

He he tube was really fun. I've surfed around tonight and checked tube related gadgets and found this.

I do not know much about tubes so I have to ask. Is this snake oil? Rubber rings around tubes, que? What would it help with? If you drive with a tube amp in a rally car that bounces on the road maybe? Or I do not know.

Edit:
Aha tube guitar amplifier, but then maybe it makes sense? Drag around guitar amplifiers, they can be handled quite tough physically.

View attachment 169119

Eurotubes Tube Damper Rings

Eurotubes Tube Damper Rings

www.eurotubes.com

They should be silicone and not regular rubber if they're to be used on power tubes.
So... I mean... the idea is to damp internal vibration (root cause of "microphonics") of the tube's -- shall we say -- infrastructure, which certainly can be audible. Do they really 'add value'? Beats me. I don't use any and never particularly felt motivated to.

 

[Billy Budapest]

New ASR Product Launch notification: Coming Soon…

ASR Panther Head Tubes…..Make your Amp purr…
View attachment 169066

Looks like it could be a tube shield! Wouldn’t do much for heat dissipation but could help with microphonics!

 

[musicforcities]

I have not done a blind test but I did try different make tubes in the two channels of a tube preamp I have and the l/r did sound different in mono with the balance knob switching back and forth. One was worse at hf. Of course variations from tube to tube may make as much difference.

The biggest joke is the EH tubes with gold pins that are 3x the ones with normal pins and are the same in every other way. Yeah that micron thick 8mm long gold plate is going to be transformative over the meters of copper trace and solder on the circuit. Lol.

Now, cyro those babies and the tachyons really flow. Lol

 

[xarkkon]

I don't think frequency response impact was brought up. In general, I don't see that impacted by tube change in audible band but maybe someone more knowledgeable about tube circuits can comment.

Here is one of the other tube rolling experiments: https://www.audiosciencereview.com/...rtuga-tpb-v1-tube-preamp-buffer-review.24897/

Ah, was just going to ask if an experiment could be done on an amp instead of a DAC. Didn't realise there was one with a preamp already. Was there any FR change from the Mullard? I'm curious to know about all the claims about certain tubes being warmer than others.

I've got a Bottlehead Crack and had wondered about tube rolling but have always found the cost prohibitive, especially when I could just EQ for my desired FR changes.

 

[xema]

But the harmonics are very different look at the h3 and h4, and the shape of high frequency harmonics, there are several dBs' difference.
The distributing of harmonics is the key of the tone color of instruments.

 

[0bs3rv3r]

The biggest joke is the EH tubes with gold pins that are 3x the ones with normal pins and are the same in every other way. Yeah that micron thick 8mm long gold plate is going to be transformative over the meters of copper trace and solder on the circuit. Lol.

The gold isn't there to make it sound better. It is there to, hopefully, improve the electrical connection with the socket, so you don't get that noise that arises from bad contacts.