Tube Talk

This is the official thread to talk all things tubes!

Information, education, triodes vs pentodes, great NOS finds, rolling, etc.


As someone that has never experienced tubes before, what are things to consider when looking for their first tube amp?

What terms are useful to know as a newbie?

I recently watched Thomas’s video about tubes for beginners. Do you guys agree with his findings/observations?

How influential are tube amp designs? In other words, if I place my favorite go-to tubes on a different tube amp…will I get the same sonic presentation but “better”? Or a different presentation because of different implementations?

Thanks in advance for the knowledge!


His video aims purely at speaker amps. While there are obvious similarities between those and headphone amps, I find the early part of the video where he makes broad generalizations on the sound differences of different amps topologies don’t translate to the headphone amp world. I am unaware of any push-pull topologies being used in headphone focused tube amps (and while I’m sure a few exist, I’m unaware of them) because you simply don’t need the extra power that delivers. Single ended is almost exclusively used in our world.

Some of his generalizations about tube sound don’t jive with my experience either. Keep in mind, he’s focusing on power tubes here, which speaker users will focus on more than we might. For example, the Pendant uses the EL84 power tube, which he groups into the “killer midrange group”. The Forge uses 6L6/EL34/KT88 power tubes, which covers the gamut of his 3 categories. I found the EL34 to be the softest of the three in terms of dynamics, yet his categorization says it should be the best. I also had to tube roll like mad to bring aspects of the Pendant’s sound to the forefront, such as impact and mid-range richness. This just doesn’t line up with his generalizations.

Why do my experiences not jive with his? Because it’s not as simple as he’s made out on the video with only push-pull/SE and tube types. Feedback, transformers, the caps in the signal chain, etc, all have very real impact on how the amp will sound.

While I think he made a very nice video, I don’t think there’s any substantive information there that’s applicable to headphone amplifiers.


You can view each amplifier as its own ecosystem. In that ecosystem you have things like flowers, bugs, rabbits and foxes. The ecosystem of Siberia has these things, as does the ecosystem of South America. Two very different ecosystems (Or, two very different sounding amplifiers, if you will.) If you take a fox out of Siberia and put it into South America, it doesn’t stop being a fox. It still feeds on rabbits and hides in the flowers, but it is definitely not a South American fox.

Tubes are like the fox. It’s behavior and general characteristics remain the same regardless of what amplifier you put them in, but the amplifier and it’s characteristics also greatly impact how the tube performs, what you hear, and does so arguably far greater than how much the tube will. This is one of the reasons why I cry myself to sleep at night knowing some idiot put a $500 ultra rare tube in a DarkVoice 336.

So while a bright tube will remain bright regardless of what amp you put it in, the characteristics of the amp may synergize well with that tube (or not) and the final sound you get may be pleasant (or not).

Generally, it’s best to look at them as two independent items regarding sound; items that have to work together to produce a final product. Putting a bright tube into an amp that doesn’t generally have much treble energy might produce a balanced and good sound. It’s very much the same thing as finding a synergy between a solid state amplifier and a headphone.


If you’re thinking of dipping your toes in the tubey water, this is a fun and informative video that @MRHifiReviews, @ProfFalkin and @TylersEclectic made about their favorite tube amps under $1000.

Tube rolling is fun, because you’re essentially customizing the sound of the amp as close as possible to your ideal. And your ideal may be different from mine, which is why you shouldn’t take anyone’s description of a tube as “great” at face value, without also learning about the sonic characteristics of that tube. As @ProfFalkin pointed out, when getting recommendations from people, you also need to take into account the amp and the other tubes that person is using, e.g. if the other tubes in my Pendant are sounding bright, and I throw a Mullard 12au7 in there to tame the brightness and add warmth, that might be perfect for me, but you may not be happy if you try that same 12au7 on the same amp if your other tubes are not bright.

Also tube rolling is only as expensive as you want it to be. You don’t have to buy a $1000 “holy grail” tube to get good sound. It’s all about setting a budget and getting the best tubes for that budget. Sounds like common sense, I know, but it’s very easy to chase the very best, especially when a rare tube pops up for sale (I’m certainly guilty of it).


Yes, I agree with you 100%. I just used that example to make a point that if someone is using a tube to balance out the frequency extremes of another tube, and calls it “great”, you need to know that that’s what they’re trying to do, and you shouldn’t blindly buy the same tube if your own system is balanced, unless you’re trying to push the sound in a certain direction.


First, you don’t buy $50 products like this. Avoiding them lets @ProfFalkin sleep and keeps his mind healthy. Learn from my mistake in buying this long ago (oddly, this is an extremely loud amp with exaggerated gain).

A clean tube amp often resembles “good” solid state amps, but people don’t usually bother with the cost and headaches of tubes if they don’t change the sound.

So sad, so sad. @ProfFalkin’s lack of sleep has him delirious and dreaming of plants and animals synergizing. Chimeras and manticores abound! But this is a good analogy. Tubes go beyond the warm versus bright spectrum (see @Wes_S and @PaisleyUnderground) and into weird tubey distortions. Some ring or chime, some thicken certain frequency ranges (e.g., voices), some roll off highs and lows and resemble 1950s style recordings. A wide variety of [often rock] songs used intentional tube distortion for a distinct timbre. It’s a qualitative experience and you may like it or hate it.

It’d be good to catalog or find a catalog tube-based recordings, because sometimes great effort went into capturing and preserving what tubes did in the studio. For example, the guitar lead-in of Guns & Roses Sweet Child O’ Mine is said to have been recorded on a rented guitar amp that had a dying tube or bad circuit. Many have struggled to reproduce that sound.


There is some good discussion/information in these posts/existing topics:

  • Output transformerless vs transformer coupled
  • Single ended vs push pull vs ultralinear
  • Triodes vs pentodes vs beam tetrodes vs directly heated tubes
  • Tube rectified vs solid state rectified
  • Use of feedback
  • 9-pin vs 8-pin vs 4-pin base tubes
  • New old stock vs new production vs re-issued tubes
  • Headphone only amps vs speaker amp capability vs preamp capability
  • Output impedance and power output matching
  • General sound signatures for various tube types, tube manufacturers (which can be different from the brand/label), tube manufacturer’s country of origin

Different tubes for different newbs. However, what I enjoy, you may not.

My Darkvoice was only $200 price matched to Drop. The tubes were upgraded to Novosibirsk 6H8C $5 each and Svetlana 6N5S $15 each including shipping. This simple $220 Darkvoice setup is more fun to listen to than any of my collection of solid state amps including my Singxer SA-1 $540, Headamp Gilmore Lite Mk2 $800, Schiit Jotunheim 2 $400, etc.

The only amp that I have that sometimes is better is a Ray Samuels Emmeline II the Raptor $1,250, but it is also a tube amp. For me, tubes trump solid state.


Thanks for starting this thread, @Grover, and thanks for @Wes_S and @ProfFalkin and the rest of you for joining in.

I’d like to wrap my head around some tube theory. It’s not hard to find simple explanations of cathodes, anodes, triodes, and pentodes. And I’m no EE. But I’ve used tube testers, and have grabbed some PDFs of old tube handbooks (I live in Lancaster, PA, home for years of a major RCA tube-making plant).

The range of tube designs and innards is astonishing. How did the folks in they come up with the thermionic valve in 1904, and what were the designers in the teens and 20’s smoking? After the war, (the 2nd one) and into the '50s we see a lot of minitureization (not possible to spell that word). What did that accomplish and what are the tradeoffs?

I did take high school electronics, and have built an “All American 5” superhet radio back then. I’ve toasted a heathkit or two. But “Enquiring Minds Want to Know”. Good tube stories and anecdotes that explain the theory and the graphs in those handbooks would be read by at least an audience of one.


Isn’t if fun putting tubes in various lighting and thousands of angles, trying to capture something magical within these glass kingdoms. I appreciate the time that you put into capturing those shots! Thanks for sharing your tube pictures.


This is all nonsense. Roll transformers, not tubes.


The toroidal ones roll pretty good, and once you get them going, they’re hard to stop.


Caps roll pretty well too. Oodles of options!!


The nice thing about transformers is that they readily “transform” into either tubes or capacitors when you roll them. This is the exact same process by which pill bugs roll up when disturbed. [To initiate a new audiophile rolling research topic right here.]

While the amp circuit and transformer have a large impact and many tube swaps result only in a smaller wallet, individual tube differences can often be heard. In my experience they fall into rough buckets for a given amp, per tone, clarity, stability, and the presence or absence of characteristic flaws (e.g., harmonics and roll-off). Worn out tubes can deliver “uniqueness” and a lo-fi effect.

I am bookmarking this thread so that each time I am hovering over the “buy now” button on a tube amp, I can quickly reference why I shouldn’t :smiley:


I see who you are quoting :wink:


I’m personally starting to understand there are very small differences between tubes. Get a batch of good tubes and a good amp, your set. I’m over collecting a couple hundred tubes to roll for enjoyment but I do have a dozen or so for a backup but some were only 10 dollars a piece and sound no different than my 50 or 100 dollar ones.

I’ve owned an 8500 tube amp and now I own a 1400 tube amp and I enjoy the 1400 just as much or more. And it takes up less space and weighs less.


I hear you, the tube-rolling rabbit hole can be a bit daunting.

I could see myself transported into old age, with hair and beard down to my knees, skin pallid from lack of sunshine, milky-eyed, toothless, and sallow-faced, abandoned by my wife and cats, rummaging around in a massive pile of tube boxes, trying desperately to find that one magical, dream tube pairing I’d heard back in my long-lost youth, never able to find it again…

Joking aside, for those new to the hobby who are intrigued by tube amps but find them daunting, my limited, rookie experience may be reassuring. Just over three years ago, I took the plunge - wife and cats eyeing me cautiously - with a tube hybrid amp, the Massdrop Cavalli Tube Hybrid. Like the Schiit Vali, it was affordable and had the advantage of only having one tube to worry about (i.e. no concerns about getting matching pairs when rolling). I still love this amp and have found it to pair very nicely with my Focal Clear. Only now that I have a better DAC have I begun to think about tube rolling with it. In other words, you don’t have to go bonkers with tube rolling.

Since I got the MCTH I’ve taken tentative first steps into proper tube amps, i.e. not hybrid ones, with the ZDT Jr. and, in the past week, the SW51+. In both cases, it helps that the designer had specific tubes in mind when making the amps. There are good options for tube rolling. But my understanding, from reading the forums carefully, is that you don’t have to worry about getting the right tubes when you purchase the amp - that the amp will be perfectly satisfactory as it is, with stock tubes (and in some cases, the amp will come with some of the best tube options out there).

In other words, you can choose how much you’re prepared to engage with the complexity of the tube amp world; it’s not an inevitable problem to be surmounted at the outset.


That was my point, you can enjoy tubes at an affordable point and not dive off the deep end. I’ve owned the fancy named tubes and couldn’t tell you much of a difference between each.