What qualifies a "bad" tube amp, or what do you get from a more expensive tube amp

[Mr. Haelscheir]

Now, one possibly incorrect assumption of mine is that modern tube amps can be divided into "audiophile tube amps" and "haute tubographie": the former regards tube amps designed to colour the sound or add pleasant distortions or harmonics; the latter regards my impression of McIntosh or makes which strive for technical proficiency (particularly from my reading https://www.audiosciencereview.com/forum/index.php?threads/best-measuring-tube-amp.35430/), whereby you would likely buy those tube amps instead of a well-measuring solid-state amp for a similar reason to why you would buy a high-end work of "haute horlogerie" instead of a quartz watch. The former has a very wide range of prices, while the latter probably typically exceeds $6k, though I suppose from my readings that many well-measuring vintage tube amps predating the advent of "audiophile tube amps" with intentional colouration could be had without breaking the bank.

Now, focusing on "audiophile tube amps", other than more features or subjectively nicer looks, what is one getting out of higher-end tube amps (e.g. let's say I am interested in Cayin amps) compared to cheaper tube amp implementations of the same power rating? Is it primarily a circuit design, components, and chassis that enable a lower noise floor, or better control over introducing more "desirable" harmonics than undesirable harmonics or distortion? Given this, are there objective ways to qualify a particular tube implementation as being "bad" other than the distortions or noise being excessive? Or is it more a matter of there being different costs for producing merely different colourations which like with headphone frequency responses, different people prefer, whereby the colourations produced by more expensive tube amps are simply different and likewise exclusive? My analogy would be that of collecting typewriters for their different typing feels: having experienced over a hundred different machines, they are all merely different, some being more comfortable to type fast on than others, and the rarest and priciest typewriters simply present the most exclusive typing experience.

 

[GXAlan]

My understanding is that the transformer quality makes a big difference.

when It comes to tubes versus solid state, four things are universal
1) there should be zero crosstalk between the left and right channels
2) the volume matching should be perfect between the left and right channels
3) power supply (60Hz) noise is not beneficial
4) it should work reliably

So the best tube amps are better in these elements.

Then you get into a lot of hand waving between good and bad distortion or non linearities. Ken Rockwell, the camera guy, has a couple of great comparisons on tube rolling and measurement results.

 

[robwpdx]

The wishful theory of tube systems is that they introduce pleasing distortion in the form of compression and even order harmonics, especially when over driven.

You can and I have put tubes on a curve tracer. They are similar to field effect transistors and different from bipolar transistors.

The concern is that the objective measured quality and tube to tube consistency of peak tube makers of the 1950s and 1960s is not present in current tube manufacturers.

From my understanding, I would look at specific tubes populating the amp, individual biasing capability, and ASR measurements which include the transformers. Specific tube biasing is a simplified way to put the curve tracer world of the tube in its linear place. The McIntosh theory is to minimize negative feedback. Negative feedback reduced distortion, but the feedback path can saturate. Using tube rectifiers is nonsensical.

Look up the specific amp, not the maker, up on ASR. No guarantee your tubes, same make and model, will be curve tracer the same as what ASR measured.

 

[solderdude]

Output power.
(Output)Transformer quality.
Used components quality.
Tooling costs for 'very nice looking enclosures in very small quantities'.
Options for tube monitoring/adjustment.

Downsides: Longevity of tubes, microphony, availability of good tubes, power consumption.
Upsides: Conversation piece (it is still jewelry), looks, bragging rights, clipping behavior (with under powered speakers), makes one feel it is something special which biases (tricks) the mind in believing it sounds better.

When you want a tube amp because ... well it is a tube amp you should buy a tube amp. Forget the cheapies and even some of the more expensive ones.
Just realize with harmonic distortion (regardless of the type) also comes IM distortion which is never 'harmonic'.
People like to believe that harmonic distortion in an amplifier (or source) is very similar to harmonics present in an instrument and that you can 'lightly change' those harmonics for the better (always more pleasing is seems) using tubes (or FETs).
As long as those harmonics (and above all IM products) stay low enough in level they are not audible degrading the sound. Some roll-off in the audible band, some modification of bass frequency response due to a high output R (speaker dependent !!) and the glow of tubes (retro feel) may help with 'enjoyment' for some.

When you want longevity and the assurance the amp will not be at fault when hearing distortion buy a good SS amp. Forget the cheapies and even some of the more expensive ones.

When you want lots of power in a small form factor buy the better class-D amps. Forget the cheapies and even some of the more expensive ones.

 

[Mulder]

I have a good quality tube amplifier. I also have a good quality class D amplifier and in the past also had traditional transistor amplifiers. With a good recording, the class D amplifier always wins in terms of good sound, but in some cases with worse recordings, I think the tube amplifier can sound better. I think it's more about the fact that it has an ability to mask weaknesses in the recording, not that it is better at amplifying the incoming signal. It is a bit like vinyl vs digital. Then the class D amplifier delivers more power. It is completely unrealistic to build a tube amplifier with the same output power. This is compensated by the tube amplifier clipping in a way that is acceptable. But that doesn't mean clipping sounds good. The sound will still be mushy. I consider the limited output as a very real weakness with a tube poweramp.

 

[dasdoing]

for "good saturation" take ¨clean tube¨ and ¨warm tube¨ of this software as an example

he later shows these on an analiser

 

[Mr. Haelscheir]

for "good saturation" take ¨clean tube¨ and ¨warm tube¨ of this software as an example

he later shows these on an analiser

To be honest, with that footage, through my FiiO K9 Pro ESS -> HiFiMan Arya Stealth setup, I can barely hear any differences (and yes, the style of presentation or the timings of the bypasses were suboptimal). I can hear when soft clipping starts as the presenter increases the gain to overdrive levels, but otherwise, any warmth that I hear can also be perceived in the bypassed case.

I've lately been playing with https://distortaudio.org/pkharmonic.html via foobar2000 (Preferences -> Components -> VST plug-ins; VB-Cable + Foo Record for playing PC audio), whereby though I can tell the change in timbre for pure tones when I have set a harmonic's level high enough, that change mostly disappears once listening to proper music (for some reason, even with no distortions added, it adds gain to the sound such that the bypass button is almost useless if one wants to do a level-matched assessment, mind one gets a cut or clip in sound when changing settings). I also haven't had much success with https://wavearts.com/products/plugins/tube-saturator-vintage/, and maybe only slight success with https://www.shatteredglassaudio.com/product/104 (SGA1566) when on high gain with quieter piano tones where I can get a better sense of "grainy warmth" not to the level of crackling or buzzing, though subsequent louder tones will clip unacceptably.

With all of these, it has only really been clipping that I could notice, and if ever I did enjoy subtle distortions, I would wish it could be applied equally at all signal levels. It has me curious whether there exist tube amp designs that can somehow have the overdrive point follow the envelope of the sound if not somehow apply to each individual frequency by the same amount at every amplitude. Could this be achieved by coupling the input signal to the tube's bias?

Lastly, while quickly switching between tracks in

(whether or not you believe YouTube compression would erase the differences, else that emphasizes the following amusement), as closely as I may hone in on individual features, I honestly find no perceptible differences, whereby reading the comments is like listening to prisoners contemplate the nature of the shadows in Plato's cave.

Anyways, in two weeks should things go well and I am able to audition an HE1000se, I might also be able to check out the tube amps and hear them for myself.

 

[gene_stl]

Bad tube amplifiers , are amplifiers that contain vacuum tubes.
Give me an LM3886 amp or a Benchmark.

 

[solderdude]

for "good saturation" take ¨clean tube¨ and ¨warm tube¨ of this software as an example

he later shows these on an analiser

This works great on certain instruments. Those effects can be added in a studio and are anything but subtle. It should be applied to only 1 instrument only.
That is very different from applying (subtle) tube effects to an entire recording.

 

[dasdoing]

To be honest, with that footage, through my FiiO K9 Pro ESS -> HiFiMan Arya Stealth setup, I can barely hear any differences

please try again...it's not that hard. listen to the highs on the clean one (upper range of background guitars) and the bass on the warm one

That is very different from applying (subtle) tube effects to an entire recording.

that's what the knob is for

 

[fpitas]

I'm sure that any number of ultra-expensive SET amps have the best transformers. As for whether they're bad...they offer massive amounts of even-order distortion and intermod by design. But the owners like the sound. Obviously we can't assess those dimensions here on ASR.

 

[Sokel]

I'm sure that any number of ultra-expensive SET amps have the best transformers. As for whether they're bad...they offer massive amounts of even-order distortion and intermod by design. But the owners like the sound. Obviously we can't assess those dimensions here on ASR.

I have listened to a 2x7 watt (I think,maybe a little more or less) Japanese 17K euros monos which looked like something one finds in recycle bin driving (big) horns.
Sound aside,the manufacturer claimed that the transformers where hand made silver ones.
I guess there's something to it to advertise it so much.

(I have to confess that under some conditions and specific dense music maybe I couldn't discriminate it from a good SS APART from the "silky" highs on some female voices (with demanding arias).

 

[solderdude]

that's what the knob is for

But the effect is very different when applied to a single instrument (during recording/mixing) and when applied to the total mix/reproduction was the point.

 

[fpitas]

I have listened to a 2x7 watt (I think,maybe a little more or lees) Japanese 17K euros monos which looked like something one finds in recycle bin driving (big) horns.
Sound aside,the manufacturer claimed that the transformers where hand made silver ones.
I guess there's something to it to advertise it so much.

(I have to confess that under some conditions and specific dense music maybe I couldn't discriminate it from a good SS APART from the "silky" highs on some female voices (with demanding arias).

Since I admit I don't understand any of the appeal, I'll take them on faith that the transformer is something special.

 

[Fontie]

when i came into HiFi, knowing nothing, i researched gear and i kept seeing gushing reviews for certain tube amps, i bought a line magnetic, i also had a cheap emotiva amp, when i decided to compare them i could not hear any difference, the emotiva costa round 150, the tube amp over a grand i think. Needless to say i sold the tube amp, and was suspicious of all the (what i now know as subjectivist reviewrs magazines) - i then found ASR which confirmed my suspicions about the Hi Fi industry - im now the proud owner of audiophonics purifi, which i funded by selling the tube amp

 

[fpitas]

when i came into HiFi, knowing nothing, i researched gear and i kept seeing gushing reviews for certain tube amps, i bought a line magnetic, i also had a cheap emotiva amp, when i decided to compare them i could not hear any difference, the emotiva costa round 150, the tube amp over a grand i think. Needless to say i sold the tube amp, and was suspicious of all the (what i now know as subjectivist reviewrs magazines) - i then found ASR

When you get into the SET world, the distortion is so enormous I have to think it really is audible. Then it's down to if that was the sound you were looking for.

 

[Sokel]

That is absolutely the wrong reason to consider something as being valid. Con men operate on the principle that a lie, repeated often enough by enough people, tends to be taken as truth. We need to understand the con man's bag of tricks, and know how to spot them and reject them.

Jim

I wish I remember the brand,never heard of it before or after,these were the entry level ones.
Specific con seems to work well though,you have to wait at least 6 months to get them from the time you order and pay for it.

 

[fpitas]

That is absolutely the wrong reason to consider something as having validity, whether in the audio world or elsewhere. Con men operate on the principle that a lie, repeated often enough by enough people, tends to be taken as truth. We need to understand the con man's bag of tricks, and know how to spot them and reject them.

Jim

And I bet every penny for advertising comes right out of the engineering budget.

 

[Astoneroad]

We need to understand the con man's bag of tricks, and know how to spot them and reject them.

Are we still talking audio?

 

[FrantzM]

And I bet every penny for advertising comes right out of the engineering budget.

Engineering ( ).. budget in High End Audio? Seriously ??!!



Peace.