Tubes vs. transistors .. Slawa Roschkow

While this is fascinating, and contains more than a few grains of truth, the author has clearly taken the Kool-Aid. When, towards the end of the treatise, he delves into how certain issues can be overcome as follows: From my personal experience, it follows that a similar effect can be obtained by a skilful selection of interconnects and output cables. Rather convincing results obtained by using OFC wire type.

This debate is as old as the technology. Writing entirely for myself, I find that well made, well designed, well maintained equipment (which I flatter myself into believing I own) tends to sound well. Tubes are remarkably different from transistors - I can agree with this statement at every level. And as the author takes some pains not to utterly reject solid-state, I also believe him to be an honest broker of his opinions and experiences.

Ah, well. I have spent enough time working overseas and in an 'international' environment to have no difficulties with incomplete language skills - for dead sure, his English is infinitely better than my grasp of his native language. And I know based on my personal experience that tubes absolutely *can* sound better than solid-state. And. Of Course. The Converse.

Peter W. wrote:While this is fascinating, and contains more than a few grains of truth, the author has clearly taken the Kool-Aid. When, towards the end of the treatise, he delves into how certain issues can be overcome as follows: From my personal experience, it follows that a similar effect can be obtained by a skilful selection of interconnects and output cables. Rather convincing results obtained by using OFC wire type.

This debate is as old as the technology. Writing entirely for myself, I find that well made, well designed, well maintained equipment (which I flatter myself into believing I own) tends to sound well. Tubes are remarkably different from transistors - I can agree with this statement at every level. And as the author takes some pains not to utterly reject solid-state, I also believe him to be an honest broker of his opinions and experiences.

Ah, well. I have spent enough time working overseas and in an 'international' environment to have no difficulties with incomplete language skills - for dead sure, his English is infinitely better than my grasp of his native language. And I know based on my personal experience that tubes absolutely *can* sound better than solid-state. And. Of Course. The Converse.

Peter W, Bob, my SWAG is that this was translated from Russian or Polish or some other user of Cyrillic.
Not sure I understand or concur with all of his points, but a fascinating read nonetheless.
The shortcomings of tube and solid-state are pretty well known. Remember Bob Carver's Phase Linear 7, most powerful consumer amp on the market at the time, incredible specs at full-pharte, not so good at listening levels, where the distortion skyrocketed.
I think what's forgotten in all this is that we humans live and listen in an analogue context, not a digital one. That's not rocket science.Which makes tube distortion more agreeable than sand-amp distortion.

I think what's forgotten in all this is that we humans live and listen in an analogue context, not a digital one. That's not rocket science.Which makes tube distortion more agreeable than sand-amp distortion.
[/quote]

I am not so sure that the difference(s) between analog and digital impacts on this discussion. Although I listen to quite a bit of CD-sourced sound, I also listen to a great deal of analog-sourced sound and find that horses-for-courses applies. There are very few tube devices on this planet - not none, just few - that will drive a pair of big Maggie speakers well. Certainly none of mine, including the big Scott LK-150 at 75 wpc/rms/8. Perhaps that 500-watt KT-88 based amp being planned/discussed in another forum. On the other hand, a single ST-70 does a very nice job on an AR Athena sub/sat system upstairs. My neighbor down the block has an amp based on 300Bs in PP (22wpc) which is extraordinary with his speakers and playing vinyl. *HOWEVER*, his sweet spot (and self-admitted as such) is a 12" cube outside of which things get pretty bad, pretty fast.

I also admit to being skeptical of the entire outboard DAC phenomenon - they, and pretty much every CD player or other device utilizing AD technology pull from the same chip-makers, and pretty much reach the same end. Whether at $35 or at $35,000. So, I try to avoid including 'digital vs. analog' as a factor into even a friendly discussion on tube vs. solid state. Sufficient that I enjoy both and tinkering with both. Over my holiday week off, I will be upgrading an FM3, installing a VTA board into one of my vintage 70s (the kids are getting one for me for Christmas), and also restoring a Revox A722 that I got for (relative) sparrow-feed. It will be a companion for my 'other' Revox A720. So, a little of both.

We make choices. I found Slawa's notes fascinating as, although he clearly had an agenda and a desired conclusion, he was pretty honest with the data and pretty honest when inserting his opinions. Not the usual behavior. But, his choice guided his process and utilization of the data - perfectly human and perfectly acceptable in that context.

not sure where I read it, so this is a semi-useless post, but sometime about a week ago I read either online or an audio magazine about why speakers and hifi components can never sound PERFECT because they
aren't real music, they are reproducing music. It's a very fine balance of the harmonics that change the way a musical note sounds, which is why a piano and a cello and a saxophone all sound totally different.
Same as why we recognize people by their voice. The MUSICAL balance of the harmonics is what makes us like tubes (most of us) better than transistors.
Those same harmonics can now be "tuned" by high-end speaker manufacturers to give the correct voicing to their speakers and make them sound more correct and accurate to us tonally.

One of the more significant differences is the way power is delivered :
a transistor amp is usually designed to have very low output impedans ( constant voltage generator) while a tubeamp has much higher output impedance.
Used with a speaker that has very varying impedance the sand amp will have peaks ans lows in the
spectrum, whear a tubeamp tends to deliver "constant power" to the speakers, which will be a more
balanced spectrum.
There is a theorty that building amps with "current feedback" should correct this, but close to none
amp is available accoring to "current feedback". Tube amps has always been in that direction.

tubes4hifi wrote:The MUSICAL balance of the harmonics is what makes us like tubes (most of us) better than transistors.

(Much Snippage)

AKA: Euphonics and a very real phenomenon. Largely (but not entirely) overcome in later SS designs that have cleaned up notch distortion, feedback-induced harmonics and other 'noise' from the signal.

But, and I hesitate to bring this up, what has not been mentioned so far is how tube amps clip vs. how SS amps clip. And, why it is that for a SS amp to sound as-good-as-better than an SS amp it must be several orders-of-magnitude more powerful than that tube amp. And, if that power can be delivered cleanly, it will sound remarkably good, often better depending on the signal.

Let me suggest  some reading. Do a Google search for "Tubes Versus Transistors - Is There an Audible Difference?* by Russell O. Hamm. This was presented to the AES in 1972. It maybe a bit over many people's heads in some areas, but I've found it to be extremely helpful in understanding what's going on. It's a fine piece of work, and I highly recommend it!

Bob Latino wrote:Hi Jim,

Thanks for the info .. That article by Russell O. Hamm is at the link below ..

Tubes vs. Transistors by Russell O. Hamm

Bob

I read this years ago, and it is still timely as far as it goes. All of my tube amps are pre-article (1972). Most, but not all, of my solid-state amps are pre-article, but three key-and-primary units are not. As follows:

Solid State                                              Tube

AR integrated                                            ST70  
AR Receiver                                           Scott LK150
Dynaco ST80                                             ST35
Dynaco ST120

Are all pre-1972

The HK Citation 16 (1976) and 19 (1987), as well as the Revox A722 (12/1973) are post.

In all seriousness, much in the world of solid-state has changed in the intervening years. Very little in the world of tubes has changed, and what has changed, hardly as much. And, in my opinion, that is specifically what is at issue here. Those of us who are committed (as with the pig) to tubes tend to stop with the evidence that best supports that position, and which was (once) entirely accurate.

Solid state manufacturers were very well aware of the limitations of the art back in the day, most especially those who started out well grounded in tube devices - Dynaco, HK, Scott, Fisher and so forth. Pretty much all of them but HK made the same mistakes going forward, reaching for power before stability, but all of them eventually "got it", if only just in time to "get out of it". AR nearly went out of business due to the early failures of their amps. Scott did even less well with their solid-state amps and receivers - they did not have much of a speaker business to help them through.

Others learned from their mistakes, or spent more time in R&D. Some went for stability over power. But the point of all this is that the mid-1970s were pivotal to the SS audio industry, and by the 1980s, solid-state devices, at least at the top end of the spectrum, were every bit as good as tube devices, pretty much in every way. I have often stated that an early Dynaco ST120 (solid-state) sounds like glass in a blender. Later versions (almost 8 iterations in all depending on how measured) sound quite nice. And I have entirely rebuilt both AR units with similar results - though they never sounded as awful.

Cutting to the chase, the divide between tube and solid state, whilst still extant, has greatly narrowed in the last 44 years. Actual primacy is now genuinely in question.

What is the difference between Ham and Eggs?

The chicken in involved. The pig is committed.

Still boils down to what sounds better. I listen with my piano-trained ears, not an oscilloscope or a VTVM. You're attempting to objectify a subjective experience.

deepee99 wrote:Still boils down to what sounds better. I listen with my piano-trained ears, not an oscilloscope or a VTVM. You're attempting to objectify a subjective experience.

That is entirely the point. Not a 44 year old article written when solid state amplification was going through the functional equivalent of the "terrible twos". All that is necessary is to enjoy the results.

My "objectification" was directed solely and only at cutting past the fallacy of 'Appealing to Authority' and bringing the discussion back to what sounds better by personal experience and choice.

Being firmly in the "Horses for Courses" camp, I get to enjoy both, more-or-less equally and more-or-less with equal frequency.

peterh wrote:One of the more significant differences is the way power is delivered :
a transistor amp is usually designed to have very low output impedans ( constant voltage generator) while a tubeamp has much higher output impedance.
Used with a speaker that has very varying impedance the sand amp will have peaks ans lows in the
spectrum, whear a tubeamp tends to deliver "constant power" to the speakers, which will be a more
balanced spectrum.

I respectfully disagree...
1) speakers (the last 40-50 years) are designed driven by ultra low impedance, constant voltage amplifiers
2) once you have a damping factor of at least 5, no positive or negative effects will be audible
3) if damping factor is lower than 5, ask yourself what is happening to the output stage of a tube amp...

This all said, I like both hollow and solid state amps and have no preference for analog or digital sources (when properly converted).

OneyedK wrote:

peterh wrote:One of the more significant differences is the way power is delivered :
a transistor amp is usually designed to have very low output impedans ( constant voltage generator) while a tubeamp has much higher output impedance.
Used with a speaker that has very varying impedance the sand amp will have peaks ans lows in the
spectrum, whear a tubeamp tends to deliver "constant power" to the speakers, which will be a more
balanced spectrum.

I respectfully disagree...
1) speakers (the last 40-50 years) are designed driven by ultra low impedance, constant voltage amplifiers
2) once you have a damping factor of at least 5, no positive or negative effects will be audible
3) if damping factor is lower than 5, ask yourself what is happening to the output stage of a tube amp...

This all said, I like both hollow and solid state amps and have no preference for analog or digital sources (when properly converted).

You are free to disaggree. I will use my ears.

Read "current-driving of loudspeakers" by esa merilöinen.

The fact that constant voltage will trigger speaker misbehaving ( and is the major source
of sound-differences between amps)is well know with some people. A speaker designed
and tested with one type of amp might not be good at all with another type ( sand/tube)

If speakers had same efficiency at all frequencys, a constant voltage is perfect.

[quote="Peter W."]

Bob Latino wrote:[size=18][b]Hi Jim,
I have often stated that an early Dynaco ST120 (solid-state) sounds like glass in a blender. Later versions (almost 8 iterations in all depending on how measured) sound quite nice.

That is true, much to the disbelief of many. When I take my tube amps out of service for routine maintenance (bias adjustment, tube testing, cleaning sockets), I replace them temporarily with something else. It has variously been a Dynaco Stereo 70, lightly modified; or a pair of Fisher 70A, or a Heathkit W-4 and its later clone on a smaller chassis (I forget the model number). On one occasion it was a Dynaco Stereo 120, an early one that I repaired and upgraded to latest-version many years ago. True to the claim in Stereophile magazine when they tested the Stereo 120, it sounds much like the tube amps and unlike the "broken glass" reputation that the Stereo 120 had. Perhaps Stereophile got a "massaged" sample (J. Gordon Holt was known to be friends with people at Dynaco)?

I left that transistor amp in the system longer than I really had to, after the maintenance work was done. It was that good.

peterh wrote:Read "current-driving of loudspeakers" by esa merilöinen.

The fact that constant voltage will trigger speaker misbehaving ( and is the major source
of sound-differences between amps)is well know with some people. A speaker designed
and tested with one type of amp might not be good at all with another type ( sand/tube)

If speakers had same efficiency at all frequencys, a constant voltage is perfect.

I'm familiar with current drive, albeit for reverb tanks (the only way to get a bit of low frequency performance out of a tank).
The problem with current drive is not the efficiëncy but the resonance frequency that's inherent in a dynamic driver.
If you current drive a classic woofer around it's resonant frequency, you would destroy it.
P=R*I^2, if you keep I constant, you can see what happens if R goes to the roof...
Sorry if we're wandering a bit off topic here.

My point is, a tube amp is a voltage source, not an ideal one, but still a voltage source.
I can't think of a topology rendering it to a current source...

OneyedK wrote:

peterh wrote:Read "current-driving of loudspeakers" by esa merilöinen.

The fact that constant voltage will trigger speaker misbehaving ( and is the major source
of sound-differences between amps)is well know with some people. A speaker designed
and tested with one type of amp might not be good at all with another type ( sand/tube)

If speakers had same efficiency at all frequencys, a constant voltage is perfect.

I'm familiar with current drive, albeit for reverb tanks (the only way to get a bit of low frequency performance out of a tank).
The problem with current drive is not the efficiëncy but the resonance frequency that's inherent in a dynamic driver.
If you current drive a classic woofer around it's resonant frequency, you would destroy it.
P=R*I^2, if you keep I constant, you can see what happens if R goes to the roof...
Sorry if we're wandering a bit off topic here.

My point is, a tube amp is a voltage source, not an ideal one, but still a voltage source.
I can't think of a topology rendering it to a current source...

True, a tube amp in itself is not a current source. But is is somewhere in between,
the lower feedback it uses its more and more like a "constant power" device.
This in it's turn, will tend to deliver "constant power" to a speaker with widley
shifting impedances.
This effect claims ( by some) to be one of the differences between sand and glass amps.

[quote="peterh"][quote="OneyedK"]

peterh wrote:Read "current-driving of loudspeakers" by esa merilöinen.

>>SNIPPAGE<<

This effect claims ( by some) to be one of the differences between sand and glass amps.

So, let me see:

VOLTS: Unit of force
AMP: Unit of Current
WATT: Unit of Power

Anything coming out of any amplifier must have all three properties, true?
If I understand the representations correctly, Solid-State amps are represented to have "Constant Voltage", True?
And, conversely, Tube Amps are represented as having "Constant Power", True?
Meaning that the measurable variations in the output from a solid-state amp at a given volume will be in amps. True?
And the measurable variations in the output from a tube amp at a given volume will be a some variation of both force and current to get a constant wattage. True?

Seems like some things quite easy to measure. But, before I try, am I correct in the representations?

Peter W. wrote:So, let me see:  

VOLTS:  Unit of force
AMP:     Unit of Current
WATT:   Unit of Power
Anything coming out of any amplifier must have all three properties, true?

Power is the result of the other two, so yes, true

Peter W. wrote:If I understand the representations correctly, Solid-State amps are represented to have "Constant Voltage", True?

You have to leave the “constant” out.
If we use the term “voltage source”, this indicates in theory, a zero ohm output impedance.
Voltage will be put on the speaker, depending on the impedance of the speaker, current will flow.
In theory, what the speaker demands, it will get.
btw, this is not limited to solid state amplification.
The reason we want this (low output impedance) is because the speaker is a moving coil in a magnetic field, so when we push it, and we stop pushing, it will not stop moving.  Thus turning the speaker into a generator. the generated current will be shorted by the output impedance of the amp and the effect will be dampened, the speaker will stop moving.
This is the theory, in practice, less than ideal speaker cables will have resistance of their own and are in series with the amp.  So no perfect current damping.
The ratio between output impedance and speaker impedance is called damping factor.
for example: output impedance 0,04Ohm, speaker impedance 4 Ohm, damping factor 100.
(without taking the speaker cables into account)

Peter W. wrote:And, conversely, Tube Amps are represented as having "Constant Power", True?

This is a claim from peterh, not mine.
In my book, a good tube amp still has a damping factor of 5-20 (some even more), which still makes it a voltage source.
output impedance << speaker impedance

Peter W. wrote: that the measurable variations in the output from a solid-state amp at a given volume will be in amps. True?

Ideally, yes, but how would you measure current without introducing resistance in the network?

Peter W. wrote:And the measurable variations in the output from a tube amp at a given volume will be a some variation of both force and current to get a constant wattage. True?

Again, something peterh should explain.

There’s only one way to measure a system (amp+speakers), and that’s measuring SPL frequency response in an anechonic room, with most of us don’t have at their disposal

A good in-line AC ammeter (as compared to a induction coil-type) uses a low-resistance shunt and measures drop across it. So, perhaps 0.5 ohms of additional resistance. Which should not be enough to change the results. My ammeter (section of a VOM) uses fine silver for the shunt.

I would pretty much think that any AC power source (and what is an audio amplifier but an AC power source of varying frequency?) driving a linear motor (and what is a speaker but a linear motor?). If the energy produced by the recover of the voice-coil is damped by a shorted (very nearly shorted) output impedance, we get, essentially, dynamic braking, correct? Back in the day when I raced slot-cars, there was a brake button on the control that shorted the tracks and stopped the car *very* fast. I expect this comes to the same thing? And why some early tube amps were considered "tubby" in the bass as things just didn't stop on time.

I have to admit to being a bit vague on this, and take the little-steps-for-little feet approach. As the difference between tube and SS is apparently so clear - and apparently electrical in nature, so should the means of demonstrating that difference by measuring electrical properties be clear. I am NOT being snarky. But as I have multiple tube and solid state amps at home, and two very good meters capable of measuring everything from capacitance, inductance, resistance, ESR and more - I would like to see for myself. Rikki Tikki Tavi's family motto is "Run and find out". That has been more-or-less my approach to things ever since I read the Jungle Books at age 6.

Peter W. wrote:If the energy produced by the recover of the voice-coil is damped by a shorted (very nearly shorted) output impedance, we get, essentially, dynamic braking, correct? Back in the day when I raced slot-cars, there was a brake button on the control that shorted the tracks and stopped the car *very* fast. I expect this comes to the same thing? And why some early tube amps were considered "tubby" in the bass as things just didn't stop on time.

Dynamic braking is a well chosen comparison.

This tends to get very broad ;.)
read the book "current driving of loudspeakers", and try some suggestions there.

Damping speakers by their electromotive power i.e. using low impedance amp to try to control
speaker "overshoots" is moot. Building speakers that does not overshoot or resonances are
the (new ) way to go. But i do not have to convince anyone, use your ears and try !

I don't think i have more to add to this subject, getting back to my beer
Happy x-mas

Oh I hope there's more to come, as this is an excellent discussion on issues that are entirely new to me. I guess I'll have to do my own reading starting with references given above.

Tube Nube wrote:Oh I hope there's more to come, as this is an excellent discussion on issues that are entirely new to me. I guess I'll have to do my own reading starting with references given above.

Tubes just sound nicer, that's all. At least to my ears.

peterh wrote:Damping speakers by their electromotive power i.e. using low impedance amp to try to control
speaker "overshoots" is moot.

Not really. This is also the only way to keep that back-EMF from entering the amp and mix with it's "new" output.
It has it's limitations, but it's good practice.

peterh wrote:Building speakers that does not overshoot or resonances are
the (new ) way to go.

I totally agree.
It's not in any way new, but speaker manufacturers often make fashion statements instead of opting for optimal performance.
And very often, try to please the customer while depriving him from some choices.

Speakers used in studio's never been so far away from their living room brethren as today...