AudioCircle
Audio/Video Gear and Systems => Tube-o-phile Circle => Topic started by: Naimnut on 17 Feb 2019, 06:41 pm
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My question is sincere and I am honestly trying to learn. Here are some thoughts to help you understand where I am coming from and why I'm asking the question:
1. I've read comments to the effect that "as you approach the state of the art, solid state and tube equipment begins to sound very similar".
2. I've read that tube equipment tends to generate more even-ordered harmonic distortion. Does this mean that distortion in a tube preamp can cause the sound to come across as "richer" and "fatter"?
3. I've read with interest Roger Sanders excellent white paper on tubes vs. solid state, and his comments make sense, for power amps. But what about preamps? Do preamps clip?
4. It seems that several factors greatly influence the sound any preamp - the quality of the power supply (bigger, stiffer and isolated in a separate box seem to be important), the quality of the volume control, the quality of the transformers...Frankly I'm out of my depth here, but some of you might be able to help me understand this better.
5. Some highly rated tube preamps have multiple tubes, and use some in the power supply. Others have very few. How should a person think about this?
Looking forward to retirement I'm thinking of trying a small group of preamps in my system and doing side by side comparisons. My main system is LP12/Ittok/dynavector 17D3/Linn Linto/Naim 82/hicap/Innersound electrostatic amplifier/ESL 63 speakers. I know many parts of this system can be improved, but it sounds wonderful as it is. I just think that a better preamp will "open the window wider" or "clean the glass"...
Candidate preamps on my short list: Audible Illusions (I can borrow a fairly new one from my brother), Teddy Pardo PR1, one of Emmanuel Go's First Sound preamps, a Prima Luna, or a used unit from one of the well known companies - McIntosh, Audio Research, Conrad Johnson
Thanks, in advance, for thoughts anyone would be kind enough to share.
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Tubes always sound more organic, natural and sport a richer harmonic content than transistors, the second harmonic is very pleased to the human brain.
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Mr. FullRangeMan -
What you say seems to be the general consensus around tubes. But help me understand - is the second harmonic of which you speak part of the recording? Or is it generated by the preamp? Or is it a subtle part of the recording that solid state preamps cannot typically reproduce accurately?
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Mr. FullRangeMan -
What you say seems to be the general consensus around tubes. But help me understand - is the second harmonic of which you speak part of the recording? Or is it generated by the preamp? Or is it a subtle part of the recording that solid state preamps cannot typically reproduce accurately?
The recording have a set of musical harmonic content and the amp translate its own version accorcing tube or SS used to amplify the music signal.
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5. Some highly rated tube preamps have multiple tubes, and use some in the power supply. Others have very few. How should a person think about this?
I like minimalist approach in audio equips, multiple tubes add a complex circuit schematic that result in a more expensive amp, more heat and expense to retube and dont sound better than a simple few tubes amp, but I sure there is some audiophools will say more tubes is better.
A solid example of minimalist school is Steve Deckert at Decware audio on the other side you have McIntosh.
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I agree the 'typical' high end tube preamp no longer 'sounds like tubes' (used to back in the 'good old days'. )
If you want a tube preamp to sound like tubes, you need a classic, and it uses 6SN7 or 6DJ8, and even 12ax7s.. All those new tubes like in ARC etc have almost no 'tube sound'. And you want to be sure to have tube rectifier! in the tube preamp. Plenty of kit tube preamps still use classic circuits.
And what makes a tube sound.. yes your friend second harmonics.. and all the rest to go along..
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On preamps there is a chinese preamp named Omo preamp sell at defunct Cattylink shop at $1038 that showed two classic sound options Matisse or Marantz with only two small tubes.
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My question is sincere and I am honestly trying to learn. Here are some thoughts to help you understand where I am coming from and why I'm asking the question:
1. I've read comments to the effect that "as you approach the state of the art, solid state and tube equipment begins to sound very similar".
The concept of, "tube sound" is only relevant at the low and middle end of the hifi spectrum. Good, high end designers can make an amp or preamp sound like whatever they want.
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It's like asking "Why do movies shot in 4K digital look different that movies shot on 70mm film?" They might have similar levels of resolution and contrast, etc... but 4K always looks different than film. Same with tubes and SS. They might end up with similar levels of overall performance, but they will always sound different because their basic design is different.
To me, 4K video never looks as pleasing as 70mm film. And by the same token, SS gear never sounds as pleasing as tube gear. Others disagree with me, and that's what makes the world a great place - we all have our preferences and half the fun of this hobby is figuring out for ourselves exactly what those preferences are.
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Harmonics is the key, even (pleasant sounding) order for tubes, odd order for solid state. But any harmonics take away from fidelity. Thus tubes versus solid state in low/mid-fi is a matter of attempting to be euphorically entertained (by however you want everything colored) versus a more sterile/accurate (lesser amount of harmonics) sound. As said above, at the hi-end they sound more alike, so at that point why bother (unless you're a follower of a particular tube designer)?
Note that tubes age, so their sound changes as they wear out. Is your goal to listen to music, or to tubes?
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This article will explain some of the reasons why tubes sound different from SS:
https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes (https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes)
Read the sidebar: distortion under test (Very Interesting)
I've owned a lot of gear over the years, but this tube preamp design is perhaps the best overall preamp (tube or ss) I've come across:
(https://www.audiocircle.com/image.php?id=190786)
(https://www.audiocircle.com/image.php?id=190787)
While better designed gear sounds more similar than not, regardless of what anyone tells you, tube gear does sound different than SS. Most musicians who play guitar will tell you that their SS emulation amps DO NOT sound like a tube amp.
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Most musicians who play guitar will tell you that their SS emulation amps DO NOT sound like a tube amp.
Stevie Ray Vaughn was one of the big ones.
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Harmonics is the key, even (pleasant sounding) order for tubes, odd order for solid state. But any harmonics take away from fidelity. Thus tubes versus solid state in low/mid-fi is a matter of attempting to be euphorically entertained (by however you want everything colored) versus a more sterile/accurate (lesser amount of harmonics) sound. As said above, at the hi-end they sound more alike, so at that point why bother (unless you're a follower of a particular tube designer)?
Note that tubes age, so their sound changes as they wear out. Is your goal to listen to music, or to tubes?
Is your goal to listen to music, or to tubes?
Its possible listen to music only live with all that ambient noises, home audio dont play a 100% real copy from the live music, nor this is desirable. For my personal taste I prefer a nice tube version from the musical facts. I dont recommend a chase for live music in a home as it will be a frustrating journey.
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Some of the very best recordings were recorded by the tube AKG microphones from the 50's-60's. Those old microphones sell at very high prices today. AKG has brought tube microphones out again because of the high demand.
https://www.akg.com/Tube%20Microphones
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Also Neumann and Schoeps make great sound quality but are expensive, usually ribbon mikes have good sound.
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Mr. FullRangeMan -
What you say seems to be the general consensus around tubes. But help me understand - is the second harmonic of which you speak part of the recording? Or is it generated by the preamp? Or is it a subtle part of the recording that solid state preamps cannot typically reproduce accurately?
I think there is a bit of confusion or misinformation here. Please do not confuse harmonics and harmonic distortions. They are not the same. Harmonics are a natural part of acoustic music. When a note is played on a musical instrument, more than the basic note, the fundamental, is created. As an example, on a violin, an "A" above middle C vibrates at 440Hz. This is the “fundamental” or “first harmonic”. The second harmonic vibrates twice as fast (ratio 2:1): 880Hz. This produces the next higher "A" a full octave above the fundamental. The third harmonic will give a ratio of 3:2. This will be an "E" a full octave plus a fifth above the fundamental. This is basic wave physics.
Harmonic distortion is a different phenomenon. It is an artifact of the voltage produced in an amplifier. All AC current is in waves, so wave physics apply. There are odd and even order distortions. The human ear finds even order distortion pleasant, (musical), but odd order distortion discordant, (not musical). Solid state devices are switches, therefore they produce switching distortion, as well, Switching distortion is discordant. Vacuum tubes are electronic valves, not switches, so most of tube distortion is even ordered.
Cheers,
Geary
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I think there is a bit of confusion or misinformation here. Please do not confuse harmonics and harmonic distortions. They are not the same. Harmonics are a natural part of acoustic music. When a note is played on a musical instrument, more than the basic note, the fundamental, is created. As an example, on a violin, an "A" above middle C vibrates at 440Hz. This is the “fundamental” or “first harmonic”. The second harmonic vibrates twice as fast (ratio 2:1): 880Hz. This produces the next higher "A" a full octave above the fundamental. The third harmonic will give a ratio of 3:2. This will be an "E" a full octave plus a fifth above the fundamental. This is basic wave physics.
Harmonic distortion is a different phenomenon. It is an artifact of the voltage produced in an amplifier. All AC current is in waves, so wave physics apply. There are odd and even order distortions. The human ear finds even order distortion pleasant, (musical), but odd order distortion discordant, (not musical). Solid state devices are switches, therefore they produce switching distortion, as well, Switching distortion is discordant. Vacuum tubes are electronic valves, not switches, so most of tube distortion is even ordered.
Cheers,
Geary
Unfortunately the speaker industry or propably the AES disregard the Fundamental musical distortion freq and named the Fundamental as H1.
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Simple. Different designs sound different, period. Selecting a preamp either SS or tubed is a SYSTEM choice. Matching a preamp to an amp is key. What amp are you using ? Digital or analog source ?
IMHO the preamp is the heart of the system. I look for accuracy, low distortion without being lean bright or hard sounding. Also like to mix SS and Tubed. meaning a SS Pre and tubed Amp or visa versa. No RULES just preference.
For example the Audible Illusions is dark and warm. A great candidate for a SS amp like Bryston. Lots of classic combos out there to learn about.
charles
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Hi,
does vacuum tube rectification vs. silicone diodes for rectification have anything to do with the sound?....Mark Korda
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Hi,
does vacuum tube rectification vs. silicone diodes for rectification have anything to do with the sound?....Mark Korda
Yes it have, it have its owns differences, inclusive different tube rectifiers have different sound accents.
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Hi,
does vacuum tube rectification vs. silicone diodes for rectification have anything to do with the sound?....Mark Korda
Why certainly. They argue mostly accuracy and noise over tonality and harmonics. Both can be executed expertly for measurements however can sound totally different.
charles
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Naimnut questioned:
Q1. "I've read comments to the effect that "as you approach the state of the art, solid state and tube equipment begins to sound very similar".
I would agree with that, however then hasten to add that "as you approach the state of the art” smaller differences have a greater effect. An analogy is wet sanding then polishing a high gloss finish on a speaker or car, the more one polishes the better all the details (and alas defects) are revealed. Thus a paradox, they sound more alike but the perfectionist builders and owners of high-end hi-fi care ever more about the ever smaller differences. Also keep in mind there is a niche branch of hi-fi tube electronics designed for a very specific house sound; beauty first, accuracy second. The sound of a Shindo Masseto Tube Preamplifier will never converge with a Boulder 3010’s.
Q2. “I've read that tube equipment tends to generate more even-ordered harmonic distortion. Does this mean that distortion in a tube preamp can cause the sound to come across as "richer" and "fatter"?”
Yes, and a universally recognized master of solid state hi-fi design Nelson Pass has shared his insight that the phase of the distortion harmonics vs. signal also has an effect.
Q3. “I've read with interest Roger Sanders excellent white paper on tubes vs. solid state, and his comments make sense, for power amps. But what about preamps? Do preamps clip?”
I would say in 99.9% of the use cases that hi-fi stereo preamps do not clip. Typical power amps only require 0.5 to 2 volts of signal input to output their hard clipping maximum power and preamps can supply 10 times that.
Q4. “It seems that several factors greatly influence the sound any preamp - the quality of the power supply (bigger, stiffer and isolated in a separate box seem to be important), the quality of the volume control, the quality of the transformers...Frankly I'm out of my depth here, but some of you might be able to help me understand this better.”
That is not so much a question as an outline for a master thesis on hi-fi electronics design. I would agree with your list adding quality of all parts to it while noting that personally I have come to doubt isolating the power supply in a separate box is always necessary. Back to the tube vs solid state question one of my pet theories is that a good chunk of the seemingly intrinsic difference flows from the fact they operate in such different voltage domains. The passive components (resistors, capacitors, diodes, switch contacts, etc.) in the tube circuit have 100s of volts on then compared to the solid state circuit with 10s of volts. Thus the ratios of the signal voltage to the parts’ non-ideal secondary characteristics are very different in the two types of circuits.
Q5. “Some highly rated tube preamps have multiple tubes, and use some in the power supply. Others have very few. How should a person think about this?”
Engineering design takes a design requirement in this case ‘sounds amazingly like real music, interfaces with my existing equipment, is reliable, X inputs, to Y outputs in format(s) Z, user interface like this all achieved in a cost budget of so-much’. Then one considers every circuit ever devised (and newly invented if one is feeling especially confident this week) these weighted towards what has worked for the designer(s) in previous designs. Fitting all that together is very much an art of weighing the compromises of the various options and picking the tradeoffs that best deliver the desired results. These tradeoffs’ weighting also very much include the designer’s and brand’s overall philosophy. As an example I highly value ‘transparency to the source’ and that tends to be easier (and less expensive and potentially more reliable) to achieve with fewer tubes as few as one per channel for a line stage. HOWEVER, if the design requirement also includes the ability to drive low impedance loads like 600 ohm pro-audio gear or (quite likely in 2019) headphones that calls for more tubes with some providing voltage gain and others following later in the circuit providing current drive.
Naimnut observed “use some (tubes) in the power supply” and Mark Korda asked “does vacuum tube rectification vs. silicone diodes for rectification have anything to do with the sound?”
First short answer is across all types power supplies have everything to do with the sound. Sometimes we find tubes in the power supplies simply because the designer(s) and/or the brand and/or their customers are dogmatic ALL TUBES, NO SOLID STATE. Sometimes because they look cool, I am thinking the blue glow of mercury vapor rectifiers. Technically using a tube in a place like the pass element of a regulator can be justified because it is regulating the 100s of volts it was designed for and in such an application if a fault develops a 6550 will survive while a MOSFET dies immediately. In rectification when compared to silicon diodes tube rectifiers generate less high frequency noise when they turn on 50 or 60 times a second. The solid state designer can answer that with filters around the silicon diodes or by using Schottky diodes. The tube rectifier can be quieter, but it will likely not deliver as much current as quickly as a solid state design.
The above just touches the questions asked above from a decidedly engineering perspective. To rework the old saying about real estate what counts is ‘implementation, implementation, implementation’. As you consider your upgrade it is fun to count the tubes like a watch collector counts the complications in a mechanical watch movement. I council to consider that as part of the story while also weighing the capability of those who take a clever design and turn it into the actual thing you unbox and wire into your hi-fi rig.
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Thank you Norman, good read ..... :thumb:
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Norman,
That is very helpful.
Markus / naimnut
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I've slowly transitioned from SS preamps, amps over to tube equipment. I started with tube buffers and tube output CD players and immediately noticed a sound that was much closer to the sound of my vinyl. From there I went into modding a dual-mono guitar amp and it was a bit of a chore/challenge but the result was an improvement as well. I've added a tube phono pre and tube linestage and the result is simply stunning. The music sounds much more 'real' with no noticeable loss of detail and an improvement in imaging as well.
If tube amplification is adding even order harmonic distortion, then I would say that harmonics are what were lost/missing in the original recordings. I listen to everything from 50's jazz/blues/country/pop to new releases and it all sounds better to me with good tube amplification.
We're talking about small amounts of harmonics, the ear can tolerate up to about 5% harmonic distortion before it's noticeable as a 'flaw', but the harmonic distortion added by a tube amp or preamp is much lower.
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Let's not forget the role of feedback. I have a pet theory that it's the lack of large amounts of feedback in a tube design that makes it sound so good, not necessarily 'second order harmonics' being added. The human ear is very sensitive to this type of feedback, so removing equipment that uses medium-to-lots of negative feedback (most SS gear) from the signal path usually results in things sounding 'more real'.
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Many excellent answers and I would like to add a few more. Implementation is extremely important.
1) Besides even vs odd distortion products, some tubes have much less distortion than others. For instance,
JJ's E88cc has some 1/9th the distortion of any other tube I have ever tested. As a reference, where as a typical
tube, say Bugleboy or a 6sn7 might measure 0,1%, the JJ measures .012%, some 19 db less. -60db vs -79db is
quite a difference.
However, there is a negative. Where as one may vary critical parts with typical tubes and not notice any changes in sound
(sonic signature problem), the JJ is extremely critical. Besides the correct parts value, a must, the JJ E88cc requires the tightest tolerance parts, 0,5%, or one will not achieve sonic consistency from component to component.
2) Both tubes and solid state parts (let us use FETs as example) have interelectrode capacitances. Vacuum tubes have metal parts with low resistance/inductance and a vacuum as the dielectric (1.0000) of the internal capacitances.
Solid state parts (transistors in our example) have semiconductor material with much much higher resistance/impedance, and dielectric constant. Silicon, itself, has a dielectric constant of 11.0 or so.
Doping materials are also high. FETs have varying junction capacitances, often up to 25 DC volts between Drain and Gate. So as the signal amplitude varies, and voltage varies the capacitances varies.
Then we have to contend with Miller capacitance, which is 1 + device gain times the grid to plate (collector to base, drain to gate) capacitance. This FET junction capacitance can become quite large, varies with voltage as previously stated, thus Miller capacitance can become huge.
3) Differences in the power supplies. Solid state generally has filter capacitors for each stage, no chokes, and gigantic capacitors in the output stage of said amplifier. Preamplifiers, generally no gigantic capacitors.
Gigantic capacitors have a tendency to become inductive as low as a couple of khz. Not good. In otherwards, they resonate as low as a couple of khz. Becoming inductive means the high frequencies might become exaggerated.
4) Tube power supplies tend to have smaller capacitors, which results in much higher frequencies before becoming
inductive. This is good. Smaller size ufd means one may be able to use polypropylend vs electrolytic type capacitors.
However, many tube components use chokes which is a bad thing. Chokes cause variable isolation between filter capacitors, which is especially important between the decoupling capacitor C2, and previous filter capacitor C1. The musical signal directly sees the decoupling capacitor, C2. For instance, suppose we use two 50 ufd filter capacitors, C1 and C2, separated by a 10 henry choke.
At 20 khz, the choke has a reactance of 1,256,000 ohms. There is huge isolation between C1 and C2
At 2000 hz, the choke has a reactance of 125,600 ohms. The isolation is lowering, but still pretty good.
At 200 hz, the choke has a reactance of only 12,560 ohms. Isolation is not that good.
At 20 hz, the choke has a reactance of only 1,256 ohms, hardly any isolation between C1 and C2. As a result,
C1 will interact with C2. So C2 is not C2 anymore. Yet at 20 khz, virtually no interaction between the capacitors.
Solid state power supplies, on the other had, use resistors, generally do not chokes in the power supply filtering system, thus much more constant isolation between filter capacitors, even if not complete isolation between capacitors. Because of the inferiority of chokes, and number of filtering stages, interactions occur between the musical stages and power rectifiers, power transformer, even power cords. Rollo is quite correct.
That is one way you can tell if the power supply has been adequately designed. Heavy weight is not always important, especially in preamplifiers. Yes, in amplifiers, the power transformer size and weight is important (except for possibly toroidal vs EI core types).
5) Generally, fewer stages are used in tube designs vs solid stage. Fewer stages can mean less distortion, interaction between stages due to common power supply. There is more to distortion than harmonic and intermodulation. There are frequency distortion, phase distortion, transient distortion, dynamic range distortion, scale distortion etc.
6) There is a difference in output impedances (Z) between tube and solid state amplifiers, that of damping factor.
Cheers and hope this helps.
steve
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Tubes are better, that's why..!!
:? :lol: 8)
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Tubes are not affected by local heating effects like transistors. Transistors also don't behave the same with small signals versus large signals. Their bandwidth and linearity is often different for small versus large signals.
Since tubes work off high voltage, the voltage range of the signal is usually a small percentage of the plate voltage. This make tubes inherently more linear. Their bandwidth is mostly identical for small and large signals. Transistors use almost their entire voltage range for the signal voltage.
Steve N.
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Hey you guys -
Thanks for continuing to share such useful information, observations and comments on this thread. Based on everything I've read on the various fora, I'm strongly leaning towards a Supratek or Don Sachs preamp. Both sound like what I'm looking for.
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Another advantage I like about tube
equipment, that I never realized before.
You can change the dynamics of your
Soundstage, Of course.. but, I recently
moved my equipment into a much
smaller room. And changing tubes now,
Means a lot more. Means adjusting the dynamics , with
Different tubes to help fit the room size..
I never heard anyone mention this advantage before, and I've never had to use tubes this way. But, its works.
"OB speakers, and a little tube equipment, sounds
Amazing..."
Just saying... :popcorn:
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All great input but you will never know until you hear both types in your system period end of story. Opinions are just that. LISTEN yourself.
charles
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Another advantage I like about tube
equipment, that I never realized before.
You can change the dynamics of your
Soundstage, Of course.. but, I recently
moved my equipment into a much
smaller room. And changing tubes now,
Means a lot more. Means adjusting the dynamics , with
Different tubes to help fit the room size..
I never heard anyone mention this advantage before, and I've never had to use tubes this way. But, its works.
"OB speakers, and a little tube equipment, sounds
Amazing..."
Just saying... :popcorn:
Agreed! Some amps/preamps can also roll different rectifiers too. For example with my Dennis Had Inspire MB12 monoblocks, I can use a 5ar4, 5R4, 5V5, 5Y3, or a Type 80 (with adapter), this changes the voltage getting to the rest of the circuit and definitely has an affect on dynamics. However, this type of rectifier rolling is very unusual, most tube circuits CANNOT step down a 5AR4 for anything lower voltage, and vice versa. So unless your manufacturer specifically says you can do it, don't even try it.
But even if you're rolling just a single type of rectifier, it makes a difference. Going from an old stock Mullard 5AR4 to a new stock Gold Lion 5AR4 (GZ34), makes a difference. Which just gives more ability to tailor the sound to your room and your preferences. Love that about tubes.
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I prefer tube preamps over SS, but passive can sound even better at very cheap prices if it will drive your system.
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The good thing about tubes is that they can significantly alter the sound. The bad thing about tubes is that they can significantly alter the sound.
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The good thing about tubes is that they can significantly alter the sound. The bad thing about tubes is that they can significantly alter the sound.
Depends entirely on the circuit design and power subsystem. My tube SET monoblocks sound like SS only better.
Steve N.
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1. I've read comments to the effect that "as you approach the state of the art, solid state and tube equipment begins to sound very similar".
Cant say its good or bad, however on the other side of low priced equip, tube amps are always better sound than SS imo.
2. I've read that tube equipment tends to generate more even-ordered harmonic distortion. Does this mean that distortion in a tube preamp can cause the sound to come across as "richer" and "fatter"?
Correct, this is opinion also.
3. I've read with interest Roger Sanders excellent white paper on tubes vs. solid state, and his comments make sense, for power amps. But what about preamps? Do preamps clip?
In the 1990s after replace a 8Ω 92dB by a 4Ω 88dB speaker after a some weeks my preamp blew a diode when running the same power amp.
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The good thing about tubes is that they can significantly alter the sound. The bad thing about tubes is that they can significantly alter the sound.
😎👊 :popcorn:
Thank you for explaining that so perfectly..friend..
Blade..
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They sound different because they are different approaches. The preamp or any other component should not have a SS or tubed character. Should add as close to zero coloration as possible. Examples of color are; bright, warm, dry, dark, sweet or hard. Music should flow with a linear presentation with proper tonality and harmonic structure. No part of the frequency range should stand out over another.
Not easy to find as most components have a house sound. So we look for synergy of components to find our satisfaction. That is why I recommend components from one manufacsturer.
charle
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Worth remember vacuum tubes was invented to reproduce voice and music in movie theaters and transistors was created to commercial and military applications.
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Worth remember vacuum tubes was invented to reproduce voice and music in movie theaters and transistors was created to commercial and military applications.
Agreed.. I started working on electronics when it was all analog. Then it turned more and more digital.. the use of transistors were crucial, in downsizing systems.. tubes just took up too much space.
It broke my heart, seeing all that equipment, military, commercial and other..being replaced with circuit brds.
🍿🍿🍿
(Not against SS.. just saying..)
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I started listen music in radio in a tube radio with the sweet EL34, no FM just AM, SW. PCBs are great to CD players, modems,satelites or radars not to analogue audio, I like this man, no half words:
https://www.youtube.com/watch?v=tsL-i8nFvdA
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Thank you for explaining that so perfectly..friend..
Allow me to elaborate....
Tube heads like tubes because they sound different from one another and you can season to taste. That's a good thing.
The bad thing is that since tubes can alter the sound, you never really know what you have. Here's an analogy --
You bake a cake, and you can add an endless variety of frosting -- chocolate, vanilla, butterscotch or whatever. The frosting will make the cake taste different, but maybe you need a better cake. In other words, you can spend hundreds, even thousands, on tubes before you realize (or not) that what you really wanted/needed was a different tube preamp.
I prefer solid state preamps, but definitely understand and appreciate why others prefer tubes.
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I like the frosting better than the cake. Maybe that explains my tube-love.
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I found this link regarding some of the differences between tubes and transistors pretty interesting:
https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes/distortion (https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes/distortion)
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I found this link regarding some of the differences between tubes and transistors pretty interesting:
https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes/distortion (https://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes/distortion)
A few interesting points concerning and adding to the article, off the top of my head.
My first point is that the distortion measured is for one stage. When two stages are considered, the distortion products of the first stage combines with the second. A stage almost always has both 2nd and 3rd harmonics. This means that for just two stages, we now have 2nd + 2nd harmonics producing a 4th order harmonic. 2nd and 3rd for 6th order, and 3rd order and 3rd order create 9th order harmonic. Thus it is imperative to use as low of distortion device as possible for at least one stage.
Another consideration is that inter-modulation distortion (IMD) is very generally around 3 times that of harmonic distortion (HD) figure. The more complex the music, the more inter-modulation products are produced. High distortion amps generally sound much better with solo rather than complex music.
A third problem that can arise is that when lower DC voltages are applied to the IRF822, and similar devices. As the voltage drops below ~25 volts, junction capacitances vary considerably. This affects the high frequency response and waveform.
One junction capacitance that is very important is the Drain to Gate capacitance. In gain applications, this capacitance times the stage gain +1 is the the "Miller" capacitance. Since the gain varies with voltage, the Miller capacitance varies. The Miller capacitance can range into the thousands of pf at very low voltages. However, in common source applications (less than unity gain), the Miller capacitance is generally the junction capacitance. Stray capacitance is generally small.
Cheers
steve
ps. Forgot to mention the Miller capacitance loads the previous stage, reducing the high frequency response.
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I don’t think you can explain the sound differences between tubes and solid state by focusing only on distortion. I’m sure that designers of both types of equipment would say that their goal is realism and accuracy…and yet even with the same goals, five different designers will likely yield five different sounds.
Is one designer right and the others wrong? Absolutely not, for the designers, it comes down to their individual understanding and therefore execution of realism (whether using tubes or transistors). For listeners, although we say we want realism, it usually comes down to preferences.
A friend of mine says that it can’t sound real unless the bass is pushing you out of your seat (decidedly unrealistic from my perspective). Another says that realism means almost painfully loud and the cymbals sound like they are inside your head. My own simplistic definition uses words like clarity and aliveness.
So, where does this leave us? As long as we realize that our preferred version of realism is probably different from what we just read in a review or on a forum, we will remain more open to trying a piece of equipment that we might otherwise overlook.
I have a tube/mosfet preamp (Belles) feeding a Class D 2Cherry (Digital Amplifier Company) feeding RAAL/transmission line speakers (Salk)…this is my current best version of realism but there is no guarantee that anyone would say that it meets their needs for realism or that it satisfies their preferences…in fact my one friend would say that at a minimum, it needs 2 or 3 subwoofers to pump up the bass.
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Tubes are linear without the need for much/any feedback. SS devices are not linear without a moderate/lot of feedback (with a few exceptions). IMO this accounts for most of the difference in the type of sound you get from them. Throw in the fact that the distortion profile is different as well, with tubes having even order predominant and SS devices having odd order predominant and that gets you to a lot of the reason they sound different.
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Aha... I should have more correctly said that you can’t explain the preference of tubes or solid state by distortion alone... and it would seem as Tyson has noted that the solid state gear that racks up the most accolades is often that gear with low feedback as a part of the design.
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I don’t think you can explain the sound differences between tubes and solid state by focusing only on distortion. I’m sure that designers of both types of equipment would say that their goal is realism and accuracy…and yet even with the same goals, five different designers will likely yield five different sounds.
Is one designer right and the others wrong? Absolutely not, for the designers, it comes down to their individual understanding and therefore execution of realism (whether using tubes or transistors). For listeners, although we say we want realism, it usually comes down to preferences.
A friend of mine says that it can’t sound real unless the bass is pushing you out of your seat (decidedly unrealistic from my perspective). Another says that realism means almost painfully loud and the cymbals sound like they are inside your head. My own simplistic definition uses words like clarity and aliveness.
I find a fundamental aspect is to define the term distortion. For me, and typically, distortion is the deviance of the output from the input. You are quite right that typical harmonic and intermodulation distortions do not fully determine accuracy. There are other distortions, from RCA Radiotron Designers Handbook, 26 engineers, 1960, a list.
1. Non-linear distortion.......... harmonic distortion. Which harmonics are involved
2. Intermodulation distortion.......... sums and differences. Unrelated to harmonics of the instrument/voice.
3. Frequency distortion.......... This includes frequency response limitations/deviations, resonances etc.
4. Phase distortion.......... Basically a alteration between the fundamental and one of its harmonics. Especially if a higher order harmonic precedes the fundamental.
5. Transient distortion.......... Peaks in signal due to design weaknesses. Usually with designs incorporating global feedback
6. Dynamic range and its limitations.......... Basically minimal to maximum signal reproduction.
7. Scale distortion.......... Basically, does the reproduction in the room mimick the spl at the live event?
I have found the frequency response to be of major importance, both from a masking perspective and the opposite, thin, bright.
As mentioned, the output accuracy to input is the ultimate form of minimal distortion and naturalness. The problem is how does one check their designs for accuracy. If those 5 designer's produce 5 different "sounds", then one at most, and probably none actually performed any sophicated listening tests to establish accuracy. More than likely, none of the 5 designs are sonically accurate.
Then there is the problem of an individuals reference. We all hear differently, however, if we all had exactly the same musical reference, then we would all agree what was most accurate. However, we all have different live musical references. We also have many who don't wish accuracy/naturalness, but another standard. That is personal preference.
Then a recording may be off, and manipulation is necessary to bring some sort of naturalness back.
It certainly can be complicated. Personally, it took me some 5 1/2 years just to get my test speaker accurate. It took some 40 years to get the preamp, amplifier, and source truly accurate. The result is simply amazing.
After all that work, all I can say is, good luck to everyone.
cheers
steve