WHY do tube preamps sound different than Solid State?

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bladesmith

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Re: WHY do tube preamps sound different than Solid State?
« Reply #40 on: 10 May 2019, 08:20 pm »
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..)

FullRangeMan

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Re: WHY do tube preamps sound different than Solid State?
« Reply #41 on: 10 May 2019, 08:35 pm »
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

Early B.

Re: WHY do tube preamps sound different than Solid State?
« Reply #42 on: 10 May 2019, 09:19 pm »
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.



glynnw

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Re: WHY do tube preamps sound different than Solid State?
« Reply #43 on: 10 May 2019, 11:30 pm »
I like the frosting better than the cake.  Maybe that explains my tube-love.

Freo-1

Re: WHY do tube preamps sound different than Solid State?
« Reply #44 on: 10 May 2019, 11:52 pm »

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

Steve

Re: WHY do tube preamps sound different than Solid State?
« Reply #45 on: 2 Jun 2019, 03:43 am »
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

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.

« Last Edit: 14 Jun 2019, 04:29 am by Steve »

RonN5

Re: WHY do tube preamps sound different than Solid State?
« Reply #46 on: 2 Jun 2019, 01:14 pm »
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.

Tyson

Re: WHY do tube preamps sound different than Solid State?
« Reply #47 on: 2 Jun 2019, 03:21 pm »
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.

RonN5

Re: WHY do tube preamps sound different than Solid State?
« Reply #48 on: 2 Jun 2019, 03:39 pm »
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.

Steve

Re: WHY do tube preamps sound different than Solid State?
« Reply #49 on: 14 Jun 2019, 05:05 am »
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