Why Tube Amps Sound Different (and better) Than SS Amps
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Ethan ,I ve watched your vid regarding the null test and I think we agree more or less , you re talking about a digital null test and digital files being equal .
I had more or less the same experience that's why I am running a 200 $$ cd player in my system .
The money I save , I spend on real value namely analogue tape and tubes
. and speakers
Secondly we don't even fully understand the electromagnetic force , which is what a acoustic signal becomes after the recording mike, it becomes a electromagnetic signal , so to say we know it all is fine with me , but only in the digital world that is
I had more or less the same experience that's why I am running a 200 $$ cd player in my system .
The money I save , I spend on real value namely analogue tape and tubes
. and speakers Secondly we don't even fully understand the electromagnetic force , which is what a acoustic signal becomes after the recording mike, it becomes a electromagnetic signal , so to say we know it all is fine with me , but only in the digital world that is
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Another thread with the expected outcome. I have not read it all but will throw out a few things I have learned below. This is for "typical" tube and SS designs, not OTL tube amps or tube/SS hybrids. I would not generally say tubes are better; they are different, and people may prefer tube or SS for various reasons. I tend to like tube preamps and SS power amps, for instance, for different technical and sonic reasons. I am also more than willing to discuss radar circuits and systems since I have a lot of experience with them but that seems pretty far off-topic.
FWIWFM - Don
- Tubes have a different distortion characteristic that leads to lower distortion terms in the series due to their factorial (tube) vs. exponential (transistor) gain characteristics. Of course, higher gain is good for other reasons.
- Tube circuits tend to be more single-ended designs, especially preamps, compared to differential SS designs. This means the tube circuits' distortion is typically dominated by second harmonic distortion and all other terms are included but smaller. SS's first major term is third harmonic and the series is primarily odd-order only (even order terms are suppressed in an ideal differential design).
- Tube circuits also clip more softly, at least in the initial stages of clipping, due to their gain and distortion characteristics. This makes them less harsh when mildly over driven.
- Tube amplifier circuits, and some SS amplifier circuits (McIntosh), use the output transformer for impedance transformation. Tube designs can put out as much current as SS, but it usually takes a lot more tubes. And the transformer adds additional distortion and power limitations, natch.
- The output impedance of most tube designs is an order of magnitude or more higher than SS designs. This makes tube components much more sensitive to the load, be it the power amp or a speaker. IME tube amp circuits roll off the very top end when presented with a low-impedance load at HF, something ribbons and electrostats tend to do.
FWIWFM - Don
Ultra sonics and lowering of sperm count. Quid pro quo.perhaps this a good PM topic on what kind of power amps are in that radar, just a suggestion unless you want to talk about the audiblily of Ghz radar amps when pulsed...
Voltage= current x resistance or E=IxR is a voltage formula and I was specifically referring to the power formula.
perhaps this a good PM topic on what kind of power amps are in that radar, just a suggestion unless you want to talk about the audiblily of Ghz radar amps when pulsed...
Tom-the guy is commenting about something of which he really doesn't know what he thinks he knows.
I suppose I brought up colorations. At least for my post you know the speakers, and the equipment by model number. Specific enough?
You have the audiophile idea of transparency that a device can pass on the signal without altering or coloring it. The Spectral transparently passed on the sound of the tube amp. The tube amp couldn't pass on the sound of the Spectral because it wasn't transparent. Simple enough even a PhD might understand, unless he doesn't wish to do so. Again, good SS amps are more accurate nothing wrong with saying you prefer tube sound, just don't present it as superior rather than your preference.
The null test is a good one. Regardless of knowing what is happening or not, when you get good nulls there isn't much else to say. Doing some of those convinced me of things I didn't believe. I have been surprised by people who learn of this method and yet aren't convinced at all by it. Usually the reaction is to double down on faith.
And everything you put in the signal path to achieve unity gain had a benign effect? Sorry I don't buy that for one, much less a microsecond.
As far as the equipment, I seemed to have missed that. Could you provide the post number?
Not surprised you don't buy it. I wouldn't have believed it before I did it. Like simply not being able to hear a power amplifier inserted or removed from the signal path. Simply could not hear it at all.
I was using Quad ESL63 speakers, amps were VTL 75/75 with some upgraded parts connected in triode, and a Spectral DMA50. Has been a few years, but I believe I was using a Meridian DAC at the time. Only one of the resistors to do the voltage division were in the direct signal path. As I recall it was a pairing of Vishay and Holco to get unity gain from resistors I had on hand. Interconnect was some homemade silver and teflon.
You can read post #13. To recap, series connected a VTL loaded with a power resistor and the output divided to achieve unity gain feeding a DMA50. The only thing extra in the direct signal path was a Vishay resistor, and silver interconnect. Sound was that of a VTL which at the time I thought superior to and a better higher fidelity amp of the two. Reversed positions and heard no change. Could insert or remove the Spectral and not hear any indication it was in circuit or out. Sounds like a definition of straight wire with gain or complete audible transparency to me.
Would be nice if some audio publication such as yours did an article about such things. I have suggested before that someone with a love for SET's but power hungry speakers could use the procedure to feed an SET which fed a good SS amp to have their cake and eat it too. Do you think the audiophile public would be interested in such a thing?
They should be interested if they care about the truth. I for one found your experiment highly interesting. Given the high similarities in sound between my (push-pull) tube amps and the Spectral DMA-260 (see above) you could have replaced the DMA 50 with my amps in such an experiment -- but on other speakers, mine or a similarly benign load, not on Quad ESL63 speakers. On those my amps would have collapsed, too demanding of a load.
Without reading the entire thread, can someone summarise why, other than the known, measurable differences, valve and SS amps sound different ?
Thanks
Thanks
I think known measurable differences are enough explanation. Most valve amps depart from high fidelity to the input signal enough they have an audible sound quality that overlays the input. Is that the kind of explanation you are looking for?
In a perfect amp, output would equal input only with more voltage and current. Tube amps depart from that enough to be heard.
In a perfect amp, output would equal input only with more voltage and current. Tube amps depart from that enough to be heard.
I think DonH summed it up pretty well in his post. Other people have surmised that there is a difference between electrons flowing through a vacuum and electrons moving through a semiconductor. Also, the majority of tube amps have an output transformer which has a big influence on the quality of the sound. The output impedance of a tube amp is also higher than the output impedance of a SS amp and if the impedance is high enough, it will effect the frequency response in non-linear ways. Some of the SF tube amps have a very low output impedance and some said they sounded too much like SS. The McIntosh MC-275 tube amp has measurements that rival a good SS amp.
And apparently enough to fool you into thinking that your VTL tube amps were much better sounding (1/3 better by your estimation) than your Spectral amp until you rigged up your test.
I believe Nelson Pass ran a test and 30% of the sample groupo preferred second harmonic distortion, 30% preferred third harmonic distortion. How the hell is there a one fits all answer if that's the case?
The measurements of the SF amps and the McIntosh MC-275 have been well documented in Stereophile. I trust JA when he makes measurements. As for the sound differences (if any) between a vacuum tube where the electrons are flowing in a stream/beam in a vacuum vice moving through a semiconductor, all bets are off. I don't know if that has ever been attempted and how it would possibly be measured.
Yes, that is right.
Audiophiles often have this notion they know better accuracy as better sound quality. That they will prefer what is more accurate. That knowing live music allows them to recognize when it is more accurately reproduced from a recording. That is not the case in large measure.
I must say mep, I don't get your fascination with this electron beam vs semi-conductor sourced electrons. The electrons move due to voltage differences they don't know where they come from. You think an electron that was sourced from a cloud in a vacuum rattles down the wire toward the speaker differently than one sourced from a semiconductor filling a hole in a crystal lattice? Maybe the one from the lattice of a semiconductor is more accurately herded versus one in a cloud bouncing around willy nilly if we must anthropomorphize the electron.
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