Why Tube Amps Sound Different (and better) Than SS Amps

[Bruce B]

The biggest PITA I had with CAT is the attached umbillical from the PS to the unit. I know other manufacturers use detachable cables for this, which is great. Just think what attached PC's would do.

 

[DaveyF]

The biggest PITA I had with CAT is the attached umbillical from the PS to the unit. I know other manufacturers use detachable cables for this, which is great. Just think what attached PC's would do.

Bruce, while i totally get your point about the umbilical cord on the PS unit of the CAT, I also agree with Ken that IF a detachable cord would effect the SQ negatively; which Ken strongly believes it would, then an attached cord it is.
As to amps and detachable cords...I'm not so sure that a good quality cord like the Shunyata IF it were hardwired in would be less desirable SQ wise than an iec with a Shunyata. I suspect that my friend is on to something in regards to the probable potential loss at the iec connection.

 

[DonH50]

I am going to leave switching supplies out of the discussion; they add mucho' complexity but generally have many of the same issues. Unless that is the topic? In that case I would go a different direction than what follows, although ultimately have the same conclusion.

The line frequency is 50 or 60 Hz. Of course diodes, FETs, or whatever used in the power supply can switch much faster than that, but they are usually on the other side of a transformer (with relative low bandwidth). The amp gets its instantaneous current from the power supply capacitors; if the supply frequency is not high enough or capacitor bank not large enough to supply the demand then the rails will sag even if you have a superconducting cable. (Aside: I have played with superconducting microwave filters and they are pretty cool, pun intended!) Wideband current delivery and thus voltage spikes are related to inductance. Voltage spikes on the line are usually filtered as noise so you don't get EMI. And I still struggle with how 3' (1 m) of power cable can provide greater instantaneous bandwidth (voltage or current) when the other end is plugged into many feet of standard house wiring to your service box. That is not an ideal voltage source.

Diodes and power devices do not switch instantly and have their own intrinsic resistance and parasitic capacitance (charge storage). They can switch much faster than audio circuits, but a standard full-wave rectifier (or half-wave) conducts for a significant fraction of the power cycle. Not sure this is the place to get into device physics.

An under-sized power cord can certainly cause problems that anyone can measure, but I am struggling to see how an esoteric power cord can increase the bandwidth supplied at the wall outlet. It seems to me that will ultimately limit power delivery.

I am obviously missing what Atmasphere and others are seeing and hearing so will bow out of this. Should have stayed away longer...

I don't feel like listing credentials or the test equipment I have access to. I shall shut up.

Good day - Don

 

[Mark (Basspig) Weiss]

Supposing you have all solid core copper 6awg into a 3 phase transformer right outside your home with less than 100 ft to your panels?

How is Mary Ann Mark? My regards to my compatriot.

The wiring from my panel to the meter outside is 000 gauge (conductors about 3/4" diameter, cable jacket about 1" diameter per conductor). From the meter to the pole, it's utility company wire, which they tell me is aluminum and maybe 2awg. Conductors only 3/8" diameter approx. 6awg for a 220 v mains run would be considered grossly inadequate in the United States and is illegal, according to the NEC.


Mary Ann is fine. Her parents and sister are here too, living with us. Quite a "close" family, given we're six people, living in a tiny 2-bedroom house! Only Asians can live this way and be happy. Amazing.

 

[Mark (Basspig) Weiss]

Man oh man, how high is that??

I don't know, because my CEL 201 meter tops out at only 140dB. But the ground shakes outside with bass below 20Hz, after penetrating 36" foundation walls.

 

[zztop7]

High powered power amps when running at high power can create harmonics on the incoming power feed, and these harmonics can radiate to nearby power cords and interconnects and tubes and wood chassis etc that are not shielded (a lot of high end crap is like that believe it or not) and this then gets amplified and some folks claim to hear it. Also, some high end transformers in the power supply apparently are quite capacitive or other coupling effects due to huge diode surges and pass noise etc through to the power resovoir caps which can be quite large in value and series impedance at audio frequencies can be enough to modulate the active components...it really mostly comes down to urine poor design (and there is a lot of that in hi end audio too). You would, as Tim says, not expect to find poor design in hi end ultra high priced audio stuff but you do, and you find plenty here, that believe that price makes right. ha

I agree that a power transformer should not pass this stuff back to the line but apparently there is some real junk out there.

Above you wrote: "mostly comes down to urine poor design" !!!

Are you checking up on us to make sure we are reading closely ???

zz.

 

[MylesBAstor]

Above you wrote: "mostly comes down to urine poor design" !!!

Are you checking up on us to make sure we are reading closely ???

zz.

Isn't it great being an arm chair QB?

 

[Ethan Winer]

I have to assume that Ethan has never done any measurements whatsoever and is talking entirely off the top of his head

I guess you don't know much about me. I've been designing and measuring audio devices for more than 40 years. I've seen it all and done it all. Don explained it well: The reserves come from the power supply capacitors. Large electrolytic caps do the heavy lifting, and smaller bypass caps for the HF transients. I agree with Tom as well, but paying $1,000 for a power cord isn't going to solve that when what's more useful is a $30 Corcom RFI filter.

--Ethan

 

[Atmasphere]

I am going to leave switching supplies out of the discussion; they add mucho' complexity but generally have many of the same issues. Unless that is the topic? In that case I would go a different direction than what follows, although ultimately have the same conclusion.

The line frequency is 50 or 60 Hz. Of course diodes, FETs, or whatever used in the power supply can switch much faster than that, but they are usually on the other side of a transformer (with relative low bandwidth). The amp gets its instantaneous current from the power supply capacitors; if the supply frequency is not high enough or capacitor bank not large enough to supply the demand then the rails will sag even if you have a superconducting cable. (Aside: I have played with superconducting microwave filters and they are pretty cool, pun intended!) Wideband current delivery and thus voltage spikes are related to inductance. Voltage spikes on the line are usually filtered as noise so you don't get EMI. And I still struggle with how 3' (1 m) of power cable can provide greater instantaneous bandwidth (voltage or current) when the other end is plugged into many feet of standard house wiring to your service box. That is not an ideal voltage source.

Diodes and power devices do not switch instantly and have their own intrinsic resistance and parasitic capacitance (charge storage). They can switch much faster than audio circuits, but a standard full-wave rectifier (or half-wave) conducts for a significant fraction of the power cycle. Not sure this is the place to get into device physics.

An under-sized power cord can certainly cause problems that anyone can measure, but I am struggling to see how an esoteric power cord can increase the bandwidth supplied at the wall outlet. It seems to me that will ultimately limit power delivery.

I am obviously missing what Atmasphere and others are seeing and hearing so will bow out of this. Should have stayed away longer...

I don't feel like listing credentials or the test equipment I have access to. I shall shut up.

Good day - Don

Do you know of any tube amps with switching supplies? They might be more germane to the conversation. FWIW Don, I had really old wiring that desperately needed replacement in a house I lived in. Try as I might I could not hear any improvement with power cords in that house. But if I took some of the power cords over to my dealer a mile away, or to a friend's house across town the effects were easy to hear. As I pointed out earlier (twice or three times now...) ROMEX has very good properties but is not legal as a power cord. Most power cords don't perform nearly as well as ROMEX. I do recommend reading the link posted earlier (here is is again: http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm). There is plenty of technical information in this link that shows what is up.

I guess you don't know much about me. I've been designing and measuring audio devices for more than 40 years. I've seen it all and done it all. Don explained it well: The reserves come from the power supply capacitors. Large electrolytic caps do the heavy lifting, and smaller bypass caps for the HF transients. I agree with Tom as well, but paying $1,000 for a power cord isn't going to solve that when what's more useful is a $30 Corcom RFI filter.

--Ethan

Yes, most of us come without credentials on forums like these. However I seriously doubt that you have seen and done it all. I know I haven't and I don't know of anyone who has; to think that you are going to be the one seems highly unlikely. So a blanket statement like this generally leads me to doubt. It is also obvious that you have not read my posts with total comprehension- I don't think paying $1000 for a power cord is always going to solve things either (nor do I think a $30 filter is going to help matters that are probably best addressed by proper design). What I **do** maintain, because I have measured it, is that power cords do indeed make a difference, one that is audible and measurable and by measurable we are talking easy measurements, although it is apparent that Shinyata Research has done good work forwarding that technique. What I mean by this is a power cord does not have to be expensive, it has to *work*.

I don't accept the 'explanation' that some power cords are 'broken' or just too cheap. If you are going to take that stand, just be informed that you are undermining your position in doing so: you are admitting that power cords make a difference.

I see that you took my comment out of context; in doing so you make it appear that you have indeed measured the effects of power cords. I find that conclusion not credible; from prior posts and your own video this is patently obvious. Again, put up or shut up.

 

[mep]

I guess you don't know much about me. I've been designing and measuring audio devices for more than 40 years. I've seen it all and done it all. Don explained it well: The reserves come from the power supply capacitors. Large electrolytic caps do the heavy lifting, and smaller bypass caps for the HF transients. I agree with Tom as well, but paying $1,000 for a power cord isn't going to solve that when what's more useful is a $30 Corcom RFI filter.

--Ethan

Wow! I guess that puts an end to questioning your credentials. Where was it that you had your electronics training?

 

[MylesBAstor]

Wow! I guess that puts an end to questioning your credentials. Where was it that you had your electronics training?

C'mon on Mark! John beat you to that question.

 

[microstrip]

The debate on credentials is ridiculous. People can have a fantastic knowledge on electronics and very challenging electronics instrumentation, but unless they fully know how to correlate the electrical performance of their amplifiers with its sound quality they will be of no help in this debate.

IMHO if someone considers from start that all decently measuring competent amplifiers sound the same and minimizes the role of the amplifier in the chain he will not be able to contribute in a positive way to these debates about the origins of the often called "small differences".

 

[DonH50]

Do you know of any tube amps with switching supplies? They might be more germane to the conversation. FWIW Don, I had really old wiring that desperately needed replacement in a house I lived in. Try as I might I could not hear any improvement with power cords in that house. But if I took some of the power cords over to my dealer a mile away, or to a friend's house across town the effects were easy to hear. As I pointed out earlier (twice or three times now...) ROMEX has very good properties but is not legal as a power cord. Most power cords don't perform nearly as well as ROMEX. I do recommend reading the link posted earlier (here is is again: http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm). There is plenty of technical information in this link that shows what is up.

I have not been here much lately and so jumped into a 70-page thread. I did not look back to see what sort of amps we were discussing. (OK, I had a pretty good idea what sort you had in mind, which is why I left out switching supplies. )

I skimmed the Shunyata thread. I prefer to not comment for various reasons (no real point as my credibility is no better than anyone's on the 'net; I do not agree with some of it, or at least its relevance in this application; and, I have too many other things going in Life at the moment).

If you throttle the connection betwixt wall and amp it will most certainly limit power. If you use a heavy gauge cord that essentially makes the in-wall wiring (which is only 14 AWG for most modern homes, used to be 12 AWG) dominate the impedance then you have resolved the choke point, at least in my mind. I can buy a 10 AWG power cord from a lot of places. I have never tried a really expensive power cord so in that sense my opinion is irrelevant, another good reason to back out of this thread. My little pea brain ain't up to all this audiophile stuff; I'm a hairy-knuckled engineer who likes to listen and perform.

 

[egidius]

Do you know of any tube amps with switching supplies?

David Berning with his fascinatingly sounding ZOTL amps springs to mind.

 

[morricab]

The debate on credentials is ridiculous. People can have a fantastic knowledge on electronics and very challenging electronics instrumentation, but unless they fully know how to correlate the electrical performance of their amplifiers with its sound quality they will be of no help in this debate.

IMHO if someone considers from start that all decently measuring competent amplifiers sound the same and minimizes the role of the amplifier in the chain he will not be able to contribute in a positive way to these debates about the origins of the often called "small differences".

Quite right, that is why I have found that engineers in general (there are always exceptions) are unaware that there is not a good correlation. It requires a scientifically inquisitive mind to start trying to put the two together.

This is why when I hear people from the engineering side of the equation making statements like Ethan's I just shake my head because it tells me that they have very underdeveloped observational skills. Of course human's can be fooled but that is also bi-directional and I would posit that people like Ethan and the great Randi are exploiting the other side of the coin to develop reputations as "Myth Busters". You put people under stress to make a definitive choice and their discriminative ability often shrinks or disappears. Not a big surprise because most people don't do so well under stress. Ethan, IMO you exploit this also well known "characteristics" of human psychology claiming that there aren't differences but perhaps you even (deep down) hear them yourself.

Comparing double blind tests in audio is not the same as with pharmaceuticals.

 

[rbbert]

And few (with experience) would try to claim that double blind pharmaceutical testing isn't fraught with problems and uncertainties.

 

[MylesBAstor]

Quite right, that is why I have found that engineers in general (there are always exceptions) are unaware that there is not a good correlation. It requires a scientifically inquisitive mind to start trying to put the two together.

This is why when I hear people from the engineering side of the equation making statements like Ethan's I just shake my head because it tells me that they have very underdeveloped observational skills. Of course human's can be fooled but that is also bi-directional and I would posit that people like Ethan and the great Randi are exploiting the other side of the coin to develop reputations as "Myth Busters". You put people under stress to make a definitive choice and their discriminative ability often shrinks or disappears. Not a big surprise because most people don't do so well under stress. Ethan, IMO you exploit this also well known "characteristics" of human psychology claiming that there aren't differences but perhaps you even (deep down) hear them yourself.

Comparing double blind tests in audio is not the same as with pharmaceuticals.

Thank you. I've brought up the inverse relationship between stressors and perceptual skills many times and it's been ignored. And that's just one of the many issues that can't be eliminated in testing. It's also much different when it's one endpoint you're asking people to answer vs. Many. Then again you get into the myriad of issues - many of which are still poorly understood- with short term memory and brain processing eg. Serial vs. Parallel. But as they say ignorance is bliss.

 

[Ethan Winer]

What I **do** maintain, because I have measured it, is that power cords do indeed make a difference, one that is audible and measurable and by measurable we are talking easy measurements ... put up or shut up.

I've said this literally dozens of times: The only measurement that matters is at the output of the connected equipment. Measuring only the output of the AC wire is irrelevant. Since changes at the output of the audio devices are never shown, the burden of proof to "put up or shut up" is clearly on anyone making the claim. What do you have?

--Ethan

 

[mep]

I've said this literally dozens of times: The only measurement that matters is at the output of the connected equipment. Measuring only the output of the AC wire is irrelevant. Since changes at the output of the audio devices are never shown, the burden of proof to "put up or shut up" is clearly on anyone making the claim. What do you have?

--Ethan

Why is it that other people have to prove your claims? What measurements have you taken with power cords to show their is no difference between a cheap power cord and what would be considered a high-end power cord? Do you have actual measurements or just supposition? Ralph has already explained that he has taken measurements and has seen differences between power cables.

 

[JackD201]

I've said this literally dozens of times: The only measurement that matters is at the output of the connected equipment. Measuring only the output of the AC wire is irrelevant. Since changes at the output of the audio devices are never shown, the burden of proof to "put up or shut up" is clearly on anyone making the claim. What do you have?

--Ethan

You can say it a million times more. You've published a book of conclusions Ethan. The old turn the table trick sucks right? So what's it gonna be?

Tom. That's not what Ethan said. Look more closely.