|   Why transistor amp technology is inherently superior to tube | skeptic
Oct 28, 2003 12:56 PM | | All things being equal (they seldom are) the potential for producing high quality solid state audio amplifiers far surpasses the possibilities for vacuum tubes. Here's why.
How vacuum tubes work. For those who only know vacuum tubes as small hot glass cylinders with pins at one end doing what transistors would do, here's a quick synopsis of their operation. In an evcuated glass envelope, electrons are boiled off a filiment (direct heated cathode) or from a metal plate heated by a filament (indirectly heated cathode) and form an ionized cloud in space. They are collected on another plate called the anode or simply plate. A power supply of several hundred volts DC attracts and collects the electrons from the plate and replenishes the electrons depleted from the cathode completing a circuit. This is a diode having 2 electrodes. A wire mesh screen called a control grid is placed in between the cathode and plate. A small change in the voltage on the control grid can cause a big swing in the rate of electron flow between the cathode and plate and therefore its signal is amplified. This three electrode arrangement is called a triode. Additional grids can be placed between the control grid and plate to form tetrodes and pentodes improving the electrical performance of the tube but the principle is exactly the same. Some of the variables of these tubes are the physical size, shape, and materials of the electrodes and their arrangements with respect to each other, how hot the filament or cathode gets, the ambient temperature, and the integrity of the vacuum. These variables determine their specific electrical properties. Vacuum tubes are inherently high voltage, low current devices and therefore have a high impedence (Voltage/Current.) In order to deliver power to a loudspeaker system, an inherently low impedence device, the designer must use an intermediate impedence matching transformer or they won't work. (The sole exception is the OTL output transformerless tube amplifier pioneerd by Julius Futterman, one of the little known geniuses of audio history.) The inefficiency and inherent distortion caused by these transformers is a major source of trouble for vacuum tube audio amplifiers. (OTL amplifiers sound very similar to transistor amplifiers at least to my ears in the limited exposure I had to them.)
By contrast, transistors consist of germanium or more commonly silicon single crystals into which doping impurities have been introduced. Their operation is very complicated to understand requiring some knowledge of quantum physics but it is safe to say that electron flow through them is controlled at the sub atomic level, far more precisely than by vacuum tubes. They are three element devices like triodes, their components being called emitter, base, and collector for bipolar transistors. Other types like FETs may have names like source, gate, and drain. Where all tubes have the same direction of electron flow, cathode to plate, transistors can be made to operate as amplifiers with current flowing in either one direction or the other giving the designer more flexibility. They can be manufactured as true complimentary symetry pairs precisely matched except opposite. Therefore we can have NPN or PNP type bipolar transistors and N type and P type Field Effect Transistors. Transistors are inherently low voltage high current devices and so have a much lower source impedence making them ideal for delivering power to loudspeakers without any intermediate devices with the possible exception in some designs of a large capacitor to keep dc out of the speaker. They are inherently very efficient especially when compared to vacuum tubes.
Where vacuum tubes are assembled from intricate mechanical assemblies, transistors are laid down by molecular diffusion in furnaces and the process can be very tightly controlled. Once the crystal sturcture is complete, the leads soldered on and the |
| transistor amp technology is inherently superior to tube part II | skeptic
Oct 28, 2003 12:58 PM | | Where vacuum tubes are assembled from intricate mechanical assemblies, transistors are laid down by molecular diffusion in furnaces and the process can be very tightly controlled. Once the crystal sturcture is complete, the leads soldered on and the assembly sealed, they are nearly impervious to physical shock and only extreme heat, high voltage, mechanical destruction, atomic radiation, or chemical attack can destroy them. Therefore they are very reliable. They are also usually very cheap being produced in enormous quantities sometimes millions at a time. The entire worldwide electronics industry is tooled to manufacture transistor circuits including their special ultra condensed versions called integrated circuits where dozens, thousands, or millions of transistors are laid down in a specific circuit pattern on a single packaged crystal substrate. Even most of these are generally cheap.
Mathematical modeling of these devices, their applications engineering, and their circuit optimization have been proceeding with the aid of computers for over 40 years. They are very well understood and for those who are skilled at designing circuits using them, can produce virtually any desired electrical effect. |
| I'm sure the gloves will come off on this one... | trollgirl
Oct 29, 2003 6:59 PM | | but I see I get first swing! I'm on my 5th tube amp, having owned a Stereo 70, Stereo 35, two HH Scott's, and now an Anthem Amp 1. The Anthem is on the shelf and has been for months, having been replaced by a Yamaha M-35. It is solid-state, and sweet sounding - also small and light in weight. What else could I ask in a power amp? I am keeping my 6DJ8 preamp forever, however. I am sure that all you say about tubes vs. transistors is true.
Laz |
| I am amazed.... | skeptic
Oct 30, 2003 5:54 AM | | ...that anyone here actually agrees with me.
BTW, I still have my HK tube amp in the basement somewhere. And it still works. And its sound still stinks. |
| Yes, IMO everything skeptic says is indeed true ... | woodman
Nov 2, 2003 6:12 PM | | ... I've been involved with audio for more than 65 years, and today you couldn't get ANY device using tubes past my front door as a friggin' gift!
I had to work with tubes for 35-40 years and grew to HATE the damned things. The inconsistencies from one tube to another literally frustrated my socks off. I onced owned an audio service facility catering to musicians - servicing their guitar and bass amplifiers primarily. At least 95% of the "problems" these amps came in for were tube-related. I had to buy certain tube types in case lots in order to find suitable replacements for the tubes that were not performing "up to snuff" - at least in the mind of the amp's owner. "Microphonics" among preamp stage tubes was a MAJOR headache. Yuck!
I also spent a whole lot of years servicing tube-based TV sets, where tubes once again accounted for 95% or more of the problems encountered. Many circuits required tubes to perform tasks for which they weren't well suited. This led to all sorts of headaches since the tubes would test perfectly in a "tube-tester" yet wouldn't perform in the circuit in which they were inserted! You can imagine the trouble one encountered after fixing a TV problem with a tube replacement - yet the set owner would claim that a tube couldn't have been responsible, because he'd already tested them all and they were all good!
I don't care what any tube-based amp sounds like - you couldn't give me one on a silver platter!
woodman
P.S. I never even mentioned the fact that tubes are now manufactured in such small quantities that the prices have become totally, irrevocably absurd! Right through the ol' roof they are ... plus I have very little confidence in the technical skills available in places like Czechoslovakia, or Russia, or who knows where else some little company is attempting to manufacture vacuum tubes. I don't believe that there is a single American company making the damned things anymore. Doesn't that tell anybody anything? There quite simply is no market worth pursuing, and it's shrinking! |
| Yes, IMO everything skeptic says is indeed true ... | RGA
Nov 8, 2003 9:26 PM | | "There quite simply is no market worth pursuing, and it's shrinking!"
Wrong...tube sales have been growing failry rapidly since the early 1990s and so have demand for LPs...Turntable sales have increased as a percentage of sales against cds.
Tube prices. Well a 12XL7 for $6.95 which will last you 5-20 years is hardly a blow to one's pocket. about $11.00 a pop for an EL 34. http://www.thetubestore.com/ And this place is more expensive than many others so you can do better.
There are tubes in certain Audio Note products that are gauranteed for 100,000 hours - which means they'll probably provide double that knowing Audio Note. That's something like 11.4 years assuming you leave the amp on 24 hours a day continuously.
Tube amplifiers today use much better parts than yester year and the tubes are far more reliable. Companies are starting production of tubes and tube amplifiers at a rapid pace. McIntosh has started in on tubes again. Their top of the line gear is Tube based. Their tube preamp is a dizzying $13,000.00Canadian.
The cheaper tube amps from ASL and Jolida are under 1k...though they have more quality control issues to be wary of. |
| Actually Western Electric has started up again as well... | RGA
Nov 8, 2003 9:35 PM | | http://www.thetubestore.com/wesel.html |
| Baloney | 300A
Nov 25, 2003 10:57 PM | | Woodman, I worked on the same crap you have and almost all the problems you mention is because of poor designing, which you should have known.
But properly designed, tubes sound far more transparent, accurate and the price isn't that high if you were to get them wholesale.
"Yes, IMO everything skeptic says is indeed true ...
... I've been involved with audio for more than 65 years, and today you couldn't get ANY device using tubes past my front door as a friggin' gift!"
That is certainly your perogative. I have seen SS components flake all the time, and sound bad, and I wouldn't use one.
"I had to work with tubes for 35-40 years and grew to HATE the damned things. The inconsistencies from one tube to another literally frustrated my socks off. I onced owned an audio service facility catering to musicians - servicing their guitar and bass amplifiers primarily. At least 95% of the "problems" these amps came in for were tube-related. I had to buy certain tube types in case lots in order to find suitable replacements for the tubes that were not performing "up to snuff" - at least in the mind of the amp's owner. "Microphonics" among preamp stage tubes was a MAJOR headache. Yuck!"
Guitar amps are Designed to produce distortion and overload tubes. SS amps blow up all the time. Contact a service center and find out. I have.
"I also spent a whole lot of years servicing tube-based TV sets, where tubes once again accounted for 95% or more of the problems encountered. Many circuits required tubes to perform tasks for which they weren't well suited. This led to all sorts of headaches since the tubes would test perfectly in a "tube-tester" yet wouldn't perform in the circuit in which they were inserted! You can imagine the trouble one encountered after fixing a TV problem with a tube replacement - yet the set owner would claim that a tube couldn't have been responsible, because he'd already tested them all and they were all good!"
Again, it is the design. A horizontal output tube is run class C, but they don't use fix bias to protect the tube.
The same failures happened to horizontal output transistors. I replaced them all the time.
I don't care what any tube-based amp sounds like - you couldn't give me one on a silver platter!
Fine, that is your opinion, but please try to be fair.
I don't have problems with my tubes at all. They have been running for years.
"woodman
P.S. I never even mentioned the fact that tubes are now manufactured in such small quantities that the prices have become totally, irrevocably absurd! Right through the ol' roof they are ... plus I have very little confidence in the technical skills available in places like Czechoslovakia, or Russia, or who knows where else some little company is attempting to manufacture vacuum tubes. I don't believe that there is a single American company making the damned things anymore. Doesn't that tell anybody anything? There quite simply is no market worth pursuing, and it's shrinking!"
I use Russian tubes and haven't had a failure in years. Maybe they are better than you thought.
ps. Skeptic needs to study some more. Check out the postings between us down below. |
| xistors & cheap ceramic caps share a distortion tubes don't have | thomasd
Oct 29, 2003 11:39 PM | | Silicon (not silicon dioxide) has a K=12 whereas vacuum has the theoretically ideal dielectric constant K=1.000000. Care to guess which amplifying device type has the cheap capacitor sound characteristic?
Every silicon transistor has its own set of three Z5U ceramic quality intrinsic parasitic capacitances that the sound is unavoidably affected by, so transistors suffer from a whole class of nonlinearities that tubes don't have. And interestingly enough, this characteristic of transistors and trash quality ceramic caps hardly shows up in conventional harmonic distortion tests. However, I don't know if anybody has come up with an equivalent to a dielectric absorption test for bipolar and fet transistors:)
Triodes, as a variety of vacuum tube, are also unique in having a relatively constant resistance transfer characteristic that usually results in a lower order distortion spectrum and perceptually 'cleaner' sound at a given distortion level than tetrodes or pentodes or transistors of any description. A couple decades ago, Sony had developed an early power mosfet called a VFET that had a triode like transfer characteristic, but it never caught on.
Btw, lithographic masking, sputtering, deposition and etching and even wire bonding techniques used in solid state device fabrication suffer from unavoidable statistical physical variations. They're not nearly as 'exact' as 'skeptic' makes them out to be, at least without trimming after the fact.
Btw I've designed my own DC coupled all triode OTL amplifier with damping factor in the hundreds and bandwidth out to 200k - it annihilates any SS power amp I've heard wrt resolution, smoothness and detail not to mention overall accuracy. |
| I never fail to be astonished.... | skeptic
Oct 30, 2003 6:13 AM | | ...by someone who has found or invented some arcane device that blows away everything else in its class by drastically reducing or eliminating distortion that 100 years of scientists, electrical engineers, and mathemeticians didn't know about.
And I'm always leery of anyone who claims that their invention "annihilates" everthing else. This is the kind of hype we often hear from people who are desparate to sell something of marginally superior merit at best, like the cable makers.
BTW, I congratulate you on having designed and built a triode OTL amplifier. I hope it doesn't require more time keeping the bias adjusted than you get to use if for listening and I hope it can put out more than a few watts. |
| Dielectric properties of materials have been commonly used | thomasd
Oct 30, 2003 9:14 AM | | parameters in the scientific and engineering community, basically since before the days of the vacuum tube, and are widely disseminated information.
Thanks. Well, I haven't said my OTL annihilates all tube amps:) Wrt the bias settings, they are extremely consistent on my OTL design (I've been using my prototype for 15 years now). I've literally run it for years without needing to adjust it and have seen it vary by less than 10% over a two year period once set. The amp is good for 50Wrms into 8 ohms per channel (it is stereo). I've also built two 140 Wrms/8ohm monoblocks using the same fully balanced topology.
I haven't attempted to sell my OTL amplifier as of yet largely because my interests tend toward creativity rather than commercialism (we all have our faults). Maybe I should buy a plaid sports jacket and get a Rolodex? |
| Truth.... | 300A
Nov 25, 2003 11:34 PM | | "BTW, I congratulate you on having designed and built a triode OTL amplifier. I hope it doesn't require more time keeping the bias adjusted than you get to use if for listening and I hope it can put out more than a few watts."
Why don't you learn something by reading these articles from the Journal of Electrical Engineers, Audio Engineering Society etc.
http://www.spectrum.ieee.org/select/0898/tube.html
http://www.gprime.com/proaudio/tubes/tubes.htm
Everyone should read these articles. |
| xistors & cheap ceramic caps share a distortion tubes don't have | Roberts
Oct 31, 2003 5:25 PM | | Where did you study? |
| The truth for all to read | 300A
Nov 25, 2003 11:23 PM | | Maybe you ought to check out some articles by Eric Barbour, Russell O. Hamm printed in the Audio Engineering Society, etc. Maybe these articles give a clue as to why tube audio is growing by 10% or more each year.
Aug. 1998 Journal of electrical engineering:
http://www.spectrum.ieee.org/select/0898/tube.html
http://www.spectrum.ieee.org/select/0898/tubet1.html
http://www.dwfearn.com/tvst1.htm
These are pretty heavy hitters who should know their stuff.
Some good reading. |
| You go, skeptic! Tell it like it is. | Feanor
Oct 30, 2003 10:10 AM | | I've been watching Discovery Channel's "American Chopper" series. The motorcycles build by Orange County Choppers, like "choppers" in general, are romantic stylish machines; however compared to a modern sports bike they're technically rubbish.
So it is with tube amps. They'll get you around with a lot of flair but they're really not a better ride. |
| Blanket statements are dangerous generalizations | skeptic
Oct 30, 2003 10:52 AM | | Fact; some tube amplifiers sound better than some solid state amplifiers.
Fact; some solid state amplifiers sound better than some tube amplifiers.
The blanket statements that (all) tube amplifiers sound better than (all) solid state amplifiers or visa versa is of course absurd. But it seems to me that given the potential of each and the inherent limitations of each, the best solid state amplifiers will outperform the best tube amplifiers and the output transformer needed for tubes is one of the big reasons why.
There are at least two kinds of serious problems with audio output transformers. One is called hysteresis loss which has to do with the ability of the core to magnetize and demagnetize linearly and identically. The best material for transfomer cores is supermalloy and it is excellent but it isn't perfect. The other is eddy current losses, heat generated by current created by the magnetic field within the core itself. The need to minimize eddy current losses is why transformer cores are made from stacked insulated laminations of metal and not a solid mass. The OTL design avoids this but Julius Futterman inventor of the OTL tube amplifier and Harvey Rosenberg who commercialized it at NY Audio Labs both died. Their designs were only bought by a niche market. (BTW, that design had been around for many decades. NY Audio Labs made a presentation to AES members in 1983 and explained the death bed testimony they had taken from Futterman and how they had modernized and improved the design with an excellent solid state power supply. Guess they didn't have the same view of ss diodes as MikE.) |
| Blanket statements are dangerous generalizations | thomasd
Oct 30, 2003 1:26 PM | | I agree that, in most cases, output transformers are definitely the major sonic limitation of tube amplifiers, particularly at the frequency extremes. Some have speculated that the energy used to switch the transformer core magnetic domain polarities with PP tube amps is a sonic detriment, although I haven't personal experience with SE tube amps which are supposed to avoid this particular pitfall, partly since I went the OTL route instead.
FWIW, I also own Crown K series switching amps for my basement high SPL system (good bass, somewhat opaque highs), and use solid state amps (a definite step up overall sonically, IMO) for my HT setup, and I often listen to CD & even MP3 (yecch! Blarrgh!) since you can only take it so far with Sheffields, RCA Red Labels, Mercury Living Presences and the Ventures.
I always thought a properly implemented tube input/mosfet output hybrid amp had the potential to give the 'best of both worlds' and actually came up with a prototype with a circuit topology derived from my OTL amps (the totem pole N-channel outputs mosfets could not be effectively biased with the circuit I used with the OTL due to their much higher transconductance & my replacement bias circuit was not wholly satisfactory - it worked ok, but I wasn't convinced that there wasn't some residual output signal being modulated onto the bias, reducing its sonic transparency) so I shelved that project and haven't yet resurrected it. |
| Blanket statements are dangerous generalizations | skeptic
Oct 30, 2003 2:14 PM | | The best tube amplifiers were manufactured with the best output transformers. The McIntosh MC275, 3000 etc. were prime examples. So was the Dynaco MKIII. Some people buy the entire MKIII amplifier used just for the output transformers and throw the rest away building the rest from scratch. You can see how many of the best preamplifiers of the tube era had outstanding specifications and measured performance very much the equal of fine solid state preamplifiers however, the power amplifiers had distortion levels orders of magnitude higher. While the phenomenon of crossover notch distortion was very common for early solid state bipolar transistor amplifiers (the Dynaco Stereo 120 wasn't one of them because of the ingenius bias circuit) it wasn't completely unknown in tube amplifiers. Some of the best tube amplfiers came with detailed instructions for measuring and adjusting bias current for the output stage to optimize performance. Periodic tube replacement to maintain best possible performance was expected.
Considering that most of the weight of any amplifier, especially vacuum tube amplifiers was in the power and output transformers, you can see with the output transformers gone that very heavy solid state amplifiers invariably have superb power supplies with gigantic transformers and tremendous capacitors. Compare the size and weight of those transformers with lesser models including many of today's smaller tube amplifiers and you can see how much more importance is given in today's top solid state designs to the power supply. Solid state power supplies, even for vacuum tube amplifiers also give the possibility for tight voltage regulation even with varying and heavy loads, something you rarely if ever saw in old vacuum tube power supplies. It makes me wonder how many of today's retro tube power amps actually have high quality power supplies. Judging from the small size of some of them, not all by a long shot. |
| high distortion SS amps | 300A
Nov 26, 2003 10:30 AM | | "gigantic transformers and tremendous capacitors."
Those tremendous capacitors have a DA and DF of 4 to 8%, real distortion, distortion, distortion producers which isn't measured and mentioned in specifications.
And cheap metal film resistors, steel leaded transistors or chips also add distortions, distortions which aren't measured or mentioned.
From what I have been reading, Not very many parts are sonically neutral, they all seem to add distortions or sonic signatures. Look at the cheap input and output brass connectors used. Run a wire, bypassing them and check the sonic differences.
So those HD of .001% don't mean alot when other forms of distortions dwarf that spec. |
| Just my attempt at levity, skeptic | Feanor
Oct 30, 2003 1:54 PM | | In fact I don't suppose than every SS amp is better than every tube amp. But to hear them, you'd think some glassheads believe the reverse is true. I was taking a little shot at those people. |
| Just my attempt at levity, skeptic | skeptic
Oct 30, 2003 2:21 PM | | One of the dangers of making sweeping statements generalizing about anything is that there is always somebody who will come up with an example, even if it's a rare exception to a general rule that will make you look like an idiot.
Who wouldn't be happy to open up his Christmas presents and find a Mc275 and a C22 or a pair of 8Bs and a 7C in mint condition under the tree? |
| Heck, I'd love a Dynaco 70 -- if just for fun {nt} | Feanor
Oct 30, 2003 2:29 PM | | nt |
| Just my attempt at levity, skeptic | DMK
Oct 30, 2003 3:40 PM | | b Who wouldn't be happy to open up his Christmas presents and find a Mc275 and a C22 or a pair of 8Bs and a 7C in mint condition under the tree?
I'd go into raptures, I'm sure! |
| Blanket statements are dangerous generalizations | thomasd
Oct 30, 2003 3:26 PM | | I agree that, in most cases, output transformers are definitely the major sonic limitation of tube amplifiers, particularly at the frequency extremes. Some have speculated that the energy used to switch the transformer core magnetic domain polarities with PP tube amps is a sonic detriment, although I haven't personal experience with SE tube amps which are supposed to avoid this particular pitfall, partly since I went the OTL route instead.
FWIW, I also own Crown K series switching amps for my basement high SPL system (good bass, somewhat opaque highs), and use solid state amps (a definite step up overall sonically, IMO) for my HT setup, and I often listen to CD & even MP3 (yecch! Blarrgh!) since you can only take it so far with Sheffields, RCA Red Labels, Mercury Living Presences and the Ventures.
I always thought a properly implemented tube input/mosfet output hybrid amp had the potential to give the 'best of both worlds' and actually came up with a prototype with a circuit topology derived from my OTL amps (the totem pole N-channel outputs mosfets could not be effectively biased with the circuit I used with the OTL due to their much higher transconductance & my replacement bias circuit was not wholly satisfactory - it worked ok, but I wasn't convinced that there wasn't some residual output signal being modulated onto the bias, reducing its sonic transparency) so I shelved that project and haven't yet resurrected it. |
| Inadvertent repost:) | thomasd
Oct 30, 2003 3:28 PM | | nt |
| You go, skeptic! Tell it like it is. | drdave
Nov 2, 2003 11:14 AM | | I'm wondering how many tube amps you have owned over the years and how they fit it with the rest of your system. I have been into audio for well over 20 years, and solid state equipment was all I knew. I've owned probably 8-10 SS amps and pre-amps over the years from a good number of the major manufacturers.
Two years ago, I became interested in the ss vs. tube debate once again - I had always kind of followed the discussions - and I decided that I didn't really deserve to have an opinion since I had always been on the SS side, with no tube experience. I bought a little Jolida integrated amp with modifcations that cost me a very reasonable $1500. I was extremely impressed with its performance with the CD sources that I mostly use. I have a lot of recordings that seem to be overly bright, compressed, and not very musical. Tubes took the edge off the high end and made them much more fluid and less edgy. Before tubes, I would get a bit tired of listening after an hour or two, with the Jolida, I would often listen all day.
Eventually, I wanted a bit more of the tube sound, and got a Cary V12R. I fell in love with the sound, which was incredible for a $4000 amp. It, to my ears, was much more enjoyable than $20,000 SS monoblocks that I've owned.
I'm not saying that tubes are for everyone. They are a bit more work, and I still don't believe, generally speaking, that they are as reliable as SS equipment. Also, they can narrow down your selection of speakers that you have to work with as they generally produce less power. But, combine them with highly efficient horns, and I don't think any SS setup can touch them - at least for the price, anyway.
What tube amps have you used over the years? What speakers do you combine them with? |
| You go, skeptic! Tell it like it is. | skeptic
Nov 2, 2003 5:34 PM | | I have listened to countless tube amplifiers since that's all there was when I was young and growing up. I've heard various Dynacos, McIntosh's, Scotts, Fishers, Sherwoods, Pilots, Once in a while a marantz, and even Lafayette Radio, Eico, heathkit. Also Stromberg Carlson, Capehardt, and I still own a Harmon Kardon A500 that works. I have always felt that these amplifiers rolled off the high end and didn't sound as bright or clear as fine solid state amplifiers. I attribute this mostly to their output transformers. I still own and like KLH 6 and heard all kinds of old speakers including various AR models, Dynaco, Bozak, Rectilinear, Altecs, Fisher's, Fraziers, University, and even some JBLs. My "reference" system consists of Teledyne AR9s enhanced with add on Audax indirect firing tweeters and a 60 wpc Mosfet solid state Power amp I built from a kit (that was once a very popular way to own an amplifier once upon a time.) Vacuum tube amplifiers can be built to be very powerful although the cost will be high. McIntosh had some 300 wpc monoblocks.
Today's loudspeakers sound brighter to my ears than those of a couple of decades ago. Not surprising that combined with solid state power amplifiers and cds, many sound systems sound too bright, shrill, and irritating. Especially when audiophiles reject the notion that tone controls or equalizers are an acceptable way to control frequency response. |
| Bright speakers | Feanor
Nov 3, 2003 9:30 AM | | skeptic, you say, "<i>Today's loudspeakers sound brighter to my ears than those of a couple of decades ago.</i>" To my ears as well.
My old Phase Linear 400 never sounded bright with my old B&W DM7's. But it does today used with my Magneplanar MMG's and definitely with my Paradigm MiniMontors and the B&W CDM 1NT's I auditioned extensively before deciding on the MMG's. But I think I'll just reach for the tone control on the Apt Holman rather than replace the Phase. |
| Bright speakers | skeptic
Nov 3, 2003 5:03 PM | | I can't say why this is so but that's my observation. They don't usually give you a tweeter level control, audiophiles hate tone controls and perish the thought that they would ever use an equalizer. What's left? Vacuum tube amplifiers with rolled off high ends due to the output transformers and high capacitance speaker and interconnect cables which hopefully won't send their amplifiers into spontaneous oscillation. If they've gone too far, they get a moving coil phonograph cartridge with a high end peak. Then they hook up a cd player and wonder why it doesn't sound very good. Go figure. |
| Dr Dave, sadly I've never owned a tube amp ... | Feanor
Nov 3, 2003 9:23 AM | | ... despite being an audiophile for over 30 years.
My first amplification was a Dynaco PAT4 pre plus a Dynaco Stereo 80 power, both solid stated. In retrospect it was too bad maybe that I didn't choose the PAS3 and Stereo 70 tube units that were available at the time. I guess I was a victim of the SS hype prevalent then.
My amp combo today is an Apt Holman preamp and Phase Linear 400 power. In fact both of these are relatively ancient, (circa 1978-79), but I'm going to have to soldier on with them 'til they die on account of financial contraints. |
| So where do digital amps fit? | topspeed
Oct 30, 2003 3:40 PM | | I'm in waaay over my head on this one and don't presume or pretend to be an engineer. From what I've read, digital amps treat this differently altogether. I have a general understanding of the difference (the whole water through a tube example) but wanted to know your take on it. I ended up buying a digital amp not because of what it was but because of how it sounded in my system. Now conversely, it apparently doesn't measure very well. However, as it's a new technology I wonder if it needs to be held to a different standard? A wise man once said if it sounds good and measure good, it is good. If it sounds good but measures poorly, you're measuring the wrong thing. |
| Hmmm! great question {nt} | Feanor
Oct 30, 2003 4:10 PM | | nt |
| re: Why transistor amp technology is inherently superior to tube | DMK
Oct 30, 2003 3:50 PM | | In some applications, I'd prefer SS. If I had very inefficient speakers and needed a lot of power, I'd go SS since it's relatively inexpensive to find a decent SS amp. However, with reasonably efficient speakers, I prefer tubes, your interesting info notwithstanding. I don't, however, think there are worlds of difference between the two. In fact, if there are (and in some cases, there may be), I'd guess the tube amp to possess too much of a sonic signature and would likely reject it. However, I find with the best tubed amps (Wyetech, Audio Research, BAT) are highly accurate sounding devices with no trace of bloated bass or rolled off highs. They sound very close to SS but with the tube "magic" for lack of a more descriptive term.
There isn't, or shouldn't be, major differences between the two but the diffs are musically important enough to me to choose tubes. SS amp technology may be inherently superior to tubes but I'm also told digital technology is inherently superior to vinyl and I find no sonically compelling evidence to support that claim, either... at least, not yet. |
| re: Why transistor amp technology is inherently superior to tube | rb122
Oct 31, 2003 4:50 AM | | Agreed. I, too, wish I could come up with a better term than "magic" for the sound of tubes. For me, tubes just provide a bit closer sonic viewpoint into the music. They seem to provide a little more low level detail making the music sound just a bit more "live". The differences are subtle but important. I could live with solid state but when I picked up a $2500 tubed integrated for $1500, the cost was more than reasonable compared to the benefits.
As for all tubed amps sounding better than all solid state, I don't know who could possibly have heard them all. As a result, I don't know who could say that that I would believe. |
| Nonsense | 300A
Nov 4, 2003 8:39 PM | | Before you can make informative comments, you must know your subject.
Transistors have inherently much higher distortion than triode tubes and the harmonics are not only predominantly odd order, but also higher orders such as 5th, 7th, 9th etc, vs 2nd and maybe some 3rd for tubes.
The OPTs of PP amps have very little distortion when designed correctly (except SET amps).
SS also use electrolytic capacitors, which themselves have inherently high distortion properties, which are not measured on conventional equipment. Very high DA and DF are typical features of electrolytic caps. See http://www.capacitors.com/picking_capacitors/pickcap.htm
I can always hear a grunge from a SS amp caused by the electrolytic caps used.
Negative feedback is a problem with any amplifier, so SS really takes a dive with there 20 to 40db of feedback used. |
| Yes, Nonsense | skeptic
Nov 7, 2003 8:32 AM | | Not all ss amps use output electrolytic capacitors. Some use direct coupling. However, all loudspeaker crossover networks use them.
"Transistors have inherently much higher distortion than triode tubes and the harmonics are not only predominantly odd order, but also higher orders such as 5th, 7th, 9th etc, vs 2nd and maybe some 3rd for tubes."
How do you explain the nearly nonmearurable distortion of solid state power amplifiers and preamplifiers? And how do you account for the orders of magnitude greater harmonic and intermodulation distortion of vacuum tube triode (or tetrode or pentode) amplifiers than well designed ss amps?
"The OPTs of PP amps have very little distortion when designed correctly" Look at the massive transformers on McIntosh Mc275 and Marantz 8B. They didn't build them that way for the fun of it. They still had harmonic and IM distortion orders of magnitude beyond ss amps. Now look at the peewee transformers in many of today's tube amps. Far beyond anything an electrolytic capacitor would do to a signal, the transformer relies on the B-H curve of the core being perfectly linear and the demagnetizaton curve overlapping the magnetization curve. It never is with the core having an inertia near zero and saturating at about 15,000 gauss. the area within a full cycle B-H curve is the hysteresis loss and of course is highly nonlinear. Furthermore, the core must be made of thin insulated lamina to reduce eddy current losses which are generated within the lamina transverse to the magnetic field. The best transformers are rarely more than 95 percent efficient. The art of winding high quality impedence matching transformers for audio amplifiers is probably by now a nearly dead art.
"Negative feedback is a problem with any amplifier"
This of course is a ludicrous myth promulgated by people who don't know how to use it effectively. Feedback control also known as servo control is not only de rigeur for all modern amplifiers but in a more generalized way of all modern instrumentation and control systems from space vehicles, fly by wire aircraft, building and production automation systems, and even modern automobiles. All you have to do is glance through a text on feedback systems such as "Feedback Control System Analysis and Synthesis" by D'azzo and Houpis to know that this is an area for tinkerers and wanabee electronic design engineers to stay away from. This is beyond their knowledge to use properly and general hunches or information gleaned at a seminar won't cut it. This is a senior level course for electrical engineering undergrad students and that's just to get their feet wet. This may explain why so many amateurs including people who thought they were engineers because they could put a speaker in a box and sell it to someone, have more than met their match.
I always find it amusing that there's always someone out there who challenges the entire body of professional engineers in a field, knowing for sure that the so called pros don't know how to design or measure anything and all the specs and tests mean nothing while their guru has the inside track on how to do it right. |
| Skeptic can't possibly be true, here is why | 300A
Nov 8, 2003 8:55 AM | | A total misunderstanding of just about everything in audio.
1) "Not all ss amps use output electrolytic capacitors. Some use direct coupling. However, all loudspeaker crossover networks use them."
We are talking about all electrolytic caps, including those in the power supply. They affect the sound too as they are in the signal path. Elementary electronics would teach one that.
2)"How do you explain the nearly nonmearurable distortion of solid state power amplifiers and preamplifiers? And how do you account for the orders of magnitude greater harmonic and intermodulation distortion of vacuum tube triode (or tetrode or pentode) amplifiers than well designed ss amps?"
Simple, huge amounts of feedback, either local or global. Transistors, individually and with no feedback, have much higher distortion than a triode, odd order, and higher orders such as 3rd, 5th etc. True that tetrode/pentode amps have similar distortion patterns of SS devices.
3) ""The OPTs of PP amps have very little distortion when designed correctly" Look at the massive transformers on McIntosh Mc275 and Marantz 8B. They didn't build them that way for the fun of it. They still had harmonic and IM distortion orders of magnitude beyond ss amps. Now look at the peewee transformers in many of today's tube amps. Far beyond anything an electrolytic capacitor would do to a signal, the transformer relies on the B-H curve of the core being perfectly linear and the demagnetizaton curve overlapping the magnetization curve. It never is with the core having an inertia near zero and saturating at about 15,000 gauss. the area within a full cycle B-H curve is the hysteresis loss and of course is highly nonlinear. Furthermore, the core must be made of thin insulated lamina to reduce eddy current losses which are generated within the lamina transverse to the magnetic field. The best transformers are rarely more than 95 percent efficient. The art of winding high quality impedence matching transformers for audio amplifiers is probably by now a nearly dead art."
Several problems. First, the best tube amps use conservatively rated trannies. I, personally, have measure the distortion OPT generate and it is nill.
Second, they are more than 95% efficient, more like 99%. Most of that loss is due to resistance of the wire.
Capacitors are very distortion prone, and sound that way. One can do a simple test by inserting one in a crossover and hear the difference.
4) "This of course is a ludicrous myth promulgated by people who don't know how to use it effectively. Feedback control also known as servo control is not only de rigeur for all modern amplifiers but in a more generalized way of all modern instrumentation and control systems from space vehicles, fly by wire aircraft, building and production automation systems, and even modern automobiles. All you have to do is glance through a text on feedback systems such as "Feedback Control System Analysis and Synthesis" by D'azzo and Houpis to know that this is an area for tinkerers and wanabee electronic design engineers to stay away from. This is beyond their knowledge to use properly and general hunches or information gleaned at a seminar won't cut it. This is a senior level course for electrical engineering undergrad students and that's just to get their feet wet. This may explain why so many amateurs including people who thought they were engineers because they could put a speaker in a box and sell it to someone, have more than met their match."
Of course absolutely false, and comparing apples to oranges.
Your entire comment about being used in industrial and space projects means nothing when it comes to when sound is involved. There is no correlation between the two.
Amplifiers, by physics, delays the signal as it passes thru, therefore the signal being fedback is not be at the same time it is being fed in. It arrives at the input late. Since the signal is constantly changing, the fee |
| Skeptic can't possibly be true, here is why | skeptic
Nov 10, 2003 6:46 PM | | This is getting too long and too far down the page. But I can't help commenting on what is obviously the most flagrant mistake, so obvious that EVEN YOU sir will see how silly your arguement is.
"We are talking about all electrolytic caps, including those in the power supply. They affect the sound too as they are in the signal path. Elementary electronics would teach one that."
EVERY POWER SUPPLY IN EVERY AMPLIFIER, PREAMPLIFIER, TUNER, CD PLAYER, TAPE PREAMPLIFIER, no matter whether the amplfier is class A, class B, class AB, class C, tubes, transistors, unless it is battery operated only, every one uses ELECTROLYTIC CAPACITORS. EVERY LAST ONE OF THEM. CAPICHE? |
| Wrong information again. | 300A
Nov 13, 2003 3:32 PM | | That is nonsense. Some tube amp manufacturers use no electrolytics. True in that I also don't know of any Solid State amp manufacturers that don't use electrolytic capacitors in their amps.
"But I can't help commenting on what is obviously the most flagrant mistake, so obvious that EVEN YOU sir will see how silly your arguement is.
"We are talking about all electrolytic caps, including those in the power supply. They affect the sound too as they are in the signal path. Elementary electronics would teach one that."
EVERY POWER SUPPLY IN EVERY AMPLIFIER, PREAMPLIFIER, TUNER, CD PLAYER, TAPE PREAMPLIFIER, no matter whether the amplfier is class A, class B, class AB, class C, tubes, transistors, unless it is battery operated only, every one uses ELECTROLYTIC CAPACITORS. EVERY LAST ONE OF THEM. CAPICHE?"
Get the facts before publishing incorrect information Skeptic. |
| Take a squint in your mirror Mr.300A ... | woodman
Nov 13, 2003 10:45 PM | | ... and see a total idiot!
If you actually were educated in electronics ... if you really KNEW one-half of what you THINK you know, you wouldn't be posting such total bullshit and at the same time chastising and belittling skeptic - who obviously has FAR more electronic knowledge and experience than you.
I shudder to think that there might be some who actually believe the nonsense that you're posting here. You should be embarassed!
woodman |
| Caught again. | 300A
Nov 25, 2003 10:40 PM | | So are you saying other brands HAVE to use electrolytics??
If so, then why are there brands that DON'T use electrolytics at all in their components, or well back away from the signal? SS can't claim that can they!
Have you even taken an electronics course?? Then give some facts instead of weirdo comments.
No wonder little of value is learned here. |
| |
