The "black beauty"capacitor phenomenon...

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It isn't...

about the degree of distortion or the "accuracy" as much as it is about the type of distortion, as clearly described in the IEEE article referenced above. A distortion of .01% is essentially meaningless when the amplified signal is ultimately perceived through analog mechanical transducers such as speakers that are lucky to have a distortion of under 5%.
 
LOL, When I rewired a building that had knob and tube (ACTIVE!) wiring, I probably could have made a fortune selling that wire (and the ceramic connectors and the 1920's dust of course) to audiofools. ;-)
 
I was told once

the only thing that matters is Gibson and Marshall. He said if you don't play Gibson and Marshall, you're a wanker!

His name was Ian St. Ian.
 
An aquantence that works with me at the transmitter plant has a friend that can "hear" the differences in battery brands in his guitar effects stompboxes.I figure that musician has a very VIVID imgination or does he have dogears?
 
Phil,

I agree that, today, in 2017, it is quite easy to get great sound out of solid state amps.

I was mainly thinking about vintage days. 

Indeed, the major advance in solid-state sound is due to logic control - look at the Class 'D' (and, as you know, but most do not, 'D' does NOT stand for digital) amps. There are now some really good ones.

I'd still wager that a really well designed class 'A' triode circuit, using logic control would equal the best solid-state design, using logic control in sound. If you're looking for high output, there's no alternative to solid-state. If you're looking for really high-efficiency, there's no alternative (realistically) to Class-D solid-state. 

 

As a victim of perfect pitch, monotonically decaying harmonics appeal to me enormously. 

 

But, again - it's 2017. I'll stick with my SET power amps when I have the choice.

 

As to the rest of the low-oxygen, single-crystal copper nonsense, etc. - pass.
 
Class "D" amp-not new-been with us since the early 70's Class D modulators in AM transmitters and high power SW transmitters.Will be turning ours on in about 8Min-500Kw.250Kw Class D single tube modulator.When tubes or SS used in a Class D ampEFFICIENY is the thing here-more power out with less power drawn.And the switch stage runs cooler-the device is acting as a switch.In our case a single TH580 tube.30 KV supply voltage.The tube also acts as a switching voltage regulator for another TH580 tube as the RF power amp.Car stereos today have Class D amps in abundance.My car has them.600W.Some receivers on the market now are equipped with them-and they work and good!If you want a single end modulator--our Continental electronics 420A 500Kw SW transmitters have this-The modulator feeds audio to the grids of the power stages.Modulator is 4 845 tubes in parallel cathode follower-driven by one 845 tube and two 807.Bet the audiophools would love that!
 
You build a speaker-"transducer" that is up to par with modern amplifiers-the world would definetly beat a path to your door.And efficiency of them too!They are still inefficient-hence all of the high power amps hawked out there.Close ones in efficiency and accuracy--Altec Lansing Voice of The Theater and Klipsch K-corner horns.These two can perform well and with lower amounts of amp power.
 
Rex,

My sole contribution to the field of transducers was my Master's Thesis - a program which identified whether a stylus was within a set of given parameters or out of range (damaged/dirty) with a calibration sequence to compensate for the (at that time) wild diffusion variations of (what we then called) hi-output LEDs.

 

Ah, those were the days.

 

I don't really get upset about 'distortion', it's a word similar to 'allergy' and about as useful without more information. Some forms of distortion really, really bother people cursed with perfect pitch (there was a study in Germany at my university about that in the 1980s. An early attempt to figure out why so many young people (good hearing) and older adults (down below 8kHz) could tell the difference between CDs and master tapes. Several interesting anecdotal results and a few repeatable observations, one being that those of us with this congenital deformity are super-duper 'allergic' to third-order harmonic distortion.

 

In the end, of course, nearly all the problems with early CD sampling turned out to be that the solid state mic. amps were driven to clipping. This is why so many recordings on 35mm tape from the '50s through the late '60s sounded so good on CD and the junk from the '70s and early '80s sounded so bad. Once sound engineers started making recordings using late-20th century technology properly, instead of acting like it was still 1957, the recordings began to sound as good as that limited sampling rate permits.

 

Too long a post, too much coffee this morning. Efficiency isn't our problem, today. Getting the transducers closer to being 'transparent' is. No clue how to solve that, gosh, we can't even figure out whether it was mold or varnish which made the Stradivarius and Guarnairi instruments sound so good - and today's precision made Baldwins sound like trash.

 

 
 
Some "young" people really don't have such good hearing-the old mans may be better-Remember those young-ems blast their ears with their cranked up car sound systems and headphones.When I talk about efficiency of speakers-they are still less than 50% efficient-most of the amplifier power is wasted as heat!Can go with you on the mic preamps.One time down here at the transmitter plant heard stranger modulator "talking" in our AEG transmitter-the one with the Class D modulator.Turned out a console module was strapped for mic preamp gain and being fed with a line lever signal-clipping for sure.And not good for transmitters!In early days of recording engineers not only didn't drive their mic levels to clipping-they knew what TYPE of mic to use for a particular instrument or singer.And the tubed custom consoles then helped out a lot-when the 60-70's came about the boards had really CRAPPY-and I mean CRAPPY mic preamps-when they were driven too hard-the HORRIBLE recordings were the result.Fortunately the custom tube RCA (3 channel) consoles were restored and used in the remakes of the SACD RCA "Living Stereo" Have these-and they do sound so good,clean and like you are there!Didn't know Baldwin made violins?Know they make pianos.I don't have perfect pitch-can't play a musical instrument-only ones I can "play"are those automatic ones played from a roll or perforated cardboard music "book".Would love to have a band organ collection-but don't have the space or money!Instead have "collections" of them on CD or MP on my phone.Also 50-60 records sounded so good,too-becuase the folks then CARFED about quality and knew how to do it!Instead when later 60-70 and onward-music was so badly and heavily PROCESSED to sound good on radio airplay than for listening.
 
Be glad you don't, Rex

It's a curse. Remember that <span style="text-decoration: line-through;">fight</span> discussion here a few years back on whether a particular <span style="text-decoration: line-through;">blonde</span> 'singer' was auto-tuned? Those of us cursed all knew <span style="text-decoration: line-through;">she</span> the singer was and <span style="text-decoration: line-through;">her</span> the aficionados were merciless in blasting us for daring to think such untrue thoughts.

Turned out, of course, they were wrong, as she freely admitted in an interview not much later. It's not a 'gift' unless you're a fretless string instrument player or play one of those wind instruments which require enormous skill.

 

Yeah, the 'hard' clipping problem were a major source of bad quality recordings, as was the 'who cares', it's just trash for the kids, they can't tell the difference mentality of much of that disposable era. Today, of course, you have many musicians (Chris Rupp, Cher, Kiri Te Kanawa, to name but a few) who know more than enough and who actually care enough to work with the studio engineers to produce the best quality sound possible. Back then, well - the problems are well enough known for me to have read about it, and my interest is purely that of a rank amateur. 

[this post was last edited: 1/24/2017-08:57]
 
It depends on how auto-tune is applied, actually.

Just a breath of the newest incarnation of the software can make a gigantic difference, to the good.

Most studios and nearly all performers, however, haven't a clue just how obvious it is.

As to Kiri, well, gosh - I've recently heard much younger singers perform far worse in some of the best houses in Germany.

Yes, each singer needs to focus on different material at each stage in their career. I've heard really good tenors who, in ten or fifteen years might well have been outstanding Heldentenore ruined by too much Wagner in their early 20's. I've heard a 74 year old pull off Zoser(Aida) with bass notes that shook my chair and a D# which was clear as a bell. Of course, that was in the National Theater, Munich. had a subscription in the Parkette Mitte for years and years. Have to say, they did Parsifal 10^14 better than Bayreuth and Der Ring about as awful, regardless of singers, as any I've ever heard, anywhere.
 
For us at the transmitter-SW,"auto-Tune" is for when the transmitter can tune itself when brought up.So far the EAG is the only auto-tune one we have that works.Took a man from its factory in Germany to correct its problems.On occasion you have to help it.The other transmitters here you have to tune them.For me tuning them is not a real problem.Have to show the other guys.Now they can do it with no problems.For musicians not familiar with their "auto-tunes"
 
Auto-Tune, Tubes

I always have to laugh when some idiot insists that 'tube' technology isn't as good as 'solid-state' on one of the Yahoo forums.

Usually one of us who actually have a brain cell or two fire back: Do you listen to radio broadcasts? Own a microwave oven? Drive a car with a bright display that you can read clearly in the glaring sun?

You do?

Oh, OK - guess you're right, then. Not.

 

I hadn't thought of your sense of auto-tune. I suppose the amount of drift permitted is pretty regulated? No idea about it, really.
 
In general it isn't a matter of tube technology not being "as good", there is no doubt that vacuum tube technology does excel is several areas, mostly durability. But alas that comes at a price, in most all applications tube technology is expensive. This is the reason that tubes have been replaced in almost all applications up through UHF at least.

Assuming that a TV or radio transmitter is still tube is likely to be an incorrect assumption. If it was built in the past 20 years, and it isn't a high UHF channel or excessively high power transmitter, it is likely to be solid state. Our local Channel 2 analog transmitter was solid state in the early 90's. Most all the TV & FM transmitters at our local tower farm are solid state today.

The advent of LDMOS solid state technology was what did in tubes for RF uses. They are even selling transistors capable of hundreds of watts at 2.45Ghz now so in the not too distant future domestic microwave ovens will probably be solid state too, although China made magnetrons are damn inexpensive.

A very common vacuum tube used for amateur radio is the Eimac 8877/4CX1500. Using one of these tubes you feed it 4000 volt at .75 amps and it will give you 1,500 watts of RF up through about 300Mhz with only about 10-15 watts drive (~15db of gain). The new LDMOS transistor boasts almost identical performance numbers, but has the advantage of running on a 50 volt supply. And 8877 is a $1000 tube today, the LDMOS transistor is ~$200 and it doesn't need the high voltage supply and high impedance high power matching network. Tubes are dying quickly for RF use. If you need many Kw of power you just combine a bunch of amplifier "pallets" to get the output you want. In this way they are more reliable then tubes as a failure of one amp hardly reduces output power. A failure of the tube final and you are at exciter power :(

Here is a neat video of the Freescale Xtremely Rugged series of LDMOS device showing it's durability. I used to be a devout tube guy (anything over 100 watts needs a filament) but no more!

 
Technology marches on!

I think that's totally cool, thanks for the info, Phil. I didn't realize solid-state had made such advances 20 years back.

Given my professional background in IT, I am obviously happy with whatever works well and is reliable.

 
 
If you want to hear

How much better tube stuff sounds in general...Listen to a Hammond Organ played thru a 147 Tube Leslie and one played thru a newer solid state leslie..its night and day, likewise listen to my 62 Zenith stereo and then listen to one a few years later....
 
I really like that BLF-570!!!!Wish we could use those in the RF drivers out our way.SW transmitters running at 100kw,250kw and 500kw still use tubed output stages.Mainly for simplicity.The modulators are solid state-PSM---(Pulse Step Modulator) it is a form of tubed PDM but without the tube.It is replaced with the PSM modulator modules arranged in series with each other they then do two things-provide the B+ DC plate voltage for the tube stage and the modulation.The first generation PSM in the BBC transmitter is VERY trouble prone-the later CEMCO version is less troublesome and more reliable.The PSM modules are easier to replace-on one big fibergalss board and use Bipolar power transistors instead of the GTO-and they are air cooled-not water cooled as the BBC modulator is.
4CX-1000,1500 tubes often were used as drivers in very high power FM and TV transmitters.TV transmitters still had some tubes in them 20 yrs ago.Typically the visual PA and Aural PA.Worked on this so I know.The drivers were solid state-and actually in those early generation (RCA) LESS reliable than the tubes they tried to replace.But with the advent of that MOSFET style power transistor-things have changed.For HDTV transmitters-those in the UHF range still use klystron and klystrode tubes.VHF digital TV transmitters are now solid state.With DTV LESS power is required as opposed to analog.LW and MW AM transmitters are solid state today-even at 500KKw,1MegW each power module is 500W They are combined to derive the final output.VOA has some of these transmitters-made by Harris -the DTX 500 and 1000 series.Haven't used these personally-those that have like them.They do take up more space than an equivalent tube transmitter.Sodlid state has made inroads--but don't count tubes out yet-they are making technical inroads ,too-better efficiency.
 

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