This is topic Analog Vacuum Tubes... in forum General Yak at 8mm Forum.


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Posted by Thomas Dafnides (Member # 1851) on July 31, 2013, 10:11 PM:
 
are being advertised in NEW Samsung Amplifiers...for "superior audio quality".
 
Posted by Paul Adsett (Member # 25) on July 31, 2013, 11:09 PM:
 
The really high end amplifiers all seem to have vacuum tube output stages. Indeed they are put on display so they are clearly visible as a feature of the design. It is pretty well established now that vacuum tube amplifiers are superior to solid state amplifiers, and many people also think that analog sound recording is superior to digital sound recording, vinyl LP'S being superior to CD's. I do not know if electronic tubes are still manufactured in the UK or USA. Fifty years ago RCA, Sylvania, and Westinghouse all were in the business. Not now though, probably all made in China! [Frown]
 
Posted by Maurice Leakey (Member # 916) on August 01, 2013, 02:26 AM:
 
A few of my 16mm sound projectors have valve (tube) amplifiers and there is no doubt that the sound from these has the edge over amps with transistors and I.C.s, it's difficult to explain the difference but there's no doubt about it to my ears.
 
Posted by Hugh Thompson Scott (Member # 2922) on August 01, 2013, 03:12 AM:
 
There was an article a few years ago in the Sunday supplement
magazine on this subject,it went on to say that they were starting to make a comeback because of the clarity of sound by using valves, but the prices were rather expensive for these units, a couple of thousand pounds and upwards.
 
Posted by Martin Jones (Member # 1163) on August 01, 2013, 04:51 AM:
 
Basic facts from an Audio Service Engineer of some 60 years experience.... purely as a reminder of some aspects of Audio often overlooked.

SOUND is pure ANALOGUE. The human ear can ONLY detect ANALOGUE. Sound can be converted to electrical signals for the purpose of processing it for a number of reasons such as simple amplification, recording etc., and those signals can be converted back to SOUND so that humans can detect it.

The most accurate way of processing Sound so that it is reproduced as close to it's ORIGINAL form is by using Analogue techniques. I say "most accurate" because no technique is perfect; distortions in the process may remove some characteristics of the original or add some nuances to it, and those distortions are subtly different whether thermionic valves ( Analogue devices), transistors (also Analogue)or Audio ICs ( also Analogue since they are composed mainly of transistors) are employed.
The alternative is processing, greatly favoured today because Digital signals are simply representations of the original Analogue signal in an On/Off form, allowing extensive processing, recording etc., WITHOUT changing the signals at all.
HOWEVER, before this "error free" processing can take place the original Analogue signals have to be converted to a Digital form. This conversion "samples" the Analogue signal to produce a Digital representation; this sampling inevitably removes some of the characteristics of the original. After whatever processing, recording etc. is performed the Digital signals MUST be converted back to Analogue so that the ear can hear them; this process not only cannot replace what was removed in the original sampling but also has losses of its own. One can attempt to replace what was taken away...but, at best, such restoration is guesswork.

It is those conversion losses that affect the perceived sound; a Vinyl LP carries, and can reproduce, a much greater frequency range than a CD (but don't play it through a "Digital" amplifier if you want to hear that range!!). FM radio is also Analogue; modulation (onto a carrier signal) and demodulation of the original Analogue signal affects it much less than Digital encoding and decoding, which is why an FM radio (with attention paid to good reception) gives much better sound than a Digital one.
And the foregoing applies applies just as much to Vision as to Sound.

Digital processing and transmission DOES have its advantages: it is much less susceptible to losses during those processes. But it can never exceed the quality of Analogue Sound or Vision since it is always derived from an Analogue original.
 
Posted by Mitchell Dvoskin (Member # 1183) on August 01, 2013, 10:57 AM:
 
> It is pretty well established now that vacuum tube amplifiers are superior to solid state amplifiers

I don't think that I agree with that statement. While tube amps tend to have a warm rich sound, which I personally enjoy, there are downsides from an audiophile perspective. First, the sound changes as the tube components warm up. Many "tube" audiophiles leave their equipment on 24/7 because of this. Second, the sound changes as the tubes wear out. Third, the sound changes when you replace a tube. Finally, the assumption that a solid state amp can not produce the same quality sound is not correct.

Many years ago, an audiophile magazine here in the USA called Stereophile took Bob Carver (of Carver Audio) up on his claim that he could build an inexpensive solid state amp that sounded identical to the expensive tube amps that they loved. Carver's premise was that if two amps reacted identically with test signals across the frequency ranges as displayed on test monitoring equipment, they would sound the identical. Carver went to Stereophile's offices with a prototype designed to allow him to tweak it on the fly, along with his test equipment. Stereophile provided him with a tube amp, and gave him an evening to tweak. The next day, in blind tests in their listening room, the golden ears at Stereophile could not tell the which amp they were listening to. Carver won the challenge. While there was much disagreement over whether the mass produced version he later manufactured also sounded identical, he certainly proved it was possible.

Back in the mid 1980's, an audiophile friend of mine who claimed that analog records sounded better than CD's brought over some Mobil Fidelity LP's and the CD version. We compared them using my Linn Sondek LP12 turntable (I still have and use it). I had to concede, the analog LP's consistently sounded better. My point however, was that the fact that a mint LP on a audiophile turntable sounded better than the CD does not make LP's a better format, because analog recordings degrade every time you play them.

On the other hand, over the last few months, I have been playing my reel to reel tapes, both pre-recorded and ones I recorded going back to the 1970's, and they still sound fantastic.
 
Posted by Hugh Thompson Scott (Member # 2922) on August 01, 2013, 05:39 PM:
 
Well this little forum is testamony Mitchell, that ancient technology
has a fascination all of it's own. It must have something when
collectors are willing to pay hundreds of $ for films they can watch
by video projection at a fraction of the cost.Remember, that before
we had modern recording tape,recordings for film use would be done on wire. The sound recording systems then were pretty
basic, but you can hear every word of dialogue, unlike some of
the modern tracks, where some of the conversations should be sub-titled, and that's with all the Dolby etc.CD''s are nice,downloads even, but taking an LP out of it's sleeve and
placing it on a turntable is something to be savoured.I've said it
many times before, enjoy this stuff while you can,it won't last
forever.
 
Posted by Rob Young. (Member # 131) on August 08, 2013, 08:26 PM:
 
Can I just say that Martin is absolutely correct in his appraisal of analogue /digital, albeit with some provisos.

His description regarding the short-falls of digital audio are totally right.

However, let us not forget that CD, for example, is 30 year old 8-bit, archaic technology.

That is like trying to emulate a perfect visual audio syn wave using big, chunky, 1980's squares of inadequate digital information, then letting a variety of processors fill in the "gaps", with varying degrees of success.

And yes, I still own a Linn LP12. [Roll Eyes]

But digital audio has evolved since "Brothers in Arms", sometimes for better, often for worse (MP3 [Frown] [Frown] [Frown] )

This could be a long discussion, but bear in mind this; audio is a wave form, a curve. Digital is a clunky square graph by comparison.

But...when you have the processing power to make those clunky squares appear smooth from a perceptible distance, you have audio in a digital form which sounds organic and doesn't suffer from surface / mechanical noise.

[Wink]
 


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