Saturday, November 22, 2014

Can the 8417 Vacuum Tube Ever Be Resurrected?


Despite the return of the formerly extinct vacuum tubes – like the 7591A vacuum tube – during the late 1990s, can the 8417 vacuum tube be ever resurrected for the benefit of 21st Century audiophiles? 

By: Ringo Bones 

If you are “fortunate” enough to have started do-it-yourself high fidelity audio during the 1980s, you might find it disconcerting – especially for American DIY hi-fi audio enthusiasts – that it was the “modern” vacuum tubes - like the 7591A power pentode and 8417 beam power tetrode vacuum tubes - that became extinct, especially during the Reagan Administration. But given that the 7591A power pentode eventually got reintroduced by Electro-Harmonix during the late 1990s thanks to Jazz electric guitarists in the former Warsaw Pact countries, is there any hope for the 8417 vacuum tube to be resurrected? 

Historically speaking, the 8417 beam power tetrode is for intents and purposes a “modern” vacuum tube because not only it was the last ones to be developed and marketed during the latter half of the Golden Age Of Stereo back in 1963 before solid state devices of similar capabilities became commercially viable years later but also like every solid state audio amplification the 8417 vacuum tube is designed to work with various degrees of negative feedback in its operation. During its early days, the 8417 vacuum tube is described as a “cavity anode” type specifically designed for the Fisher SA-1000 audio amplifier.
The 8417 vacuum tube has a rated anode dissipation of 35-watts RMS that results in a 100-watt RMS output in push-pull AB1 fixed bias configuration that results in an audio amplifier using a pair of the tubes. Even though it first gained popularity in the Dynaco Mark III amplifier during the early 1970s, it was Quicksilver Audio that brought the 8417 vacuum tube to worldwide fame back in 1981 when the former founder and owner of Quicksilver Audio Mike Sanders began selling the Quicksilver MS 190 stereo amplifier. 

The Philips 8417 Mono Amplifiers were later developed in 1984 to bring that great vacuum tube sound to the average consumer. Harry Pearson of The Absolute Sound magazine published a positive review of the amplifier during that time. Philips managed to manufacture the amplifier until 1998 before manufacturing their batches of the 8417 vacuum tube became no longer economically viable at the tail end of the 1980s. Quicksilver kept manufacturing their versions of the 8417 vacuum tube amplifier well into the 1990s to take advantage of the 1990s era Hi-Fi Renaissance despite of the output tube becoming virtually extinct at that time.      

Given that the 8417 beam power tetrode vacuum tube has no “modern” equivalent – i.e. post Soviet Russian and post Warsaw-pact manufactured equivalents – various replacement schemes for the output tubes of 8417 equipped audio amplifiers were proposed. Owners of Dynaco Mark III amps that use 8417 beam power tetrodes can be “rebiased” to use the more plentiful and still manufactured 6550 vacuum tube, but unfortunately the Dynaco Mark III’s output transformers are primarily optimized for the 8417. Too bad nobody manufactured electric guitar amplifiers that used the 8417 vacuum tubes during the 1960s because if one company did, Electro-Harmonix would be remanufacturing their very own 8417 beam power tetrode vacuum tube back in the late 1990s. 

When buying new old stock – or NOS – 8417 beam power tetrode vacuum tubes, Sylvania are considered the best brand and is relatively widely available, while General Electric and RCA manufactured ones too with varying quality and some batches are prone to grid overheating in long hi-fi listening sessions. It’s best to consider buying General Electric and RCA 8417 vacuum tubes only when they are those of “specifically manufactured for the U.S. Air Force types” – i.e. reinforced anode military specification  mil spec  types. 

Wednesday, November 5, 2014

Is Live Music Really Better Than Hi-Fi?



The debate between live and recorded music has been opening countless cans of worms since the first affordable Victrola was launched, but is live music really better than hi-fi in this day and age? 

By: Ringo Bones 

Staunch supporters of touring musicians may have Napster creator Shawn Fanning to thank because ever since that time, the only way for “rockstars” to earn ungodly amounts of money is via touring and doing live concerts. But has hi-fi audio technology really advanced to a point since that time that a well set-up hi-fi rig this day and age can now rival the sound quality of a live music concert? Sadly, like all things in the real world, the “concept” of a live music concert wholly depends upon your perspective. 

Sometimes, I do find it strange on how most “hi-fi” journalists that are vehement critics of how different hi-fi music and live music – Classical or rock – are had never played live on stage during the last 20 years or so, never mind within their whole lifetime. Remember that scene in the Bruce Willis and Kim Basinger movie titled Too Hot To Handle - or was it Blind Date back in 1987? - when the two of them witnessed a “live-in-the-recording-studio” performance of Jazz guitar legend Stanley Jordan? Well, that’s my idea of live musical performance that our hi-fi rigs no matter how expensive still can’t touch though we’re getting there closer everyday but most tenured hi-fi journalist this day and age conveniently overlooks. 

By the nature of the beast, hi-fi journalists, more often than not, tend not to talk about the hard realities of being a touring musician – never mind a “roadie”. Remember that incident during the Extremist tour back in 1992 where Joe Satriani’s trusty electric guitar amps – i.e. Soldano heads and a 1969 era 100-watt Marshall amplifier were stolen in lieu to being transported from their touring truck to the stage? Equipment theft incidences seem to be furthest from the minds of these “tenured hi-fi journalists” when it comes to comparing between live music and hi-fi. During that time, vacuum tube gear were getting scare during the Reagan years – imagine if it were the “hi-fi journalists” McIntosh amp that used 7591A vacuum tubes? Try finding a replacement in two weeks time, never mind waiting for Electro-Harmonix to manufacture one in eight years time. 

Sound quality wise, rock bands that top my own sound quality list during their live performances tend to be the older ones – as in The Grateful Dead and Pink Floyd. But form the location – as in perspective - in the audience where I and most of us can no longer the direct sound of the unamplified drum set and most of what we hear is the concert PA system, I’ll stick with my home hi-fi rig thank you. From 500 feet from the stage, the last Pink Floyd concert I’ve been to back in 2002 has the PA system’s sound quality just slightly worse than a Denon PMA-350SE amplifier or a Rotel RA970BX amp connected to a Tannoy Westminster loudspeakers being fed from a 1995 era Linn Sondek turntable. 

Tuesday, November 4, 2014

Whatever Happened To Hi-Fi Gunshot / Gunfire Recordings?


Though the last time I saw one being displayed in my neighborhood’s record store, Miami Vice’s first season was just about to end, but are there any technical difficulties in making “audiophile” gunshot / gunfire recordings?

By: Ringo Bones 

Weird fact – even though sound effect CD’s featuring gunfire / gunshot recordings of widely varying sound quality are “more or less” are still stocked in most record stores around the world, not one of them claimed to be of audiophile or even of “hi-fi” quality. Politics aside, are there really technical difficulties in recording true “audiophile quality” gunshot / gunfire recordings that sound like the real thing when played in a well set-up hi-fi system? 

Maybe 1990s era Madison Avenue hi-fi admen overlooked the hype and potential big money of advertising an audio product that has the seal-of-approval by either Mikhail Kalashnikov or Eugene Stoner as being able to reproduce the sound of either an AK-47 or an M-16 assault rifle in full auto mode with the timbre of the actual acoustic event. And, believe-it-or-not, the topic of how your hi-fi rig replicates the sound of a modern assault rifle firing 5.56-mm X 45-mm NATO rounds can generate “howls of derision” in either Twitter or Pinterest despite the howler being unable to fully articulate their derisions in an erudite manner using 140-characters or less. 

Even though there are quite a “handful” of movies that got the gunshot recording right, like that “zombie apocalypse movie” 28 Days later where Cilian Murphy stars in, most gunshot / gunfire Foley – i.e. sound effects – used in movies are, timbre wise, far removed from the real thing. But are there truly “technical issues” that hamper in the creation of truly “audiophile quality” gunshot / gunfire recordings? 

Recent figures of peak decibel sound pressure levels of most small arms widely used in most Hollywood action moves are as follows: small rifle = 140 to 145 dB SPL, medium rifle = 157 to 160 dB SPL, large rifle = 160 to 174 dB SPL, shotgun = 152 to 166 dB SPL, small pistol = 150 to 157 dB SPL, large pistol = 158 to 174 dB SPL. Most microphones are capable of recording sounds up to 130 dB SPL – but only with its built-in L-pad switched in when recording jet-engine level sounds, but in practice, most microphones commonly used in music studio recording sessions tend to distort badly when recording sounds above 110 dB SPL – even with peaks lasting just several milliseconds. And L-pads have a tendency to add an overall “grunginess” that makes most recorded gunshot sound effects sound “less-than-audiophile”. 

Back in 2005, an episode of Discovery Channel’s Future Weapons were doing an episode on a new squad automatic weapon that uses 7.62-mm X 51-mm rounds instead of the older M-249 SAW that uses 5.56-mm X 45-mm rounds (I think it was M240L or the Mk 48) where presenter Richard Machowicz suddenly pointed out that they’ve just busted the diaphragm of their tubed ribbon microphone when recording the sound of the weapon. This highlighting the technical difficulties of recording sound pressure levels several orders of magnitude louder than a heavy metal rock concert. 

When it comes to recording live acoustic events these days – either music or ambient sounds – it always more often than not boils down to a compromise of choosing between a condenser microphone and a tubed microphone. Condenser microphones are known for their openness and more air while tubed microphones have a nice EQ sound without resorting to using too much EQ during final mix-down that could result in unwanted phase shifts that makes the recorded sound acquire an unnatural electronic timbre. Stereophile’s recording-engineer-in-residence John Atkinson overcame this inherent live recording limitation during the 1990s with his “time-aligned microphones” that combines the air and openness of condenser microphones with that you-are-there timbre of tubed microphones, but I don’t think he’ll be recording audiophile quality gunshot / gunfire recordings anytime soon.                

Thursday, July 31, 2014

Is Binaural The Best Domestic Two-Channel Stereo Format?



Despite of the under-narrated history of this particular audio recording and reproduction method, is binaural the best domestic two-channel stereophonic audio format? 

By: Ringo Bones

Despite the recent advancement of various audio digital signal processing methods now widely available online in App form that can even convert the lowly MP3 audio – whose digital music data rate is one-tenth that of 16-bit 44.1KHz Redbook spec digital audio - to sound as good as mid 1990s entry level CD audio like Bob Burwen’s Burwen Bobcat and other similar schemes, it seems that no gifted audio engineer has ever devised a digital signal processing / DSP scheme that converts plain two-channel domestic stereo – that may sound remarkably good via a pair of speakers - into binaural that doesn’t sound as if the studio recorded two-channel stereo music is playing inside and in the middle your head. Given that binaural recordings had been widely available – probably since John Sunier of The Binaural Source set up shop to sell binaural recordings in CD, LP, prerecorded cassette and open-reel tape form and can also be bought online via www.binaural.com – for some time now, it seems that - since around 1995 – binaural audio seems to have languished in obscurity in mainstream hi-fi circles. Especially today where the “headphone-bound” Apple i-Pod is the now de rigueur way for everyone use in listening to recorded music.  

To the uninitiated, binaural literary means sound for two ears. Or in technical terms, a two-channel (left and right) sound recording and reproduction method in which each ear of the listener hears only one channel – and implies the use of headphones. Normal human hearing is binaural in nature; each ear hears from a slightly different distance and direction. Even though most people are largely unconscious of this difference, it gives the depth and reality to sound as does dual seeing does to the stereoscopic / binocular nature of normal human vision. 

So why not just use two speakers? Dual speakers can help around the sound by giving the illusion that it comes from two directions but in actual practice, true binaural recordings sound “lousy” when listened to via left and right speaker set up the same reason why conventional two-channel stereo recordings sound as if the musician / band sound as if they are playing inside the middle of your head when listened to via headphones.
Believe it or not, binaural sound has been around since reasonably realistic sounding headphones and transcription (recording) discs more advanced than the first ones invented by Thomas Edison had been around. True binaural sound – especially ones recorded via the dummy head method where the two left and right microphones were placed where the human ears are supposed to be had been making audiophiles jump for joy since that time. During the 1933 – 1934 Chicago World’s Fair, an exhibition by a company called Cook Binaural are attracting hordes of early audio enthusiasts after the word spread of early listeners swore that a binaural recorded haircut recording recorded on an early electrical transcription disc – using a dummy head recording method while a wig placed on it was cut by scissors – sound as if the listeners are getting an actual haircut while sitting in a barber’s chair!  In truth, binaural audio seems to pre-date the advent of everything that has become the infrastructure of what we now call as hi-fi sound – even the Zenith-General Electric VHF FM stereo radio system that has been approved by the US Federal Communications Commission back in June 1, 1961. 

During the 1950s, before the advent of modern Fast-Fourier Transform based electrocardiogram machines, medical students in the United States were trained to listen to binaural open-reel tape recordings of heart sounds after medical schools at the time found out that it provided a vast improvement over medical diagnosis via plain-vanilla stethoscope listening. Besides affording a permanent record, these binaural open-reel tape recordings is said to permit – at the time – a more accurate analysis of heart irregularities.  
Even though almost any audio enthusiast during the Golden Age of Stereo can “roll their own” binaural recordings using existing domestic open reel tape technology of the time, the wonderful virtues of binaural seems to be the most under-narrated in the annals of high-fidelity sound. But after around 60 years of domestication / home use, the largely specialized binaural market is mainly aimed at serious headphone listening / earphone / in-ear headphone listening based audiophiles. Should current stereo headphone platforms – like the Apple i-Pod – be so now equipped with a stereo to binaural digital signal processing / DSP system?

Friday, July 25, 2014

Did Stereophonic Sound Originally Consist Of Three Channels?



It may come as a shock to two-channel stereo purist but did you know that the original standard for stereophonic sound originally called for three – as in left, center and right – channels? 

By: Ringo Bones 

If you have “audio-buddies” old enough to have lived through the Golden Age of Stereo and has a deep-seated animosity against multi-channel, and especially, surround-sound, chances are he (sadly it is overwhelmingly always a he) may and could hate you for weeks if you tell him that the original standard being called for commercial stereophonic sound for domestic applications originally called for three channels – as in left, center and right channels of audio. But are there still “surviving” examples of three-channel stereo recordings? 

To the still unfortunate few audiophiles still not in the know, the greatest Jazz recording of all time – as in Miles Davis’ Kind of Blue – was originally mastered in three-channel stereo. And even though Kind of Blue was originally released for “domestic use” in those now venerable Six-Eye mono Columbia LPs, many inquisitive audiophiles that had lived through the Golden Age of Stereo has since found out that music originally mastered on three-channel stereo format onto open-reel magnetic tapes seems to sound the best whenever they are transferred – as in mixed down - to either mono or two-channel stereo vinyl LPs. 

Even though the two-channel stereo format is quite adequate in our domestic listening rooms where the “soundstage” is seldom greater than 20 feet in width, those audiophiles fortunate enough to possess true three-channel stereo recordings had found out that these work best in larger than average listening rooms than those typically found at the home. This is due to the fact that sound travels at a finite speed and much slower than that in comparison to the speed of light. This results in practice the phenomena on why the two-channel stereophonic sweet-spot doesn’t scale in large auditoriums. To their “horror” the two-channel stereo sweet-spot in large auditoriums is about the same that heard in a 25-feet wide listening room!!! Fortunately for these ├╝ber-rich audiophiles with Wembley Stadium sized listening rooms the three-channel stereo format of Miles Davis’ Kind of Blue has been released in three-channel stereo Super-Audio-CDs and has been relatively widely available since 2003.