As a decibel drag race that was formed independent of the American IASCA, does the Great Car Stereo Wars of the 1980s in Cebu City the definitive setting of the AN214 IC amplifier’s “finest hour"?
By: Vanessa Uy
This ad hoc and largely forgotten and unknown “hi-fi” movement of the 1980s probably started when a bunch of hi-fi audio enthusiasts began – maybe independently from each other - reverse-engineering their Pioneer KP-500 FM / cassette tape equipped car stereos in order to find out what makes them tick. Sure enough, this tinkering spawned a hi-fi revolution that probably rivaled the single-ended triode revolution in Japan that began in 1970.
Unlike the present incarnation of decibel drag racing using IASCA approved high-powered (supposedly 160 decibels loud but a Pratt & Whitney F100 afterburning turbofan jet engine in test compliance burns sounds way, way louder while roaring on its static test stand at just 135 decibels) switching-mode power amplifiers of dubious musicality. They sound really gray and really colorless to me! The “audio gear” used in the Great Car Stereo Wars of the 1980s still has a sound quality that those with musically-literate ears and brains can appreciate without prejudice.
Primarily, it was the Pioneer KP-500 that became the audio gear of choice back then. With its now iconic circular tuner display, dinky volume, bass and treble knobs. A then-cassette era mandatory loudness switch and if you cover the old illuminated Pioneer logo with its stylized tuning fork and ohm symbol, an audio enthusiast from the 1990s would honestly mistake it for a 1996 era Musical Fidelity X-A1 integrated amplifier.
Given a lack of Nakamichi tape deck dealership in Cebu – then and now. Cassette tape era audiophiles attempted to replicate – to a degree of success – a “Nakamichi Solution” to make the cassette tape sound “musical” by boosting both the low and high frequency portions of the audio spectrum via tone controls / equalizers. A bloke by the name of Edwin – a.k.a. Big Boss Edwin – with his Kansas Sound, developed a novel equalization method – probably in the late 1970s - to improve the inherent limitations of the stock Pioneer KP-500 car stereo sound. Edwin even extolled the use of Pioneer’s in car PT-6 horn-loaded tweeter in conjunction with his audio system designs despite the Pioneer tweeter’s 8kHz bandwidth limit. Audiophile-grade tweeters today can easily reach 120kHz.
Even though Edwin blacked-out the capacitor and resistor values of his signature design tone control preamplifier to avoid his design from being unlawfully ripped-off noting that it is much coveted back then. After I reversed engineered now “abandoned” units of his famed preamplifier / tone control. I do agree that Edwin’s novel preamplifier / tone control is based on the great studio equalizers / tone controls then in studio use during the “Golden Age of Stereo”, specifically the famed Abbey Road Studios where The Beatles used to record.
I found it of similar design to a vintage tube / valve-based Pultec Model EQP-1R, which was first manufactured by Pulse Technologies Inc. of Englewood, New Jersey back in 1955 and has spawned many derivatives. Amongst which are some of the cream-of-the-crop “vintage” vacuum tube-based studio equalizers of today! The Pultech’s power lies in its ability to independently select the frequency range or frequency band over which boost and cut may be applied to a degree of subtlety way beyond that of a standard Baxandall-based tone control circuit. Although in actuality, the EQP-1R in its original form is so complicated that offers too much of a good thing for domestic use. Edwin’s version uses “blue input captain” – i.e. I.F. transformers that are color coded blue – as the inductors for his tone control circuit while the original Pultec uses dedicated E and I core-based chokes or inductors.
The important detail to notice is that the user may, for instance cut bass frequencies below 100Hz and – at the same time – boost those frequencies below 30Hz. Using the Pultec Model EQP-1R tube studio equalizer or Edwin’s tone control design, it is possible to clean up a “boomy” recording – i.e. excess sound energy in the 100Hz to 200Hz region – without unduly emasculating the bass frequencies. A tone control with this capability can also be very useful for correcting for room resonance effects - which we all suffer, especially in the cramped quarters of our “compact” cars.
The flexibility of this type of tone control can also be used to “tame” the high frequency audio band. For cassette tape users, a conjunction of boost in the 5kHz region and a treble cut above 10kHz can help restore sparkle to cassette tapes recorded with incorrect azimuth or tape head alignment without introducing too much tape noise or tape hiss in the process. Thus bringing the cymbals and other high frequency sounds back to dull cassette tape music.
The only disadvantage of Pultec’s passive approach is that the circuit introduces about 24dB of static attenuation at all frequencies when adjusted for a flat response. In the original circuit, this loss was compensated by the introduction of a push-pull tube amplifier constructed from pre-amp tubes with relatively low output impedance and high anode dissipation (4 to 5 watts) like the 12RX7, 12RU7 tube and a couple of transformers. Whether this is the influence of the transformer-coupled amp booster for the AN214 is still open to speculation though.
While Edwin’s method employs the Pioneer KP-500’s built-in AN214 IC-based amplifier as a preamplifier for his tone control design before the signal is amplified again by an another AN214 stage en route for amplification into the MJ2955-based transformer-coupled booster amplifier. I think these types of tone controls - though lossy – are more musical than multi-band graphic equalizers that use solid-state integrated circuits. Or the op-amp based Baxandall tone control – which is plagued by group delay distortion and a high degree of transient inter-modulation distortion due to the relatively high levels of negative feedback. A prime anathema for audiophiles with musically trained ears and brains.
Edwin’s tone control design was effective enough to be used as an ad hoc “vocal eliminator”, since it can be tuned to cut only frequencies in the human voice part of the audio spectrum. The problem with it, however is that the “multiplicity / flexibility” makes it very easy and also very tempting to emphasize the spectacular over the real. To turn the system into a hi-fi “fireworks display – which their users often would in decibel drag races. Some “seasoned veterans” of the “Great Cebu City Car Stereo Wars” often had 8-Track variants of Pioneer circular tuner display car stereos. Probably the older version of the cassette tape-based Pioneer KP-500 playing a special “Bill Laswell-style remix” of Scorpions’ song “China White” for use in "audiophile quality" decibel drag racing back around 1981 to 1982.
I would have liked to have a first-hand experiment on the bass enhancing effects of 8-Track tapes. Sadly, these "Beasts” had become increasingly rare over the years. Pioneer 8-Track car stereos are virtually extinct nowadays, never mind Pioneer 8-Track tape decks that allow you to record from vinyl LPs. I wonder how would those Bill Laswell recorded Motörhead albums, with Lemmy Kilmister’s Rickenbacker bass guitar and Philthy Taylor’s drumming captured in full glory, sound through these systems? Or what about Nina Gordon and Louise Post of Veruca Salt, or Lunachicks, how will they sound through a Pioneer KP-500? We will probably never know because even the Pioneer KP-500 is about as rare as a German EMT 927 broadcast turntable.
Wednesday, August 5, 2009
Thursday, July 16, 2009
Don’t Forget the Heatsink
Despite of its relatively low power output does the AN214 IC still deserve the tender loving care of adequate heatsinking to achieve better sound quality?
By: Vanessa Uy
During the AN214 IC-based amplifier’s heyday in the early 1980s, heatsinking is usually of little concern due to the device’s relatively low power output that barely reaches 5 watts. Hobbyists back then – especially those that lack adequate knowledge on how semiconductor ICs work – usually bolt the AN214’s metallic tab / backside of it’s 9-pin single inline package to a piece of scrap metal to serve as an ad hoc heatsink. Or maybe to the aluminum chassis of the amplifier’s intended housing, without further concerns on how hot it might get during the AN214 IC’s intended lifetime.
Ideally, when operated under the right conditions, solid state devices tend to last for hundreds of thousands of years. Some of these inadequately heatsinked amps just manage to last up to 8 months at most. As most electronic engineering textbooks – then and now – often states that low-powered applications require minimum thermal mass, a few centimeters of sheet metal, to transfer the small amount of heat generated by a low-power semiconductor device to the ambient air. But is common-sense engineering good enough for the perfectionist audiophile-grade applications for the AN214?
The raison d’être of heatsinking IC-based power amplifiers – even low-powered ones – is to obtain the IC amplifier’s maximum output voltage swing as specified by the manufacturers’ spec sheets. This can easily show up under triangular-wave or sine-wave tests when the inadequately heatsinked IC-based amplifier can’t even output one-tenth of it’s intended maximum output voltage swing - on the cathode ray oscilloscope, the sine and triangular wave peaks would be melting or clipped like crazy.
Non-linear reactive loads like loudspeakers – or the inter-stage transformer of the MJ2955 PNP transistor-based booster amplifier – tend to have some unwanted effects on inter-stage amplifiers (the AN214). The resulting back-EMF of the load may attempt to swing beyond the power supply voltages applied to the amplifier. Thus in order for the IC’s output protection circuitry – assuming it has one – to work, then a heatsink is always a necessity in “controlling” the inductively-generated electromotive force of whatever inductive load that happens to be connected to the AN214 IC-based power amplifier.
To obtain the best theoretically possible sound quality from your AN214 IC-based amplifier, an infinite heatsink – or a realistic equivalent – is a must. To make your intended finned aluminum alloy heatsink approach the heat-dissipating performance of an infinite heatsink, its main body – the point where you bolt-on the IC / semiconductor package – should be thicker than 1/16 of an inch. And this part should be polished to maximize heat transfer. You can also add silicone grease with metal oxide to further boost heat transfer. After bolting-on the IC to the heatsink, you can paint the aluminum alloy heatsink’s surface with a mat black-colored oil paint – preferably thinned a bit with linseed oil – to further boost the heatsinks’ emissivity rating. If done properly, your AN214 IC-based amplifier now has the potential to perform its very best.
By: Vanessa Uy
During the AN214 IC-based amplifier’s heyday in the early 1980s, heatsinking is usually of little concern due to the device’s relatively low power output that barely reaches 5 watts. Hobbyists back then – especially those that lack adequate knowledge on how semiconductor ICs work – usually bolt the AN214’s metallic tab / backside of it’s 9-pin single inline package to a piece of scrap metal to serve as an ad hoc heatsink. Or maybe to the aluminum chassis of the amplifier’s intended housing, without further concerns on how hot it might get during the AN214 IC’s intended lifetime.
Ideally, when operated under the right conditions, solid state devices tend to last for hundreds of thousands of years. Some of these inadequately heatsinked amps just manage to last up to 8 months at most. As most electronic engineering textbooks – then and now – often states that low-powered applications require minimum thermal mass, a few centimeters of sheet metal, to transfer the small amount of heat generated by a low-power semiconductor device to the ambient air. But is common-sense engineering good enough for the perfectionist audiophile-grade applications for the AN214?
The raison d’être of heatsinking IC-based power amplifiers – even low-powered ones – is to obtain the IC amplifier’s maximum output voltage swing as specified by the manufacturers’ spec sheets. This can easily show up under triangular-wave or sine-wave tests when the inadequately heatsinked IC-based amplifier can’t even output one-tenth of it’s intended maximum output voltage swing - on the cathode ray oscilloscope, the sine and triangular wave peaks would be melting or clipped like crazy.
Non-linear reactive loads like loudspeakers – or the inter-stage transformer of the MJ2955 PNP transistor-based booster amplifier – tend to have some unwanted effects on inter-stage amplifiers (the AN214). The resulting back-EMF of the load may attempt to swing beyond the power supply voltages applied to the amplifier. Thus in order for the IC’s output protection circuitry – assuming it has one – to work, then a heatsink is always a necessity in “controlling” the inductively-generated electromotive force of whatever inductive load that happens to be connected to the AN214 IC-based power amplifier.
To obtain the best theoretically possible sound quality from your AN214 IC-based amplifier, an infinite heatsink – or a realistic equivalent – is a must. To make your intended finned aluminum alloy heatsink approach the heat-dissipating performance of an infinite heatsink, its main body – the point where you bolt-on the IC / semiconductor package – should be thicker than 1/16 of an inch. And this part should be polished to maximize heat transfer. You can also add silicone grease with metal oxide to further boost heat transfer. After bolting-on the IC to the heatsink, you can paint the aluminum alloy heatsink’s surface with a mat black-colored oil paint – preferably thinned a bit with linseed oil – to further boost the heatsinks’ emissivity rating. If done properly, your AN214 IC-based amplifier now has the potential to perform its very best.
Thursday, July 2, 2009
Is the AN214 IC Amplifier Hi-Fi?
Given that it resides in the 12-volt world of car audio, does the AN214 IC amplifier fulfil the tenets of high-fidelity audio reproduction – namely a good to excellent sound quality?
By: Vanessa Uy
Today, we audiophiles – at least the sane ones anyway – judge an audio amplifier’s performance by its ability to realistically reproduce the sound of a recorded musical performance. As opposed to how many watts it can deliver or how low it’s overall total harmonic distortion – i.e. a good to excellent set of measurements, and even the amplifier’s circuit topology / technology.
The practice of using our ears – as opposed to a 10,000 US dollar multi-function audio analyzer – probably gained fashion (again?) back in January 1994. When Stereophile magazine released a correspondingly dated magazine with a riddle posted on the cover that goes “If either of these amplifiers is RIGHT…the other must be WRONG”. An idea probably influenced by James Carville’s book titled “We’re Right, They’re Wrong: A Handbook for Spirited Progressives” – a reactionary idea born out of chronic bullying by Rush Limbaugh and his global warming / climate change denying ilk directed at us liberals. It looks like our too liberal postmodern dictum of everyone’s opinion is right is our own downfall - at least according to Mr. Carville.
Returning to the world of hi-fi, it does seem like sound quality has indeed gained vogue in assessing the pride of ownership potential of audio components, especially audio amplifiers. The circuit topology and technology used seems no longer relevant, probably due to the single-ended triode “revolution” in Japan during the 1970s which made audiophiles around the world reexamine their views about what’s important about their hobby.
Given that the AN214 IC amplifier might be cheap, its hi-fi credentials easily manifest by the overall improvement in sound quality every time you over-engineer one. Use larger than necessary output transformers and the bass quality improves, just like its single-ended triode counterparts. Use larger than necessary heat sinks and the AN214 amplifier rewards you with a more agile pace, rhythm, and timing. In fact if you tweak the AN214 amplifier’s power supply with Rubicon Black Gate capacitors, it could even sound better – from a musical perspective – than a standard Pioneer A400 amplifier. The only way a Pioneer A400 can be more musical than a tricked-out AN214 amplifier is by doing a T. Evans Audio Design-style modification to its power supply.
During the AN214 amplifier’s heyday, many audiophiles – especially absolute beginners – have never been told about the wisdom of trusting their own two ears as the ultimate arbiter of sound quality. This is why back then solid-state high-powered full-complementary output stage direct-coupled power amplifiers were touted as the ultimate in sound quality. Even though most of them sound sluggish in the pace, rhythm, and timing department because their power supply capacitors have not been designed to take advantage of time-constants. Ad given that solid-state full-complementary amplifiers are relatively complex in terms of component count, tweaking one – especially if you are an audiophile on a budget – seldom makes fiscal sense. It is even cheaper – time and labor wise – to buy very expensive solid-state amplifiers from Mark Levinson, Krell, and Spectral.
So, is the AN214 IC-based amplifier hi-fi? If you trust your own two ears, then the answer is a resounding yes. If the music matter’s more to you than the circuit complexity of your audio amplifier, then maybe it is about time you should check out the AN214 amplifier - especially if you can’t afford exotic single-ended triode tube-based amplifiers, or if you live in a place where the 50 caliber Browning Machine-Gun cartridge is way more plentiful than 300B vacuum tubes. During the AN214 IC amplifier’s heyday, it might have the requisite resolution to play out the full beauty of Larry Carlton’s guitar playing on Michael Jackson’s Don’t Stop ‘Till You Get Enough.
By: Vanessa Uy
Today, we audiophiles – at least the sane ones anyway – judge an audio amplifier’s performance by its ability to realistically reproduce the sound of a recorded musical performance. As opposed to how many watts it can deliver or how low it’s overall total harmonic distortion – i.e. a good to excellent set of measurements, and even the amplifier’s circuit topology / technology.
The practice of using our ears – as opposed to a 10,000 US dollar multi-function audio analyzer – probably gained fashion (again?) back in January 1994. When Stereophile magazine released a correspondingly dated magazine with a riddle posted on the cover that goes “If either of these amplifiers is RIGHT…the other must be WRONG”. An idea probably influenced by James Carville’s book titled “We’re Right, They’re Wrong: A Handbook for Spirited Progressives” – a reactionary idea born out of chronic bullying by Rush Limbaugh and his global warming / climate change denying ilk directed at us liberals. It looks like our too liberal postmodern dictum of everyone’s opinion is right is our own downfall - at least according to Mr. Carville.
Returning to the world of hi-fi, it does seem like sound quality has indeed gained vogue in assessing the pride of ownership potential of audio components, especially audio amplifiers. The circuit topology and technology used seems no longer relevant, probably due to the single-ended triode “revolution” in Japan during the 1970s which made audiophiles around the world reexamine their views about what’s important about their hobby.
Given that the AN214 IC amplifier might be cheap, its hi-fi credentials easily manifest by the overall improvement in sound quality every time you over-engineer one. Use larger than necessary output transformers and the bass quality improves, just like its single-ended triode counterparts. Use larger than necessary heat sinks and the AN214 amplifier rewards you with a more agile pace, rhythm, and timing. In fact if you tweak the AN214 amplifier’s power supply with Rubicon Black Gate capacitors, it could even sound better – from a musical perspective – than a standard Pioneer A400 amplifier. The only way a Pioneer A400 can be more musical than a tricked-out AN214 amplifier is by doing a T. Evans Audio Design-style modification to its power supply.
During the AN214 amplifier’s heyday, many audiophiles – especially absolute beginners – have never been told about the wisdom of trusting their own two ears as the ultimate arbiter of sound quality. This is why back then solid-state high-powered full-complementary output stage direct-coupled power amplifiers were touted as the ultimate in sound quality. Even though most of them sound sluggish in the pace, rhythm, and timing department because their power supply capacitors have not been designed to take advantage of time-constants. Ad given that solid-state full-complementary amplifiers are relatively complex in terms of component count, tweaking one – especially if you are an audiophile on a budget – seldom makes fiscal sense. It is even cheaper – time and labor wise – to buy very expensive solid-state amplifiers from Mark Levinson, Krell, and Spectral.
So, is the AN214 IC-based amplifier hi-fi? If you trust your own two ears, then the answer is a resounding yes. If the music matter’s more to you than the circuit complexity of your audio amplifier, then maybe it is about time you should check out the AN214 amplifier - especially if you can’t afford exotic single-ended triode tube-based amplifiers, or if you live in a place where the 50 caliber Browning Machine-Gun cartridge is way more plentiful than 300B vacuum tubes. During the AN214 IC amplifier’s heyday, it might have the requisite resolution to play out the full beauty of Larry Carlton’s guitar playing on Michael Jackson’s Don’t Stop ‘Till You Get Enough.
Saturday, June 20, 2009
A Transformer-Coupled Booster Amplifier for the AN214
Due to it’s inherently low power output design, does addition of a transformer-coupled booster amplifier to an AN214-based amplifier aid or hinder it’s sound quality?
By: Vanessa Uy
Given it’s inherently low power output – between 4 to 5 watts into an 8-ohm load. It was therefore inevitable to find a way of increasing the “meager” output of the AN214 IC-based audio amplifier without sacrificing it’s inherently good sound quality (on the cheap?). I wonder how many ways were “engineered” during the past 30 + years or so history of this device. Surprisingly, a consensus was reached of choosing a “primitive” transformer-coupled PNP transistor-based design that probably dates from the 1950s.
The design configuration of the transformer-coupled booster amplifier used to increase the 5-watt power output of the AN214 IC-based power amplifier for all intents and purposes resembles that of a transformer-coupled 300B-based push-pull tube power amplifier circuit. Except that the 300B tubes (or valves as they say in Merry Old England) were replaced by MJ2955 PNP power transistors in a TO-3 package. From my point of view, this transistor-based transformer-coupled booster amplifier circuit was probably based on the first transistor-based audio power amplifier designs first published in the US-based audio electronics magazine called AUDIO. Probably those issues dated between January 1960 to December 1961 - i.e. the Golden Age of Stereo.
During my experimentation of the MJ2955-based transformer-coupled booster amplifier – which to all intents and purposes is a continuation of the experiment done by my older audio-buddies during the last 25 years or so – I did optimize the input transformer winding design. By eliminating stray capacitance of the input transformer / driver transformer winding and optimizing it for a near-perfect square wave performance and transfer function characteristics. I did manage to reduce the booster amplifier’s recommended negative feedback level, which only improved the sound quality to no end.
Compared to its 300B tube-based sibling sound quality wise, it was a close match. Although the 300B-based push-pull amplifier did manage to display irreproachable beauty where it excels. Like in the Middle-C region of the musical performance – i.e. upper bass and lower midrange region of the audio spectrum. And even though it was criticized during the 1980s that transistor-based transformer-coupled booster amplifiers are notorious for having high total harmonic distortion (THD) in comparison to a full complementary direct-coupled solid-state power amplifier. But if you wind the transformers properly by eliminating stray capacitance – especially the input / driver transformers, the inherently high THD (total harmonic distortion) of transformer-coupled solid-sate booster amplifiers can be dramatically reduced. Although high-quality audio frequency transformers – driver transformers and output transformers - that are wound at artisan levels to optimize their square-wave performance and optimize their transfer-function characteristics across the audio spectrum are magnitudes more expensive in comparison to matched pairs of high-power output transistors.
The bad news is – from a perfectionist audiophile’s perspective – a lot can go wrong, sound quality wise, in the actual construction of full complementary direct-coupled solid-state power amplifiers. Especially if the “engineer” doesn’t trust their own ears and chose to trust on measuring instruments instead could result in a sluggish sounding power amplifier with unlimited reserves of power - but one that is sorely lacking in the pace, rhythm, and timing department. That's why I really hate musically illiterate audio engineers. Looks like the old-school wisdom gained by audio engineers during the Golden Age of Stereo still applies well into the 21st Century. And it also provides a low-cost route to audio nirvana via the AN214 IC-based audio power amplifier route. Ain’t it fun to be an audio cheapskate?
By: Vanessa Uy
Given it’s inherently low power output – between 4 to 5 watts into an 8-ohm load. It was therefore inevitable to find a way of increasing the “meager” output of the AN214 IC-based audio amplifier without sacrificing it’s inherently good sound quality (on the cheap?). I wonder how many ways were “engineered” during the past 30 + years or so history of this device. Surprisingly, a consensus was reached of choosing a “primitive” transformer-coupled PNP transistor-based design that probably dates from the 1950s.
The design configuration of the transformer-coupled booster amplifier used to increase the 5-watt power output of the AN214 IC-based power amplifier for all intents and purposes resembles that of a transformer-coupled 300B-based push-pull tube power amplifier circuit. Except that the 300B tubes (or valves as they say in Merry Old England) were replaced by MJ2955 PNP power transistors in a TO-3 package. From my point of view, this transistor-based transformer-coupled booster amplifier circuit was probably based on the first transistor-based audio power amplifier designs first published in the US-based audio electronics magazine called AUDIO. Probably those issues dated between January 1960 to December 1961 - i.e. the Golden Age of Stereo.
During my experimentation of the MJ2955-based transformer-coupled booster amplifier – which to all intents and purposes is a continuation of the experiment done by my older audio-buddies during the last 25 years or so – I did optimize the input transformer winding design. By eliminating stray capacitance of the input transformer / driver transformer winding and optimizing it for a near-perfect square wave performance and transfer function characteristics. I did manage to reduce the booster amplifier’s recommended negative feedback level, which only improved the sound quality to no end.
Compared to its 300B tube-based sibling sound quality wise, it was a close match. Although the 300B-based push-pull amplifier did manage to display irreproachable beauty where it excels. Like in the Middle-C region of the musical performance – i.e. upper bass and lower midrange region of the audio spectrum. And even though it was criticized during the 1980s that transistor-based transformer-coupled booster amplifiers are notorious for having high total harmonic distortion (THD) in comparison to a full complementary direct-coupled solid-state power amplifier. But if you wind the transformers properly by eliminating stray capacitance – especially the input / driver transformers, the inherently high THD (total harmonic distortion) of transformer-coupled solid-sate booster amplifiers can be dramatically reduced. Although high-quality audio frequency transformers – driver transformers and output transformers - that are wound at artisan levels to optimize their square-wave performance and optimize their transfer-function characteristics across the audio spectrum are magnitudes more expensive in comparison to matched pairs of high-power output transistors.
The bad news is – from a perfectionist audiophile’s perspective – a lot can go wrong, sound quality wise, in the actual construction of full complementary direct-coupled solid-state power amplifiers. Especially if the “engineer” doesn’t trust their own ears and chose to trust on measuring instruments instead could result in a sluggish sounding power amplifier with unlimited reserves of power - but one that is sorely lacking in the pace, rhythm, and timing department. That's why I really hate musically illiterate audio engineers. Looks like the old-school wisdom gained by audio engineers during the Golden Age of Stereo still applies well into the 21st Century. And it also provides a low-cost route to audio nirvana via the AN214 IC-based audio power amplifier route. Ain’t it fun to be an audio cheapskate?
Wednesday, June 17, 2009
What in the World is an AN214 IC?
In spite of it’s age – and apparent manufacturing extinction – are AN214 IC-based audio power amplifiers still “noteworthy” in our 21st Century hi-fi world?
By: Vanessa Uy
If you asked me – or any of my older audio-buddies – about AN214 IC-based audio amplifiers, they do admit – albeit reluctantly – to have “once upon a time” taken this integrated circuit route to audio nirvana. Given that this low powered audio-amplifier-on-a-chip is about as technologically advanced as a cassette tape when viewed from our 21st Century perspective, does it still deserve serious discussion? Though the short answer by audiophile die-hards lucky enough to stock significant quantities of the AN214 IC is: “you betcha!”
Part of the allure and mystique of the AN214 integrated circuit-based audio power amplifier is that manufacturer authorized and approved – i.e. reliable – spec sheets and application notes are few and far between. In my opinion, it is safe to say that anyone who has seen first hand “proper” AN214 IC spec sheets – especially the device’s slew rate and power output rating – are either: a) had forgotten about it due to illicit drug use during the past 25 years. b) Have gallantly gave their lives during Operation Desert Storm, or more likely c) had joined a technology-rejecting / technology-abhorring religious cult.
But what everyone lucky enough to remember the virtues of the AN214 power amplifier during it’s heyday is that it has always been inexplicably linked with the ubiquitous back in the 1970s and 1980s Pioneer in-car stereo cassette tape deck and FM tuner combo. Which from an electronic engineer’s standpoint is inevitable given that both live in the 12-volt world of car audio. Although I’m lucky enough to have heard first hand Pioneer’s 8-track version of this in-car tape and FM tuner combo that sounds as if it was designed by famed recording engineer Bill Laswell due to it’s legendary ability to reproduce recorded music with tons of electric bass. I f you’re an unabashed reggae music and dub fan lucky enough to demo this legendary Pioneer in-car 8-track tape and FM stereo combo. Buying it would be the next best thing to hanging out with Bill Laswell in the recording studio capturing your favorite bass-based musician on analogue tape.
Although the AN214 IC audio amplifier was famed in its heyday for “heroically” bringing out the musicality of the cassette tape medium despite of it’s “engineering” limitations. This 5 watt (according to bench test measurements, although it sounds apparently more powerful in real life use) integrated circuit-based power amplifier has still so much to give in our wide bandwidth wide dynamic ranged hi-fi world. Even in the era of DVD Audio and SACD whose bandwidth could easily stretch to 100,000 Hz. Compared to CD’s 22,050 Hz Nyquist Frequency criterion limitation – never mind cassette tapes, which have a hard time reaching past 15,000 Hz.
Given that the first decade of the 21st Century is almost over, I find it real surprising than an integrated circuit-based low-power amplifier whose heyday pre-dates the discovery of the AIDS virus can still hold its own in 2009. If any of you out there has something extra to add to my woefully inadequate knowledge to the electronic engineering aspects of the AN214 IC-based power amplifier, please drop me a line. Your help is greatly appreciated. Especially the slew rate part of this venerable device.
Subscribe to:
Posts (Atom)
