Wednesday, August 5, 2009

The Great Car Stereo Wars of the 1980s

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.