Logic dictates that the car’s 12 volt DC system never rises above 13.8 volts DC, but does your car’s AN214 amplifier equipped with an alternator load dump filter, nonetheless?
By: Vanessa Uy
Some “mainstream” electrical and electronics engineers may consider the practice of installing an over-engineered alternator load dump filter for your car’s audio system to be a “tweak-extravaganza”, but have you ever wondered what these “mainstream” electrical and electronic engineers complaining about back in the early 1990s when their do-it-yourself installed car audios went kaput in just eight months after installation?
Well, maybe they should have done their research about one of the “electrical nasties” that can be encountered in a typical automotive 12-volt DC electrical system called alternator load dump.
Alternator load dump occurs when the load to which a generator is delivering current to is abruptly disconnected which causes a very brief – but sometimes very high – spike in voltage. In a typical automotive electrical system, this applies to disconnecting the car’s battery while it is being charged by the alternator.
Automotive technicians using electrical measurement equipment have since found out that the voltage generated by an alternator load dump can be as high as 87 to 120 volts and could take up to 400 milliseconds to decay or return back to 13.8 volts. This can be enough to burn out the solid-state electronics of car stereos and their associated power amplifiers. But is there a solution?
A typical alternator load dump filter consists of an L-C or inductor-capacitor filter where the inductor is rated at around 100 to 300 milliHenries at 1 ampere while the capacitor is a 1,000 microfarad 16 to 25 volt electrolytic capacitor connected to the car’s negative ground.
An over-engineered alternator load dump filter for an AN214 based automotive audio amp can be advantageous because an over-engineered L-C filter can also filter the hum of atypical full-wave-bridge 12 Volt DC power supply tapped in your home’s 220-volt 60-Hz AC wall socket.
A knowledgeable electronic enthusiast can even wind his or her own inductor for a fraction of a cost of a commercially made one. Just wind a 30-foot long piece of number 20 AWG magnet wire on a ½-inch plastic transformer bobbin then place the laminated E-I silicon-steel cores to increase its inductance into the 100 milliHenry range.
To make the capacitor part of the L-C filter alternator load dump filter last almost indefinitely, use an electrolytic capacitor in the 35-volt range.
An alternator load dump filter consisting of a 300 milliHenry inductor and a 10,000 microfarad 35-volt capacitor can limit the voltage spikes to 18-volts during an alternator load dump – which is more than necessary to protect the AN214 IC and related electronics since according to their spec sheets, automotive audio IC amplifiers can supposedly withstand voltage spikes as high as 48 volts for 500 milliseconds.
Wednesday, December 26, 2012
Monday, November 28, 2011
Does Meticulous Circuit Layout For The AN214 Still Matter?
It may just be a “mere” 3-watt IC power amp, but does meticulous circuit layout still matter for the AN214 if you want the ultimate in sound quality?
By: Vanessa Uy
If you have been experienced as I am when it comes to audiophile-grade audio power amplifier design, chances are you may have already encountered power amplifiers whose circuit layouts are definitely not worth the solder that binds them – sound quality wise. But can a reasonably good sounding DIY amplifier still be had without resorting to break-the-bank exotic and esoteric components? Well, the answer is definitely yes, and if you’re interested, read on.
Tweaking does still matter even if you are designing a power amp from a fairly generic circuit. And if possible, you can keep the negative feedback levels of the power amp design to a minimum, provided that the resulting harmonic distortion is reasonably low and of low harmonic order. To my ears, very low measured harmonic distortion never resulted in subjective improvement in sound quality. After all, if mainstream consumer electronic manufacturers like Sony or Pioneer wanted everyone to know how low the harmonic distortion of their power amplifiers are, Sony and Pioneer could have long ago provided as a free add-on 20-thousand US-dollar Hewlett-Packard FFT machines to their power amplifiers.
Even passive parts lay-out is of paramount importance, too. From my experience in designing AN214 power amp modules, I always made sure that the resistors – even if they are not esoteric audiophile-approved types like Vishay – should be oriented in phase on the master board. Proper orientation of resistors on the left and right channel is very important if you want your power amp to have natural-sounding stereo imaging and sound-staging; And orientation of fuses matter too – even changing the power supply fuse from a quick-blow to anti-surge results in a subtle-but-audible change in sound quality.
Lastly, the wiring has to be oriented in the same direction as well. With experience, you could even tweak the sound of your AN214 by strategically using a combination of solid-core and stranded wire where they provide the most benefit in improving subjective sound quality. This is very important when the AN214 you are designing is either used as an audiophile-grade power amplifier or a practice guitar amplifier that you want to sound like an EL84-tube equipped guitar amp.
By: Vanessa Uy
If you have been experienced as I am when it comes to audiophile-grade audio power amplifier design, chances are you may have already encountered power amplifiers whose circuit layouts are definitely not worth the solder that binds them – sound quality wise. But can a reasonably good sounding DIY amplifier still be had without resorting to break-the-bank exotic and esoteric components? Well, the answer is definitely yes, and if you’re interested, read on.
Tweaking does still matter even if you are designing a power amp from a fairly generic circuit. And if possible, you can keep the negative feedback levels of the power amp design to a minimum, provided that the resulting harmonic distortion is reasonably low and of low harmonic order. To my ears, very low measured harmonic distortion never resulted in subjective improvement in sound quality. After all, if mainstream consumer electronic manufacturers like Sony or Pioneer wanted everyone to know how low the harmonic distortion of their power amplifiers are, Sony and Pioneer could have long ago provided as a free add-on 20-thousand US-dollar Hewlett-Packard FFT machines to their power amplifiers.
Even passive parts lay-out is of paramount importance, too. From my experience in designing AN214 power amp modules, I always made sure that the resistors – even if they are not esoteric audiophile-approved types like Vishay – should be oriented in phase on the master board. Proper orientation of resistors on the left and right channel is very important if you want your power amp to have natural-sounding stereo imaging and sound-staging; And orientation of fuses matter too – even changing the power supply fuse from a quick-blow to anti-surge results in a subtle-but-audible change in sound quality.
Lastly, the wiring has to be oriented in the same direction as well. With experience, you could even tweak the sound of your AN214 by strategically using a combination of solid-core and stranded wire where they provide the most benefit in improving subjective sound quality. This is very important when the AN214 you are designing is either used as an audiophile-grade power amplifier or a practice guitar amplifier that you want to sound like an EL84-tube equipped guitar amp.
Monday, August 23, 2010
AN214 Versus Wicked Bitch Wives From Hell
Ever since high fidelity audio became a domesticated hobby, an overwhelming number of women had been taught to hate it with extreme prejudice. Can there be a middle ground?
By: Vanessa Uy
As a woman – the last time I checked – I won’t be stomping over political correctness when I talk about the hot-button topic of why an overwhelming number of women are conditioned to grow up to abhor high fidelity audio in all forms. Before you accuse me of turning into another female misogynist – like former Alaska governor Sarah Palin managed to do during the 2008 US Presidential Campaign, I’m just initiating a frank discussion about where the facts and myths lie when it comes to why an overwhelming number of women – conditioned or not – tend to hate hi-fi with extreme prejudice despite being one time in their lives an avid music fan.
Fortunately, women who are accomplished musicians seldom – if ever – complain about the size of their musical instruments. I’ve yet to hear an accomplished woman pianist or cellist mouthing off why can’t piano and cello makers create a great sounding Steinway or a Pietro Pallotta – even a Bösendorfer - the size of a late-model Nokia mobile phone. Never mind a full-sized heavy metal concert compliant Marshall stack.
Unfortunately, an overwhelming number of women non-audiophiles tend to listen with their eyes – instead of their ears – judging that smallness and cuteness as a really plus point in hi-fi instead of ultimate sound quality. They are never impressed by a lab-gear looking audio gear that sounds as if Yungchen Lhamo and the rest of the Tibetan Freedom Concert performers sound as if they’re as if right in your listening room. Just give them something small and unobtrusive and they’ll be happy – even if it sounds like crap to us audiophiles.
Pain-in-the-ass interior decorators are partly to blame too. Amusingly, a typical modern floorstanding hi-fi loudspeaker occupies the same amount of space as a pair of tiny monitor on a 24-inch tall stands. The difference is that a cabinet measuring 950-mm tall with a 200-mm x 200-mm footprint simply “looks” more intrusive from a pain-in-the-ass interior decorator’s perspective than a 350-mm x 200-mm x 200-mm speaker on a 600-mm pillar. Maybe pain-in-the-ass interior decorators should be subjected to high-altitude induced hypoxia while in your living room to make it appear bigger in their heads before they eventually succumb to altitude-induced cerebral edema.
So where does this leave the AN214 enthusiasts? Well, despite almost 40-years of the women’s liberation movement, an overwhelming number of women are still conditioned to hate with extreme prejudice big sized hi-fi gear that sounds like live music. The “older” members of this bigoted sorority would rather “sleep” with an original Rolling Stones member that have their living rooms look like a Rolling Stones concert stage. Given that the AN214 amp – despite its great sound – always look like a piece of authentic lab gear, wicked bitch wives from hell will probably always hate it till the end of time – or when hell freezes over whichever comes first.
By: Vanessa Uy
As a woman – the last time I checked – I won’t be stomping over political correctness when I talk about the hot-button topic of why an overwhelming number of women are conditioned to grow up to abhor high fidelity audio in all forms. Before you accuse me of turning into another female misogynist – like former Alaska governor Sarah Palin managed to do during the 2008 US Presidential Campaign, I’m just initiating a frank discussion about where the facts and myths lie when it comes to why an overwhelming number of women – conditioned or not – tend to hate hi-fi with extreme prejudice despite being one time in their lives an avid music fan.
Fortunately, women who are accomplished musicians seldom – if ever – complain about the size of their musical instruments. I’ve yet to hear an accomplished woman pianist or cellist mouthing off why can’t piano and cello makers create a great sounding Steinway or a Pietro Pallotta – even a Bösendorfer - the size of a late-model Nokia mobile phone. Never mind a full-sized heavy metal concert compliant Marshall stack.
Unfortunately, an overwhelming number of women non-audiophiles tend to listen with their eyes – instead of their ears – judging that smallness and cuteness as a really plus point in hi-fi instead of ultimate sound quality. They are never impressed by a lab-gear looking audio gear that sounds as if Yungchen Lhamo and the rest of the Tibetan Freedom Concert performers sound as if they’re as if right in your listening room. Just give them something small and unobtrusive and they’ll be happy – even if it sounds like crap to us audiophiles.
Pain-in-the-ass interior decorators are partly to blame too. Amusingly, a typical modern floorstanding hi-fi loudspeaker occupies the same amount of space as a pair of tiny monitor on a 24-inch tall stands. The difference is that a cabinet measuring 950-mm tall with a 200-mm x 200-mm footprint simply “looks” more intrusive from a pain-in-the-ass interior decorator’s perspective than a 350-mm x 200-mm x 200-mm speaker on a 600-mm pillar. Maybe pain-in-the-ass interior decorators should be subjected to high-altitude induced hypoxia while in your living room to make it appear bigger in their heads before they eventually succumb to altitude-induced cerebral edema.
So where does this leave the AN214 enthusiasts? Well, despite almost 40-years of the women’s liberation movement, an overwhelming number of women are still conditioned to hate with extreme prejudice big sized hi-fi gear that sounds like live music. The “older” members of this bigoted sorority would rather “sleep” with an original Rolling Stones member that have their living rooms look like a Rolling Stones concert stage. Given that the AN214 amp – despite its great sound – always look like a piece of authentic lab gear, wicked bitch wives from hell will probably always hate it till the end of time – or when hell freezes over whichever comes first.
Tuesday, June 1, 2010
Those Cheap Chinese DVD Players: Real Hi-Fi?
Given that they managed to display exemplar sound quality despite of their cheapness, are those cheap Chinese made universal DVD players real hi-fi?
By: Vanessa Uy
For the DIY audiophile who cut his or her teeth on assembling AN214 amplifiers, bargain basement Chinese universal DVD / CD players may seem to be too good to ignore. Despite of their cheapness – some are no more expensive than a second-hand Kalashnikov – but do these 25 to 30 US dollar Chinese made universal DVD / CD players truly qualify as hi-fi? Bad news first – they won’t play the high-resolution audio layer of SACD discs, their DVD Audio performance can be crappy when you don’t use a good external 24-bit 96-Khz capable DAC – more on the Redbook CD performance later .
The DVD Video performance is a few notches below that of entry-level DVD players of leading brands like Pioneer, Sony, Philips, etc. But these el cheapo Chinese players make up for it by their capability to play uploaded Internet site videos without being converted first to Video CD or DVD Video. I mean it can play those despicable militant website rant videos and child porn videos that were hastily burned into CD-R or DVD-R that wont run major brand universal DVD / CD players.
Surprisingly, these cheap and cheerful Chinese universal DVD / CD players raison d’être is in playing your stockpiles of supposedly obsolete 16-bit 44.1-Khz Redbook speck music CDs – although you should avail yourself of a good external digital-to-analog converter in order to find out the magical properties that many have discovered with such players. The model we tested is a Hug DVD-H6757 DVD Video player whose primary raison d’être is to play those “pirated” compressed DVD videos – mostly illegal porn that supposedly illegal in my neck of the woods, some even has stars as young as me.
Sound quality wise, this particular lowly Hug DVD / CD player managed to play CDs like a thousand-US dollar CD player from 1995 – especially when hooked up to external DACs that were languishing unsold for years in our local second-hand hi-fi shop. But first select the digital SPDIF out mode to raw. It sounds so gorgeous at this setting when connected to an external DAC when playing Redbook spec CDs. It made the Orelle DA-88 DAC and the Audio Alchemy Digital Decoding Engine version 2.0 that were sitting idly by since 2003 sound as if their processor chips were upgraded so that the anti-aliasing filters of the analog output stages can be configured to a lower-ordered configuration. Making it sound as if the still-audible –to-me phase and group-delay distortion near the 20-Khz roll-off point had been magically removed. In short, the Hug DVD Audio Alchemy DAC combo or the Orelle DA-88 DAC combo sounds as if it was a thousand US dollar CD player from 1995 – considering the current price (2010 that is) of the set up is still a few dollars less than a brand new Kalashnikov.
Sadly, given my political views when it comes to fair compensation of ones labor, I cannot wholeheartedly recommend the Hug DVD-H6757 universal DVD / CD player that my older audio-buddies and I tested for a number of reasons. The company who manufactured the DVD player, probably based in Guangdong Province heavy industry district, has not reassured their buyers about their workers getting adequate 401-K plans, healthcare, and not being paid slave's wages. And also the company should be more forthcoming on the issue of using prison labor as often is the practice in the Chinese mainland – as in Free Tibet and Uyghur political detainees. Hard to recommend a product made by a company clueless about what happened in that notorious FOXCONN plant where the workers where defenestrating themselves just to end their suffering. If the American hi-fi loudspeaker manufacturer takes the time to remind prospective customers – and those fortunate enough to be invited in one of their plant tours – of their commitment to providing their workers a liveable wage and decent healthcare and dental plans.
Another thing that bugs me about initiating an audiophile equivalent of a carrot mob to promote the Hug DVD / CD player is that given the open business / close politics stance of the Beijing Communist Party functionaries, the company’s R n’ D budget might be siphoned off to develop a Green Dam Youth Escort-type electronic censorship device. One that could be installed in a latter generation of Chinese made universal DVD / CD players. Imagine you being unable to play your Tiananmen Square Massacre remembrance DVD documentary because your newly-bought Chinese made DVD player has now an automatic Green Dam Youth Escort-type electronic censorship device. Same goes with your Minzhu and Dalai Lama / Free Tibet DVDs or anything referring to that tragic June 4, 1989 massacre on Tiananmen Square.
Or given if the DVD’s e-censorship system is like the Green Dam Youth Escort internet censoring tool in capability, you can’t watch your Garfield DVDs anymore because this cat’s fur looks like the color scheme of the Dalai Lama’s tunic. Your Uyghur friends’ home movies will be censored because it will use the Green Dam color-based censorship excuse and classify it as hardcore pornography. Yes according to the Green dam Youth Escort color-based censorship scheme, it doesn’t discriminate between pink skinned farmed pigs and Uyghurs. Maybe Taylor Swift was fortunate enough not to be playing near Xingjian Province during the Uyghur riots because the Chinese authorities probably can’t tell her apart from the local Uyghur population.
By: Vanessa Uy
For the DIY audiophile who cut his or her teeth on assembling AN214 amplifiers, bargain basement Chinese universal DVD / CD players may seem to be too good to ignore. Despite of their cheapness – some are no more expensive than a second-hand Kalashnikov – but do these 25 to 30 US dollar Chinese made universal DVD / CD players truly qualify as hi-fi? Bad news first – they won’t play the high-resolution audio layer of SACD discs, their DVD Audio performance can be crappy when you don’t use a good external 24-bit 96-Khz capable DAC – more on the Redbook CD performance later .
The DVD Video performance is a few notches below that of entry-level DVD players of leading brands like Pioneer, Sony, Philips, etc. But these el cheapo Chinese players make up for it by their capability to play uploaded Internet site videos without being converted first to Video CD or DVD Video. I mean it can play those despicable militant website rant videos and child porn videos that were hastily burned into CD-R or DVD-R that wont run major brand universal DVD / CD players.
Surprisingly, these cheap and cheerful Chinese universal DVD / CD players raison d’être is in playing your stockpiles of supposedly obsolete 16-bit 44.1-Khz Redbook speck music CDs – although you should avail yourself of a good external digital-to-analog converter in order to find out the magical properties that many have discovered with such players. The model we tested is a Hug DVD-H6757 DVD Video player whose primary raison d’être is to play those “pirated” compressed DVD videos – mostly illegal porn that supposedly illegal in my neck of the woods, some even has stars as young as me.
Sound quality wise, this particular lowly Hug DVD / CD player managed to play CDs like a thousand-US dollar CD player from 1995 – especially when hooked up to external DACs that were languishing unsold for years in our local second-hand hi-fi shop. But first select the digital SPDIF out mode to raw. It sounds so gorgeous at this setting when connected to an external DAC when playing Redbook spec CDs. It made the Orelle DA-88 DAC and the Audio Alchemy Digital Decoding Engine version 2.0 that were sitting idly by since 2003 sound as if their processor chips were upgraded so that the anti-aliasing filters of the analog output stages can be configured to a lower-ordered configuration. Making it sound as if the still-audible –to-me phase and group-delay distortion near the 20-Khz roll-off point had been magically removed. In short, the Hug DVD Audio Alchemy DAC combo or the Orelle DA-88 DAC combo sounds as if it was a thousand US dollar CD player from 1995 – considering the current price (2010 that is) of the set up is still a few dollars less than a brand new Kalashnikov.
Sadly, given my political views when it comes to fair compensation of ones labor, I cannot wholeheartedly recommend the Hug DVD-H6757 universal DVD / CD player that my older audio-buddies and I tested for a number of reasons. The company who manufactured the DVD player, probably based in Guangdong Province heavy industry district, has not reassured their buyers about their workers getting adequate 401-K plans, healthcare, and not being paid slave's wages. And also the company should be more forthcoming on the issue of using prison labor as often is the practice in the Chinese mainland – as in Free Tibet and Uyghur political detainees. Hard to recommend a product made by a company clueless about what happened in that notorious FOXCONN plant where the workers where defenestrating themselves just to end their suffering. If the American hi-fi loudspeaker manufacturer takes the time to remind prospective customers – and those fortunate enough to be invited in one of their plant tours – of their commitment to providing their workers a liveable wage and decent healthcare and dental plans.
Another thing that bugs me about initiating an audiophile equivalent of a carrot mob to promote the Hug DVD / CD player is that given the open business / close politics stance of the Beijing Communist Party functionaries, the company’s R n’ D budget might be siphoned off to develop a Green Dam Youth Escort-type electronic censorship device. One that could be installed in a latter generation of Chinese made universal DVD / CD players. Imagine you being unable to play your Tiananmen Square Massacre remembrance DVD documentary because your newly-bought Chinese made DVD player has now an automatic Green Dam Youth Escort-type electronic censorship device. Same goes with your Minzhu and Dalai Lama / Free Tibet DVDs or anything referring to that tragic June 4, 1989 massacre on Tiananmen Square.
Or given if the DVD’s e-censorship system is like the Green Dam Youth Escort internet censoring tool in capability, you can’t watch your Garfield DVDs anymore because this cat’s fur looks like the color scheme of the Dalai Lama’s tunic. Your Uyghur friends’ home movies will be censored because it will use the Green Dam color-based censorship excuse and classify it as hardcore pornography. Yes according to the Green dam Youth Escort color-based censorship scheme, it doesn’t discriminate between pink skinned farmed pigs and Uyghurs. Maybe Taylor Swift was fortunate enough not to be playing near Xingjian Province during the Uyghur riots because the Chinese authorities probably can’t tell her apart from the local Uyghur population.
Thursday, March 25, 2010
AN214: The Last Great IC Audio Amplifier?
Audio enthusiasts know that it is not the only “kid on the block” when IC audio amps are concerned, but how does the AN214 compare to others of its kind?
By: Vanessa Uy
Ever since I got on that steep learning curve called DIY hi-fi back in 2006, I also managed to gain familiarity with integrated circuit-based audio amplifiers with sound quality that rival that with the well-touted amps in the hi-fi world. There might be thousands out there and probably countless more that got marketed only to be discontinued 18 months later due to lack of demand, which I am fortunate enough to gain familiarity with some. So far, here are the shortlist of other IC audio amps and how they compare – in sound quality terms – to the AN214 and other venerable hi-fi amps.
The pedestrian-sounding-to-me types: those that fall into this category – believe it or not – are probably still in widespread production since their introduction during the 1990s as a building block of domestic karaoke machines and mini boomboxes. Like the LM1875 and LM383T – both are 5-pin TO-220 packages - which are even pressed into use as a cheap and cheerful guitar amplifier. They are easy to build using the recommended layout and heatsinking guidelines of the IC manufacturer and can work in the 12-volt automotive environment very well. But to me, I found the sound quality of both types wanting. Another widely used in karaoke and boombox units of the 1990s is the TA8216A 13-watt per channel IC audio amp. This 12-pin single in-line package IC in sound quality terms sounds just like any other run-of-the-mill solid-state amplifier.
Another one that falls into this category – although it manages to sound better in the musically important midrange band – is the LM2005T-M IC audio amp. Often used in bridge configuration in 12-volt automotive applications, it did manage to sound about as good as the AN214 during the 1980s. But when the alternative rock of the 1990s came – especially the Seattle-flavored David Geffen record label signed kind. The LM2005T-M was found wanting in portraying the analogue-like warmth and musicality inherent in these releases.
The ambitious-sound-quality-but-now-discontinued types: two great IC audio amps that came into my way fall in this category and they even exceed the AN214 in some important aspects of sound quality, but unfortunately they are discontinued after being available in electronics supply stores for 18 months in the mid 1990s. Like the HA1388 18-watt IC amplifier and the HA1393 19-watt IC amplifier. Both are 12-pin SIP IC amplifiers and could work very well in the 12-volt automotive environment due to its built-in ASO protect and surge protect circuits and became popular in some karaoke and boombox units marketed during the 1990s.
Sound quality wise, both the HA1388 and the HA1393 managed to sound like a EL84-equipped tube amp – make that a premium tube like an EL84 with the words Record by Mullard printed on the tube’s glass enclosure. Excellent sounding both IC amps are, they suffer from unacceptable levels of hiss – especially when used with speakers with sensitivities better than 93dB per watt / 2.8 volts at 1 meter. Probably having a signal-to-noise ratio no better than 69dB. The HA1388 and HA1393 can be also considered commercially extinct since it is only in antique audio swap meets that you have a chance of finding one. In guitar amp applications, they are better than the AN214 due to its tube-like tonality – making that aeolian mode opening riff of Judas Priest’s Breaking the Law sounds so symphonic as if it is played on a Mullard tube equipped Marshall amp. Unfortunately both the HA1388 and HA1393 are even rarer that the Record by Mullard type EL84 tubes.
The temperamental diva types: there’s an IC audio amp that gained popularity during the mid-1980s that fell into this category. The most famous one is the STK 439 IC amp, a 15-pin SIP containing two amplifier circuits and often used in single-ended mode. Using the two amps inside the IC package in stereo. The STK 439’s 24-volt operating range limits its compatibility somewhat in the car audio world, but it makes up in sound quality with midrange purity approaching that of dpa Renaissance integrated amplifier. Also, there seems to be no schematics of STK 439 in bridge configuration.
During the mid-1980s, the rivalry between the AN214 and the STK 439 in the DIY audio world seems almost to mirror that between the divergent design philosophies of Mikhail Kalashnikov’s AK-47 and Eugene Stoner’s M-16. I don’t know much about the present availability status of the STK 439, I only knew – from my older audio-buddies – that the left channel portion is prone to failure. Currently, I’m using two STK 439s with still functional right channels in monoblocked stereo.
I never knew one using the STK 439 in guitar amp applications, but it is safe to assume that it could sound rather too clinical in comparison to tube-based guitar amps. But the STK 439’s clinical nature can be very useful in monitoring less-than-pristine audio sources. Like my pet project of digitizing an old BETAMAX-based amateur home movie that captured a Twisted Red Cross-era punk band called The Wuds during their July 1988 concert in PHILCITE Cebu. The STK 439 is also very pre-recorded cassette tape friendly that it even managed to make some old cassette tapes that I recently bought from a garage sale sounds much more listenable and musical. Like the old Heavens Edge, Rumble Militia and even a 1992-era cassette of GWAR’s America Must Be Destroyed album.
Unfortunately, linear IC-based audio amplifiers are no longer popular in the DIY audio world. The pedestrian-sounding but widely available IC amps mention before are probably the only IC amps that anyone in my age bracket can DIY – barring switching mode Class D IC audio amps that tend to make Avril Lavigne sound like she’s hocking a loogie during her glottal stops. Worse still, most “affordable” – i.e. cheap – computer speakers with subwoofers tend to use switching-mode Class D IC amps in favor of efficiency rather than sound quality. The AN214 could probably be reign for the foreseeable future as the last great IC audio amplifier.
By: Vanessa Uy
Ever since I got on that steep learning curve called DIY hi-fi back in 2006, I also managed to gain familiarity with integrated circuit-based audio amplifiers with sound quality that rival that with the well-touted amps in the hi-fi world. There might be thousands out there and probably countless more that got marketed only to be discontinued 18 months later due to lack of demand, which I am fortunate enough to gain familiarity with some. So far, here are the shortlist of other IC audio amps and how they compare – in sound quality terms – to the AN214 and other venerable hi-fi amps.
The pedestrian-sounding-to-me types: those that fall into this category – believe it or not – are probably still in widespread production since their introduction during the 1990s as a building block of domestic karaoke machines and mini boomboxes. Like the LM1875 and LM383T – both are 5-pin TO-220 packages - which are even pressed into use as a cheap and cheerful guitar amplifier. They are easy to build using the recommended layout and heatsinking guidelines of the IC manufacturer and can work in the 12-volt automotive environment very well. But to me, I found the sound quality of both types wanting. Another widely used in karaoke and boombox units of the 1990s is the TA8216A 13-watt per channel IC audio amp. This 12-pin single in-line package IC in sound quality terms sounds just like any other run-of-the-mill solid-state amplifier.
Another one that falls into this category – although it manages to sound better in the musically important midrange band – is the LM2005T-M IC audio amp. Often used in bridge configuration in 12-volt automotive applications, it did manage to sound about as good as the AN214 during the 1980s. But when the alternative rock of the 1990s came – especially the Seattle-flavored David Geffen record label signed kind. The LM2005T-M was found wanting in portraying the analogue-like warmth and musicality inherent in these releases.
The ambitious-sound-quality-but-now-discontinued types: two great IC audio amps that came into my way fall in this category and they even exceed the AN214 in some important aspects of sound quality, but unfortunately they are discontinued after being available in electronics supply stores for 18 months in the mid 1990s. Like the HA1388 18-watt IC amplifier and the HA1393 19-watt IC amplifier. Both are 12-pin SIP IC amplifiers and could work very well in the 12-volt automotive environment due to its built-in ASO protect and surge protect circuits and became popular in some karaoke and boombox units marketed during the 1990s.
Sound quality wise, both the HA1388 and the HA1393 managed to sound like a EL84-equipped tube amp – make that a premium tube like an EL84 with the words Record by Mullard printed on the tube’s glass enclosure. Excellent sounding both IC amps are, they suffer from unacceptable levels of hiss – especially when used with speakers with sensitivities better than 93dB per watt / 2.8 volts at 1 meter. Probably having a signal-to-noise ratio no better than 69dB. The HA1388 and HA1393 can be also considered commercially extinct since it is only in antique audio swap meets that you have a chance of finding one. In guitar amp applications, they are better than the AN214 due to its tube-like tonality – making that aeolian mode opening riff of Judas Priest’s Breaking the Law sounds so symphonic as if it is played on a Mullard tube equipped Marshall amp. Unfortunately both the HA1388 and HA1393 are even rarer that the Record by Mullard type EL84 tubes.
The temperamental diva types: there’s an IC audio amp that gained popularity during the mid-1980s that fell into this category. The most famous one is the STK 439 IC amp, a 15-pin SIP containing two amplifier circuits and often used in single-ended mode. Using the two amps inside the IC package in stereo. The STK 439’s 24-volt operating range limits its compatibility somewhat in the car audio world, but it makes up in sound quality with midrange purity approaching that of dpa Renaissance integrated amplifier. Also, there seems to be no schematics of STK 439 in bridge configuration.
During the mid-1980s, the rivalry between the AN214 and the STK 439 in the DIY audio world seems almost to mirror that between the divergent design philosophies of Mikhail Kalashnikov’s AK-47 and Eugene Stoner’s M-16. I don’t know much about the present availability status of the STK 439, I only knew – from my older audio-buddies – that the left channel portion is prone to failure. Currently, I’m using two STK 439s with still functional right channels in monoblocked stereo.
I never knew one using the STK 439 in guitar amp applications, but it is safe to assume that it could sound rather too clinical in comparison to tube-based guitar amps. But the STK 439’s clinical nature can be very useful in monitoring less-than-pristine audio sources. Like my pet project of digitizing an old BETAMAX-based amateur home movie that captured a Twisted Red Cross-era punk band called The Wuds during their July 1988 concert in PHILCITE Cebu. The STK 439 is also very pre-recorded cassette tape friendly that it even managed to make some old cassette tapes that I recently bought from a garage sale sounds much more listenable and musical. Like the old Heavens Edge, Rumble Militia and even a 1992-era cassette of GWAR’s America Must Be Destroyed album.
Unfortunately, linear IC-based audio amplifiers are no longer popular in the DIY audio world. The pedestrian-sounding but widely available IC amps mention before are probably the only IC amps that anyone in my age bracket can DIY – barring switching mode Class D IC audio amps that tend to make Avril Lavigne sound like she’s hocking a loogie during her glottal stops. Worse still, most “affordable” – i.e. cheap – computer speakers with subwoofers tend to use switching-mode Class D IC amps in favor of efficiency rather than sound quality. The AN214 could probably be reign for the foreseeable future as the last great IC audio amplifier.
Saturday, February 27, 2010
The Pioneer TD-900 8-Track Car Stereo: The AN214’s Soul Mate?
Many old school car hi-fi enthusiasts swear by it, but is the Pioneer TD-900 8-track car stereo the AN214 IC audio amplifier’s soul mate?
By: Vanessa Uy
Unless you’ve managed to buy those limited edition Cheap trick albums being released on 8-track format being promoted on the Colbert Report back in 2009, buying prerecorded 8-track music albums this day and age is not going to be easy. Compared to vinyl LPs, 8-track tapes – being a magnetic recording media like cassette tapes – tend to get dull when improperly stored as the years go by. Aging recording media aside, does the Pioneer TD-900 8-track car stereo really is the audiophile soul mate of the AN214 IC audio amplifier?
If you’re fortunate enough to own an 8-track recorder – especially with a line-in proviso for CD, DVD-audio, Super Audio CD player, even MP3 downloads – then you’re in luck to test the audio beautifying effects of transferring / recording Red Book standard resolution digital music to analog magnetic recording media. I tried it with my recently acquired Pioneer RH-65 8-track player / recorder using new music that has probably been never ever released in 8-track format. Sound quality wise, digital media – even the lowly Red Book standard 16-bit 44.1 KHz CDs and MP3s – tend to improve when transferred to analog magnetic media. And the 8-track’s higher tape speed – twice that of standard cassette – tend to trick my ears that there’s more musical information that’s actually present in the two most common digital music media available to today’s typical CD and digital download aware music lover.
Given that the Pioneer RH-65 8-track player / recorder is old enough to appear that it is made in pioneers US headquarters in 178 Commerce Road, Carlstadt, New Jersey 07072, although the 8-track player / recorder’s back fascia says Made in Japan. For a product that’s made when NASA were still sending men to the Moon, both the Pioneer TD-900 8-track car stereo and the RH-65 8-track player / recorder can play music in a manner that a typical i-Pod will probably be capable 15 to 20 years from now, despite of both 8-track player’s very limited playlist and the 8-track format’s inherent signal-to-noise ratio that can barely reach 70 dB even with Dolby on.
Using fresh TDK blank 8-track tapes that from time to time turn up in garage sales in my neck of the woods, I tried transferring the Wyldsky’s debut CD which one of my audio-buddies purchased from Japan since our local music stores stopped stocking cool music back in 2005. By the way, Wyldsky is this band founded by former Great White guitarist Tyler Nelson and other former Great White members, in which Tyler Nelson named the band after her daughters Wylie and Skylar. All I can say is that the music of Wyldsky probably deserved to be recorded on 8-track in order for it to sound more soulful. Although I used a cheap CD / DVD universal player made in the People’s Republic of China at around 30 US dollars when new is probably cheaper than a second-hand Kalashnikov that sounded very great when connected to my trusty-but-rusty Audio Alchemy DAC. Hopefully, all i-Pods will sound as good as this in 20 years time.
Other tunes worthy for 8-track transfer includes the CD ¡Viva Zapata! by 7 Year Bitch and even those ¡Viva Zapata!-themed songs on their Gato Negro album do make good long haul driving tunes once transferred on 8-track. Even those Lunackicks albums in CD format seemed to become like 24-bit 192 KHz DVD Audio recordings or SACD in sound quality terms once recorded to 8-track. Even digital downloads and MP3s of those obscure but really great under-aged-teen girl punk groups will sound better without those 500 to 1,000 US dollar software-based DAC upgrades being pitched on-line supposedly to make your digital downloads sound like vinyl. Recording them to 8-track is a much cheaper proposition.
Concerned about 8-track’s wow and flutter problems? I tried recording Mother by Tori Amos from her Little Earthquakes CD – probably the most torturous wow and flutter test tune fortunate enough to be played on mainstream FM – and both domestic and car stereo decks passed with flying colors. And by the way, I chose not to test for the Classical Music capabilities of the 8-track car stereo since the car environment is too noisy for critical listening when it comes to this genre of music. Even the alternative rock’s version of Trinity and Beyond / “that atomic bomb movie” – Earthcrosser by Veruca Salt – can be spoiled in such noisy acoustic environment. Maybe 8-track is vinyl LP for cars?
By: Vanessa Uy
Unless you’ve managed to buy those limited edition Cheap trick albums being released on 8-track format being promoted on the Colbert Report back in 2009, buying prerecorded 8-track music albums this day and age is not going to be easy. Compared to vinyl LPs, 8-track tapes – being a magnetic recording media like cassette tapes – tend to get dull when improperly stored as the years go by. Aging recording media aside, does the Pioneer TD-900 8-track car stereo really is the audiophile soul mate of the AN214 IC audio amplifier?
If you’re fortunate enough to own an 8-track recorder – especially with a line-in proviso for CD, DVD-audio, Super Audio CD player, even MP3 downloads – then you’re in luck to test the audio beautifying effects of transferring / recording Red Book standard resolution digital music to analog magnetic recording media. I tried it with my recently acquired Pioneer RH-65 8-track player / recorder using new music that has probably been never ever released in 8-track format. Sound quality wise, digital media – even the lowly Red Book standard 16-bit 44.1 KHz CDs and MP3s – tend to improve when transferred to analog magnetic media. And the 8-track’s higher tape speed – twice that of standard cassette – tend to trick my ears that there’s more musical information that’s actually present in the two most common digital music media available to today’s typical CD and digital download aware music lover.
Given that the Pioneer RH-65 8-track player / recorder is old enough to appear that it is made in pioneers US headquarters in 178 Commerce Road, Carlstadt, New Jersey 07072, although the 8-track player / recorder’s back fascia says Made in Japan. For a product that’s made when NASA were still sending men to the Moon, both the Pioneer TD-900 8-track car stereo and the RH-65 8-track player / recorder can play music in a manner that a typical i-Pod will probably be capable 15 to 20 years from now, despite of both 8-track player’s very limited playlist and the 8-track format’s inherent signal-to-noise ratio that can barely reach 70 dB even with Dolby on.
Using fresh TDK blank 8-track tapes that from time to time turn up in garage sales in my neck of the woods, I tried transferring the Wyldsky’s debut CD which one of my audio-buddies purchased from Japan since our local music stores stopped stocking cool music back in 2005. By the way, Wyldsky is this band founded by former Great White guitarist Tyler Nelson and other former Great White members, in which Tyler Nelson named the band after her daughters Wylie and Skylar. All I can say is that the music of Wyldsky probably deserved to be recorded on 8-track in order for it to sound more soulful. Although I used a cheap CD / DVD universal player made in the People’s Republic of China at around 30 US dollars when new is probably cheaper than a second-hand Kalashnikov that sounded very great when connected to my trusty-but-rusty Audio Alchemy DAC. Hopefully, all i-Pods will sound as good as this in 20 years time.
Other tunes worthy for 8-track transfer includes the CD ¡Viva Zapata! by 7 Year Bitch and even those ¡Viva Zapata!-themed songs on their Gato Negro album do make good long haul driving tunes once transferred on 8-track. Even those Lunackicks albums in CD format seemed to become like 24-bit 192 KHz DVD Audio recordings or SACD in sound quality terms once recorded to 8-track. Even digital downloads and MP3s of those obscure but really great under-aged-teen girl punk groups will sound better without those 500 to 1,000 US dollar software-based DAC upgrades being pitched on-line supposedly to make your digital downloads sound like vinyl. Recording them to 8-track is a much cheaper proposition.
Concerned about 8-track’s wow and flutter problems? I tried recording Mother by Tori Amos from her Little Earthquakes CD – probably the most torturous wow and flutter test tune fortunate enough to be played on mainstream FM – and both domestic and car stereo decks passed with flying colors. And by the way, I chose not to test for the Classical Music capabilities of the 8-track car stereo since the car environment is too noisy for critical listening when it comes to this genre of music. Even the alternative rock’s version of Trinity and Beyond / “that atomic bomb movie” – Earthcrosser by Veruca Salt – can be spoiled in such noisy acoustic environment. Maybe 8-track is vinyl LP for cars?
Friday, November 27, 2009
Boosting the AN214 – How to do it Right
The heyday of the boosted AN214 DIY amp may be over, but has this iconic hobbyist audio engineering design ever been properly implemented for ultimate sound quality?
By: Vanessa Uy
During the past few weeks, I’ve received some disused but still functional “homemade” AN214 IC amplifier paired with its MJ2955 transistor-based transformer-coupled booster amplifier soulmate for possible tweaking to improve their sound quality. Sadly, I’ve found that an overwhelming number of them – though can function as intended – have been insufficiently designed from an audiophile perspective. Either on the basis of saving money as most electronic DIY-ers are not particularly rich anyway, or following the sway of fashion based on audio electronic myths centered on the AN214. Especially concepts that had been perpetrated by very influential – if rather misinformed – self-styled electronic engineering gurus who are to afraid to be adventurous when it comes to spending a bit more to create a more realistic and natural sounding audio amplifier through over-engineering. Despite of money-saving necessity to skimp on better parts and layout hanging like the Sword of Damocles on the prospective hobbyist, is there a better way to design a boosted AN214 amp without breaking the bank?
I’ve mused before on the virtues of using oversized input and output transformers – to the dismay of electronic and electrical engineering degree holders – for the MJ2955 transistor-based transformer-coupled booster amp design to improve its bass output and quality. But the units I received for tweaking not only have standard sized input and output transformers hindering them from achieving their sound quality potential. Some not only have even smaller than standard transformers in order to save money, but their cost-saving measures can only prove to be expensive in the long run due to the potential damage they might inflict to the loudspeakers connected to them. Fortunately, I have two ways of tweaking the boosted AN214 design not only for better sound quality but also to maintain loudspeaker longevity as well. By avoiding – make that not doing the following if funds allow – when constructing your very own boosted AN214 amp design.
The first is you should not ground the primary / input side of the input transformer of the MJ2955 transistor-based transformer-coupled booster amp. Just because in an overwhelming number of applications of the AN214 IC audio amplifier is in its single-ended output configuration, where the minus side of the speaker output terminal is connected to the ground of its power supply. Does not mean one should ground the input side of the input transformer of the booster amp. Some DIY-ers usually ground the input transformer either to minimize – with the emphasis on minimize – the hum of the AN214 stage. Which is probably either caused by insufficient size of filter capacitors in the AC / DC power supply or just a bad circuit layout. Floating the input side of the booster amp not only makes it sound more dynamic, but also allow you to experiment other IC amplifiers other than the AN214 – especially those in bridge configuration where grounding the negative terminal could destroy the IC amp and the booster amp.
The second is please use separate power supplies for the AN214 section and the MJ2955 transformer-coupled booster amp section. Just because these two sections share the same 12-volt battery in automotive applications doesn’t mean you should use a common AC / DC power supply for both. Some farsighted DIY electronic enthusiasts who care about speaker longevity have even configured a power on delay for the boosted AN214 design by allowing the booster amp to turn on several seconds after the AN214 section turns on in automotive applications to prolong loudspeaker life. Those turn-on thumps heard on the partnering loudspeaker produced by simultaneously turning on both the AN214 and the booster amp section does not exactly bode well to the longevity of the connected loudspeaker.
A significant number of boosted AN214 designs have been paired with the venerable budget wonder of the 1990s, the Mission 731 LE speakers. These types of loudspeakers and their ilk are not exactly as indestructible as their raunchy sounding concert public address speaker system brethren. And those DIY electronic enthusiasts fortunate enough not married to bitch wives from hell who have the ideal set up of a domestic listening room for their hi-fi, a separate power supply for the AN214 section and the MJ2955 transformer-coupled booster amp is the perfect way to go. Favorably if equipped with high-speed Schottky Diode / Schottky Barrier Diode rectifiers and Rubycon Black Gate capacitors for the best possible – and tube amp-like dynamics – sound quality.
By: Vanessa Uy
During the past few weeks, I’ve received some disused but still functional “homemade” AN214 IC amplifier paired with its MJ2955 transistor-based transformer-coupled booster amplifier soulmate for possible tweaking to improve their sound quality. Sadly, I’ve found that an overwhelming number of them – though can function as intended – have been insufficiently designed from an audiophile perspective. Either on the basis of saving money as most electronic DIY-ers are not particularly rich anyway, or following the sway of fashion based on audio electronic myths centered on the AN214. Especially concepts that had been perpetrated by very influential – if rather misinformed – self-styled electronic engineering gurus who are to afraid to be adventurous when it comes to spending a bit more to create a more realistic and natural sounding audio amplifier through over-engineering. Despite of money-saving necessity to skimp on better parts and layout hanging like the Sword of Damocles on the prospective hobbyist, is there a better way to design a boosted AN214 amp without breaking the bank?
I’ve mused before on the virtues of using oversized input and output transformers – to the dismay of electronic and electrical engineering degree holders – for the MJ2955 transistor-based transformer-coupled booster amp design to improve its bass output and quality. But the units I received for tweaking not only have standard sized input and output transformers hindering them from achieving their sound quality potential. Some not only have even smaller than standard transformers in order to save money, but their cost-saving measures can only prove to be expensive in the long run due to the potential damage they might inflict to the loudspeakers connected to them. Fortunately, I have two ways of tweaking the boosted AN214 design not only for better sound quality but also to maintain loudspeaker longevity as well. By avoiding – make that not doing the following if funds allow – when constructing your very own boosted AN214 amp design.
The first is you should not ground the primary / input side of the input transformer of the MJ2955 transistor-based transformer-coupled booster amp. Just because in an overwhelming number of applications of the AN214 IC audio amplifier is in its single-ended output configuration, where the minus side of the speaker output terminal is connected to the ground of its power supply. Does not mean one should ground the input side of the input transformer of the booster amp. Some DIY-ers usually ground the input transformer either to minimize – with the emphasis on minimize – the hum of the AN214 stage. Which is probably either caused by insufficient size of filter capacitors in the AC / DC power supply or just a bad circuit layout. Floating the input side of the booster amp not only makes it sound more dynamic, but also allow you to experiment other IC amplifiers other than the AN214 – especially those in bridge configuration where grounding the negative terminal could destroy the IC amp and the booster amp.
The second is please use separate power supplies for the AN214 section and the MJ2955 transformer-coupled booster amp section. Just because these two sections share the same 12-volt battery in automotive applications doesn’t mean you should use a common AC / DC power supply for both. Some farsighted DIY electronic enthusiasts who care about speaker longevity have even configured a power on delay for the boosted AN214 design by allowing the booster amp to turn on several seconds after the AN214 section turns on in automotive applications to prolong loudspeaker life. Those turn-on thumps heard on the partnering loudspeaker produced by simultaneously turning on both the AN214 and the booster amp section does not exactly bode well to the longevity of the connected loudspeaker.
A significant number of boosted AN214 designs have been paired with the venerable budget wonder of the 1990s, the Mission 731 LE speakers. These types of loudspeakers and their ilk are not exactly as indestructible as their raunchy sounding concert public address speaker system brethren. And those DIY electronic enthusiasts fortunate enough not married to bitch wives from hell who have the ideal set up of a domestic listening room for their hi-fi, a separate power supply for the AN214 section and the MJ2955 transformer-coupled booster amp is the perfect way to go. Favorably if equipped with high-speed Schottky Diode / Schottky Barrier Diode rectifiers and Rubycon Black Gate capacitors for the best possible – and tube amp-like dynamics – sound quality.
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