Repairing the Sony TA-F444ESX – Regulator failure


The Sony vintage TA-F444ESX – protector and regulator failure

As a follow up to our previous article on speaker protection we thought it pertinent to look at this classic vintage amplifier, the Sony TA-F444ESX. Good in looks, solid in build and of course exceptional audio.

The Sony TA-F444ESX is similar to the TA-F700ES with international supply voltages 100 – 240V. Continue reading “Repairing the Sony TA-F444ESX – Regulator failure”

Micro and Mini sound systems versus Dock

Logitech Bluetooth Receiver

The iPod Dock and Other Things

One of our readers,  13 year old Craig wants to know why we don’t do reviews, especially on docking stations.  Unfortunately as we don’t retail products and neither get support from resellers or manufacturers in this beautiful land of ours this can be pretty difficult unless we go out and buy the stuff ourselves.

Castle Knight 1
Castle Knight 1

What I can tell you is that over the years a common problem picked up is dirty or broken contacts in the dock which although replaceable does make it a weak link in the interface.  Line inputs are a better way to go but now that from Bluetooth 2.0 and up, wireless seems to be the cheaper and more practical way to go.   Docking stations are still popular but the home user wants more exciting permutations. Continue reading “Micro and Mini sound systems versus Dock”

Class G and H Audio Amplification – Gimmick or Wizardry

Texas Instruments TAS 2559

Class G and H Audio Amplifiers

One design that has been out for eons and still catches us off guard is the rail shifting Class G or class H boost supply amplifier.  Most purists agree that this concept is ideal for PA work but not high fidelity audio.  To a certain degree I must agree but then this would imply that class D is also in the same boat. There I disagree, they are in the same boat but some very high quality amplifiers are class G, H as well as class D. What is this class stuff anyway? Continue reading “Class G and H Audio Amplification – Gimmick or Wizardry”

National LM4702 Vs Sanken STK350-xxx

A look into National Semiconductor’s LM4702 VAS

First thing here for those that aren’t aware:  “SANTA CLARA, Calif., Sept. 23, 2011 /PRNewswire/ — Texas Instruments Incorporated (TI) (NYSE: TXN) today announced the acquisition of National Semiconductor (NYSE: NSM) is complete.”

I thought the first paragraph is relevant to our subject based on the confusion come across in forums on who owns what.

The LM4702 driver Continue reading “National LM4702 Vs Sanken STK350-xxx”

Amplifiers & Light Control

Autona 125W 4 Ohm

Mixing loud music with a light show

Pink Floyd and Electric Light Orchestra, music enhanced by the control of light.  What is great powerful music without a visual experience.  Not Ozzy Osbourne biting a bat or dove’s head off of course but something more appealing, sound to light, chasing, strobing and laser. Of course it’s every young inventor’s dream to build their own dazzling light show but where to begin?

Autona 125W 4 Ohm
Autona 125W 4 Ohm

Sound amplification:

Sound or audio engineering is not just a profession but an art….. exactly the same applies to an engineer who spends his life building top quality audio amplifiers.

40W Audio Amplifier - Quasi Complimentary
40W Audio Amplifier – Quasi Complimentary – More Information below

Audio amplification is split into two parts (1) the voltage amplifier or pre-amp. This amplifier has a number of pre-requisites:  being able to amplify a tiny signal like that from a microphone or turntable (with RIAA equalisation),  being able to boost the bass or treble or equalise the signal for different room parameters (stage, hall etc) and (2) the power amplifier, which takes this signal and amplifies it further to feed a loudspeaker.  All pretty simple, right? Continue reading “Amplifiers & Light Control”

The Golden Ear vs X-Ray Vision

Fact versus Fiction – our hearing is pretty hairy

There is a gem of a website call Audio Check which allows you to test your sound system, DACs, headphones as well as hearing. I recommend all those interested in audio to pop over there, light a cigar, grab a cup of tea or your favourite brew and do some reading.

Another great read is “Testing Audiophile claims and myths“.

To sum it up:

Look, it has all but gotten pretty boring over the years.  When in my early 20s and in the 80s I had a sound system which I would rate as pretty powerful, about 100W per channel into a 4  Ohm load. When it came to parties and the venue owner’s system ran out of steam we’d plug in this baby and crank the volume. The quality of the sound was proportional to the amount of alcohol.  It probably deserved to have a rating of about 2/10 compared to modern lower powered systems.

What I have learnt through the ages is i) to take your time to build an amplifier ii) use the best components possible in the power supply, cooling, consumer controls, jacks and plugs iii) we now have a much wider access to and better quality patch cables and connectors iv) electronic consumer goods have become much more reliable generating some pretty exotic powers. Oh, this list goes on.

Good looks until it opens it’s mouth

A good looking amplifier doesn’t mean it was well built. It’s under the hood that counts. Also, knobs and good quality pots cost good money.

Don’t be hood-winked into buying an amplifier or any component for that matter without doing your homework. In South Africa, unless it’s very high end audio, the retail store is not going to do a delivery and then a collection again after you have done a test over the week-end.

Brands we know and trust

Most of the better known amplifiers (and pre-amps) which would include Yamaha, NAD, Harmon-Cardon, Denon, Onkyo, Rotel are well designed, are great for normal listening and more.  Get something which likes your speakers and the speakers like the amplifier. Reading up about ‘which’ loudspeaker is crucial and is always the best bet – it’s going to cost.  Be warned again, a set of loudspeakers may sound good with one amp but not the other. In South Africa Mission is often partnered with NAD.  I don’t know about this match but there’s thousands of people out there raving about the dimension, the colour, the warmth, the depth, the ooh, ooh, the orgasm of things.


Headphones are a touch more personal – each one to their own of course. I don’t believe most of the marketing hype.  A set of LG headphones which I received as a gift about 15 years back astonished me in the quality (excellent). I like Senheisser. That does not mean you have to.

Bitrates and Sampling

Too many articles pointing to the hazards of dubious marketing – our hearing is only 20Hz. to 20kHz. Mine is maybe 30 Hz to 14 kHz. 24 Bit / 192kHz may not sound better than 44.1kHz at 16 Bits. Maybe 8, but not 16.

Milking the snake of all it’s oils

What does all of this mean of course?  Have you seen the advertisements adorning Hi-Fi mags promoting audio and power cables?  R 1 000/m or more. In a magazine years back the fundis tested numerous cables and the one they thought sounded best was telephone cable. (yep ma’am, that cable running to your house, not to your telephone).  Now we get told how good CAT-5 cable can sound, both on the input and output. Kettle plugs?  Just make sure the L is Live. Some aren’t and don’t ask me where they come from.


Spectacles may improve one’s eyesight but a high powered amplifier is not going to improve your hearing. Most of what we want doesn’t always follow the rule of logic. Do read “Testing Audiophile claims and myths” and Audio Check!

Changing the argument in modern audio – the digital sound

Asus Xonar U7

The DAC and digital sound – big quality at half the expense

Coming from an analog website it may sound as if we are doing a 180 here but the truth remains, we still have the analog versus digital argument.  Something which will never quite be put to bed, the digital war continues.

My first CD player was the Sony CDP1, a small, heavyweight, state of the art digital ‘icon’ to the audio world. In fact at the time I was not even aware that it was first commercial release, rather just wanting to get my hands on a CD player, a Sony, to impress my friends.

The vinyl years

Two things stood out at the time, one without doubt the easy way to play the media – damn but vinyl was finicky, and then you had the problem of friends playing disks which were so bad that it would damage the stylus (was I the only guy that had a freakin’ sound system) and the big one,  no crackles, pops, buzzing, clicks, jumping, feedback and of course,  the big one – lifting the arm to change tracks.

As time went by CD players dropped in price, had more functions and became quite a part of our lives. Everyone had one by the 1990s. Turntables were packed away or trashed, vinyl was dead. Or was it?

The CD years

I stopped listening to vinyl for about fifteen years, it was always cassette tape or CD and then DVD.  I gave away both my Sony turntables which I DJ’d with in the early 80s. The marketing machine was fine tuning us for the silver disk and they did a remarkable job except for one thing – multimedia computers came on the scene in the mid-90s.  (PCs and Windows, Apple was always the front-runner).  We suddenly could compress our 40MB file to 4MB in the form of MP3s. We became used to this,  piracy was no longer something we found on the high seas, it was in everyone’s home.  iTunes suddenly kicked in and we could buy individual tracks not the whole CD where the artist possibly had only one good track. CD prices started falling and before we knew it the audiophiles started reminded us of a couple of things that we had forgotten about.  CD quality is 20 to 20, vinyl is so much more.  In the last decade suddenly we found vinyl on the shelves again.

The shortest route between two points is the straight wire

The digital versus analogue argument is all about the shortest path, sampling frequency and DAC quality. Vinyl has two paths, de-emphasis at the RIAA amplifier (where disk cutting excursions on the lower registers uses a lot of space the engineers de-emphasise these excursions and boost the treble). On playback the reverse is applied. The second path is the amplifier itself.  Simply put, cut out the unnecessary and only amplify the necessary.  Add tone controls if you wish but make sure the amplification is flat, as close to dammit from 0Hz to 100kHz. Wishful thinking but yes, technology can allow this.  Makes one think how the NAD 3020 became so popular with an output stage using transistors from the Ark.   But let it be said that these amplifiers were very popular and indeed, more because of vinyl than anything else.

Vinyl supposedly reduces fatigue, is non-sterile, not compressed to hell and back and also, importantly, does not have the 20 to 20 limitation.  A guru even went so far as to say that music is something we also sense outside the audio spectrum.  He is a very good musician, who am I to argue. So what has made that incredible CD player now near redundant?  The DAC and the internet of course.  Breaking up an analog signal into parts and then re-assembling  these parts or as in a CD, taking 1s and 0s and then re-assembling to get a ‘resemblance’ of analog is just not on.

Technology has allowed us to push the clocking of a digital circuit into the hundreds of Megahertz, the Digital to audio converter now even runs at 384kHz or higher.  CD players, or rather the media is sampled at 44.1 kHz. Using the Nyquist–Shannon thereom, sampling frequency must be a minimum double the sample rate – 44.1kHz also encompasses anti-aliasing filters which reduce the bandwidth.  Lots more of that on wiki.  Bottom line is that all CD players run at 44.1kHz – man decided that our uppermost frequnecy limit is 20kHz so let it be. But DACs have improved in leaps and bounds over the years, high end DACs costing upwards of R30 000.00.  Ouch. But here’s the thing.

We take an analog signal, slice and dice so it can fit nicely onto your computer and then rebuild this signal through the DAC to reproduce a nice sliced and diced analog signal. Why not just copy your vinyl onto a high end tape recorder, preferably an R2R where the media can sit for 10 to 20 years and hopefully not be subject to degrading.  Oh, yes this happens.  The Audio Technica AT-LP120-USB Turntable sells for about R 7 500.00, throw in a RTR for about R 10 000.00 and Bob’s your uncle, or aunt.

Asus Xonar U7
Asus Xonar U7 – 192kHz A-weighted 114dB front at 24bit/96kHz freq response 10Hz to 46kHz

But no, not to be, not to be.  Just have a look at how long it takes to set up your reel to reel – your computer boots up in 20 seconds and then you have the Xonar U7 as I have. Exceptional quality and in only 60 seconds you have YouTube, access to free downloads, very good quality audio. And that’s the thing – if you want a no frills, high quality audio setup go the digital route. If you are looking at the pseudo-acoustic route go analog. Real analogue. In the real world a high quality setup of either can be expensive. For Sunday afternoon listening pleasure I opt for the analogue.  Day to day listening, digital. It’s all in the head any way.

The Internet of Everything

We have all heard this phrase and it’s not one which will go away quickly – the IoT or Internet of Things is going to change the way we react with the net and the universe.  At home you will have a menu listing trillions of songs and movies. You won’t need to keep a library – you will need to pay royalties but as the companies supplying this service become more popular these royalties will be measured in terms of cents.  It’s happening now already.  We live in a quick fix world – digital streaming media is the way things are happening.


The Harman/Kardon AVR161S

Harmon/kardon AVR161 review

Home Theatre AVR161S 5.1 harman/kardon

Being pretty frugal when it comes to buying audio equipment I felt it time to replace my tattered old 2004 JVC with a receiver which would not break the bank. Having four options at hand,  Yamaha RXV379, Harman/Kardon AVR161S and the new Yamaha RXV381 or HTR4068 I was stumped for choice. Knowing someone years back with a harman/kardon repair job who was a first class arsehole left me dodging the 161 like a Bryan Habana. But and this is a very big BUT, many folk have raved about the reliability of this brand and of course the quality. As the retailer was selling this unit for at least R500.00 cheaper than competitors I felt it was money well spent for a known good brand with a switched mode power supply. Not that I have anything against either Yamaha or linear supplies.

Harmon/kardon AVR161 review
Harmon/kardon AVR161

The audio output is nothing to write home about, 85W RMS x 2 channels driven.  I needed the HDMI more than anything which was 5 inputs, more than I needed in any event. Optical and coaxial inputs, 2 x analog RCA inputs and composite video output make this HT receiver as barren as the Sahara but this is what appealed to me.  And the setup is ridiculously easy. Neat and tidy. An omni-directional microphone is part of the package and we were up and running within ten minutes.

AVR161S - rear connectors
AVR161S – rear connectors

Not going into what it can and cannot do, it’s all in the manual, it must be emphasised that this little receiver has excellent reproduction quality, it is quick to set up and the power is more than ample.  The on screen display is simple to understand and all inputs are easily allocated – in fact I would say it’s the easiest installation I have ever done. But then again this is what HK is all about.

This is not a multi zone receiver like the 171 – I really don’t know of many people using this function either properly or on a practical level.

I did not like the volume control illumination but I did like the fact that the dimmer on the remote reduces this to a pleasing level.

For a little home theatre amplifier albeit big brand coming in at just under R 8 000 on the South African market is a rare steal.  Thumbs up to Govan Mani in Durban.

harmon/kardon AVR161S
The AVR161S all set up and in action

I’d like to say this was an elementary review but when one purchases something for their own entertainment and nobody else it may come across as being biased justifying the purchase. In essence – just Iove it.

[Editor’s Note:  Harman International Industries is headed up by Dinesh C. Paliwal as CEO. In November 2016 the company revealed it was to be acquired by Samsung. I wonder what Mr. Trump thinks of this?

Brands include: Harman Kardon, Becker, JBL, Crown Audio, dbx, Martin Professional, AKG Acoustics, Lexicon, Infinity, Mark Levinson, Revel, Soundcraft and Studer]

The JVC RX5042 – Some say it’s Good

RX-5042 - some say they are good

First up on the operating table – the JVC RX-5042

If ever I had to give an entry level home theatre amplifier 6 stars it would be the JVC RX5042.  Purchased in 2004 at the Hypermarket in Brackenfell for a mere R 1 600.00 I was expecting an amplifier from hell.  In fact, I did a little bit of research and on a forum and in German an owner said “Buy it!”. This was the only information I had so like a stupid boy blowing his pocket money I did just that. And was I surprised.

RX-5042 - some say they are good
JVC RX-5042 Great performance at low cost.

The RX5042 did not come with all the bells and whistles but it did have five shift rail power amplifiers rated at 100W into 8 Ohms. An entry level Yamaha at that stage cost R 5 000.00.  Home theatre is home theatre isn’t it, I thought. In fact the JVC was better than the Yamaha – in power that is.

Pink Floyd thundered into the night at full volume and after two six packs of Amstels. It ran hot, mightily hot into 6 Ohms.  It did not fall over, cry or blow off steam. This year I replaced it with another entry level amplifier, a Harmon Kardon. It has nowhere near the power nor the fidelity but it does have HDMI and Bluetooth.

Paying more for HDMI

This poses the question. Should one replace their amplifier because it doesn’t have HDMI capability?  Hell, no! Should you buy the 2017 Mercedes now that you have the 2015 Mercedes. Hell, no.

The big problem as I see it is for the corporate machine to continue rolling out new products to keep their sales up. We need to add more technology to make it more attractive. Ditto Mercedes. Ditto clothing, food, hygiene and cosmetics. The JVC was plonked into an entry level market at a sub entry level price. Think cheap. Think nasty. It’s none of those. It seriously whacked the competition in many ways except for the damned inputs.

RX-5042 Shift Rail Technology

The shift rail power supply technology is nothing new. It’s designed to be very efficient. Even NAD uses it.  Hey, NAD! But that’s expensive gear. The RX5042 uses the STK412-300 IC which is rated I believe at something like 150W per channel (two channels per IC).  Supply rails are +27, +55 and -27, -55V. Into 8 Ohms this equates to about 180W into 8 Ohms continuous or 350W into 4 Ohms.    ((Vcc^2)/(8RL)). These chips are even available at Communica for about R240.00 per pop. Actually, most of the power amp parts can still be easily obtained.

The amplifier is heavier than a lot of the modern entry level stuff which puts even the power transformer into a different league.  But no, be careful here – this is not a 500W machine.  On the safe side I would say the transformer is at most 200VA.

Digital Signal Processing – how to mess up the analog signal

The problem I find with home theatre is that the preamplifier and DSP circuits should not be designed by a kid with braces. I don’t like the DSP on most of these amplifiers, even some of the more expensive models. The JVC is no different. Actually, why would anyone want to reproduce a movie to sound like that coming from a tin can. We do need Dolby Digital though. Of course.

The JVC doesn’t come without problems of course. The gurus will shout out that the loudspeaker terminals are disgraceful, which they are.  Sometimes the optical loses sync. Sometimes there is no output at all. Sometimes it’s all user intervention and troublesome fingers. Mostly the JVC is mediocre input wise but all the analogs work.  So what to do, what to do?

Let’s Arduinofy it!

We won’t touch the DSP, we won’t even touch the audio circuits. We will add circuits though. We will add an RIAA preamplifier for vinyl, MC and MM. We will add a Baxandall tone circuit for the front left and right channels.  We will even bypass the preamplification and digital stages. We want analog. We will mute the other channels. We will equalise and have drive for a sub, just in case you want it. And of course this will all be driven off a remote control. I like my amplifiers simple and easy.

Next phase:  Getting to grips with the technology of 2004


(Editor’s note:-  these receivers get very good reviews based on price and in comparison to similar models of other brands. A common problem was the setup through remote and switching between analog and digital although there is an auto switch.  JVC was never known for building high quality audio equipment, their niche supposedly being in TV and of course the ever famous JVC VHS video recorder. The reality is that they largely make very good audio amplifiers. JVC is in many ways compared to Sony.  In our own tests the JVC outperformed power wise any models in a similar price range. Without blowing or tripping/fusing the thermal link to the mains transformer. In stereo mode, well over 130W RMS per channel. These amplifiers plus big brothers, the 6042 and 7042 can be picked up for under R 1 000.00 in the RSA. If you don’t have the wallet for the more expensive gear, try these models. You may be pleased at the results 🙂   )