Vintage Audio Vs Modern Technology

Is vintage audio better than modern releases?  (post 2000)

This reminds me of the first argument I had regarding the merits of mechanical VU meters over LED.

Yeah, we like vintage stuff, especially with those big VU meters. Hell, I was looking at the specs of the Pioneer SX-1980 the other evening and thought  what a beast this must have been in the 1980s. At 270W this is certainly by no stretch of the imagination much in modern times thanks to PWM, Class D and mounted on a one inch square heatsink.

McIntosh_MA6800
McIntosh MA6800

en:McIntosh Labs MA6800 amplifier. *Source:  *Credit: [http://www.flickr.com/people/ux/ Akira Kamikura] *License: cc-by-2.0 {{cc-by-2.0}}

Continue reading “Vintage Audio Vs Modern Technology”

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 New Vinyl – magnetic tape

And the final outcome: Magnetic tape beats vinyl.

Well we don’t really know about this one but based on our research this seems to be the case.  But let us be realistic.

A good turntable is going to put us back about R7 000 to R8 000 and then we are only just starting up our engines.  A good professional series tape recorder, which you don’t really need is going to be upwards of R20 000.  But here’s the crunch: the tests get done on a master tape copy or at least as damned near to a master reproduction. These cost upwards of R4 500 per tape.

Magnetic Tape beats Vinyl
The cat “eMotion” enjoying some analog Part I Act II

If we take the vinyl and record to a professional series reel to reel deck the reproduction can never be better. Likewise tape recorder to vinyl unless you have the master copy vinyl already. We won’t bicker here – most people will understand this but here’s the crunch.  Just what amount, what value do we put on this reproduction which is so outstanding, so good, that the hairs stand up on your arms? What came first, the chicken or the egg?

Value wise digital lies top of the list.  I will argue the point that the Zoom H6 hand held recorder from record to reproduction at under R7 000.00 cannot be beaten by any analog system.  The audiophile community understand the rationale about having an excellent DAC and of course, ADC. Your digital CD player output frequency range varies between 20 Hertz and 20 kHz.  Those engineers behind CD format weren’t on Opium when they devised that 44.1kHz was the optimum sampling frequency. It’s twice the maximum frequency we can hear after all.  What then makes vinyl then second best and tape, the ultimate in audio luxury? Well these are analog pages after all, right?

Magnetic Tape beats Vinyl
The cat “eMotion” enjoying some analog Part II Act II

To put things in perspective one needs to be the right age, that age which brought us through analog into our digital world.  The first listenings to digital after twenty years of vinyl, R2R and cassette tapes. Crystal clear, frighteningly clear in fact. Great dynamic range and when played loud, no feedback. No skipping, jumping, popping and cracking. Just beautiful sound. Picture this in your mind for thirty seconds and now jump to 2010.  Invited into a friend’s home to undergo a blind listening test. No reason given – just blindfolded, ears open and listen.  Dark Side of the Moon.  Different, very, very different.  Ambience, colour, warmth.  No new amplifier, no new speakers just a Linn Sondeck and a brand new vinyl reproduction. This was the same freaky feeling I had when listening to my brother’s vinyl reproduction of The Wall after years of listening to the digital format.

What do you think?

Next:  Part II – start your engines folks and open your wallets – here comes the 1950s and 1960s Reel to Reel….

 

 

Akai M8 Restoration – Part Two

Akai M8 Restoration – The Process

We recommend you also read our sister website’s write up on the Akai M8 – certain aspects are covered there which is not covered here.

akai m8 restoration part 2
Akai M8 Restoration part II

The two amplifier modules from the M8 are both very high gain so care must be taken to keep the dressing of the interconnecting  leads the same as the factory to keep hum and noise as low as possible.

Electrolytic Replacement

All the capacitors replaced were polarised electrolytics, no bipolar types.  Shown with a blue rectangle.

Schematic below

Vintage Akai Schematic
Akai M8 Schematic – click to view full

Capacitors changed:

C3 1u 150V elect with 1u 450V
C2 25u 25V elect with 22u 25V
C7 20u 300V elect with 33u 350V
C10 25u 25V elect with 22u 25V
C12 25u 25V elect with 22u 25V
C16 25u 25V elect with 22u 25V
C17 20u 300V elect with 33u 350V
C22  3u 350V elect (this was not replaced)
C25 20u  (add extra 10u) elect
C26 20u  (do not add more capacity) elect

None of the resistors on the tag board showed any signs of stress.

Some things to note:

C26 is a 20u+20u capacitor. This was replaced by a 22u 350V on the input side of the choke and a 33u 350V on the output side.

The 6X4 dual diode is a comparatively hard to come by device. Adding a higher capacity to the immediate output may have caused undue loading. We did not know the condition of these devices because we do not have a tester but was relevant to our restoration was to keep the original tube compliment intact. The choke reduces inrush current.

C22 was not replaced possibly the reason why the bias oscillator does not light up the neon in record mode. (or the neon is faulty which we doubt).

From the owner’s manual

Power Input Levels:

Microphone input level -55db (VR.max) at 1000cps.
Phono and radio input level -15db (VR. max) at 1000cps.

Power Output:

Head output 1mv at 1000cps.
Pre-Amplifier output 0.8V at 1000cps, impedance 10,000 ohms.

For more on dBu and dBV go to the website http://www.sengpielaudio.com/calculator-db-volt.htm

Things to know

The supply rail is about +260V (we measured 255V).

Don’t test without a load of sorts.  Tube amplifiers are resilient but definitely do not like high voltage swings across the output transformer.

By replacing the rectifier tube with a fast recovery rectifier your supply rail will be over 300V.  This will increase anode current of the EL34 marginally. We did not toy with this idea as we wanted to keep the original tubes.

When working on the amplifiers remember that the amplifiers are removed first and then the deck mechanism.

If planning to use only the amplifiers it would be best to modify the record/playback switching and remove the selector slides.

Turntable input goes directly to the EF86 control grid. Check schematic J3, P1 and P3 head connections.

Although these amplifiers are not of bad quality remember that this was 50 years back when they were popular.  Some enthusiasts complain that the output transformers are “limp” and are of poor quality. I beg to differ. These amplifiers are rated at 6W max per channel and the transformers are more than adequate. I would never tinker with this area because to be brutally frank you could build a 100W amplifier (without PSU) for the price of just one EL84 tube. The output transformer is going to cost more. Let it rest.

The M8 also came with an important part – a capstan sleeve designed for 7.5 ips. The only one I received has a small crack running down the cylinder wall.  Not known to be all that hardy (alum) they can be purchased through:  http://www.oaktreevintage.com/Akai_Reel_Tape_Deck_Capstain_Speed_Sleeve_Replacement.htm

Finally

head block m8
Head Block M8

Note the new pinch roller. And this one is brand spanking new.

m8 rear showing amplifiers
Rear showing amplifiers
akai m8 ready for action
Akai M8

Sadly one of the VU meters has a dead illumination lamp. To be replaced soon. How though? – the plastic housing seems very, very tight.

Please don’t forget to read:  http://parts-ring.com/akai-m8-schematic-just-a-simple-tube-amp/

 

Akai M8 Restoration

Akai M8 Pre and Main Amplifier - restoration of Akai

Akai M8 Restoration – Part One

Many of the older or vintage tape decks or open reel recorders finding its way onto the market use thermionic tubes or valves in the circuitry.  This has made them a very attractive collector’s piece albeit sometimes at a cost.

Akai M8 Pre and Main Amplifier - Akai M8 Restoration
Akai M8 Pre and Main Amplifier

The Akai M8

Now here’s an open reel tape recorder which gets a lot of publicity. One needs to understand that most of the positive publicity comes from the EF86, ECC83 preamplifier and EL84 output stage.  If one can pick up a unit in working condition for about R1 000.00 (these were about R300-R350 new in the 60s) then it works out as a very cheap alternative to building your own low powered tube amp. But before we all start our engines and run to OLX, Gumtree or eBay remember the following:

a) Look up the Roberts equivalent units on the net e.g. the 770X series was the M8. The M9 does not use tubes, neither the 1800 etc. Buying a reel tape recorder for the sake of it can prove to be an expensive and costly mistake – in many cases the machines up for sale are shot in one way or the other. An M8 in exceptional working order is going to set you back about 200 U$ and then shipping is an extra U$ 200 through eBay. And there are plenty of them around.

b) If you have never heard the so called “tube” sound maybe this is what you need to do first.  Sometimes it’s not always cut out to what people say it is.

c) If you then decide to go ahead, what do you want to do with it?  Will it become only a mic pre-amp, a modular stereo amplifier, will you trash the deck or restore? We see just one module, modified for two mics input only going for about $1 000. And they sell!

First and foremost note that Akai mechanical parts are notoriously hard to find.  Secondly if you do have a working deck in excellent condition then why trash it – these have become collector items. They are 50 years old now.

M8 rubber parts - Akai M8 Restoration
Akai M8 Rubber parts kit

The kit above covered idlers, capstan and tape counter belt and wonder of wonders, a brand new pinch roller. The parts cost R400.00 (this is super cheap) and the shipping about R500.00 through eBay’s global shipping program. (this should mean it will get here). Pinch rollers are hard to come by but bear in mind that many Akai models share the same roller.  (Top secret).

So I went and purchased an Akai M8 off Gumtree for R1 000.00. The lower head cover was missing, the box was in bad shape and the pinch roller had a crease or indent in it where the capstan had been running against it – the process is always to switch the motor off, there is a slide switch for this purpose. In any event…

Slowly applied 60V DC from a variable PSU to the high tension section of the amplifiers to form the still original electrolytic capacitors and then with a 100W bulb in series with the live input applied power. No shards of electrolytic anywhere, things looking good. Then  apply full power by removing the current limiter and still no explosion. Lights on, action, camera.  High tension at 230V. Very little residual hum. Microphone input worked, much distortion.

Next I purchased another M8 off Gumtree and managed to drop the seller from R2  000.00 to R1650.00. My intent was to get one good condition M8 out of the two. This one looked the worse for wear but strangely enough besides using one round knob to control the record and play function and a volume control knob missing this one was amazingly enough still in very good nick except for the pinch roller which was hard as a rock.

Before moving on I do need to show you something which is after all the very reason why we discard the mechanical parts and use the electronics as raw amplifiers.

 

Head block - M8 A Akai M8 Restoration
Head block – M8 A (bottom two heads erase and playback with the head opposing the playback head being the crossfield bias head)
Head Block M8 B - Akain M8 Restoration
Head Block M8 B

Although both these head blocks are filthy they are actually in a remarkably good condition.  (once we have cleaned them of course). The giveaway which makes the bottom image head block look in such a disgusting state is not rust but the tape oxide from lots of use and no cleaning.  I have cleaned tape heads and path for the last 45 years with meths (denatured alcohol) and have never had a problem. Purists will say you need to use isopropyl. By all means use what ever floats your boat.

Akai M8 Restoration – What is recapping?

Although I do believe that some of the older equipment on the market used a better quality of electrolytic capacitor compared to the common and garden variety purchased at your local electronics convenience store it is sometimes advisable to replace all the electrolytic capacitors in the circuit.

Electrolytic capacitors do have a tendency to dry out and become ineffective.  In this case we removed and replaced all the electrolytics in the high voltage section as well as the cathode bypass capacitors for all the tubes.  We kept the split reservoir capacitor in place to act as a mount for the two individual capacitors in the smoothing section using a 22u 350V pre- choke and all the rest 33u 350V after.  Bypass capacitors 25u 25V were all replaced with 22u 25V.

Akai M8 Amplifiers - Akai M8 Restoration
Akai M8 Amplifiers – about to begine the restoration.

Part Two – the process

Beginning your analog dream – the Otari MX5050

Otari MX5050

The Otari MX5050

I am fortunate enough to own both a Zoom H6 and an Otari reel to reel.  When one looks at the technical advances in the recording industry be it for home studio or a multi-million Rand setup there is just no comparison between the analog of the 1960s to early 1990s and the modern digital installation. The H6 is virtually a home studio in the palm of your hand.  And lets not talk about price.

Otari MX5050
                             Otari MX5050 B2

Whilst the Otari comes in various models, some even being 8 track it is still one of the favourites amongst the home collector, along with Pioneer, Teac, Technics, Akai, Revox and Studer.  And no, this list is or should be infinite because each for his or her own.

A well maintained machine, which includes new or lapped heads is a crowd puller.  The question that arises is it because most of the crowd were born post 1990 or is it the quality.  I know of umpteen people that have never heard or even seen a reel2reel. Is it truly vintage and what determines whether something is vintage or not?  In a race against time, setting up the H6 is a breeze and the quality of reproduction will always surpass the Otari, even the highly ranked Studer.  That’s my opinion.  Try to over-modulate the H6 and we end up with one hellava mess. The reel deck is going to beat it hands down.

This is called record slam – pushing into saturation. We have all heard of the wonderful advantages of tube over solid state when it comes to distortion right?  Well it just so happens that some musicians like to slam their recording. You just don’t get the same result with digital.

So is record slamming the only advantage of R2R?

Zoom H6
Zoom H6 – 6 Channel simultaneous recorder

No, it’s not all doom and gloom – reel recorders have their place. We’ll move on later to the real Otari and why people buy open reel recorders.