4-12-2014

Audio-GD Master-10 review
by Maarten van Druten



Introduction

After having a lot of listening pleasure with my previous amp, It was time for something new.
I decided to sell my "old" stuff and start all over again.
I wanted to buy a new stereo high-end "set", especially for playback of high resolution audio ...



Looking for a new amp

I wanted a like a "solid state" class A amplifier.
Why? because I had good experiences with Classe A, and class A is one of the best amplifier techniques.
I would prefer an amplifier that plays entirely in class A, also the final stage.
Unfortunately, there are not many "real" class A amplifiers made anymore, because
this technique has a very poor efficiency and thus consumes much power.
Classe A also require expensive components, such as transformers,
you probably already understand; all this makes it more difficult for manufactures to build a cheap and good class A amplifiers

After some research, I noticed a interesting new brand: "Audio-GD".
I had never heard of it before, but after some searches on the Internet, I found a very impressive photo from the inside of an Audio-GD amplifier.
This amp was beautiful, hand-built (!) inspired by KRELL and Mark Levinson technologies and features audiophile quality components.
 

 


The Audio-GD website can also find more information about how the amplifiers built and tested. Since I already had good experiences with fidelity from China
I dared to order an amplifier blind.

I liked the model Master-10 the best, it's an integrated amplifier
2 x 250 watts into 8 ohms (2 x 500 watts at 4 ohms)
This is a fully balanced design with KRELL "CAST" technology
Audio GD calls it "ACSS".
Later I will tell you more about this remarkable technology.

The Master 10 integrated amplifier is a wonderful  product designed without any compromises,
and made entirely by hand and for a very attractive price!


The first stages of this amplifier works in class A without feedback and without any opamps.
the last stage work in "high idle current", in fact this is "Class AB",
but Audio-GD uses a technique that is quite unique, namely the so-called "Diamond Cross output stage".
more technical information about this technique can be found in this forum:
http://www.audioasylum.com/forums/amp/messages/18/185962.html

The advantages of this technique appealed to me, and I have therefore done a bit of water to the wine,
and apart from my first intention to choose for a amplifier that works entirely in classe A.

Well, there was a problem; I had never heard this amp before, so this for me would be a "blind buy".
This can be risky because there is a chance that the character of the sound to me at once perhaps not on, and what then?
My last "blind buy" was a pair of Meixing Mingda's MC3008-A, these were superb amps and I really liked them
in terms of sound quality.

A day later I saw on the website of Audio-GD, that The Netherlands also an official importer! Magna Hifi (http://www.magnahifi.com)
This gave me an extra sense of confidence, Magna Hifi is also authorized to make repairs with original Audio-GD parts, and Audio-GD provides a 10 year warranty on their products.
That's not nothing.


I had a good feeling about this, and after having email contact with Rob and Jos from Magna Hifi
I decided two weeks ago to buy this amp.

And this weekend I received an email that I could pick up my amp!



 

SPECIFICATIONS


Audio-GD Master-10 (2014 version)
 

S/N Ratio

>115DB

 Output

250W @ 8ohm
500W @ 4ohm

 Output Level (Max)

58V


Input sensitivety
 

0.775 V RMS @ RCA
1.55V RMS @ XLR
2mA RMS @ ACSS


Input impedance
 

47K ohm @ RCA
94K ohm @ XLR
<10 ohm @ ACSS

Frequency Breadth

20Hz - 20KHz ( + / -  0.01DB )


Channels cross
 
> -120DB

Channels imbalance
 
< 0.05DB

Power Requirement

1 Version  100-120V  AC 50/60 Hz
2 Version  220-240V  AC 50/60 Hz

Power Consumption

130W static @240V or 120V

Transformer Power

1500W (2 transformers)

Package Weight

Approximately 38KG


Dimensions
 
48CM(W)*44CM(D)*19CM (H) (MM, Fully aluminium ) 

Accessories

Power cord            X1

Operating Temperatures

+5 °C to +40 °C

Operating Humidity

5 % to 90 % (without dew)



That the amplifier was big and heavy I knew, but that this amplifier was so big and heavy came
surely as a surprise!
The Audio Master GD-10 is a beast of amplifier,
38 kilo's clean on the hook, and the dimensions remind me of those huge power amplifiers that you often see standing on the ground by High-end shows.


The amplifier is packaged in a sturdy cardboard box fitted with foam so that the amplifier during his long journey from China to Netherlands is well protected.
Although it is wise to pack the amplifier with two people because 38 pounds is still quite a weight.
Luckily for me, the amplifier (just) fitted on my Spectral Catena audio-furniture with black glass top.
Before I put the amp on my furniture I placed first the supplied rubber caps put under the metal feet to avoid scratches.

The supplied power cables are of type standard, they are fine,
but I have
nevertheless replaced them with firmer powercables with Furutech connectors.



Connections

Because I also ordered an Audio-GD NFB-1 dac, I could connect the DAC with the amplifier with ACSS.
This stands for "Audio GD Current Signal System"
ACSS is a technique that is similar to KRELL's "CAST" (Current Audio Signal Transmission)
More technical information can be found on the website of Audio-GD

http://www.audio-gd.com/audio/ACSS.htm

To make a complex and technical explanation simpler; Audio-GD's philosophy is to make the signal paths as short as
possible, so that the signal remains as pure as possible.
I'm a big proponent of simple and effective solutions
and I was very curious how this technique sounds in practice.

The connection of the DAC to the amplifier with ACSS cables is very simple.
The connector can only connected one way in,
they look similar to mini XLR connectors.
Luckily these special ACSS cables were not so expensive.


Audio-GD "ACSS" cables




"IN5" (on the Master-10 amplifier) is the input connector for ACSS
 


The standard powercable is replaced with a powercable from the German company "Audio Connexion"
model
"Furutech FI E11CU".
These are very good and affordable power cables, and they can also be ordered in any
lengths.
 For more info: http://www.audioconnexion-shop.de/


Both ACSS balanced cables are going from the amplifier to my Audio-GD NFB-1 DAC, which also has connections
for
ACSS.

After I connected everything, I couldn't wait to listen to some music!



Music listening session 1

Gently I pushed the large metal power button on the amplifier
Wow! what a feeling, the button feels very solid.
inside you hear briefly some soft clicks confirming that you have
turned on the amplifier, and the display will show some blue letters.
Very impressive!



The on and off switch feels solid and solid, in the picture it looks like a small button but in reality
it
's quite a big button!



This amplifier comes with a solid remote control made from aluminum
where along the different input "sources" (or channels) can be chosen,
there are also two buttons that let you adjust the volume.
The latter I find very
usefull, because it happens frequently is that you want to change the volume


Audio-GD has a very purist technology developed for the volume control of the Master-10,
which
according to their saying would sound even better if the volume control system of Mark Levinson.

 

          
  ASIN : B00CBIROA8                                                                                 http://www.hdtracks.com/rumours-super-deluxe



First I listened to the song of Michel Jonasz – Le temps passe from the double cd “La fabuleuse histoire de mister swing” (CD 16bit 44.1 kHz)
And immediately became clear that the Master-10 has a lot of power, and my speakers (Lyric Audio LS5) completely under control.
The bass was response
and also sounded tightly and went very deep.
what
struck me even morewas the ease with which the amplifier
presented everything.
He squeezed all what was possible out of my Lyric loudspeakers and I heard details that I had never heard before, remarkable!

Quickly I listened
to another music number, "Fleetwood Mac" with the song "Dreams" a nice cheerful and swinging number from HDtracks 24bit 192kHz (Super Deluxe Version)
The song sounds clear and dynamic, the is sound image
is presented with an almost arrogant ease by the amplifier.
It became clear that the Master-10 emits a lot of details, so much so that it almost seems that you're listening to a completely different CD!
(A better version that you had never heard before)

In the song "Love Someone" from "Jason Mraz" from the album "YES!" (HDtracks 24bit / 96kHz) an another aspect of the amplifier became clear, namely: "reality".


        
http://www.hdtracks.com/jason-mraz-yes                                                http://www.hdtracks.com/in-the-moonlight


The sound is so presented so realistically, that you naturally are going to listen more attentively.
Or should I say experience? Because you almost dare not turn off the track before it is finished, you are afraid that the artist tells you
"What are you doing? can I not finish my song?"

When I showed the new amplifier hear my girlfriend, she was also hit by the wonderful quality of the amplifier
when
I played the number of "Puccini - La Boheme "O soave Fanciulla" she crept close to me, and she was moved by the music.

When I played the number of "Sophie Milman" - "Do it Again" Get her voice showed so realistic that it almost equals the 3D quality of my Meixing Mindga single ended tube amps.
Or exceeded? Because if you close your eyes is almost
that Sophie is singing in front of you, so realistic it sounds.


Speed and dynamics

What is striking about this amp is the ease, but also the speed at which the music is presented to the listener.
sometimes
the dynamics are so big that you even get scared of a sudden music part.
This is accomplished by the precise projection of the amplifier in combination with the large amount of details.
Because this amplifier shows so many details, also less pleasant sounds or studio errors
become audible.
Normally you with other amplifiers not suffer from this, but in the Master 10 are small studio flaws evident reality.

Normally analytical sounding amplifiers are not really musical or pleasant to listen to, but the Master 10 knows to combine these
aspects in a very pleasant way. the Master-10 sounds very open, clear and is very comfortable to listen to.
The Master-10 misses perhaps the warm coloring of a SET tube amp, but he makes it up with an endless power, control and tremendous detail and precision.

The aspect that you hardly dare to stop a song, I think says enough, I got the feeling that you truly experience music instead of listening to it.
This amp is a remarkable performer, and you'll really want to play all the old CDs again with this amplifier, wondering how it would sound.

 



Music listening session 2

"Patricia Barber - Cafe Blue" 24bit 192kHz FLAC was played from my HTPC (Intel i7, passively cooled) and sounded very beautiful.
What I was experiencing, was
the same kind of sound what you also often hear at very expensive high-end show sets namely,
arrogance and control.
It seems as if the amplifier has no trouble to give you everything, just because he is very good, and that is what we want,
we want
that every product in
our audio chain, do his job optimal as possible.
So that we can finally enjoy high quality music.


 SACD: Patricia Barber: Cafe Blue (serial: UDSACD 2002 )                                    https://shop.klicktrack.com/2l/411252   
 http://www.sa-cd.net/showtitle/536                                                                (select the "Stereo DXD WAV 2ch 352.8 kHz/24bit" for best quality)

On the website: http://www.2l.no/hires/ you can download songs in different high-resolution formats.
Including a song from the album "Quiet winter night - Hoff ensemble"
I have downloaded the song called "Blågutten" in DXD 352.8kHz / 24bit WAV format.
This song was 331 Mb big!

This song in DXD format (
Digital eXtreme Definition)
sounds really amazing, it has huge transparent and spatially.
The Norwegian label "2L" (the Nordic Sound) is quite busy in promoting high resolution music in a proper way.
They let "you" (the listener) decide which format sounds the best.
DXD is an studio master format, from which al other versions (DSD, DSF,  and 192 kHz FLAC) are being made.

Because of this, I decided to make a special in the future, called: High Resolution Audio,
the quality of this recordlabel
will certainly going to be discussed!

Because CD's doesn't have an eternal life, I recently started archiving my CD collection.
For this I use the program: "exact audio copy" (http://www.exactaudiocopy.de/)
I chose this program because this program reads the CD very precise, and also indicates precisely of
there were no errors during reading. it takes a lot of time to "archive" a lot of CD's
But after this you will be rewarded with a lot of
comfort.
Just copy the music files to your NAS (or external hard drive) and play!




The Master-10 amplifier is beautiful and well built, like a tank!
The front plate is no less than 10mm thick.


"Made in China" is for me the new "Made in Germany"! solidity to the top!


I save my CDs in the WAV format.
FLAC might be more efficient, but I think WAV is still a better format.
WAV uses no compression,
it is just an exact copy of the PCM track from a CD.

Theoretically FLAC should sound as good as WAV, but why compress the music, when if you
want to play
it has first to be "un-packed" again?
Especially during this extraction (un-packing) process, errors could arise and that is something
were I'm not
waiting for.
Almost all studio masters are
recorded in the PCM (broadcast) WAV format
so why should I
opt for less?
Even DXD (the ultimate studiomaster format) is WAV!





http://www.maplemusic.com/dept.asp?dept_id=6521


The 16bit 44.1kHz WAV files from the CD "Misstress Barbara - I'm No Human" sound great.
This dance CD has a booming bass. hum synthesizer sounds are projected very precise and displayed with full control by the Master-10 amplifier.
I personally think that this Audio-GD Master 10 amplifier is also a very good choice for recording studios.
Who is looking for an extremely neutral and analytical amplifier that has a lot of details and also has a lot of power.
And power he has! the two 750 watt transformers provide enough power and keep the most difficult speakers
easily in control.

 


Conclusion

Audio-GD is a young company which is headed by Mr. He Qinghua, "the first prize winner" of the National Semiconductor (USA) Audio Design contest.
The Audio-GD team are professionals who create new products with great enthusiasm
And combine the latest techniques
with passion for music to get a perfect high-end audio experience.
These products are also very affordable, and this sounds to me as music to my ears!
I expect the prices of this brand will rise, when this brand will gain more recognition...
(this was also the case with my previous Meixing Mingda tube amp)
so be quick, and enjoy these top products.
Many other Audio-GD owners on the internet have indicated that these products sound better than the current so called
"
high-end" brands that cost four times more!

The Master-10 amplifier pleased me very well, and does exactly what he should do: amplify music
and add nothing.
The amplifier is very neutral, and that can be both positively and negatively.
Positive in the sense that well recorded music recordings will sound very precisely and spatial with great detail
and also with a lot of power and speed.

Negative in the sense that poorly recorded studio recordings, will also sound poorly and you can hear regularly small studio glitches that you first had never noticed before.
For me, this neutrality is a big plus because I only buy music that is
also good recorded.
This limits maybe my choice of music, but you have principles or not right?


Does this amp doesn't have any disadvantages?
Yes, of course it has; the weight of this
amplifier is huge, so make sure to lighten the load of transporting this amp to handle it with two persons.
another disadvantage is that the transformers (2 x 750 watts = 1500 watts!) are so heavy that when you sometimes turn off the amp
the automatic
circuit breaker goes out! this is because the inrush peak is then a little bit too high ...

On the internet I found that also owners of big KRELL power amplifiers had this same problem.
This is no fault of the amplifier, but rather a disadvantage of the (over) sensitive modern (automatic)circuit breakers.
Old fuse circuit breakers are not so sensitive and properly will not have this problem.

So give this amp it's own electric group, and maybe an external inrush current limiter like the "Block - ESG3" will fix this little problem?

I will be contacting
an electrician soon to ask what the possibilities are.
And then I'll definitely come back about this issue.

Fortunately, these little disadvantages could not kept me from enjoying pure, spatial and energetic
music coming from this monster of an amplifier!

(Note: recently this amplifier has been updated to "2015 edit release" this review is of the 2014 model)

 

 


Special thanks to Rob & Jos from Magnahifi for
excellent support and service!


http://www.magnahifi.com/

 



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