Audio-GD headphone AMP and DAC
I have been searching for a headphone amplifier and a new DAC for my Audeze LCD-3's for some time now. The thought of changing gear all the time annoys me so I want to make sure I get what I want.
High-end audio is a funny thing, everyone has there own taste and will fight for what they feel sounds the best. I am not going to say other brands of headphone amps are bad, how ever what I will say is what I have brought matches my taste. After all its about enjoying the music right...?
Take a look at the inside of this amplifier.
What is the first thing that comes to mind? For me its well designed and extremely well built. You can see that there has been a lot of though put into this. Take note of the high end parts, OCC copper wire, Nover capacitors , huge R-Core transformers. This thing means business.
Now what would you say if I told you this came out of China.. Unlike other parts of the world China is developing a big hi-fi/head-fi scene, there are a lot of people with large disposable incomes who want extremely good sounding kit. It is also still quite cheep to make things in China compared to other western counties.
Just like Fiio, Audio-gd are in the business of making well built and amazingly good sounding kit. The man behind Audio-gd, He Qinghua (Known as Kingwa) is a very smart guy. What set's him apart how ever is his honesty and willing to help you out when selecting products from Audio-gd. I can't praise him enough for his personal attention to any of my questions.
Before I move on to the re-view/un-boxing of my new gear I want to make it 100% clear that Audio-gd in no way has sponsored me or offered me any financial incentives. I paid for everything with my own cash.
If you where wondering about shipping quality here are a few images of how my gear came shipped :
The two shipping boxes:
Inside the box, well packed:
Let me introduce the gear I have brought.
Firstly is the DAC. The Audio-gd Reference 5-32
The Ref-5.32 is based around the Burr-Brown (Ti now) PCM1704UK muli-bit DAC (Digital Audio Converter) chip. Don't confuse the term multi-bit for the bit rate, lets take a quick look at the official specs :
- 24-bit / 96kHz
- Sampling frequency of 16kHz to 96kHz
- Up to 8x oversampling
- Input word width 24-bit
- THD of 0.0008%
- Muli-bit Sign-magnitude architecture
Let me go though some of the above facts.
Firstly Multi-bit Sign-magnitude architecture, makes use of a resistor ladder to process all 24 bits of data at once. A lot of DAC's these days are a Delta-Sigma design and use a 1 bit "bitstream" for reference DSD is also a 1 bit stream. This is the key difference between this chip and most other chips on the market at the moment.
The input word width is the data size in bits that the dac processes at once, this is not related to the bitrate of the dac how ever.
The 8x oversampling is a hot topic if it helps or hinders the sound. You can disable oversampling on the PCM1704UK so its really up to the end users preference.
Lets take a look inside the Ref 5-32 :
You can see up the front is a huge R-core transformer in theory R-Core type transformers should generate less noise.
You can also see heavy use of through hole mounting of components vs SMT. Its often believed that though hole allows better selection of higher quality components to be used.
In the center you can see the custom DSP board designed by Kingwa, under that are the four PCM1704UK DAC chips. Wait four! Why do you need four? Kingwa is a smart guy he has managed to work out how get the PCM1704UK to support 192kHz at 24-bit, I can't comment how he's done that but it works. Another reason for the need of four is that the Ref 5-32 is a fully balanced DAC. Each one of the PCM1704UK processes only a mono stream, thus to work in fully balanced mode you need two chips per Left/Right channel so a total of four chips is required. The Ref-532 can also work in single-ended output too if you wish.
The four square black boxes around the DSP board form part of the ACSS (Audio-gd Current Signal System) output stage. ACSS is similar in concept as Krell's CAST and Bakoon's SATRI designs. So whats so good about ACSS ?
ACSS transmits the analog audio single in the current domain rather then the voltage domain, this cuts down on the need for the I/V stage output conversion in turn this allows shorter single paths too.
None of that will matter unless your connecting the Ref 5-32 to another Audio-gd system.
Lets move on to the front of the Ref 5-32. Its nice and clean with a total of four buttons.
From the left hand side you have power, Output setting(low/high output voltage), Input selector. You also have the LCD display to show you the current settings. Kingwa was also nice enough to modify my Ref 5-32 to support an IR remote. (told you he was a good guy!).
Moving on to the back of the Ref 5-32 you can see the many inputs and outputs. Once again Kingwa lets you somewhat customize this for a small fee.
On the output side of things you can see a pair of RCA, balanced XLR, balanced ACSS. As for the inputs you have USB, 2x Optical, RCA coaxial, I added a 75ohm BNC coaxial socket. Not exactly shy of inputs!
I have put together a simple PDF manual for the Reference-5.32, you can download it here
You can find hi-res images of my Ref-5.32 on my flicker
Audio-gd Master 9
Next, the Master 9
The Master 9 is a fully balanced Class A headphone/Pre-amp. Take a look inside the Master 9 :
Once again you can see the high attention to detail and heavy focus on power regulation. The Master 9 also makes use of high end components. Including OCC copper writing and high end resistors and capacitors. You can see up front the 3 R-core transformers , they sure do add to the units 19kg weight! The Master 9 separates each channel with its own set of output transformers and the front panel circuit is isolated on a septate power feed to avoid any interference.
Lets take a look at some of the specs :
- THD of 0.002%
- S/N ratio of under 130db
- Headphone output : (Balanced; 40ohm @ 9000MW, 100ohm @ 3800MW, 300ohm @ 1250MW, 600ohm @ 630MW)
: (Single-ened; 40ohm @ 2500MW, 100ohm @ 1050MW, 300ohm @ 350MW, 600ohm @ 175MW)
- Channel imbalance 0.05db
- ACSS input and output (Krell CAST and Bakoon SATRI supported)
- Separate pre-amp output mode
Taking a look at the front panel:
You will find the following on the left hand side Power button, Headphone/Pre amp selector button, Gain (high/low) selector and the input selector button (XLR,ACSS,RCA). On top of that you have the LCD to show you current status and volume. In the middle you have the volume nob, this is an exponential volume control so no issues with the sensitive headphones or the power hungry giants. The Master 9 also comes with a IR remote by default and all button functions (except power) can be done via the remote control.
On the right hand side you have the headphone outputs. From left to right you can see the Left and Right XLR out puts then the 4pin L+R balanced output and lastly the 6.5mm single ended output.
Moving on to the back :
On the output side of things you can a 3pin balanced XLR output, a 4pin ACSS output and a RCA single ended output.
For the inputs you have 2x balanced XLR, 2x single ended RCA and the mini-XLR ACSS input.
The debug button allows you to reset the memory volume on every power on of the Master 9 or leave the previous volume setting in memory. I like to leave the previous value in memory.
Each section inside the Master 9 is well isolated from each other. You can see from the below image of one side of the amp.
Once again you can see heavy use of through hole mounting and high quality components.
If you where wondering what makes the Master 9 weight just shy of 20kg , the three r-core's may have something to do with it.
Lastly hear is a quick image of the remote control :
The remote is milled from a solid block of aluminum. Its very sturdy in hand and certainly does not feel cheep
I have also put a small manual together for the Master 9, you can down download it here
You can find hi-res images of my Master 9 on my flicker
Well thats it! I have on purpose left out how I think the gear sounds, as its personal. However I do love the way it all sounds. The sound stage and detail that comes out of this setup is simply amazing. A very excellent paring with the LCD-3.
Keep an eye on my blog for an up coming post where I build an software interface to the IR sensors of my new gear.