[froger]

Fantastic review, Darryl! I had a great time reading it and I also found much of your review resonated with what I have been hearing, and you are able to express them in words so well. Excellent, detailed and clear comparison with the other DACs too. Purrin reported that Master 7 improves much with OR5 in place. I wondered how much improvement the OR5 will make to the Master 7 (The improvement of DP-777 over Master 7 is quite big IMO), as adding the OR5 will bring the cost pretty close to the DP-777 and one might as well get the DP-777 instead.

 

[preproman]

Thanks froger.  The funny thing is.  I never used the USB on the Master 7.  Never loaded the drivers.  At the time I used the SOtM USB converter with an external PSU - I used the AES input of the Master 7.  So I have no idea about the USB issues.  
 
Another funny thing is - I'm now using the USB on the AMR - and I'm not a USB person per say - I've always used converters.  USB is never done right "inside" a DAC IMO.  I got caught waiting for the OR6 to come out - that's why I don't have a converter now.  So I'm now looking at either the Alpha USB or the OR5 I guess..
 
Yet another funny thing is the AMR manual says this:
 
3.6 HD-Valve Digital input The Compact Disk standard was never conceived with the notion of distinctly separate transport and DAC sections but once this became so, SPDIF was adopted as the method to link the two together. However, SPDIF is an ana- logue transmission system that uses what was originally a video signal format to transmit a digital system. Clearly, this is not an elegant solution as the SPDIF clock and signal are transmitted together as if the red, blue and green signals for a television were cobbled into a single run.
 
 
In the DP-777, to overcome this set of essentially analogue problems we devised a completely analogue solution. AMR’s proprietary Valve Digital input technology (VDi) is a world’s first: it is the use of the 6N11 (high-speed valve operating into the 100MHz region) in a zero feedback circuit derived from military radar technology to re- establish the clean waveform of the original incoming signal from the two HD SPDIF Inputs.
 
 
Firstly, this ensures that even if the input SPDIF signal has an incorrect output level or poor waveform, the SPDIF input receiver will have a clean and perfect SPDIF signal to lock onto.
 
 
Secondly, as all SPDIF receivers use Schmitt Trigger input circuitry, the receiver will create a glitch noise at the trigger point, this noise travels back into the SPDIF cable, returning to the source component. It is this errant noise that is at least in part responsible for the major differences between SPDIF cables and sources in the input system of common DACs. As the HD-VDi isolates the SPDIF receiver from the outside world, HD-VDi eliminates the detrimental effect caused by this noise once and for all.
 
 
The DP-777’s HD SPDIF inputs employ a NOS valve input circuit for everything all the way up to the 24/192 high- definition standard. The result is clearly visible on an oscilloscope as the SPDIF signal is restored back to its perfect wave form. This input ensures the “right note at the right time” to give the music the “life” that is missing from all other DACs.
 
 
Therefore, we recommend that for the optimal signal transfer (i.e. highest sound quality), please use Inputs 1 or 2 (R1/R2) on either BNC or XLR. Even with an RCA connector, simply use the accompanying BNC > RCA adaptor. Inputs 3 and 4 (R3) do not use the HD-VDi (as they are more for convenience/comparative purposes). The USB input 5 (R4) is not required as the signal is not SPDIF.  
 
 
What does this mean exactly?  
 
Does this mean the HD-VDi inputs 1 and 2 ie.. the SPDIF BNC and AES are superior to the USB input?  If so then how much more would you think a high end convert like the OR5 or the Alpha USB would improve the sound?  This is a question for everyone...

 

[Clemmaster]

   

Spoiler: Warning: Spoiler!

Thanks froger.  The funny thing is.  I never used the USB on the Master 7.  Never loaded the drivers.  At the time I used the SOtM USB converter with an external PSU - I used the AES input of the Master 7.  So I have no idea about the USB issues.  
 
Another funny thing is - I'm now using the USB on the AMR - and I'm not a USB person per say - I've always used converters.  USB is never done right "inside" a DAC IMO.  I got caught waiting for the OR6 to come out - that's why I don't have a converter now.  So I'm now looking at either the Alpha USB or the OR5 I guess..
 
Yet another funny thing is the AMR manual says this:
 
3.6 HD-Valve Digital input The Compact Disk standard was never conceived with the notion of distinctly separate transport and DAC sections but once this became so, SPDIF was adopted as the method to link the two together. However, SPDIF is an ana- logue transmission system that uses what was originally a video signal format to transmit a digital system. Clearly, this is not an elegant solution as the SPDIF clock and signal are transmitted together as if the red, blue and green signals for a television were cobbled into a single run.
 
 
In the DP-777, to overcome this set of essentially analogue problems we devised a completely analogue solution. AMR’s proprietary Valve Digital input technology (VDi) is a world’s first: it is the use of the 6N11 (high-speed valve operating into the 100MHz region) in a zero feedback circuit derived from military radar technology to re- establish the clean waveform of the original incoming signal from the two HD SPDIF Inputs.
 
 
Firstly, this ensures that even if the input SPDIF signal has an incorrect output level or poor waveform, the SPDIF input receiver will have a clean and perfect SPDIF signal to lock onto.
 
 
Secondly, as all SPDIF receivers use Schmitt Trigger input circuitry, the receiver will create a glitch noise at the trigger point, this noise travels back into the SPDIF cable, returning to the source component. It is this errant noise that is at least in part responsible for the major differences between SPDIF cables and sources in the input system of common DACs. As the HD-VDi isolates the SPDIF receiver from the outside world, HD-VDi eliminates the detrimental effect caused by this noise once and for all.
 
 
The DP-777’s HD SPDIF inputs employ a NOS valve input circuit for everything all the way up to the 24/192 high- definition standard. The result is clearly visible on an oscilloscope as the SPDIF signal is restored back to its perfect wave form. This input ensures the “right note at the right time” to give the music the “life” that is missing from all other DACs.
 
 
Therefore, we recommend that for the optimal signal transfer (i.e. highest sound quality), please use Inputs 1 or 2 (R1/R2) on either BNC or XLR. Even with an RCA connector, simply use the accompanying BNC > RCA adaptor. Inputs 3 and 4 (R3) do not use the HD-VDi (as they are more for convenience/comparative purposes). The USB input 5 (R4) is not required as the signal is not SPDIF.  

 
 
 
What does this mean exactly?  
 
Does this mean the HD-VDi inputs 1 and 2 ie.. the SPDIF BNC and AES are superior to the USB input?  If so then how much more would you think a high end convert like the OR5 or the Alpha USB would improve the sound?  This is a question for everyone...

 
They don't specifically said so.
 
They just say they have a better S/PDIF interface than the competition; and they provide a more "traditional" S/PDIF interface in the same unit, to prove their claim. .
It would be interesting that you compare inputs 1/2 (HD) vs 3/4 (regular) to see if you can hear any difference.
 
As for the USB input, from their explanation of the shortcomings of the S/PDIF interface - and the elegant solution they came up with - one can assume they are knowledgeable in digital audio and came up with a good implementation of the USB interface.
You ears will be the final judge. I wouldn't be surprised it you like the built-in USB better than the SOtM. USB is probably not an afterthought in the AMR.

 

[ericfarrell85]

D,

Beautiful write up and I'm glad you gave the Lampi a good going over. Hell, you've put a lot of my disorganized thoughts into a coherent, accessible writing manner. I have Deulands in my Lampi and agree with others who mention that they take time to really reveal their capabilities. I don't know how the DP-777 responds to converters, but the OR5 has shown itself superior (yet again) to the USB section of my Lampi and also considerably better than the Master 7. You've talked about trying the OR5 many times and I still think you should. It radically changes the superficial depth issues of the M7, which says a lot. While expensive, the AMR proves to be a bargain vis a vis the Lampizator, which outfitted with Deulands, USB and i2s exceeds $5.5k after currency conversion.

 

[preproman]

Thank E,
 
The Lampi I borrowed had the V-Caps.  I've heard many people prefer the Deulands over the V-Caps and it's been unanimous.  So your Lampi should sound better based on that.  
 
Yeah the converter is next on my list.  Although the Lampi with Deulands is tempting as well.  

 

[SleepyOne]

I checked today, seems the updated AMR DP-777SE is going to be around £900 more than the current DP-777. Will know exact pricing when it comes out in around a month time. According to them the current DP-777 can be refit to SE version.

 

[Duckman]

Prepo,
 
I friend of mine has the 777, and reckons its usb implementation is superior to the Sonicweld Diverter (non-HR) he had (and consequently sold); which is saying a lot as the Diverter is simply awesome.

 

[stainless824]

The PWD is always a hard one to figure out. It really depends what firmware you're on. I find the 2.4.1 to be the best

 

[ChiAki]

Beautiful DAC.

 

[Greed]

DAC, the CD player is CD-777 

 

 

[ChiAki]

  DAC, the CD player is CD-777 

 

 

[DefQon]

Nice review but damn huge price tag on that DAC. 
 
Does this mean you've settled on a DAC that you won't be upgrading in a long while? lol you know you always swap out DAC's. hehe
 
Maybe MSB Analog DAC next or the entry level dCS? Both around $9-11k.

 

[preproman]

Thanks..
 
Well - It was going to be the end game DAC yes.  Just found out the output impedance is to high for the Dynahi.  So after I get the Dynahi build I'll try it out and see.  If it's a no go I'll be on the DAC hunt again for the Dynahi.  However, the AMR is not going anywhere.
 
Looking at the Lampi with Deulands or the Metrum HEX.

 

[antonyfirst]

I found the USB of the AMR is extremely sensitive to the USB cable used. The AMR dp777 sucks with the wrong cable (like the Wireworld Starlight, where the sound gets sterile sounding and plain boring). It gets a lot better with good sounding usb cables. The absolute best I tried have been the Jplay JCAT and the RAL Prophecy.
 
This, to me suggests a few contrasting things:
- the USB input in the amr can scale, which is good
- by converse, the USB input in the amr is not very cable tolerant, which is quite bad.
 
Depending on how one sees it, it can be either a good or bad input. In my own opinion, it's not a great quality when a usb input has such a huge fluctuations like the amr. Anyway, technicalities aside, if pairing it with a high end cable, it yelds great results.

 

[preproman]

Currently I'm using the Mercury cable and the Gemini cable.  I plan to use Silver cables from Cabledyne from top to bottom.