Abbingdon Music Research DP-777SE DAC/preamp NEW latest version

This is a brand new model of the latest (SE) version of the extremely well-reviewed AMR DP-777, cutting-edge preamp/DAC, from an authorized dealer.   It has separate digital pathways for standard CD and high resolution formats for complete optimization of both.    Rare, if not non-existent at this price point, it includes an super-high quality resistor ladder analog volume control, not the typical digital volume control found in most DACs.  With two analog inputs as well as several digital inputs including asynchronous USB, it's a complete preamp that can run straight to your amp.    The use of NOS tubes further distinguish this DAC -- it's a seductive yet highly resolving sound that, as the cliche goes but is true in this case, outperforms far more expensive DACs.    Note too that the analog inputs are NOT digitized -- this is a full function top quality line preamp that allows you to run a turntable in a full analog pathway.
Anything but an off-the-shelf solution, the DP-777SE includes several proprietary digital technologies developed by AMR.   This is the exact opposite of so many DACs that basically use off-the-shelf parts, and more importantly, software.  AMR does the hard work on the software side using proprietary decdoding technology.  Parts quality and build quality, which you might see from the pics, is off-the-charts, especially for a piece of this price.   In sum, it's a unique, superb sounding piece that can handle all your sources, digital and analog.  Buy this, and you are done with the front end of your system. 
Buyer pays shipping.  3% paypal charge/2.7 credit card
Below is the summary of upgrades from the stock 777 to the SE being sold here -- they are comprehensive and audible.   

777 Special Edition: Ground‐breaking technology

AMR is very proud to announce the launch of the 777 Special Edition or “SE” series. The SE series benefits from a raft of not evolutionary, but revolutionary revisions that take the sonic performance into a whole new realm.

The new changes are as follows:

1. AMR Tri‐Core Silver output capacitors

2. GE 5670 tubes (with adapters)

3. Quad‐Core Digital Engine*

4. Additional clock buffers to lower system’s intrinsic jitter even further*

5. Re‐optimised Clocking arrangement*

6. Latest XMOS interface with proprietary customised firmware*

7. Completely re‐designed 4‐layer gold‐plated circuits boards)

*For CD‐777 and DP‐777 only (not applicable to AM‐777)

The following is a detailed overview of each aspect of the 777 Special Edition features as compared to the previous standard production model.

1. AMR Tri‐Core Silver capacitors

Each and every capacitor will have a small range of frequency in which it operates optimally.Different frequency range requires different capacitors for the best performance. With the all new AMR Tri‐Core Silver capacitors, each capacitor is operated in its best environment to produce the best sound. Along with the silver wiring, its coverage and transparency is as close to the “no capacitor” principle as it gets.The high‐end normally practice is to parallel different capacitors – but all the capacitor share the same loads, AMR developed an unused topology which even spreads the load inside the tri‐core capacitor.

The upper frequency range is covered by a silver leaf capacitor. The mid‐range is covered bya film & foil electrolytic capacitor and the lower frequencies are covered by a polypropylenecapacitor. Just as important, they all work within their most optimal frequency range by sharing the load intelligently. Finally, all of the elements are casted in a natural wood body in a special resin for nil microphonics and a natural, organic tonality that is unsurpassed.

2. General Electric 5670 NOS valves

The 6922 tube family is ubiquitous. It is a mainstay of nearly every tubed‐product out thereand for very good reason; it has become one the most popular tubes. With AMR’s in‐depth tube knowledge, we have upped the ante and brought the GE5670 as a replacement for the venerable 6922.

The GE5670/2C51/WE396A/6N3 traces its roots back to its original design as the premium version of the 6922. Compared to its 6922 cousin, among other features, the 5670 has much tighter warm‐up, grid current, noise and microphony tolersances. There is just no comparison.

With these features, it comes as no surprise that the GE5670 “sounds heads and shoulders” above the 6922 family. Despite the same physical 9‐pin setup, the electrical configuration is different hence the 5670 family requires a specialist adapter which AMR developed from the ground‐up, commissioning a specialist mould to install the GE5670.

3. Quad‐Core Digital Engine

We have always been enamoured with the Multi‐bit chipsets as their technology reflects a“golden era” of digital design based upon sonic performance as opposed to profit.  With a Quad‐Core configuration of four Philips UDA1305AT Multi‐bit chipsets, the sonics arenow even deeper and richer with an inner resolution that is right up there with the very bestof an “analogue sound” that is startlingly close to vinyl.

Along with an all‐new Digital Engine design (see later features), the new Digital Engine iright at the edge of digital audio design.

4. Additional clock buffers

AMR’s digital is already renowned for its digital technology, and the SE takes it even further ahead with jitter that is now at the vanishing point. With state of the art digital design and implementation, the original DP‐777 already uses Femto seconds clocks that in its own special way, surpasses the very best industrial‐grade Femto clocks have to offer. Now with the SE version, we added a specially designed clock buffer for the Femto seconds clock, which further improves the performance of this state of the art design. This is the AMR difference, we start where others finish and push on, much further than what is thought possible.

5. Re‐optimised Clocking arrangement*

There is the XMOS USB platform and there is the AMR/iFi XMOS USB platform. Inside the XMOS, there is a radical “Star‐Clock” scheme in the AMR/iFi‐XMOS implementation. This is a major departure from the traditional “Daisy Chain” clocking scheme provided originally by XMOS which many others use.

Why? On the stock XMOS USB platform, we were not 100% happy with the overall jitter level, especially with high‐speed signals. Hence one of our senior software engineers, who has military defence programming experience, spent a few sleepless nights on the XMOS standard source code and discovered that the standard XMOS used a traditional “Daisy Chain” clocking scheme, which is perfectly fine for low‐speed audio signals, but not the best topology for high‐speed audio signals.  The reason he discovered this was he actually did his entire programming in Ada (yes, Ada) when he used to work for low‐level military projects. One of the reasons (of course there are many other reasons too) for doing the military stuff in Ada is because of the real‐time requirements (he was once working on a targeting system for an air‐to‐air missile!) So everything must be in real‐time and must have zero‐timing error. In other words, this guy is super “timing sensitive”.

After discovering this, he went on to redesign the whole clocking topology inside XMOS USB platform and utilised a “Star Clocking” scheme which he used before in the missile targeting system he was part of. To put this into an audio context, parallels can be drawn from theJVC “K2” mastering grade clocking scheme below:

Inside the customised iFi‐XMOS, just imagine “what if” all those internal XMOS software modules received their reference clocks from a single, ultra‐low jitter master clock? This is exactly what happens and improves the overall system jitter performance significantly and is easily audible.

6. Latest XMOS interface with proprietary customised firmware* AMR is one of the very manufacturers to write its own software to run with the hardware.  So in the case of the XMOS USB chipset, it was hand‐picked for its best performance but webrought it in‐house and our software development team analysed it down to the silicon‐die level and wrote a completely new program from there which optimises the latest 8‐Core XMOS chipset.

Traditionally for USB audio, the 6‐core chip is more than enough, however we are packing ina lot of extra features and XMOS internal clock optimisations hence the two extra cores are required. This is like a Dual‐Core versus a Single‐Core computer, no comparison when itcomes to benchmark tests and in use.

7. Completely re‐designed 4‐layer gold‐plated circuits boards)

All‐new 4‐layer PCB improves ground and PSU decoupling.  For example, X7R‐1210 and C0G‐1206/0603 capacitors improve PSU decoupling about 10‐100 times over Sanyo OS‐CON (which are already audiophile‐grade!). The C0G capacitors are Teflon/Polystyrene grade of performance and are used widely in the DP‐777 SE and backed by the very best option X7R capacitors for large capacitance ‐ theX7R 1210 types have around 100 times lower parasitic resistance than OS‐CON and are effective to well past 1MHz (OS‐CON drop out at 300KHz).

The original 777 design used X7R in place of C0G and Y5U where we now use X7R in a special format. Along with the previously outlined improved clock system, along with the more widespread use of SMD components, current loop distances have been halved (with 50%+ improvement in most cases).

Several years back, at the time of the development of the DP‐777, one could only get X7R insmall sizes and largish values, anything real big was electrolytic or Y5U.  By comparison OUR X7R cap's from TDK Japan are about equal to Mylar Film Cap's, but 10times smaller = 10 times shorter current loop, if applied with real attention to detail.  The exceptional parts count continues including ELNA Silmic Cap's for example.  What is the measured upshot of all this? Our decoupling system now is good to >> 100MHz,including 4‐layer PCB (using the PCB as capacitor) to > 1GHz  It just has to be measured to be believed.

Conclusion

What is the sonic summary of the 777 Special Edition?

Bass is deeper and more powerful, there is more air in the treble, background is darker with an overall improved resolution.  Sonically speaking, expect simply more, significantly more of what the original AM‐777, CD‐777 and DP‐777 all delivered in spades – pure, natural music that flows through your music system.