Graham had always preferred the sound of a good analogue source (turntable) to the digital sources with the most illuminating musical performances. For years the concept of improving the performance of a digital source remained a nagging thought in the back of Graham’s mind. What was missing in the conversion of music into digital information, and how could Graham build a solution that did the music justice? The answer could be found in the reverse of this process, the reassembly of the digital signal back into analogue; putting all the pieces back together as music not data. It was clear after listening to all the top high-end CD players over the years that to achieve superlative performance in the digital domain, pretty radical things needed to be done. Basically this involved throwing away the CD red book standard and designing for maximum audio performance without adding or taking anything away. Designing a CD player/DAC to measure to red book standards ironically actually makes it sound poor. It took many years of development and a lot of discussion with digital engineers to solve some of the more fundamental problems of musical integrity that digital reproduction can ultimately lack. The final results are spectacular, as one customer summarised it “this sounds more analogue than any other CD system I have heard, but what I actually mean is more musical and less digitally contrived.”
The Seven DAC uses a “state of the art” 16 bit chip. There is no up-sampling, no over-sampling and no digital filter. In other words all the things that interfere and degrade the original 16 bit data stream are removed so the original data is preserved. This is then fed to a really elegant class A tube output stage. Digital replay really doesn’t get any better than this.
Inputs: 1 RCA input SPDIF & 1 XLR AES/EBU – USB to order.
Outputs: 1 RCA Phono output (L & R).
Valve Complement: 2 × 6072 (low noise).
Frequency Response: 5Hz–37.5kHz ± 3dB.
Output Impedance: <1000 Ohms
Mains Supply: 115–240 volts AC (50–60Hz). Earth lift included.
Power Consumption: Nominal 12 watts
Dimensions (mm): 450w × 103h × 335d
Weight: 8kg (net)
Warranty: 2 years (parts and labour)
The Seven DAC can be upgraded to the Reference specification to further improve the musical performance from your valuable record collection. Graham painstakingly sources truly unique resistors that in such a simple circuit really bring out a richer and more intimate performance from the artist. We also upgraded the capacitors to a custom specification to work in harmony with the improved resistors; as in most development activities changing one thing in isolation hardly ever results in a balanced improvement. Graham says “it never ceases to amaze me how improving one component can impact the music in such a significant way, and also how long it takes to find the right combination to retain true harmony.”
The Ultimate is the last but one step towards analogue perfection, and involves the use of solid silver wiring throughout the critical signal path, and silver interstage transformers. Silver as a conductor has the advantage of a more revealing and transparent reproduction of the music, however care needs to be taken to ensure that this is delivered in a complete and unified manner as sections of silver in a component in isolation rarely provide a benefit. Finding the right dielectric (insulation) for the cables is also critical to extract the best from this expensive material. Graham has also redesigned and built a more significant power supply that is unique to audio, which has the effect of making silences darker and dynamic shifts in the music more dramatic. The result is a little like cleaning your windows; you did not necessarily notice they were blocking any light, until afterwards.
The Seven GT DAC is the final step towards digital to analogue perfection, and involves the use of a completely new power supply circuit for all the critical stages. Graham says this power supply was 5 years in the making and makes a huge improvement in fidelity taking the Seven GT DAC to one of the finest performing DAC’s ever made.