Could this be the new Killer, reasonably priced DAC?

[morris_minor]

I think an Inca-Yellow Morris Minor is even more exciting

I trust you're not casting aspersions at my wheels? It has an external power supply, tuned thrust bearings and micro-dynamic resonance absorption.

Or to put it in anti-snake-oil terminology: some mates to push-start it, a clutch from a scrappy, and a lounge cushion on the driving seat.

[Paul Hynes]

I have decided to order the quad version to get a flavour of the sound quality produced by the design.

I would not write off NOS dacs by what you have heard so far as most of the digital products I have seen, NOS or otherwise, have severely limited performance due to inadequate power supplies. Many high-end manufactures are still using industrial three terminal regulators that are unable to keep up with the load current changes caused by high-speed digital circuitry. Most of these industrial regulators have stopped regulating by the time the load frequency reaches 10 MHz allowing the power lines to fluctuate in time with the data stream and local decoupling capacitance and ground planes do not address this problem.

As an example, I use an Altmann Attraction DAC in my system, which is a NOS dac. Out of the box (no pun intended for those who are familiar with the DAC) the Altmann shows good musical performance. Once the on-board three terminal regulators are replaced with high-speed regulation modules and the master power supply is upgraded with separate pre-regulation and master supply for each signal stage that requires a regulated voltage, the DAC is in a totally different league capable of excellent musical performance. This technique works for all types of DAC, not just NOS, but until a power supply like this is applied, there is no way you will be able to hear what a DAC topology is capable of. Out of interest it also works with analogue signal stages too.

Also Vertex have merged NOS DAC technology with their own RFI and vibration control treatments, high quality materials and my regulator designs to produce a DAC that is at the highest level of musical performance.

The Metrum DAC concept interests me because I did some work on analogue to digital and digital to analogue conversion in the 1980’s as the research director for OmniPhonics Research. This was in the early period of sampling instrument design and we were investigating the use of the IMS Transputer CPU (forerunner of the Pentium and another good idea the UK let go abroad). Part of the design brief was to enable high fidelity sampling and playback as well as pitch shifting of the recorded sounds effectively providing a high fidelity musical instrument. It soon became obvious that any attempt to achieve high fidelity required high speed digital signal processing and conversion. The available ADCs and DACs at the time were just not fast enough and showed poor settling time. The conclusion was that the design would have to wait until technology reached the level of at least 500 KHz, preferably 1 MHz conversion rates to give the required fidelity for the project.

It looks like the Metrum DAC has made it in the speed stakes although it remains to be seen if it will give me the musical performance I am looking for in my system. With high DAC speeds there is no longer any need to mess with over-sampling/up-sampling and high speed bit perfect data processing becomes possible.

No doubt I will be voiding my warranty pretty soon and upgrading the regulators and power supply to really make it sing.

I will report back once I have received the Metrum DAC and had chance to assess how well it works.

Regards
Paul

[Welder]

Do you have a suitable power supply in production Paul?

In theory as I mentioned, I would prefer a Dac that neither up-samples, nor over-samples; (never quite sure what manufacturers mean when choosing one description over the other) It seems to vary from manufacturer to manufacturer.

[Paul Hynes]

I do not have a specific power supply in production for the Metrum Dacs yet, but that can be arranged.

I get a little concerned when people start manipulating digital data streams with their version of what they think is perfect. The up-sampling/over-sampling solutions are only there to try and provide an answer to limited processing rates of generally available chips. Unfortunately the industry has a habit of throwing the baby out with the bathwater in the guise of new technology. Instead of solving problems they stick a plaster on the wound.

There is a lot of development work going on to progress the state of the art with digital signal processing and I think we are about to see dome radical breakthroughs in the chip design and implementation in the near future. The successful designs, as well as considering the data processing requirements, will consider the power supply much more thoroughly than has been done historically.

Regards
Paul

[Welder]

Let us know what you think about the Dac Paul

I’ve been largely unimpressed by the “this months rave” Dacs I’ve heard; its not that they sound bad, just not noticeably better than their predecessors.
It seems that greater bit depth and frequency handling is the current goal for many manufacturers. I would rather see better output stages and improved power supplies.

Any reason for picking the Quad model over the Octave other than the Octave comes with PS?

[Paul Hynes]

John,

Will post once I have some burn-in on the DAC.

I have to agree with you about “this months rave”. There is usually some new and radical chip, application or technique being touted as the answer to all our prayers but often little substance to the claims for improved musical performance, and, whilst the equipment in question may sound different, in some ways quite noticeably, it doesn’t necessarily advance the art of music reproduction.

There also seems to be a tendency for manufacturers to use tried and tested textbook application to enable rapid product placement in the market. This leaves little room for products that can stand out from the crowd. The accountant usually has his say too so the budget may be quite limited.

I picked the Quad version because I did not want to purchase a power supply that I would never use. I mean no disrespect to Metrum with this comment but I only use my own custom designed transformers in my system. The Metrum designer has stated that his intention was to provide a high level of performance at a cost effective price. Fitting a large high performance transformer would require a larger case and the combined cost penalty of this action would add considerable cost the Metrum DAC pushing it out of reach for many. The Metrum transformers are quire good actually and are about the best of the “off the shelf” budget toroidal transformers currently available. I use this range in my budget products as they are manufactured with materials of a good quality standard and are relatively quiet in their smaller sizes (below 80 VA).

Both the Quad and the Octave appear to be using the same DAC chips and interface topology, so I am assuming, rightly or wrongly, that the sonic signature will be similar. This sonic signature is what I am looking for initially, and if the Quad provides what I am looking for, and the word on the street is that the Octave is a worthwhile upgrade, I may well get an Octave and sell the Quad on.

Regards
Paul

[morris_minor]

My Octave has arrived . . .

http://theartofsound.net/forum/showthread.php?t=15182

[Paul Hynes]

Hello Bob,

Nice to see some positive comments about the Octave. It sounds like it could be what I am looking for as an improvement over my Altmann Atraction DAC. I have ordered the Quad version, minus the power supply as I already have one of my custom built transformers ready for power supply duty.

It will be a while before mine arrives and I will await delivery with keen anticipation.

Do let us know how the burn-in proceeds.

Regards
Paul

[morris_minor]

Hi Paul,

Yes - I'll certainly post some more thoughts in a while!

Of course the problem is that my findings, with my kit, might not necessarily be replicated for others. I guess it's the conundrum at the heart of writing about sound, and hifi in particular. Hopefully as the Metrum gets more widely used other opinions or reviews will surface, and maybe a consensus view will emerge?

But I'm certainly very happy with it at the moment! In fact a good week all round since Richard from Vantage brought back my serviced SL7 this morning and I decided to start running in my Jico SAS stylus for the Technics P22 I have. That, too, sounds pretty darn good

B

[oldson]

what happened to this thread?