Diva Audio M7 Preamp - Latest update

For all you Diva Audio M7 users out there, T.S. Lim has just revised his flagship M7 preamp.



The latest revision combines two stages of modifications.

The first stage involves new voltage supply filtering on both the B+ and the heater, combined with star ground wiring arrangement.

The second stage is a rewiring of the tube arrangement to allow easier tube rolling, and the installation of a new internal bracket that allows higher quality smoothing capacitors to be installed.



More on the tube rolling - previously the tube stages in the M7 are arranged as follows, the bottom tube uses one triode (the 12ax7 is a dual triode) as first stage, and the other triode as the second stage of the left channel. The top tube is identical and is used for the right channel. This then passes through the third stage in the middle tube (one triode for each channel). This means that you can only roll two different type of tubes at the most since the first and second stage use the same tube.



The M7 is now wired with each stage using one triode in the tube, i.e. the bottom tube is the first stage, the middle tube is the second stage and the top tube is the third stage. Now you can roll tubes to your heart's content.

Anyway, enough talk about the technicals. How does it sound ? I only managed to put in an hour of listening before sleeping but here are my initial thoughts on the latest incarnation of the M7 :-

1. Resolution - There is a noticeable increase in low level resolution and background "blackness". For example, on guitar notes, you can hear more of the body resonance of the guitar instead of just the plucked strings. Even in loud and complex passages, the increased level of detail is obvious.

2. Bass - Bass is substantial with more depth and extension.

3. Soundstaging - More 3D like with an noticeable increased in soundstage depth. Image sizes also are slightly larger.

4. Dynamics - The dynamic contrast between the loudest and softest passages is increased. Interestingly even at very high volumes, the dynamics are realistic and never fatiguing.

Note that my M7 uses a vintage military choke and NOS silver plated internal wiring. The volume pot is the standard Alps blue model though.

Oh yes, most importantly, T.S. Lim is offering this upgrade to existing M7 users for S$ 700. If you have already done the voltage filter and star ground, then the cost is S$300.

If you take this as an unreserved recommendation to upgrade your M7, you are not wrong. I highly recommend this upgrade. In current times when sought after NOS 12AX7 has reached silly money levels, this is money well spent.

Acrolink 2070II

The Acrolink 2070II is the junior member of the 7N interconnect range of Acrolink of Japan.

I had earlier written about the 2400II which is the top of the range of the 6N interconnect range. An opportunity arose to acquire the 2070II at a decent price and I took it without hesitation. I have actually heard the 2070II before briefly at Audio Basic in Adelphi but did not want to consider it due to its considerable expense.

Physically, the 2070II and 2400II are quite similar in that they have a transparent outer insulation layer which shows off a metal braid shield underneath. Both utilize extremely bad and mean (I mean that in a complimentary way) looking RCA plugs that looks like they can be worn as hi-fi bling bling. Sporting carbon fiber bodies and rhodium plated pins, they certainly look the price and exude class.

The 2070II is physically larger and substantially heavier than the 2400II and its RCA plugs are quite large (and actually too close for comfort on tightly spaced RCA sockets). Owners of light weight T-amps beware, your cable will probably end up pulling down the amp if you are not careful. To its credit, the cable itself is relatively flexible. On an utterly trivial and sonically unimportant note, the 2070II comes is a beautiful wood presentation box that was stunning enough to lead my partner to hint that the box was perfect to store her jewelry in.

If you refer to my earlier posts, Acrolink cables have a house sound. Generally detailed, they have extended high frequencies and an overall airy feel to them. The 2070II does not disappoint in this respect. The 2070II differs from the 2400II in the following areas,

1. Bass – Most of the Acrolink cables I have heard are bass light or appear to be bass light due to their emphasis on the high frequency end. The 2070II does not suffer from this at all and has firm and tight bass with appreciable heft compared to the 2400II.

2. Midrange – The 2070II has less forward midrange projection compared to the 2400II. It sounds more mellow in comparison. Also, the midrange has a highly textured feel to it with fine nuances and changes in timbre clearly audible. The 2400II is like sitting a few rows closer with the midrange more 2-D like.

3. Treble – No surprises here. The 2070II continues in the Acrolink tradition of delivering the most beautiful shimmering highs with excellent communication of acoustic space of instruments and the venue. The extra expense here gets you even more refined treble with composure even in the most complex of mixes.

One interesting characteristic of the 2070II is the absolute blackness and quietness of the cable, as well as the sheer amount of micro-detail available. The 2070II in my humble opinion is a significant upgrade over the 2400II although it is quite obviously intended only for fairly high end set-ups given its cost. I like this cable very much. One reservation I have in general is that there is a nagging feel that what is being conveyed is not the truth, but rather than the manufacturer’s artistic impression on what music should sound like. Seriously though, if its artistic viewpoint is this much fun and musically satisfying, why not ?

B&W 804S Floorstanding Speakers

I recently had the opportunity to build a system around the B&W 804S for a non-audiophile family setting up their first serious system.

They were brought around to audition a number of speakers, before they settled for the B&W.

For those unfamiliar with the B&W 804S, it is the smallest (its actually quite big physically) floorstanding speaker in B&W's 800 series line-up. At approximately double the price of the stand mount 805, the 804 has 4 drivers in a boat shaped cabinet with front firing port. Its a 3 way design with a Nautilus tweeter mounted on top of the cabinet.

On the rear, bi-wiring terminals are provided and jumper cables (not stupid brass links) with one end intelligently terminated with spades and the other with banana plugs, thereby ensuring compatability with cables terminated with either spade or banana plugs. Why can't all manufacturers do this ?

The B&W was heard twice in two different dealers. Pairing equipment included an all Arcam setup, Classe amplification and CD players and an all Cyrus setup. The B&W sounded very different through each of the three systems set up for demonstration purposes, suggesting that it is quite sensitive to matching with partnering equipment. Tonal balance wise, it managed to sound bright and fast with one setup and rich and somewhat slow on another.

Eventually, the 804 was paired with a Bel Canto S-300i. The combination is quite nice with very good grip and control over the lower registers and a neutral midrange tonal balance. The high frequencies manages to be extended with a fair bit of sparkle coupled with slightly rich bass. So who says your speaker can't sound clear and clean, while being weighty too ?

The B&W is versatile enough to handle varied music types with aplomb. Classical works, female vocals, jazz, rock and pop doesn't faze the 804 one bit. What I like about the 804 is that the presentation is not overly analytical. It doesn't stress out the owner by limiting him to a diet of audiophile recordings. Neither is it so non transparent that good ancillaries are wasted on it. A speaker of all seasons, it has enough qualities to please the hard core audiophile while being easy going enough to suit the casual listener.

One issue though is the local pricing in Singapore. This speaker retails for more than USD 5,000 (at today's exchange rates of about SGD 1.46 to USD 1.00) which puts it in serious speaker territory. There is a lot of quality competition at that price range, some of which are to my ears preferable to me compared to the 804. But I do digress. The 804 still warrants serious consideration, so do check it out if its in your budget range.