I have had the Kingrex T-20U for a few months now and so a post about this is long overdue.
The Kingrex has been around for sometime and has garnered a reputation for being one of the best sounding of the many low powered Tripath chip powered amps out there.
The designers of Kingrex must have paid careful attention to the many tricks that the DIY community were incorporating in Tripath amps as many of these tweaks and part changes can be found in the Kingrex such as :-
1. Film coupling caps
2. Premium air core inductors
3. Uprated low ESR local power supply caps
4. Heatsinked Tripath chip
5. Socketed op-amp for ease of opamp rolling (for the DAC only)
The icing on top of the cake is the Burr Brown PCM-2702E DAC with USB interface. Looks like this amp is clearly targetted at the PC audio crowd and you can say is perfect for powering small speakers on a computer desktop.
The T-20U is based on the Tripath TA-2020 chip which is capable of about 10-20 watts per channel into 4 Ohms (power varies depending on measured distortion level).
Rather than try to make this a detailed analysis of the circuit design and features of the T-20U, you would be better served to refer to the 6moons review on the T-20U at www.6moons.com/audioreviews/kingrex2/u.html
I didn't plump out for the matching linear power supply (hi-fi has a mysterious way of emptying the wallet ... so it has to wait for the time being), so any observation on the sound is based on the supplied switching power supply provided.
The Kingrex sounds like most other Tripath based amps. Quite similar in balance to my Trends TA-10.1, the Kingrex has a weighty and slightly full bass. I prefer Tripath bass compared to Icepower bass which is extremely tight and extended, to the point that I find the bass too prominent, attention grabbing and somewhat unnatural.
The midrange and high frequencies are fairly neutral and the slight lack of depth in the midrange and air in the high frequencies differentiate the Kingrex from its much more expensive competitors.
I don't do PC audio, so I did not have a chance to evaluate its USB input and DAC.
Keep the load easy (stick to a speaker between 4-8 Ohms and sensitivity of at least 89 db/w/m or higher) and the Kingrex represents a good value amp with clean and musical output that belies its price tag.
Comparison with my modded Trends TA-10.1 were most interesting. My Trends amp is moderately modified, with the following changes made :-
1. Coupling caps changed from Bennic metalised polypropylene to Auricap
2. Stock volume control changed to Panasonic miniature pot
3. Inductors shielded with copper
4. PCB tracks cut for direct wiring from RCA input to pot and back to coupling caps
The Trends was clearly better in every aspect and was also much cheaper to start off with. Sound was clearer and more coherent with low level resolution superior to the Kingrex.
I don't think this means that the Kingrex is a bad buy. However, it indicates that a stock standard T-amp (check out the many cheap T-amps on ebay nowadays) is capable of performing just as well, or even better than the Kingrex with some judicious modding.
The Kingrex is therefore suitable for the audiophile who does not have the desire or ability to mod the unit, or one who attaches a premium to the professional finished look of the Kingrex.
Saturday, September 19, 2009
Thursday, September 17, 2009
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.
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.
Thursday, August 13, 2009
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 ?
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 ?
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