Amp/Preamp Asylum: REVIEW: Plinius SA250 IV Amplifier (SS) by mark

Model:	SA250 IV
Category:	Amplifier (SS)
Suggested Retail Price:	$8000
Description:	Class A/B or class A 250 watt amp
Manufacturer URL:	Plinius
Model Picture:	View

Review by mark_nz ( A ) on July 02, 2003 at 21:08:00
IP Address: 203.97.2.243

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for the SA250 IV

I have owned the SA250MK4 for just over year. It replaced a SA100MK3 that I also owned for about a year.
I have not taken advantage of the SA250MKIV update (no charge for modification, but transport at ownerâ€™s cost.) Apparently the update is a minor modification that reduces the overall distortion further and is mostly noticeable in the treble. This review is therefore without the advantage of this update.
The SA250MK4 is rated at 250W per channel while the SA100MK3 is rated at 100W. Both seem to have conservative ratings and are capable of higher output.
One unique feature is the class A/AB mode switch, which allows the amplifier to be used for casual listening in class AB mode without the penalty of heat and power consumption required for class A mode. There is also a Mute switch that disconnects the input that allows for cable changes. The SA250MK4 takes this a step further by also disconnecting the speaker outputs.
Despite the comments from one magazine review, the class A/AB switch is an excellent option that allows casual listening without unnecessary power consumption and heat generation associated with class A mode. The most important advantage for me is that in conjunction with the mute option, the amplifier can be left on for extended periods that reduce the warm-up period.
I upgraded to the SA250MK4 without comparing it to the SA100MK3 since I trusted the advice of the local retailer (The Listening Post in Hamilton, New Zealand â€“ great service). I also wanted the silver finish instead of the black finish on the Plinius SA100MK3. Both finishes look great, but I do find the silver looks less imposing and better matches my other components that are mostly gold finished.
I was not disappointed with the sound quality improvement; in every respect the SA250MK4 was an improvement over the SA100MK3. The bass - perhaps a touch more depth, midrange - a bit more transparency, but it was the treble range where the SA250MK4 vanquished a small but persistent edge that SA100MK3 never quite lost even in class A mode.
The SA100MK3 was a great amplifier and gave me my first real taste of high-end sound. I never found its power lacking, but then again I only used it on the bookshelf speakers B&W CDM1NT and Jamo D830 (Concert 8). It will still make a good second hand buy.
But I am sensitive to treble quality and hence the SA250MK4 additional refinement was worth the price of admission.
As with the SA100MK3, the bass quality is superb, deep, but with depth and precision. The Jamo D830 has amazing deep bass for a bookshelf speaker (difficult to believe until you hear it).
While it possible to identify the SA100MK3 sound signature due to the small change in quality from the smooth midrange to the slightly sharper treble, the sound signature of the SA250MK4 is elusive. Every time I thought I nailed it, a change of another component, room acoustic treatment or music selection left the SA250MK4 as the most neutral component in my system. The only time an obvious sound signature can be identified is just after switching from class AB to class A mode, the sound is initially a bit thick, but then slowly loosens up until an hour later it is fast and responsive.
Again, despite some comments in reviews to the contrary, there is a big difference between class AB and class A modes. Anybody that listens to a fully warmed up SA250MK4 in class A mode for a few minutes, and then switches to class AB mode will notice the significant diminishing of the image body and tonal quality. It is bit like the difference between LP and CD tonal quality when I have done the rare comparison. But despite the difference, the class AB mode is still very good, and unless ones does the direct comparison, most folks will wonder the all the fuss is about class A.
One aspect of the Plinius SA250MK4 performance that is very important to me is the excellent sound quality at low volumes. I listen often late in the night and it is critical for me to enjoy the sound at low volumes without waking up the kids. This is one amplifier where it does not need be cranked up to make it come alive. This was an unexpected improvement over the SA100MK3, anecdotal evidence normally favours less powerful amplifier. Please note that this also implies that the speakers need to perform well at low volumes. The Jamo D830 is rare in its ability to maintain tonal balance and depth at low volume.
I haven't done any direct comparisons to equivalent amplifiers, but have had the following in my system for a significant time to make some useful comparisons.
Marantz PS17SA: Surprisingly good AV amplifier - warm, musical and more powerful than the 60W specification will lead you to believe. It is suppose to use the same amplifier technology as the SM17SA, but to my ears sounds slightly different. The PS17SA is used with the TAP9000ES connecting directly to the amplifier, bypassing internal preamplifier and DSP processing. In comparison, the SA250MK4 (class A mode) is a bit more smoother, more neutral, slightly tighter control of bass, but it is the treble quality where the Plinius is really outshines the Marantz in being that more extended but without the a bit of edge that seems to haunt most class AB solid state amplifiers. Put the Plinius in class AB mode, and the differences are much smaller - the most significant difference being in the favour of the Plinius feeling of effortlessness power. One area where Marantz did seem to seem edge the Plinius was the impression of speed. I donâ€™t know whether this is due to inherent advantage that a smaller amplifier has (less power supply reserve, therefore can respond more quickly to transients) or the slight edge in the treble. This was only noticed on simple music compositions, but when the music became more complex with many layers of instruments, the Plinius seem to hold the performance together a bit better. The most important aspect of both the Marantz and Plinius is that they will both be enjoyed equally well by the music lover, though the audiophile will appreciate the additional virtues of the Plinius amplifier.
Gainclone: Had find out what the hype was about. Built one based on the LM3886 chip with good quality components in an aluminium case. Sorry, it is not the Goliath slayer that some are hoping for. While it sounds surprisingly good, I found both the Marantz and Plinius more musical, in particular both had more harmonic richness in the critical midrange. While the Gainclone sounded good at low volumes, it absolutely fell apart at high volumes. To be fair I was only using one chip unlike the paralleled versions used by some commercial amplifiers. Where the Gainclone excelled was it's amazingly low noise floor - the quietest amplifier I ever had in my system. I can imagine that this virtue would be very important for efficient loudspeakers. This amplifier did show that there are possible further gains to be made with the Plinius design by lowering the noise floor, though this was not an issue for my loudspeakers.
In conclusion, this has been the most consistently neutral performing component I have had in my system. It favours no music style. It is sufficiently transparent to show up any flaws in other parts of my system. Interestly for someone that has the persistent upgrade bug, the SA250MK4 is the component I feel least likely to change. But because I am changing my system to cater for multi-channel music, I am planning to replace the SA250MK4 with a pair of Plinius SA102 (I will also check out the new Odeon), only because I cannot accommodate a pair of SA250MK4.
The Company
Both the principal owners (Peter Thomson and Gary Morrison) have taken the time to personally answer my queries. I also appreciate that the company has offered an update that will effectively maintain oneâ€™s investment.
Wish List
* I will always wonder what a special edition of the Plinius amplifier design with the best quality components (e.g. Gold Tune Nichicon or Black Gate capacitors, Vishay resistors etc) and fully regulated power supply (as used in new Krell amplifiers) will sound like.
* Three-position class mode switch that provides half way class A mode for late night listening at low volume.
* It would be nice for New Zealand to get a transferable warranty like the States, though I have always been assured that any problems will be resolved by Plinius. This was important when I owned the SA100MK3 which I bought secondhand. (On the other hand I am immensely grateful for the reasonable local prices that has allowed me to own one of best amplifiers.)

Product Weakness: * Mmmh, only thing that really annoys me is that I have to ask for help in moving it about because of the size and weight.
* Some mechanical transformer noise.
Product Strengths: * Effortless power.
* Transparent, but without the edge that afflicts most solid-state amplifiers
* Neutral, no significant sonic signature
* Sounds equally good at low and high volume with no obvious tonal shifts
* Looks stunning in silver, mechanically very well built.
* Class A/AB switch is a very useful option.
* Mute switch that turns off both the input and outputs that in conjunction with the class AB mode allows amplifier to be safely left in standby mode.
* Power and mode LEDs brightness can be adjusted.
* Amazing value in New Zealand (at least half the price of any comparable amplifier).
* Reliable - no issues with both the SA100MKIII and SA250MKIV

Associated Equipment for this Review:
Amplifier:	Plinius 250MKIV, Marantz PS17SA, Gainclone
Preamplifier (or None if Integrated):	Sony TAP-9000ES, Proceed PAV
Sources (CDP/Turntable):	Sony SCD-777ES, Sony CDP-XA555ES (re-clocked)
Speakers:	Jamo D830 (formerly known as Concert 8)
Cables/Interconnects:	Kimber Interconnects, Audiotruth/Audioquest Forest Speaker cables, WBT connectors
Music Used (Genre/Selections):	Pop, Jazz, Classic
Room Size (LxWxH):	4.5m x 6m x 2.3m
Room Comments/Treatments:	Some DIY Absorption Panels
Time Period/Length of Audition:	1 year
Other (Power Conditioner etc.):	DIY Surge protection and capacitor noise filtering
Type of Audition/Review:	Product Owner