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Archive: Plinius 2.4 mk2

By Charles Thomson

June 2009 (originally appeared February 1990)

Plinius 2.4 preamplifier. $950 in 1990 ($1340 with 4B power supply)

The Plinius 2.4 during the company's "red lettering" phase. This example may be a mark one preamplifier.

Inside the Plinius 2.4

Going back through my notes I was surprised to find that it is nearly two years since the Plinius 2.4 Preamp was connected to my system. This came about because the product under review at the time was the Plinius 3100 power amp and I wanted to hear how the two units worked together, so while the 2.4 was not the object under review, I did make notes pertaining to its performance. Little did I realise then that they would be of use many months later when reviewing the Mark 2 version.

Questioning upgrades

A question which often comes to mind relating to hi-fi products is whether or not there really is a worthwhile improvement in sound quality between the old and new versions. Sometimes the only differences are a redesigned front panel or more features added – neither of which improve sound quality. In the case of the Plinius 2.4 this certainly isn’t the case. Visually one cannot tell the difference between them. The Mark 2 doesn’t even have Mk 2 featured on the front panel.

For those not familiar with the appearance of the Plinius 2.4 it is a black box measuring 435mm x 200mm x 58mm with a pilot light, four rotary knobs and two push buttons on the front. The overall visual effect is neat, elegant and functional. Rotary knobs are provided for line switching (CD, Tuner, Lines 1 and 2) volume and two for balance (one for each channel). The push buttons select source/monitor and phono/line. On the rear panel there are nine sets of gold plated phono sockets. These provide inputs for phono, CD, tuner, Lines 1 and 2 and outputs for tape monitor, tape out and main out. The ninth pair of sockets accept loading plugs for matching a phono cartridge to the amp. A ground terminal for phono, a switch to change the gain from moving magnet to moving coil and a socket for the power supply complete the picture.

The 4B power supply is a small black box 175mm x 180mm x 58mm with an on/off switch and pilot light on the front. Rear panel features nothing more than the mains power cord, fuse holder and the power output socket.

Many pieces of audio equipment threaten the voiding of guarantees should the owner dare to look inside. Plinius adopts a much more liberal attitude, in fact encourages one to take the cover off - after the plug has been removed from the mains of course. This is not an invitation to tinker as there are no consumer serviceable operations to be performed, but an invitation to admire the simplicity of layout and the obvious build quality.

Here is a manufacturer who is proud of his product. Even if you don’t understand electronics, you will be impressed with the tidy appearance – no rats nest of wires inside this unit The more knowledgeable will recognise good quality components and a high standard of workmanship.

Install and initial listening

Owing to the clear identification on the rear panel and a well written instruction sheet, installation of the 2.4 and 4B is a simple matter. One may need help from the dealer in providing the correct loading plugs, but only if the requirements of your cartridge is other than the common 47kohms.

Listening first to CD – Opus 3’s Test Disc No.1, I was most impressed. This disc is designed to test depth of image and the 2.4 performed well in this respect. On one track which features a Symphonic Band, solo instruments fall into perspective with the piccolo on the front right, the trombone further back and the bassoon about as far back but on the left hand side. The music was a Polka from the Bolt by Shostakovich.

Returning to discs which I had listened to on the original 2.4 confirmed my impressions that the Mk 2’s line stage is a definite improvement, particularly in the areas of space and depth.

Overall clarity is improved as was demonstrated when listening to massed voices on the Philips recording of Hadyn’s Nelson Mass. My earlier notes recorded that words were indistinct and that voices often became confused with the orchestra. The Mk 2 was now allowing me to hear the words. Another CD that had earlier been slightly disappointing was Beethoven’s Piano Sonata Op 57, recorded by Delos. Here the Bosendorfer Imperial concert grand piano had sounded overblown and murky - notes tended to run together. Now I was listening to the Bosendorfer displaying its enormous power with notes starting and stopping as they should. It was as though a curtain had been removed from in front of the speakers.

Other CD’s that followed included selections of jazz by the Dutch Swing College Band and tracks from Van Morrison and Clannad all displayed the improvements noted above.

Changing to the other line inputs and using both tape cassettes and hi-fi video confirmed that the Mk2 offers an improved line stage. With regard to sound quality, bass displayed good attack and detail. It was only when the depths were reached that it became more difficult to determine what instrument was playing. Midrange was clean and uncoloured. Coupled with a treble that was never excessive or harsh the 2.4 proved to be easy to listen to. Sound was relatively uncoloured and certainly non-fatiguing.

Listening to black discs

Changing to phono proved, in comparison, somewhat of a disappointment. Having become used to the improvement offered by the Mk2’s line stage I was obviously expecting the same from LP. Don’t get me wrong, the phono stage is not bad, but its improvement was only slight compared with my recollections of the original 2.4.

For its asking price, the 2.4’s phono stage is exceptional- it beats many preamps I have heard which are up to four times more expensive. But it is not in the same league as the line stage.

Research showed that the phono stage is the same in both versions, which made me wonder why I felt that it was improved even if slightly. Where I felt it was better as in the areas of space and dynamics. Bass had more clout, orchestral crescendo’s were reached more effortlessly and there was a wider spread to the sound stage.

4B or not 4B

After much thought I began to wonder about the effect of the power supply. Bear in mind my original experience with the 2.4 was when it was driven by the internal power supply provided by a 3100 power amp. With the aid of a neighbour who has a 3100/2.4MkI, I was able to confirm that the dedicated 4B power supply offered improvement to whichever model preamp it was coupled to. It didn’t bring the Mk1 up to the Mk 2’s performance on line stages but the improvement I had noted in the phono stage was certainly present.

Conversely, when the Mk2 was driven by the 3100’s power supply there was a noticeable down grading in clarity, depth and dynamics on line inputs. These experiments were of help when it came time to write the conclusion to this review. The only problem with all this is that said neighbour is begging Santa to put a 4B in his Xmas stocking, and for his birthday wants his Mk1 upgraded to Mk2 status.

One of the policies of our editor is that reviewers must listen to any item they are reviewing in at least two different systems so that 2.4 Mk 2/4B was removed from Audio Research Classic 60, Magnaplanar MG3, Sony 557 and Roksan Xerxes etc setup in my lounge and installed at a friends home. Equipment here included B&W 801’s, Plinius Class A monoblocks and a Mission CD player.

This was an interesting comparison, as being a CD only system no preamp is normally in use (the Mission player has a variable output). The most noticeable aspect here of the 2.4 was that it added very little to the sound other than a slight loss of detail. Even the addition of a well-known passive preamp tried previously changed the sound quality noticeably - particularly in the area of clarity.

Conclusion

There is no doubt in my mind that the 2.4 Mk 2 offers a considerable improvement in its line stages over the Mid. Owners of original 2.4’s need not weep nor gnash their teeth lifter reading this review as an upgrade service is available which will bring their Mk1’s up to Mk2 standard for $150 + freight cost + GST. I also believe that for those driving their 2.4’s with a Plinius 3100 or 3200 power amplifier the purchase of a 4B power supply ($345) is recommended.

One aspect of the 2.4 Mk 2 that deserves the highest praise is that its line stages add little to the sound – this is as it should be. Added colouration from a hi-fi component is definitely not desirable. In a well balanced system of comparatively priced components both line and phono stages will perform above expectation. However the temptation will be to use the 2.4 with far more expensive components than would normally be the case, based on the performance available from the line stage.

For the asking price of $950 (when powered by a Plinius power amplifier; $1340 with 4B power supply), the 2.4 Mk2 is a must to audition by anyone looking for a good sounding, well built, five year guaranteed preamp. But do yourself a favour and couple it to the 4B power supply.

Well done Plinius – another New Zealand product to be proud of.

Do you have any better images of this model? Please contact the editor.