We loved the Trilogy Audio Systems 907 phono stage when we tested it in issue 85. But it is a bit ‘spendy’. So when we saw the 931 headphone amp (a stripped down version of Trilogy’s top 933 model), we hoped there might be something smaller, lighter and cheaper than the 907 in the pipeline.
There was, and it’s called the 906. Trilogy doesn’t really go in for funky names.
As with the 931 headphone amplifier, the 906 phono stage incorporates a lot of what goes into its bigger brother, but in a single chassis. There is a likely a performance boost in going for the original 907 model (enough to justify the £1,000 price differential), but the 906 never once sounds ‘cheaper’.
Trilogy came up with a smaller, simpler chassis in the 931 headphone amp, and the same casework is used here. This not only keeps cost down, but includes a folded top and side plate that allows the 906 phono stage to come in one of at least three colour accents; silver as standard, dark grey (Nero Carbonio), and a fetching shade of mid blue (Mediterraneo Blue) as standard options, and a wealth of colour options to special order under Trilogy’s ‘Chameleon’ paint finish system. The standard three finishes match – and two contrast – the silver of the front panel and side cheek.
The 906 is extremely configurable, although it eschews the ‘on-the-fly’ adjustment of models like the Cyrus Phono Signature. Instead, a six pole block of tiny DIP switches on the baseplate of the unit can be used to adjust the phono stage. The first switch in line moves between moving magnet and moving coil. The second and third adjust capacitance, while the last three alter the resistance setting. Notionally at least, you could adjust these while the 906 is still connected to the power, as long as you mute the input of the amp to which the phono stage is connected. In reality, you will probably power it down, adjust, and power it up again. The switches do allow a surprisingly wide range of load settings, but unless you are in the habit of playing ‘guess the capacitance’, you are best served consulting the manual.
There’s arguably not much more you can put on a phono stage at this level, but the 906 is minimal in the extreme. There’s a power light on the front. End of paragraph! If you want a phono stage that can switch between cartridges, support a wide range of pre-RIAA curves, includes legacy rumble filters, and the rest, this isn’t your phono stage. As I said, there’s a power light on the front.
It’s under the covers where the 906 shines. Its signal path is free from cheap, off-the-shelf op-amp integrated circuits. The gain stages are single-ended Class A and fully discrete. Despite being the baby of the Trilogy phono line, each component has been chosen purely for its audio performance. The integral low noise, linear power supply sports a custom-designed transformer and quality branded reservoir capacitors. As you might expect from a designer who spends half his time making high-grade power products under the ISOL-8 banner, there are no generic, electrically noisy, switching wall-warts power supplies here.
The development of Trilogy’s hybrid power amplifiers also leaves its mark on the 906, as the power supply rails are shunt regulated. Although this means the component count is higher than the more common (and relatively inexpensive) series regulator IC solution, their performance is far superior because they can sink as well as source current to the active circuits. This crucial difference gives the 906 superior transient response. A DC servo eliminates the need for large value output capacitors, bringing further performance gains.
The 906 uses active current sources and cascode gain blocks with zero global feedback. Its RIAA equalisation is passive, which means it needs to be carefully implemented with precision components. This increases the overall cost of the 906, but in placing all the electronics in one box, and slimming down relatively out-of-harm’s-way circuitry, the 906 manages to retain much of the performance of its bigger brother, while saving a lot of money for the listener.
There is little in the way of warm-up required for the 906. Yes, it does improve over time, and if you leave the phono stage powered up constantly, the sound is noticeably better. But, once it settles in from the original journey to your equipment table, it comes on song fast, and doesn’t waver. If you are energy-conscious, just give it half an hour of power-up first and you’re golden!
What is really impressive about the 906 is just how ‘expensive’ it sounds. Looking back at Jason Kennedy’s review from issue 85, it was clear the additional £1,000 is money well spent, but the 906 is no slouch.
The overall sound is one of great authority and solidity, but not to the point of being authoritarian. It manages to retain both the drive and energy of a recording without sacrificing its innate musical qualities. Playing Frank Sinatra’s ‘Come Fly With Me’ from the album of the same name [Capitol], a good phono stage needs to be able to cope with both the taut, powerful big band sound, and the passing tones of The Chairman of the Board, without making the former sound insubstantial, or the latter sound too much like someone doing a Sinatra impression. Few phono stages at this level get this right, but the 906 nails it!
Although it sounds like a contradiction in terms, ‘nimble’ doesn’t usually meet ‘dynamic’ at this price level, either. At higher price points, we start to discuss ‘micro-dynamics’, but at lower prices we don’t. There’s a reason for that – most of the lower-cost phono stages simply don’t resolve down to that level. The 906 is one of the very rare exceptions this side of four figures. Here, you get the delicate inner detail of a recording like Beck’s Sea Change [Mobile Fidelity] that mean you get to hear more information behind that 1970s-esque drum sound that is so distinctive. And yet, it also works extremely well when dealing with more full-thickness dynamic range.
The only downside I can see is if you are an inveterate traveller, flitting from country to country with your record collection, the 906 does not have an auto-sensing power system. You need to either buy one for 220V, one for 110V, and a third for 100V regions, or have it constantly sent back and fourth to Trilogy to adjust the taps from the transformer. In reality, that probably means another phono stage, and equally in reality, that’s not exactly a ‘deal-breaker’ for most people.
It’s hard not to be impressed by the Trilogy 906. It has much of the authority and inherent ‘rightness’ of more upmarket designs, and retains its extremely cogent and coherent sense of musical ‘groove’. Unless you are using the 906 in a really high-resolution system (where the power cord connecting the Trilogy to the wall would likely cost many times more than the 906), or unless you compare the two side by side, you might find the 906 is all you need. We felt its bigger brother warranted a strong recommendation, and given the 906 gets you about 90% of the bigger brother’s performance for less than half the price, the highest recommendation is mandatory. The 906 is very, very good indeed!
Input impedance: 47 kΩ (user adjustable)
Input capacitance: 100pF (user adjustable)
Gain: 40dB or 60dB (user adjustable)
Output impedance: 150 Ohms
Size H×W×D: 4.8×14×22cm
Manufacturer: Trilogy Audio Systems
UK Distributor: Symmetry
Tel: +44(0)1727 865488
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