Pro-Ject Phono Box MM, Phono preamplifier with metal case and special low-noise ICs

Product Information

Again, the portrayal of the piano was a little sharper and more muscular in solid-state, richer and more embodied with tubes. In tube mode, I had a slightly better sense of the recording venue, an unspecified church in New Orleans. Engaging the subsonic filter (also available via front panel pushbutton produces less low frequency rumble, but it also takes from a lot of the energy in the music resulting in an emotionally “flat” sound. Pro-Ject lists the filter as 20Hz with a slope of 18dB/octave however, the “20Hz” part confuses me because the filter doesn’t sound like it starts to drop at 20Hz. In fact, it sounds like it drops off at around 30-35Hz. Lately, I’ve been listening to a new cycle of Beethoven’s piano sonatas by the Turkish pianist Fazil Say (24/96 MQA, Warner Classics/Tidal), which I played from the Tidal client on the Stream Box S2 Ultra. While Say has drawn some criticism for his interpretive gestures and choices of tempo, I really like what I’ve heard from this set so far -- I find it fresh and invigorating. And the sound is superb. Stage 1 can have a gain of 0 or 6dB (voltage gain of 1 or 2, respectively). As shown, gain is 6dB, and to reduce it to 0dB replace R3 with a link, and leave out R4 in each channel. The table shows the different gains available from the entire preamp (with volume at maximum) for various values of R7 in each channel, and with Stage 1 having 0 and 6dB of gain. Generally, it will be quite rare that you need more than 10dB of gain in a preamp. The sensitivity referred to 1V means that this is the input voltage needed for 1V RMS output, with the volume at maximum. With all switches closed, the second stage has a gain of 5.36 (14.6dB), far more than anyone is likely to need. Intermediate gain can be obtained by closing more than one switch (I leave this to the constructor). The preamp performs a process on a scale that no other component in the phono audio chain comes close to matching. Instead of just being an added-on component that helps your system run smoothly, it actually shapes your turntable’s performance and ensures it is able to work with the rest of your system.

Carnhills are widely used in 1073-type units and contribute to the Junior’s vintage sound. It’s not the most transparent transformer, but it has bags of character and responds well to being driven hard. The Junior’s circuit is quite straightforward in a traditional style, with just three transistors used in the gain stage and three in the output stage; the output transformer is driven by a 2N3055 power transistor running in pure Class-A mode. There is much to recommend using pots on the inputs for CD and Tuner in particular, so their levels can be matched to the other signal sources you have. Although this option is not shown here, it is described in Project 02, and the pots would be used in exactly the same way as shown in the original hi-fi preamp schematics. In addition to boosting the signal, a preamp also applies the RIAA equalization curve to the signal. This ensures that the equalization curve has the same shape after amplification as it did before, meaning that the sound does not change at all, apart from being amplified. According to the manufacturer Pro-Ject, the new Phono Box RS2 is their most sophisticated phono preamplifier to date.Radar Love«: Vinyl passion over radio waves – is that even possible? Yes it is! The Cambridge Audio Alva TT can also send its signals via Bluetooth as an alternative to the phono cable. At best an emergency solution? Quite the contrary!

There’s actually a pretty simple way to determine this. Try hooking your record player up to your audio system or speakers. If the volume level is high and there are no signs of distortion, then you have a model equipped with a built-in preamp. Another way to determine whether or not your model has a phono stage is to plug in your record player and try turning up the volume. If it sounds clear and the volume is booming, then it comes equipped with a built-in phono stage. Knopfler’s Fender seemed to have this percussive bite every time he dug into the strings, yet his tone was so sweet and lush. The expansive reverb started to produce an image I could almost see with my mind’s eye. The image specificity produced as big an improvement as the portrayal of the reverb’s decay. This gave the guitar as well as Knopfler’s voice much better spatial placement and solidity on the soundstage, which made for very involving listening. However, most audiophiles argue that an external preamp offers better sound quality on average than an internal phono stage. Read our article comparing a built-in preamp vs external for for more on this. The headphone amplifier is the ultimate design. No compromise. No coupling capacitors. Not even on the output. All of the the amplifier is DC coupled. A very fast DC servo assures no DC voltage on the output. Its output power is suitable for all kind of headphones.Most preamp manufacturers work hard on designing models that are extremely low noise, which is a huge plus for any serious audiophile. That said, it really doesn’t matter if you have a phono stage that’s only a few decibels quieter than the vinyl itself. The vinyl surface noise will still dominate. Three plastic push-buttons are provided, which engage the DI input, 48-volt phantom power and phase invert; a single LED light indicates the presence of signal passing through the unit. Like the larger units, this junior model delivers up to 70dB of 1073-style microphone preamplification, while doing away with features that some users might not need. The first thing we noticed, apart from its unusual proportions, is the simplified input gain rotary switch. Whereas the other models feature the unique 1073-style Mic/Line switching arrangement, the Junior offers mic gain only in 5dB steps from 20 to 70dB. A continuously variable Output control pot is provided, along with an instrument DI input. The smooth, full-bodied performance, coupled with the inclusion of a headphone amp, makes this stylish box certainly worthy of consideration.

Because we are always asked how to connect the equalization preamplifier or phono preamplifier, we would like to write a little guide. Only 'booboo' this preamp designer made, IMO, is the use of switching power supply BUILT-IN on the same circuit board ! To save manufacature cost, I guess. The audio world knows of Pro-Ject Audio Systems as a major brand of turntables, but this Vienna-based company also makes an extensive line of electronics that lately have been winning all kinds of awards. For the past three years, Pro-Ject has received awards for its turntables and its electronic components from the Expert Imaging and Sound Association (EISA). Sound quality is first-rate: fantastically detailed, with the upper register particularly impressive. It’s difficult to imagine a more detailed presentation from a phono stage for the money. There are rivals with an equally wide soundstage, but they perhaps don’t shine the spotlight so intensely on each instrumental strand. Detail is where it stands out, but the Gram Amp 2 is also a dab hand at dynamics and timing – although perhaps not with as much bite and punch compared with the Rega.The 'alternate' connection for R5 is useful if you include the tape monitor switch. By making R5 external, the 'AL' (and 'AR') positions are a direct connection to the opamp's outputs, ensuring that operating the 'tape monitor' switch doesn't cause any level change. It's no imposition as it's just two resistors that are relocated. The R5 position on the PCB is replaced by a link or a 10Ω resistor. Although shown with 10k resistors for gain, you can reduce these for lower noise if you prefer. With the suggested OPA2134 (or NE5532) opamps, these resistors can be as low as 1k. The opamp input resistor (R2 L+R) can also be reduced in value, but at the possible expense of lower RF interference immunity. I wouldn't recommend less than 220Ω. The nominal options are for a gain of 0dB or 6dB, but you can get an intermediate gain of ~3dB by making R4 27k. This gives a gain of a bit under 3dB (2.74dB or ×1.37), which may be useful. You can change the gain easily by changing the value of R4... Vertere already had a great phono stage on its hands, but this updated version manages to deliver significant performance gains, thanks to some careful housekeeping and honing of the circuit board and power supply. The tidy little box remains the same; an orange power LED is the only addition to the design.

As shown, the maximum gain through the unit is 9dB (2.8 times), and this is in keeping with many of the latest offerings. More or less gain is readily available, simply by changing a 4-pole DIP switch. Use a 2 pole 6 position selector switch for your inputs, and you will have a preamp with enough inputs for everything. Following the motto "balanced vinyl for everyone!", the turntable and electronics manufacturer Pro-Ject wants to push balanced signal transmission forward and thus introduces the new turntable Pro-Ject X8 and the two phono preamps Pro-Ject S3 B and DS3 B. Measurements on this preamp were difficult - mainly because noise and distortion are too low to measure accurately. I haven't even tried to measure the distortion, but the figures I do have are as follows... ParameterAdditionally, if your audio system comes with a phono input with a ground screw installed next to it, this means that it has a built-in preamp. As long as it is compatible with your turntable, you don’t need to buy one separately. When you cut the built-in phono stage out of the loop, and replace it with something better, your vinyl will begin to reveal its true potential. A dedicated phono stage is easy to install: it sits in the signal chain between the turntable and any line-level input on your amp. A word of caution: Don’t take the output from your phono preamp and connect it to the phono stage on an amplifier, as that will double amplify the signal, resulting in catastrophic distortion (which isn’t as good as it sounds).