Pro-Ject TUBE BOX DS3 B phono preamp

This new Pro-Ject Tube Box DS3 B phono preamplifier is a balanced version of the famous Pro-Ject Tube Box DS2. It uses the same cabinet as the DS2 and doubles part of the circuitry, while using Dr. Sykora's tube technology and exceptional circuitry.

Pro-Ject Tube Box DS3 B: Chassis

The cabinet is made from a sandwich of aluminium and metal. The front and the cover are made of a magnificent black or natural brushed aluminium. This guarantees protection against electromagnetic interference and limits mechanical vibrations. How it's made

Pro-Ject Tube Box DS3 B: Front panel and settings

The Tube Box DS3 B is of course compatible with MM cartridges, high-level MC cartridges and low-level MC cartridges. You can connect two decks at the same time and adjust everything easily on the front panel.

Small push-buttons allow you to select gain (40/45/50/60/65dB) and +6dB using the XLR output. The capacitance can also be optimised with positions ( 50 / 150 / 300 / 400 pF ). The load can be fixed ( 47k ) or variable. On this position, a large potentiometer varies the resistance from 10 to 1000 Ohms. Each input setting is stored in memory.

A switchable subsonic filter cuts ultra-low frequencies below 20Hz, limiting noise and rumble.

Pro-Ject Tube Box DS3 B: Connections

It offers connection and selection for two vinyl turntables.

On the input side, it offers 2 RCA, two XLR or a 5-pin mini XLR connector.

On the output side, you can choose between a traditional pair of RCAs or a pair of balanced XLR outputs.

There's also a mini-Jack 12v trigger input and output.

Pro-Ject Tube Box DS3 B: Electronics

This phono preamp benefits from research and circuitry developed by Dr. Sykora.

It is optimised by the top-of-the-range choice of components. All the components, including the output tubes, are of audiophile quality and all the capacitors are made of polypropylene.

The RIAA curve has been specially designed to achieve 0.5dB accuracy from 20Hz to 20kHz! The 12AX7 tubes have been replaced in this new version by 6922/ECC88 double triodes. These double triodes provide the balanced output gain stage and impedance matching per channel. To limit microphonic effects, they are fitted with Cool Dampers EAT.

The left channel circuit is totally independent of the right. It is a totally dual mono and symmetrical design.

All components, including the output tubes (Low Noise) operate with low noise and microphonics. Enjoy detailed lows combined with warm highs. and polypropylene capacitors, are audiophile quality and guarantee a stunning sound experience.

Pro-Ject Tube Box DS3 B: Testing and listening

We paired it with MC phono cartridges on a budget of between €400 and €2,000. Frankly, we don't see the point of using such a phono preamplifier with an MM cartridge, so we deliberately didn't carry out these tests... even though the result would certainly be very convincing.

The first measurements reveal the potential of this phono stage. We found the neutrality and precision of the Box RS, with a little more substance and fullness ... but certainly less transparency and neutrality.

The soundstage and openness are remarkable. The timbres are beautiful and very realistic.

It remains precise, with plenty of substance and presence at the same time. Room ambiances are perfectly reproduced. It is possible to appreciate the distance of the microphones on the recordings of the solo voices. The midrange is superb in its presence and organic quality.

The bass is excellent, very analogue, deep and articulate. The treble is certainly the most successful part of the spectrum. It remains silky without any aggressiveness. All the qualities of MC cartridges can be found here.

The front-panel load adjustment allows you to optimise the load precisely and fine-tune the tonal balance. This ‘little’ preamp can be combined with very high quality links.

As always with the Pro-Ject brand, the build quality is beyond reproach. It should also be noted that the technology employed, the ergonomics, the flexibility of use and the possibilities of connection and association with a cartridge, make this Pro-Ject Tube Box DS3 B phono preamp a product without competition. And if there is any competition, it's not at this price!

FAQ: Everything you need to know before buying the Pro-Ject Tube Box DS3 B

Which cartridges is the Tube Box DS3 B compatible with?

It is compatible with MM cartridges, high-output MC and low-output MC. It offers several selectable gain values (40, 45, 50, 60 and 65 dB, plus 6 dB via the XLR output), adjustable capacitance (50, 150, 300, 400 pF) and fixed (47 kohms) or variable loading from 10 to 1000 ohms via a potentiometer. Each input setting is stored in memory.

Can two turntables be connected at once?

Yes. The DS3 B offers connection and selection for two turntables. On the input it provides two pairs of RCA, two pairs of XLR or a five-pin mini-XLR connector. On the output it lets you choose between a pair of RCA and a pair of balanced XLR outputs. A 12 V Trigger input and output on mini-jack complete the set.

What does its balanced tube design involve?

The left channel circuit is entirely independent from the right: it is a dual-mono, balanced design. The 12AX7 tubes of earlier versions have given way to 6922/ECC88 dual triodes, which per channel handle the balanced output gain stage and impedance matching. They are fitted with EAT Cool Dampers to limit microphonic effects.

Is there a filter for very low frequencies?

Yes. A switchable subsonic filter cuts ultra-low frequencies below 20 Hz, limiting noise and rumble. The RIAA curve has been carefully refined for 0.5 dB accuracy from 20 Hz to 20 kHz, and the front-panel loading adjustment allows precise fine-tuning of tonal balance according to the cartridge used.