[Listening test] ZeroZone - remote controlled passive preamplfier

Product: ZeroZone (GZLOZONE N-10) - 4 line inputs passive preamp with remote
Manufacturer: ZeroZone - China
Price (approx): ±100€
Reviewer: Lucio Cadeddu - TNT-Audio Italy
Reviewed: September, 2024

Foreword

After the review of the incredible ZeroZone Class D monoblocks, many enthusiasts expressed the need to combine them with a preamp that wouldn't cost a fortune, given that the power amps are pretty inexpensive, and that it doesn't limit the performance of the amplifiers. In one of our recent comparison tests between low-cost preamplifiers, the Tisbury preamp, a multi-configurable passive unit, came out on top. Sonically, the Tisbury proved to be up to the task and its low cost made it an absolutely ideal partner. Unfortunately, the Tisbury preamp does not have a remote control and this is a serious lack for many enthusiasts. Being able to select the inputs and, above all, adjust the volume, without having to get up from the listening chair is, in fact, almost mandatory, especially if the system is placed far away.

Having identified a passive preamp with multiple inputs and remote control, at an extremely low cost, and made by ZeroZone itself, sparked my curiosity, so I purchased it and decided to test it against its close competitors.

A closer look

It is a simple but very well built preamp: it offers four line inputs selectable by remote control, and volume adjustment. It has no digital, wireless, phono inputs, nor headphone output. Obviously, in order to be remote-controlled, it needs to be powered, but the audio part is totally passive: the signal does not pass through any component or circuit, but only through a 50kΩ ALPS logarithmic volume potentiometer branded 139M-50KAX2. In practice: you get all the simplicity of a pure passive preamp, with the added convenience of the remote control. Furthermore, from the remote you can select the MUTE function, which temporarily silences the preamp, useful if you need to answer to a phone call, for example. Two beautiful and comfortable aluminum knobs control volume and input selection. The latter is connected to a board branded The Audio Crafts, an Indian company well known to DIYers all over the world for its catalog of audio components. An STC 89C52RC microcontroller manages everything. A series of LEDs on the front indicate the selected input and muting.

The construction is excellent for the asking price (and well beyond that!) and confirms ZeroZone's attention to finish, materials and aesthetics. The connectors on the back are massive RCAs, unfortunately Chinese clones of the famous CMC (Charming Music Conductor) USA. At this price, they couldn't have been the expensive originals, of course, though they look damn close. An IEC socket with ON/OFF switch completes the rear panel. The preamp, though being passive, needs to be switched on. The rear panel allows the use of bulky connectors and cables. The finish is a classy satin silver or satin black, your choice. Available voltages: 230V and 115V.

ZeroZone strikes again?

The use of this preamp is intuitive, as the remote control works perfectly and there are no particular switching noises when passing from one input to another (just a small click from inside the cabinet). Being passive, the preamp is, obviously, extremely silent, as there are no circuits in the signal path. The sound quality therefore depends only on the input connectors and the internal wiring but, above all, on the quality of the volume potentiometer. This is of course much less sophisticated than the Tisbury's multiple-resistor one, but the convenience of the remote control comes at a cost! Both preamps have been tested together with a pair of ZeroZone power amps.

However, the ZeroZone preamp does nothing clearly wrong and, in certain parameters, competes with the nice English passive preamp. From a tonal point of view it is less open in the mid-high range and, in direct comparison, the general tonal balance appears warmer and amber-like. The bass range is good, full and deep, fairly articulated, although with less dynamic impact than the Tisbury.

In the medium-high range the differences become more evident, especially in terms of harmonic content, which is lower, precision and meticulousness in capturing and reproducing the smallest details. The presence effect on the voices is less evident, and this can sometimes be beneficial, especially with certain recordings that are a little too bright. The general realism of the sound is of a slightly lower level than the Tisbury, but overall I don't feel like making too many criticisms in this sense. The ZeroZone preamp appears musical and enjoyable, even without having the transparency and precision of the competitor.

From a dynamic point of view the distance between the two preamps is small, but there is still a small advantage for Tisbury, which appears slightly faster in attacks and decays. However, the ZeroZone preamp does not sound boring, as has happened with other preamps of the same price. Even the most up-tempo genres are reproduced in an engaging way. A curious note that should raise your interest: during a first quick comparison I adjusted the levels of the two preamplifiers by ear. Then I took a sound level meter and adjusted the sound pressure to a fraction of dB with a pure sinusoidal tone. Well, I realized that in reality the Tisbury was playing 1 dB lower than the ZeroZone. Explanation? It's simple, the ear is easily fooled, and the more lively and dynamic sound of the Tisbury makes it appear as if it plays at the same level as the ZeroZone, despite the -1dB difference! For this reason I always recommend carrying out comparison tests between preamplifiers, power amplifiers or integrated amplifiers (but also DACs and speakers) with a good sound level meter that allows you to equalize the output levels. Comparing by ear is always tricky and dangerous!

A positive note for the ZeroZone preamp comes from the reconstruction of the three-dimensional image which, thanks to a certain roundness at the top range, moves the virtual stage further back compared to the English preamp, so as to make it seem that the sense of depth is better. The effect is not unpleasant and I would say surprising, given the price class of the product. It is already a surprise there's a 3D image to deal with! On the other hand, the stage reconstructed by Tisbury is richer in elements, more focused and more airy.

In summary: the ZeroZone preamp does not sound better than the Tisbury, in fact it gets beaten on practically all parameters, but it leaves the battlefield with the honor of the weapons: compared to other cheap preamps I tested it sounds better, and without a direct comparison with the Tisbury, there is nothing in its performance that raises any eyebrow. Therefore, taking into account the price difference (the Tisbury costs twice as much and has no remote control) I would say that this nice ZeroZone preamp is a welcomed surprise.

Remarks & Complaints

Nothing to remark from any point of view: for the price requested the preamp is even too sophisticated and well finished. The four line inputs are more than sufficient in any system. Bluetooth connectivity is missing, but you can always add a Bluetooth antenna/dongle to one of the inputs, there would still be three inputs, free for traditional line sources. The phono input and the headphone output are also missing. If you fancy, a satin black version is also available.

From a sound point of view it has no obvious defects, unless compared to something clearly superior. However, it doesn't do anything particularly wrong. Compared to the Tisbury it loses ground a bit on all parameters, but the differences are small and evident only within extremely revealing systems.

Availability

I purchased it on AliExpress (here), I don't rule out it being possible to find it elsewhere (eBay, Amazon etc.). At the moment (Sept. 2024) it appears on special offer at 99€, but the prices - as usual - can vary greatly on AliExpress depending on the period. Shipping costs are more or less around 30€ and in a week or so you should receive the unit. Upon arrival, the small parcel was not burdened by customs duties, but this - as we know - depends on the customs officials who are responsible for passing the product across the border. I do not exclude that some more zealous employee may apply the usual tax which, between VAT and various charges, is around 25-30% of the declared value (this might be different in your Country).
N. B.: this preamp has no model name or number/code, not even a marking of the factory on it. Just search for “passive preamplifier with remote” on AliExpress and it will eventually pop up (just in case the link above expires). The store labels it as GZLOZONE N-10. Yes, that's odd.

Conclusions

It's not the miracle I expected, but until now, of all the cheap preamps I've tried, it's still the one with the highest quality/price ratio. It is well built, easy to use, has four line inputs, a nice remote control and sounds substantially correct. No, it's not the precise, transparent sound of the Tisbury, but it's surprisingly close.

Did you enjoy this article? You can support our free, advertising-free magazine with a small Paypal donation using the button below. Thank you!

DISCLAIMER. TNT-Audio is a 100% independent magazine that neither accepts advertising from companies nor requires readers to register or pay for subscriptions. If you wish, you can support our independent reviews via a PayPal donation. After publication of reviews, the authors do not retain samples other than on long-term loan for further evaluation or comparison with later-received gear. Hence, all contents are written free of any “editorial” or “advertising” influence, and all reviews in this publication, positive or negative, reflect the independent opinions of their respective authors. TNT-Audio will publish all manufacturer responses, subject to the reviewer's right to reply in turn.