Computer audio has come a long way since the days of MP3 and it’s products like the Lindemann network Bridge that cements our belief that not all digital music is evil.
Inconspicuous in a big system due to its diminutive dimensions, the Limetree Bridge can easily be mistaken as an external power supply or a computer DAC but it’s meticulously designed on the inside and extremely well made on the outside. With high-quality DACs for its stereo outputs and resampling along with a MEMS FemtoClock to keep jitter down to immeasurable levels, it plays a crucial role in between your music server and your existing DAC. It’s closest competitor may be the SoTM SMS200 which we reviewed a few issues ago, but the Limetree Bridge makes it easier to integrate into a slightly older system without support for USB DACs.
The front panel of the unit itself is sparse, with just a toggle switch that powers it on/off or switches between PCM or DSD modes if you long-hold it. An accompanying LED glows in different colours to depict the output format of the signal and is quite pointless unless you memorize what the sampling rate for each corresponding colour is. This can definitely be worked on for other iterations, but having said that, most users will just refer to the handy app to get their information anyway.
You can also use the Bridge as a streamer, with its support for Spotify, Deezer, Tidal, Qobuz and High-Res Audio. A USB-A socket at the back also accepts an external hard drive with your music or even a CD-ROM should you wish to resurrect your optical dreams. Being Roon-ready means you can use your laptop or an external streamer too, with the ability to output via coaxial or optical digital to your DAC. You could use WiFi or Bluetooth too, but if you’re buying a niche product like this, you’re most likely going to want to extract the maximum fidelity from it, making wired LAN the connection of choice. You could even use it as a basic preamp if you have active speakers in the system. There’s a built-in remote player in the Lindemann app too that shows you album art and lets you have control over basic track modes but doesn’t show your Roon library.
Tech behind the sound
In my existing system with the Roon Nucleus serving as the core, connected to the Limetree Bridge via LAN, then to a Soul Note DAC and onwards to an AVM 30th Anniversary preamplifier, the set-up was quick and simple, aided by the excellent Lindemann app. The primary job of the Limetree Bridge is to render any digital file coming from the Roon Nucleus core (or any other music server of your choice) in a sampling/bit-rate that your DAC can recognise and playback without any errors. But more importantly, without any sonic degradation too, which is more often the cause for audiophiles to stay away from the myriad of filters, conversion rates and bit-depths associated with a digital playback system.
The Limetree Bridge allows you to toggle between 48/96/192kHz sample rates from its app but if you use the Roon Nucleus as the server along with the Roon app, a whole world of possibilities open up where you can even convert PCM signals all the way up and down from DSD256 or PCM 384kHz/32bit, regardless of what DAC you’re sending the digital output to! You’ll have to dig into the DSP settings of the Roon control app where you will control over filters, DSD-to-PCM gain control and everything in between. Of course, herein lies the true worth of your system and its resolution capabilities along with your personal listening preference. After spending a few weeks trying out a huge amount of combinations between the Roon and Lindemann apps, I settled in for sample rate of 192kHz on the Lindemann and upsampling to the power of 2 from the Roon app, essentially outputting a 88.2kHz/32-bit signal from our DAC for a traditional 44/16 CD-quality rip of an incoming digital file. If your native source file is of higher resolution, of course, these values will change accordingly.
Sound behind the tech
First impressions of the sound was a remarkable and instantly tangible improvement, which itself was a surprise for something that seems expendable in a complex system. Settle down with a few of your favourite tracks and you realise what exactly is happening. The improved timing of the signal caused by the ultra-low jitter snaps everything in focus, yes, even when you thought there’s nothing wrong with your system's sound! An ALAC 96/24 file of Big Love from Fleetwood Mac’s classic album Tango in the Night reveals guitar with more timbral richness and vocals that just sound more real and ‘in-the-room’ than ever before. Even older and more commercial recordings like Dheemi Dheemi from 1947 Earth sound breathtaking with Hariharans voice floating over the fluid bass line with immediacy and just more warmth than you could imagine from a digital source. And that’s the beauty of the Limetree Bridge; it plays such a significant role in the overall sonic tapestry of your system that it’s almost as big a change as upgrading a component like a DAC or power amplifier.
Audiophiles love to constantly tweak their systems and the Limetree Bridge along with a Roon set-up allows you to play endlessly with the cornucopia of settings, filters, sampling and bit rates. There are defined rules to digital audio but as a listener, there is no wrong or right and the Bridge lets you experiment to your heart’s content until you can put your finger on exactly the flavour you like.
It breathes new life into older DACs by letting them “read” Hi-Res audio files without any compatibility issues. The difference in many cases is quite stark between a 16/44 and a 24/192kHz or DSD file of the same track and the Limetree Bridge had enough resolution to tempt me into buying a few DSD albums only for their sonic qualities if not for music content. Eventually, whether it’s the studio-grade sample rate converters or the medical-grade power supply or the ultra-precise re-clocking of the input signal by the Femto clock...the result is a heightened emotional connect to the music that isn’t normally associated with an affordable digital front-end. The Soul Note DAC isn’t exactly entry-level but even then it displayed renewed verve and the background became blacker than ever, letting instruments come through with more air around them and with more realism.
Sure, the Limetree Bridge isn’t an impulse purchase, but even at its relatively modest price tag, it uncovers a few more layers of haze from your music collection that you never thought existed. The soundstage is deeper, the centre image more anchored, the tonality of voice and instruments much more palpable and the bass a tad more defined. These are improvements I honestly didn’t hear as vividly even on the SoTM SMS200, making the Limetree Bridge quite a revelation, thanks to Absolute Sound from Surat, who are the authorized distributors of Lindemann in India. It’s an easy upgrade to recommend to any digital music convert, especially if you already run a Roon-based system, this is a great little add-on that will deliver much bigger gains than you’d expect. That’s always a great surprise, isn’t it?