When dealing with media converters, it was noticeable that the one installed in the Melco S100 switch could keep up with even the audiophile Sonores in terms of sound. When asked whether the converters from the S100 would also be available separately, Alan Ainslie, Melco's European representative, asked for patience: Now the first Fibre Kit from ADOT - arrived at the editorial office.

The fact that optical transmission paths with two media converters and one optical fibre can be sonically superior to electrical Ethernet connections in digital playback chains has already been explained in detail in Hifistatement in four articles about media converters and accessories. Therefore, I will not mention the advantages of the complete galvanic isolation of the audio components from the Internet and of reclocking - provided the media converter has a good clock - again here and refer to the reviews mentioned. By the way, the Audiophile Digital Optical Technology - ADOT - Fibre Kit mentioned in the introduction is ideal if you want to use it together with the Melco S100, which was awarded a Statement In High Fidelity, or another switch with a built-in media converter such as the SOtM sNH-10G i. Of course, I would also like to try out the Fibre Kit with the PowerSwitch from Ansuz for example. For this, you need a second media converter, which Alan Ainslie also brought on the way to Gröbenzell some time ago. The second ADOT Media Converter and power lead is supplied in the ADOT accessory kit allowing ADOT fibre kits to be used with any dataswitch even if there is no SFP port. Probably thanks to Brexit, however, it has been flickering around for more than a month in the UPS warehouse in Nuremberg or at customs. I fear that we will have to get used to such delays. So for the time being we will make do with one media converter and in a second part we will compare the second converter from ADOT with the one built into the Melco switch.

When I asked Alan Ainslie last year about media converters that could be purchased individually, I assumed that Buffalo, the Japanese computer peripheral specialists, of which Melco is a subsidiary, had such converters in their portfolio. That is indeed the case, as I later found out from the Amazon Japan website. But it is not a Buffalo media converter that has now arrived in my place. The manufacturer is ADOT, or by its full name "Audiophile Digital Optical Technology", and our test object trades under the name "Audiophile Grade Optical Fibre Kit". The company's organisation is based in England, where the concept for the products was also developed. The manufacturing is, how could it be otherwise, in China. That the kit is intended for use with a Melco switch is already suggested by the scope of delivery: In addition to the one media converter, there are two SFP adapters - SFP stands for "Small Form-factor Pluggable" - which convert the electrical signal provided by the media converter into light waves. As described in the first article on media converters, there are different adapters for single or multimode optical fibres, each with different wavelengths. The SFP adapters included in the kit carry a label identifying them as ADOT products. Alan Ainslie notes that it was not easy to find adapters with good characteristics for audiophile purposes, as they were usually designed for IT applications. The optical fibres also had to be of good quality to avoid transmission losses and jitter. Duplex multimode optical fibres with a wavelength of 850 nanometres were chosen because they were more reliable at a reasonable cost. However, jitter increases with short multimode optical fibres due to path length differences or modes. Measurements have shown that jitter above one metre is reduced to an acceptable level. Therefore, the fibre optic cables of the kits have a standard length of 1.5 metres. Lengths of up to 50 metres are available from stock, and lengths of up to one kilometre are available upon customer request. Each fibre optic cable is supplied with an individual test report, after all, it is impossible to use an ohmmeter for an optical cable! At a later date, a single-mode update will be offered for a fee. ADOT ist still looking for a reliable provider for short connections.