Introducing the Aletheia PSUs


The Aletheia psu-1 and psu-2 are hybrid mains conditioners that provide four balanced power outputs for source components and two unbalanced outputs for power amplifiers. This topology offers the best compromise of flexibility, size, weight and performance – bringing a very significant upgrade to any high-end hi-fi.

psu-2 front obliqueThe Aletheia psu-2

Philosophy

To understand what the Aletheia PSUs are all about, we need to first consider the broader approach behind our infrastructure products. Vertex AQ’s USP is focussed on the reduction of system interaction faults caused by RFI/EMI and microphony. Without this approach, systems will pickup, generate and pass around large quantities of RFI, EMI and acoustic vibration, thus adding considerable distortion to the hi-fi’s output. The Vertex AQ products significantly reduce these effects, bringing huge gains in performance. The idea of the Aletheia PSU’s is to take this Systematic Approach ‘inside the box’ and combine it with balanced mains technology.

The PSUs use our excellent custom-built balanced mains transformer which brings the significant benefit of ‘common mode noise rejection’. This is just like any balanced configuration that we might use anywhere in a hi-fi – any noise that is picked up will be exactly the same on both of the balanced lines, so there is no net differential across whatever is at the other end of that balanced feed. In this case, the power supplies in your source components. Our mains transformers are built using specialist techniques and additional features not normally found in standard transformers such as methods to reduce vibration and the risk of saturation caused by mains DC offset.

But also of course, within the PSU’s we provide lots of protection from vibration, RFI and EMI, both coming in and out and also what might be generated internally (particularly from the transformer). So in essence, we have the same type of modules within the PSU’s as we use on our mains leads (Roraimas) and shunt mains filters (Jayas). This is the same as the approach used in our Balanced HiRez Taga distribution blocks, which also contain the same balanced mains transformer. But the big difference with the Aletheia PSU’s is that each balanced output feed has it’s own dedicated module with a special balanced RFI shunt filter built onto its own acoustic absorption labyrinth.


The transformer selected is limited to 300W continuous output in order for us to optimize the performance and quality, in a sensibly sized package – it provides plenty of power to feed four source components. But it is also a considerable performance benefit to keep power hungry amps away from the supplies to your precious source components. It’s a mistake pull the ‘demanded current’ for power amps through the balanced transformer that is also feeding the source components. This would ‘pulse’ the transformer, causing more waveform distortion and vibration that would then pollute your source components.

There are 3 significant differences between the PSU-1 and the PSU-2:
1. Where the PSU-1 uses silver-plated copper wiring with extruded PTFE insulation, the PSU-2 uses solid-core silver wiring with a loose teflon tube for insulation. And then over that we fit our bespoke EMI absorptive foam tubing.
2. The modules within the PSU-2 also contain additional EMI absorption compounds.
3. All of the modules and the transformer housing in the PSU-2 have additional secondary acoustic drain modules coupled to them to further reduce vibration levels.

Topology

The electrical topology of psu-1 and psu-2 is identical. From the IEC input socket, the feed is filtered by the shunt input filter. This shunt filter does not add any inline restriction to current flow, and is designed primarily to be working at very high radio frequencies. Next the feed splits, and the first line passes through an acoustic absorption module, then to the bypassed output sockets. This arrangement provides the feed for power amplification – it has been well conditioned by the shunt input filter, and has the acoustic absorption module inline to lower the progress of vibration from your domestic mains wiring into your power amps. This also blocks the feedback of vibration from your amps and into the feed to the balanced section.

Next is the feed to the balanced section, which is taken through its own acoustic absorption module, keeping the feed to the transformer as acoustically quiet as possible, and also draining back any vibration that may be generated by the transformer itself. The balanced mains transformer is wound to the ratio of 1:1, but the output winding is centre tapped to ground, to produce the antiphase 115V outputs at each end of the output winding. The transformer is mounted it its own poly box, with an acoustic absorption labyrinth to drain vibration away from the transformer itself – a very important factor for the performance of these PSUs. The box is decoupled from the chassis with soft rubber mountings. Note that this is a further benefit of the Aletheia PSU’s over the Balanced Tagas, where the transformer is bolted straight to the chassis.

Then finally, the feed to each balanced output socket has an individual module with a special balanced shunt filter, plus acoustic absorption to lower further any residual RFI and vibration. These modules also act to drain back vibration and RFI out from the source components being fed.

Click on the diagrams to the right to see the topology and systematic architecture, and the differences between the PSU-1 and PSU-2.


Aletheia PSU rear oblique full Rear view of Aletheia psu-2 showing mains input IEC socket and the two bypassed output sockets and four balanced output sockets. Also available with Schuko sockets