Thought I’d write a piece about my long-term battle with transformers. And I don’t mean cars that turn into robots.

Transformers, particularly mains transformers, are a ‘systematic faults’ nightmare – if you’re not careful.

In the early days of Vertex, one of the first things we learned was the relationship between sound quality from a system and the amount of acoustic absorption in that system’s mains loom. Increase the acoustic absorption and sound quality always got better. This principle is one of the main features in the systematic approach.

But why did we hear such an improvement? We knew that our acoustic labyrinths would drain vibration from the mains loom, but where was the damaging vibration coming from? So we carried out many experiments and listening tests in those early days (and we still carry out these tests today, as we continually develop new products).

What we did, by repeatedly acoustically treating, and un-treating different parts of the system chain, right from the mains wiring in the wall, to the processing circuits in the system components, was work out where vibration was coming from externally, and being generated internally.

What we found was that some vibration comes in from the wiring in the wall, some is picked up by the cables themselves, and some is generated internally in the boxes. And it’s the internal vibration I want to focus on here.

We knew we could deal with some of that internal vibration by draining it out with a Vertex mains lead. We also knew that we could lower the internal vibration by using our support platforms speaker leads and interconnects. But this was nowhere near enough information, particularly when it came to developing our Aletheia components.

(In parellel with this work of course, was Steve Elford’s and Gareth Humphreys-Jone’s work on the measurement alliance. So we had confirmed what we were hearing with those time domain measurements).

Okay,,. Inside your typical hifi box, a lot of the subsystem elements are remarkably similar. And so too, importantly (or unfortunately), is component quality, construction and assembly techniques. A metal box with sockets bolted in the back panel, circuit boards bolted to the chassis, a mains transformer bolted to the chassis and standard hookup wiring often with cheap push-fit connectors to connect everything up. When we did all our experiments to quantify internally where vibration was being generated, no prizes for guessing which component was at the top of the list – the mains transformer.

So why was the mains transformer such a problem. In the early days I used to think a transformer was only a problem if it was buzzing audibly. But they always vibrate – they are a static motor, converting electrical energy to a force (in a magnetic field) and back into electrical energy. They cannot be 100% efficient, so some of that energy is always bled away as heat and vibration.

So I’ll summarise the issues that we found.

All transformers vibrate. This vibration essentially varies with the quality of the transformer and the load on the transformer. Plus, how it’s installed in the equipment and wired up has a big effect on the migration of any vibration into the rest of the electronics.

The transformers voltage rating. A mains transformer needs to have extra voltage headroom. Many power companies ramp the supply voltage up these days to meet their average legal requirements so It’s not uncommon in the UK for example for the supply to hit 250V during parts of the day. It’s no good having a transformer in your hifi that reaches core saturation at 245V.

The quality of the core laminations and the tension and accuracy of positioning of the wire during the winding process is essential to help reduce the generation of vibration.

To achieve these requirements to a ‘hifi standard’ it seems you need to have transformers specially made to your requirements. At Vertex we have never found an off-the-shelf transformer that has been good enough (although we have not tried them all). All the transformers we use are specially wound for us in the UK.

Then the power rating and the amount of power you draw from a transformer are also important considerations. I recon the transformer rating should be around 40% above the maximum power required, as a good compromise between performance verses size and weight. A transformer run right up at its max power rating sounds like a diesel engine with a stethoscope on it!

How a transformer is mounted is also critical. Just bolting a transformer straight to the casework, or worse, to the main circuit board in the component, is certain to increase microphony in the system.

But why am I telling you all this? Well first I have to say that this is just my opinion, others in the industry might tell you different. But I suggest you have an awareness of the issues about transformers and their problems. If you are buying new components find out about the manufacturer’s approach to transformer quality. Those manufacturers that clearly feature high spec’d transformers (and the rest of the power supply too hopefully) are likely to be offering a more musically satisfying product compared to the competition that doesn’t.

Find out about other peoples’ experience with the products you’re interested in, perhaps on the web, and look for people commenting on audible hum or vibration coming from the unit – not good!

And paint a picture in your mind of where all the mains transformers are in your system, and which ones are small and which ones are big. Remember they all vibrate so consider thIs in you plan where to put vertex components.

Oh and one other thing, don’t assume switch mode power supplies remove the problem. Oh boy, those things vibrate like crazy, but at much higher frequencies. And as for the RFI switching noise that they generate…….

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