Monday 5 March 2012

HiFiSounds.......the quest for audio perfection

Welcome - Whats it all about then???


Hi, welcome to my HiFiSounds.co.uk blog!

Following several years and hundreds of hours of work 'improveing' hifi equipment, I thought I'd post the details of my latest work here. I'd already pushed my SB3 quite a long way and always thought that I'd turn my hand to the Touch at some point. The recent temporary price drop on Amazon was enough for me to dip my toe into the world of the touch. It was at least 10 minutes before I invalidated my warranty by getting inside the touch and starting to investigate possible modification. There is already a fair bit of info already available through various sites on the web so I already had a heads up on what people were doing. My plan was to see if I could spot anything new that hadn't been tried yet and it wasn't long before I was deep in my initial investigation.
The key to everything is the power supply. By power supply, I don't mean just the unit you plug into the wall. This is the heart of the PSU but inside any electrical equipment there derivatives of this main PSU feeding different area's. In the Touch, the 5v supply split to several internal PSU's. For the DAC, the voltage is increased to approx 10v via an internal smps which in turn feeds a small surface mount regulator. For the clocking circuit, the 5v rail is directly fed a 3.3v regulator. Separation of the PSU with devices being fed by their own regulation is a good way to achieve improvements and so this side of things needs to be understood. I have also come to accept that in most cases, the introduction or replacement of cheap caps with modern very low impedance, low ESR caps make a significant difference to the performance. For a long time, people have been improving the performance of audio equipment with the use of caps like the now obsolete Black Gate caps from Rubycon. Recent improvements in the cap performance (probably brought about by the requirement for low noise circuits in digital circuits) have lead to changes in construction and have brought us the solid polymer electrolytic. I always use these type on digital circuits. Caps like Rubycon ZA or ZLH are very good on analogue circuits.  Often another quick win in digital equipment is to improve the clocking. Standard 2 pin oscillators tend to be noisy. Every piece of logic the clock passes through adds jitter. It would be fair to make the assumption that each logic gate could easily add  2-3ps of jitter There is plenty on the web explaining why this is bad and why you should improve this. I'll not get into the why's here but we'll just proceed on the basis that the cleaner the clock signal the better. If you want to understand more you can look here
Much of the same theories learned in tinkering with CD players and amps can be reused again and again . To give some idea of what can be achieved, take a look at either my CD52 blog or my CD67 blog.