Hello everyone,
Guess I should've introduced myself before doing a lot of posts!
I'm an electronic engineer working at the University of Stellenbosch. My field of research is on digital (Pseudo-Natural Sampled PWM) class-D amplifiers. Some of you may have seen me demonstrating one of our early prototypes at the Randburg expo last year.
My love for hifi was actually the reason why I became an engineer in the first place, and all the time and access I have to high-end resources and funding dedicated to audio made it my career.
Because it's my profession I guess I cannot be called an audio DIYer per se, but I've been long involved in audio before it became my full-time job, and I have a lot of private projects on the sideline.
My prime areas of expertise besides class-D amps are digital design with DSP's and FPGA's, high-speed low-noise analog circuitry, high-speed PCB design and others. Truly utilizing the advantage of 24-bit formats such as DVD Audio is one of my primary job functions, as well as research on digital transmission protocols such as Firewire and physical layer standards such as LVDS and ECL. Room equalization has also been part of the research at one stage.
My DIY interest is mostly digital-related, and a new DAC project incorporating a few non-standard ideas is in the pipeline. A few people are already interested, and depending on further interest it may even turn into a non-profit group buy. I'm doing some preliminary measurements at the mooment and will probably have a final whitepaper with a detailed description available before the end of September.
So far I've built four pairs of DIY speakers, a centre speaker and three subwoofers for myself, and helped many others, especially with subwoofers.
I've built a few analog amps, but will soon replace my own ones with our own class-D models. One of the latest ones was a Krell KSA50 clone, and I'm working on a bigger KSA100 one as well as a super-large Aleph-X. To experiment with tubes I built a clone of an AudioNote preamp, and although the results are good and measured very impressive (120dB noisefloor with ONLY 2nd harmonic visible as one would hope and expect), it wasn't worth the cost and effort.
There are many more this and thats that I made, modified or repaired over the years but these are some of the highlights. Having access to an audio analysis apparatus worth over R240k, specialized software, a reference set of speakers, reference microphone, DVD-Audio player, TacT amplifier, PCB fabrication facilities and a whole passageway full of professors should I need some assistance in an area I'm not familiar with also makes these things much easier and more enjoyable :lol:
A brief description of my own system is (as it is in a constant state of upgrade some of the components may appear a bit low-end):
- Main speakers: DIY 2.5way bass reflex, using two Scan-Speak 18W/8543 woofers and a 9500 tweeter. Swopped on occasion for a pair of DIY ProAc 2.5 clones.
- Centre speaker: McIntosh CS350, that replaced a slightly revised DIY version of the fronts as I could not shield the magnetic fields sufficiently.. and the McIntosh is better, but at its price one would hope so!
- Rear speakers: Boston Acoustics VRS (back) and VRS Pro (side)
- Subwoofers: 2 Peerless XLS12's in 50l sealed cabinets, equalized flat to 20Hz
- Power amplifier: Rotel RB985 5-channel, heavily modified on components and power supply
- Subwoofer amplifiers: Two DIY 240WRMS continuous class-AB, one per sub.
- Preamplifier: DIY AudioNote M7 clone
- DAC: Rotel RDP980, heavily modified power supplies, analog circuitry, clocking and added sample rate conversion.
- Transport: Cheap Sony thingy, couldn't hear a difference between it and a dedicated Rotel transport so it's fine for the time being until the format war has settled someday.
- HT processor: Rotel RSP985 THX, heavily modified power supplies, analog stages and digital circuitry.
- DIY 16A mains conditioner
I'll try posting a few pictures within the next week.
On a side note, if I come across as a bit critical or brash, keep in mind that I try to never denounce somebody's subjective opinion, unless it is in direct opposition to a law of nature ;-)
For manufacturers, agents, retailers, magazine reviewers and everybody else who wants to exploit the naive man on the street with blatant lies and misconception for financial gain I have little patience for though.
Regards,
Pierre Watts
