Some people may find the files I've just put up on my old University website of interest. These are at http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/iandm/intro.html and are pdf versions of chapters from my book on 'Information an Measurement'. They go though the basics like sampling theorem, noise in amplifiers, etc. However please note that 1) The book is now getting 'old'. So some of the...

There used to be a fairly small loudspeaker that used a short folded trnasmission line as loading. I seem to remember them as being about 2ft high, maybe 8-10in across (or less) and about 10in deep. I am talking 1970-1980 vintage. I've got the name Paradigm buzzing around in my head - I'm sure that was not it but I'm fairly certain the name began with P. Anyone any ideas?

I've just put a quick page up at http://jcgl.orpheusweb.co.uk/temp/dttv.html This is to show the results I've produced having obtained a set of data for the current UK DTTV TXs and the changes intended for 4G. I'll write the blurb later on, but thought some people would find the maps of interest. I've posted this message to rec.audio as well as digital-tv because of the relevance to audio...

Hi, I have many files stored on my Brenan JB7 (OK!) and backed up on an external HD. To preserve full quality I saved them uncompressed and they are in .wav format. I want to put them onto my MP3 players (Cowon and Samsung ACE phone) but would like to compress them in order to get more onto the players. Please can anyone advise as to the best way of doing this? Are there good, free wav to...

My Apogee Caliper Signatures are probably the best speakers I've ever heard - the only thing that was better was Apogee Duettas which were a foot taller!! These are full-range ribbon panel speakers. Spare parts are available from a company still making similar ribbons and servicing the old Apogees, so you won't be stuck for ribbons, not that they wear out. The delicacy, detail and clarity of...

I have a pair of Royd Coniston speakers. The front covers are made of foam, and are starting to disintegrate into a crumbly black mess. Any suggestions on how to get or make replacements? Daniele

Got what I reckon is a problem with a pair of Audax HD 13D34 H tweeters. What sounds like a large resonance at about 3 kHz. They are about 30 years old, so treated them to new voice coil assemblies - although the old ones looked ok. Absolutely no improvment. Before I buy new complete units on spec, any guesses? -- *Learn from your parents' mistakes - use birth control. Dave Plowman ...

Hi all Anyone recognise this tonearm ? A friend picked up a Thorens deck, and this was with it in a shoebox. No markings on it that I can see, and not one that I recognise or even remember seeing before. http://i46.tinypic.com/25oymw4.jpg http://i50.tinypic.com/20ifgom.jpg

Just to let people know I've now put up a page on a new cheap and simple DIY headphone amp at http://www.audiomisc.co.uk/HFN/HeadDAC2/HeadDAC2.html Slainte, Jim --

Anyone know if a Behringer PP400 is any good? Or is there a decent MM phono preamp with USB output? I seem to have mislaid my preamp during a couple of house moves. The best option would be to build one, if I want an excellent one. Or check the charity shops for an old Rotel amp. Or just buy one. But the Maplin one I bought a few years ago was a crap 2-transistor jobby and didn't sound good at...

Am having some problems with Audax HD13D34H tweeters. Both are exhibiting annoying resonances at around 2.5kHz. On some material it doesn't show much - on others it's very nasty. They come apart easily and replacement diaphragms/voice coil assemblies are available, so I bought some despite the originals looking ok. No improvment. Only obvious thing is the foam 'dome' glued to the magnet centre -...

Any UK suppliers? It is on Ebay, but only from Oz or the US. Tried Wilmslow, but they don't seem to list it. -- *I can see your point, but I still think you're full of ****. Dave Plowman London SW To e-mail, change noise into sound.

Hi all, I need to collect a Thorens TD 160 Super turntable tomorrow. (An impulse ebay purchase.) Anyone know where the transit screws are? And does the platter just pull off to save the bearings from the journey? -- Eiron.

I have a Mission Cyrus 1 amp, that has been working very nicely for the last 24 years (what a good investment that was, back in 1988). I need a new CD player, and I would like to get one of the shoe-box sized Cyrus ones to match the amp, mainly for aesthetic reasons. Which model would be most appropriate? I'll buy it second-hand, and would prefer to spend £200 at the absolute maximum. Daniele

IIRC, this is often used for a rough check on a speaker if you don't have an anechoic chamber. Can anyone send me a WAV of a sweep from their oscillator? Or know of a circuit to produce it from a sine wave one? -- *No husband has ever been shot while doing the dishes * Dave Plowman London SW To e-mail, change noise into sound.

** My colleague, Rod Elliot of ESP has come across a little publicised phenomenon regarding IM distortion. The fact is easily demonstrated that if two sine (or near sine) tones are fed into a symmetrical ( ie diode) clipper, NO sum and NO difference frequency are generated. Many other frequency products are created, but NOT the simple sum and difference ones that are so often assumed to...

Have a Yamaha amp with a motorised selector switch. Which is getting rather dirty - just tapping the knob can make the signal break up. Before I go to the trouble of getting at it - no mean task - can they sometimes be cleaned or is replacement the only option? -- *Growing old is inevitable, growing up is optional Dave Plowman London SW ...

I've been looking at headphones for a few days, on Amazon, the Koss website and today trying about 40 pairs in London with in-shop demo equipment and also my phone. I'm just about a layman when it comes to hi-fi, albeit with some sincerely held views that might make some here a wee bit cross. I know what I like and I have a half articulate way of attempting to describe it even if the spec sheets...

I've been following these with interest. Obviously no shortage of money around. Everything on sale there will be well used and often a bit cosmetically challenged. Broadcast turntables and CD players seem to go for silly money. Speakers too. LS 3/5a go for over 500 quid the pair plus auction fees and VAT LS 5/8 with amps 1000 - 1500 a pair. LS 5/9 800 or so a pair.

I find this gadget at Amazon: http://www.amazon.com/LE-40010357-3-Cassette-Converter/dp/tech-data/ B0065DMVUI/ref=de_a_smtd I want to convert old cassette tapes to mp3. I have tried using Audacity but the results were not good. I was told that Audacity is meant for low-quality voice recording, but this gadget is said to produce excellent results, even though it makes use of Audacity.