New (to me) loudspeakers

The latest refinement to my Quality Amplifier is a pair of loudspeakers designed for use with valve amplifiers. I've been looking for something suitable on Ebay for some time. This week I managed to pick up a pair of original Leak Sandwich speakers for £32 locally. Large heavy items often don't make high prices here in the UK because shipping is very expensive - it would have been over £30.

So what are they like? Well at first they sounded great, then after a day one started to sound rough. I did a bit of Googling, took a close look at the sandwich driver and decided that gravity had probably got the better of the cone and surround. Though the cones and surrounds all looked to be in great condition there was a slight tilt downwards. This is apparently a known problem. So I tried standing the speaker upside down - it sounded fine again. So all the was required was to remove the driver and turn it through 180 degrees!

History of the Leak Sandwich here http://44bx.com/leak/sandwich.html

Music to code by

For many years I've had SlimServer (now SqueezeCenter) installed on my Linux server and found it very good for streaming music to my Nokia tablets. These tablets have excellent sound quality so I often plug one into the hi-fi. These days it's usually the Quality Amplifiers.

But I wanted more music - what to do? I tried "tuning" the N800 to last.fm but the results weren't good. Nokia tablets run Linux and have limited computing power, they are great at streaming audio and video, but not so good at running Flash, and can't run any Windows software. So I had an idea...

How about running Spotify on my laptop and streaming the audio to the hi-fi? Simple - well - simple-ish. I used a Pinacle USB TV thing to grab the audio from the laptop headphone socket and Helix-producer on the laptop to convert it to a Real Audio stream. From there to Helix-server running on the Linux server and via wi-fi to the media player on the Nokia tablets.

From this description it's probably hard to believe that the results sound very good indeed. No dropouts, no machine being loaded too hard; each can carry on with its normal duties.

Very happy! I'll wait a while before I think about paying to not hear adverts.

Mobile communications to revolutionize African weather monitoring

Weather Info for All

From a press release by Ericsson today -

* Global Humanitarian Forum, Ericsson, WMO, and Zain and other mobile
operators to deploy up to 5,000 automatic weather stations in
mobile network sites across Africa, where less than 300 are
reporting today

* Partnership will increase dissemination of weather information via
mobile phones to users and communities, including remote farmers
and fishermen

* First 19 stations deployed more than double Lake Victoria region
weather monitoring, where 5,000 people die every year due to storms
and accidents

http://www.cisionwire.com/ext/ericsson-b/mobile-communications-to-revolutionize-african-weather-monitoring

See also http://news.bbc.co.uk/1/hi/sci/tech/8105814.stm

Jai Ho! The millionth word is web2.0

See http://www.dailymail.co.uk/sciencetech/article-1192131/Word-Millionth-phrase-English-language-Web-2-0.html

Stereo quality amplifier

Late last year I started building a Wireless World Quality Amplifier.  The original design for this amplifier (mono) was published in 1934 and it became the reference British hi-fi amplifier - holding this position until the Williamson replaced it in 1947.

As my intention was always to create a useful working piece of equipment I was going to need a preamplifier suitable for use with modern sources - OK maybe LPs aren't considered modern any longer.

The solution was to build a stereo pre-amplifier to the 1950s Mullard design, but subsituting 1930s style octal valves for the 1950s 9 pin EF86s.  Plus I needed to add a phase splitter.   Six of the the excellent EF37A  made a quality pre-amp.  Now I just need to complete the cabinet.

From Quality Amplifier