Life Observed

Clearing my desk. My final day of paid work after fifty two years. Fifty two years! Really? Where did the time go?

The continuing saga of my home designed Princeton Plus amp. After a six week wait for the post from China* I finally have my tweed covering. Now the amp looks as good as it sounds. I gave it a blast when the house was empty recently. It makes seven or eight watts, but they are very loud watts. The sound hits you in the chest and leaves your ears ringing. Fortunately I can switch it down to one watt - which is still extremely loud in a domestic environment. The question is, what's the next project? *China: Look, we know your stuff is cheap. Free postage is the icing on the cake, but not if it takes a month and a half . I would rather pay £5 and get the thing in seven days. Grrr.

This is how it begins: Buy an empty amp case and pull all the nice black covering off it. Then saw a gap in the top for the new amplifier. Now stand back and admire your craftmanship.

Oh dear me, I have been overtaken by another addiction. I have entered the seductive and slightly shocking world of valve amplifier modifications.  You thought those old noisy valve guitar amps were dead didn't you. You thought it was all done on computer these days.  Well, yes it probably is, but there is a growing group of individuals who stick to the old fashioned ways in search of that elusive and perhaps unobtainable tone.  So, after a summer spent modifying Leo Fender's commercial valve amplifiers, I decided to start from zero and build an amp. This has now reached the point where the next step will be applying power. I think I will check the circuit carefully, twice, before I do that.  If you are interested, this will be a dual 6V6 version of the 5F2A with my own tone stack and pre-amp modifications. Oh, you aren't interested.... :-)

Roughly forty years ago, in 1971 I left work and went to University to take a degree. (In those days it was worth having a degree, only five percent of the population had them, and you could get a small grant as well). I maintained my links with the electronics industry and was delighted to get a packet from Texas Instruments offering me a free red LED to try. This was the point that LEDS passed from esoteric specialist items to a commodity product. I recall my amazement when I connected a battery and it lit up. It didn't get hot, it didn't have a filament to break and it took hardly any current. What an amazing invention. Of course the only colour commercially available was red, and so it remained for some years. Slowly orange, amber and green appeared and LEDS became mainstream. They revolutionised electronics with their low power and long life. You could now build indicators into equipment without any thought of how the "bulb" would be replaced when ...

I suppose by my time of life I should be retired, or I should be in charge of some large admin department somewhere, devoting my weekends to perfecting my golf swing. Instead I solder on at the bench and the CAD pc screen, spending my time chasing impossibly small electronic components around tiny circuit boards with tweezers and iron. (Here's one I designed earlier) Later that same month: Here we are, attacking the unsuspecting board with test equipment and data manuals.  This is one of the lonelier moments in the Electronics Designers life: Making a new design work for the first time is always a testing time (pun inteded). This new thing has never seen the light of day before, there are no previous examples to fall back on for comparison. No-one else in the company understands it to the detail that I do, so there's no-one else to ask.   Is the schematic right? Did I make any mistakes on the layout? Will the processor start? Are there mistakes in the ...

We all like a bargain don't we? I know I do. I'm guilty of scouring ebay for some little gem that no-one has noticed, or some broken item that I think I can fix. Here's an example. This is a Tamron SP90 macro lens I bought some years ago. It had a focusing fault, and I had to dismantle it completely to locate and fix the problem. Re-assembling the twin helicoid was a massive task and took several evenings work. In the end I had a splendid lens that I used for a year and eventually sold to fund another purchase. Perhaps I should get out more, but I do like repairing and re-using things. Its a sort of technical recycling I guess. Sometimes this goes all wrong. I have been trying to buy a Nikon SB28 flash gun. These have become sought after courtesy of the Strobist blog and prices have leapt up. I see plenty for sale in excellent condition but, having some Yorkshire blood in me, I can't thoil 80 to 100 pounds on the purchase. So - I bought a non funct...