Wow - managed to start this month before it finished.... however, with the going's on from last month on the job front, the car is still taking a back seat - if it had one.
Mandy does have a couple of interested parties, my favorite being from an engine tuner/restorer/supplier. It would be great and after a couple of months I might have to twist her arm to get a club area visit arranged. We;ll see how things go.


24th April - Valve Amp

Today was a good day. I managed to build up enough enthusiasm to make a start on a new board and duly sat in front of the F1 qualifying to get it finished. Not only did I do that but Jenson Button got his first ever pole for the BAR team.
I took it out to the garage where I had the amp hooked up to my tape deck and some very naff speakers for testing. The new board was transplanted and I took the opportunity to fit new silicone components at the same time (regulator and Fet) just for good measure.
At the first power up, it was obvious before I put the meter on it that all was well. The Led's are meant to gradually come up to brightness as the power builds, and whereas before the left channel would come on fully bright, it now built up over the predetermined 12 seconds or so. The board gave a nice rock steady supply of 462v which matches the original side and it sounded good.
A slight humm is audible as the power comes up from about 100v onwards, but this dies away as it gets to the full voltage and it isn't audible unless your ear is up against the speaker, so I shall not worry to much about that.
I then spent a while gluing in some supports so that the signal wires could be kept tidy and I also shortened these down to the correct length. I swapped in two new blue Led's which give a nicer glow than the red's I had before and look a bit 'cooler' - well, different at any rate, most Hi-Fi have red, so better to be different. Maybe I should have gone for Red and Green, for Port (left hand) and Starboard (right hand)... na, now don't get silly.
Can't wait to have the space to hook it up to the decent speakers indoors and the CD player - although I don't think it is good enough for it, but will have to do for the foreseeable future.


Mid March to 19th April - Valve Amp

To help take my mind off things, I've gotten back into the valve amp project that Steve F and I started a long time ago (June 2002 if you must know!). Steve finished his quickly - the benefit of working with the guy who designed it. I wasn't quick enough and when they parted company - literally - mine started collecting dust. Well, after some gentle hassling from Steve, we got together one Sunday morning and I got a few more things sorted out. I had actually done nearly all the wiring, it was just the final few things like connecting the power board up, etc.
We braved it and connected it up in his garage and on an old pair of speakers it made it's first noises. Not for too long though as it dropped out after a short while and didn't have any power/depth to the sound. As neither of us are electrical bods, we called it a day and Steve contacted another one of the amp builders to see if he knew any more. Fortunately he does and we arranged another meeting where we could try to sort out his problems as well.
The problem with mine was eventually found to be lack of power. With both channels running off of the same power supply board, the amp would drop out as the valves started pulling full voltage. By wiring one channel at a time we proved that both worked perfectly on their own and that an extra board was required. Guess what I've been sorting out since then.....
I ordered the new parts, bought a new board and set about making a copy of the original circuit. Unfortunately when we came to test it out it was found that the power was ramping straight up to the full voltage of ~500v rather than steadily building. Having tried changing components I decided that I should just start again, this time with a proper circuit diagram.
I must get on with it - I want to set it up this weekend on my good speakers!

 
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