02-04-2017, 09:03 AM
The following below comes with a do not try this at home warning
Thanks all for the hints and tips, the Audio Note Preamplifier kit that I had was a variation on the veroboard style of mounting the components, in that there was holes where the components went and the leads were linked on the underside of the board, sort of a halfway house between pcb come veroboard and hard wiring.
Yes I do know that impedance is a variable not a constant. But also checking my understanding here. Andy in your example on using Ohms Law (which I do follow) what does the 6.28 represent and where does it come from?
OTL uses PL509 or Pl519 remember my preference for not solid state. Its a variation or based on a Futterman and as far as I can tell no chance of putting DC volts on the speaker.
Ah yes and finally those good old chemistry days, a friend of mine (a group of girls no less) made a hole in the school playing field, when they threw the bottle of nitroglycerine which they had made in the school lab, the tech support knew what they were doing. But the best one was their chemistry teacher who was due to go to a wedding that weekend and they had stuffed the tap with potassium permanganate. I do not remember why she was rewarded with this but, the class that did the deed were not the one she was teaching at the time.
My family friends went to a proper school and I went to a state school so of course were much more advanced than me but I had enough of an understanding. We did all sorts with sulphur, sugar and nitrate, adding weedkiller (his father suggested that one), its a wonder we did not burn the house down. I seem to recall that the father suggested using aspirin as well. Of course in those days you could go to the chemists and get these items, no chance of that now, oh those were the days.
When I was much younger I got a chemistry set for a present and proceeded to use it in the Kitchen, I mixed up my chemicals and heated it up, it boiled, then it spurted up the wall and I wiped it off along with the paint. What I had made was paint stripper, oh yes I was popular I think it had just be repainted at the time.
My goodness if you did any of this these days or attempted it you would have special branch round before you knew where you were and would be under a very strong light whilst being interrogated. There's not a lot of fun in life if that is the case growing up any more for kids.
Another trick was once we had made our mixture we would get two nuts and a bolt pack it with the stuff and then heat it, other tricks were to take bare mains wire (his house had no on off switches on the sockets either) and drop the bare lead into water and watch it bubble. We often had the leave the room after some experiments as you could not see across it and even with the windows open it took time to clear, of course there were other tricks their garden was big enough for us to drive cars around, which we did and we were encouraged to do so by the parents, again these days we would all be under special provisions or in care. It's what I call a childhood we were not wrapped up in cotton wool we lived full and productive lives and were encouraged to experiment.
But I digress....its a habit....now I recall we tried to that too if only we had know you could get the concentrated nitric acid from the chemist (we tried making it but could not get it strong or pure enough), probably that time had past even though we are talking 40 years ago approx.
Oops did it again.....
