Hi John
I don't think it's a question of "learning algebra" as you put it as whether you realise it or not, you can already do it. You might ask how this is possible. If you think about it for a bit, algebra involves nothing more than adding, subtracting, multiplying and dividing, which I presume you are competent with.
All a formula or equation does is tell you which operation to do and in what order to do it to get the answer required. The numbers on which you carry out these operations are arbitrary and must be supplied by you.
Simply put you say I have this resistor, this cap, what will I end up with if I put these into my formula?. Hmmm not quite right let's try these, that's nearer so if I increase this cap by a few uF, OK that'll do.
These formulae and equations describe for example the behaviour of an amp from input to speaker. So if you take a bit of time and use these concepts you will find that you can make your amp behave as you want it to. You will also find that if you calculate that a certain voltage should appear at a certain point then it will, unless you have done something wrong in your construction. The joy of finding that voltages you yourself calculated actually do appear where they are supposed to is something to savour.
Once you have made the amp behave as you predicted it will then you will get such a brilliant sense of achievement. Now just because the thing you built behaves as you wanted it to, does not mean it will sound any good but that's just the beginning of the learning curve.
I started as a new member of the old WAD forum as a complete novice with tubes. I was good at wiring, as that had been my job but I had little understanding of how what I was wiring up actually worked. I built a WAD phono II then a PreII simply by following the instructions.
I then did a Loftin White 2A3 amp from Philip Ramsay at Bluebell audio by using the circuit diagram supplied, and telephone support from Phil.
The real learning came however when I tried to design my own EL34 SE amp "Rocky" as it has become known. It would not have sounded half as good as it did without the help of Paul Barker and James Doddington who advised on how to mate a 6SL7 to the EL34 output valves. Neither of them would have done it that way and did not hesitate to say so but they helped me realise the design and get the best out of it, throwing in a few math hints and tips here and there.
It sounded very nice when built. Ed built one himself but using a different input valve and still uses it.
However because I had become more confident with the maths I was able to refine the design further with a cathode follower first stage. Now this is what Paul and James would have done in the first place, and I understood why when I fired it up and the sound was indeed better. This version has also been built by Al and gave a good sound at Owston.
I have built quite a few amps since then culminating in the 6AS7 push-pull amp, whose design process is on the WD forum, reading it from the beginning you can see how the design evolved with help from Nick and Alastair Stuart. A bit of applied maths was learned from Nick and Alaistair doing that as PP design is little bit different from SE. Paul also advised on how to construct the pair of very powerful differential input and driver stages that lie at the heart of the amp and IMO contribute a great deal to the good sound this amp produces.
I learned an awful lot about Miller capacitance, gain, how these things are inextricably linked and how to work out filters from Andrew and Nick when I built a phono stage based on the RCA "Orthophonic" circuit. I still love the sound that that phono stage produced, although Nick and Andrew might beg to differ there
On the speaker front I was able, using simple maths to design and build the Metronome speaker. Further input from Scott, using a more sophisticated computer modelling method and his vast experience of quarter wave designs enabled me to load the drivers correctly and turn a merely OK speaker into something really rather good.
What you may ask is the point of this post?
All I am trying to say is that with the help of the guys on here and some work myself on the maths I have gone from complete novice to reasonably competent in the space of about two years. I am getting far more out of the hobby now than ever before and all because of a bit of maths.
We have on here, amp experts, phono stage experts, speaker experts
and digital experts. What a great resource to have available, free gratis and for nothing!
I listened, took their advice and have benefitted immensely in terms of what I now get out of this hobby compared to what I would have done if I had stuck to kits.
It takes a while but it is well worth it.
Steve
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