I did mention, oh….a year or two ago….. that I would like to design and build the Best Amplifier In the World. I didn’t? Well, I meant to. It’s your fault if you can’t follow simple smoke signals and temporal-time-warp-speke.
We have actually got some little way into our Best Amplifier….blah…blah…design.
Mr. Dumble based his designs on somebody else’s (Leo, no less), and a stratospheric pricing philosophy. There’s no doubt if you’re going to copy somebody (allegedly) you would be sensible to make sure that the ‘somebody’ knew what they were doing. There would be no point codging your neighbour in the next desk’s answers to your French exam if he happened to be doing the geography of Beijing.
The overiding piece of understanding we need (stratospheric pricing philosophies notwithstanding) is that we have so far loosely put together a number of parts.
Mains input transformer primary…goes to secondary…..goes to rectifier….goes to smoothing. IT IS MODULAR !!!!! And so is the rest of our Best Amp in the….blah, blah.
The power amp section of a solid state amp is less simple to section off into a modular form, because there are so many negative feedback loops (ac and dc), but it is still modular in essence.
So we have got as far as the smoothing section in our Best….blah, blah. What next?
Well, staying within our so far unmathematical approach, we get to the decoupling stages of the various dc rails, which supply the different preamps and power amp.
Onwards and upwards…………
Yes it’s true! My favourite person in the whole Solar System has yet again, in his infinite generosity, awarded me another packet of macaroons!!!!!!!!
So this is to digitally set my gratitude in stone. This is, un…..fortunately, rather like setting it in wax over a hot grill pan. Such is the immense value of the free information society. The stuff that is really valuble is written on rice paper and kept in an alligator’s anal tract.
That is not to detract from Dave’s wonderful generosity. Thank you Dave, you are indeed a gentleman. Un….fortunately I’ve eaten them all.
So it only remains for me to be miserable until Dave’s gear next breaks down.
And if you remember Flash Gordon, you must qualify for ‘Old Git’ status. Surely.
Let’s clarify this. There’s a first time for everything.
The ‘Flash Gordon’ I’m on about is not the one that Freddy Mercury waxed lyrical about. No. The Flash that I’m referring to was the one where the smoke from the rockets in outer space went upwards…..? I’m ashamed to admit that that is the only thing I can recall from my hundreds of Saturday morning visits to the local bug’s hut, the Coliseum.
Back on the topic. I think that might have been the shilling each way I bet on the dog with three legs called ‘Flash Gordon’. It lost.
A phase splitter in not a ‘phase inverter’. They are often called that these days (just as a thing you lose or break regularly is called a ‘phone’), but the phase inverter, is actually any valve that has its output from the anode. Whereas the phase splitter actually splits the phase of the input and is a specific circuit arrangement that is designed to drive two halves of a push-pull output stage. One side anode goes positive and the other side anode goes negative. Hence the phase splitting thing.
The point of this (there’s a POINT?), is that, although a lot of emphasis (and money) is put on output valve matching (and rightfully so), the phase splitter which feeds the grids of these output valves are rarely spoken about. But an internally matched ECC83 is basically a double triode valve, and if the outputs of those anodes are not well matched, the big bucks you’ve spent on some really nicely matched output valves wasn’t worth the dog I bet on called Flash Gordon.
The output valves can only reproduce whatever is going in, and if that is not symetrical, neither is your output signal.
It’s always hard to describe a sound, but the effect of this imbalance, to me anyway, is a loss of clarity and weakness of the sound. So next time you need to change output valves, get a nicely matched phase splitter to go with them.