Guidelines:
Before we enter explanation of the technical solution of our invention and patent:
Linear Audio MOSFET Power Amplifier 1000W@1Ω and 5000WRMS@0,2Ω Load (500W RMS@8Ω load) With Wide Choice Possibility Of Working Voltage From +/-25V DC to +/-90 V DC, we would like to present the guidelines by which we were led to the unique way of designing quality audio power amplifier.
Before (s)he starts thinking of electronic design of the amplifier, the designer has to know for which purpose it will serve him. The same thing goes for the potential buyer of the amplifier.
In other words; if you need off-road vehicle, you will not choose Ferrari to drive on mountains. Also it would not be very clever to buy Ferrari and drive it on the crowded streets of Skopje, just to say that you have Ferrari.
Other thing is the rule which says: sound system is as good as his weakest link.
Clearly there are solutions that are well suited for wide consumption and give satisfaction to the needs of reproduction of sound for average listener. Important changes in the design of power amplifiers happened in last few years.
We were always exited by the esoteric and uncompromising designs like the amplifiers of Nelson Pass, Mark Levinson and Kaneda. We were always attracted by constructors like W. Marshall Leach and Nelson Pass and their philosophies; we learned great thinks from them for which we are very grateful.
To establish all served philosophies as well the experiences and used materials it took lot of time to discover that they are not the same as the authors wanted to show them. For example, a declaration that they (amplifiers) work without feedback can be easily denied by an experienced designer. Or the consumption of 3-4 kW for one designed A-class amplifier, just to use only 20W useful audio force, to justify the need for high- quality reproduction is way too unpractical.
As response to the challenges and dilemmas, we came up with uncompromising 300W RMS audiophile MOSFET 8Ω electro amplifier, with incredible characteristics and with working rate (frequency range) to 700 kHz in range from +/- 3dB in AB class.
In AC DC workshop was made one prototype in which was implemented our first innovation from 1998: Very Cheap Stabilizer With 4-decimal Accuracy. This AB class amplifier has three stages in signal route and current feedback. The technical characteristics are flawless. Speaking of speakers, this amplifier appears to be stable into any load, all the way down to a dead short across the speaker terminals. Beside all measurements, we have made countless blind comparative sound hearing tests which ensured us that we are talking about unique sample that literally can play everything and brings out the best from the speakers.
With time we realized that except audiophile merit, this relatively expensive project has no bright future in Republic of Macedonia. For worldwide market: it will need time and money.
To return to the guidelines:
First to clear up the meaning of distortion i.e. the eternal dilemma: lamp or semiconductor.
Imagine you have two amplifiers: one with 2%THD, and the other one with 0.0005%. The ratio of the distortion among these systems is unbelievable 4000:1. That is mathematical fact. If someone told you that the lamp with THD=2% sounds far better, than inevitably comes the dilemma that the distortion is not important element when we comes to characteristics of the amplifiers. More surprising fact is that these amplifiers with high distortions are sometimes much more expensive than the others.
Our conclusion is that the distortions are not desired and that subjectivity while evaluation of the amplifiers brings only improvisations and self deceiving. The sale and marketing are something completely different. It is better distortion to be produced somewhere in the signal line path (processor or mixer) instead in the output triodes. One more additional thing to these analyses: always use balanced input while measuring, to avoid forced second harmonic.