The reason old school car amplifiers sound so much better is because of quality. Names like ADS, Rockford Fosgete, U S Amps, Precision Power, Orion and a few select more. If you had one of these Amps made from 1977 till about 1999 You had something you do not see being built today. If you see one for sale in my blog and you have an old one Similar to it I will buy them from you no matter what shape they are in.(I do not pay very much for them especially broken or untested)
The car stereo situation today is sad I am not even sure if you can get an amplifier that uses discrete components.(This means an individual transistors that operates the driver and final stages of the amplifier )BUT WHY DO THEY SOUND SO MUCH BETTER?
These individual transistors give you better sound because they do not bleed through to the next component like an IC dose. An IC is actually multiple components like several transistors and diodes packed into a nice little package that cost much less to the manufacture this is why Electronics cost so much less than they used to. This and much cheaper watt per dollar design like Class D Amplifiers(Which I will talk about later) and a lot of deceiving wattage ratings makes the consumer think he is getting a high output system for cheep. And it will make a tremendous amount of noise for very little watt per dollar spent and break down is soon as the warranty runs out. You can nearly count on it going out quickly. I do not care what brand it is it will breakdown and you will have to buy another in a short while if they cut corners on cost when they were built. And all the major car stereo manufactures I used to love to listen to have been outsourced overseas and most lie about their true power output delivered to the speaker.(Which I will explain in great detail later)
BUT WHY DO THE OLD SCHOOL AMPLIFIERS SOUND SO MUCH BETTER? It complicated to explain but it boils down to loss of low frequency production and distortion at the bottom end of the audio spectrum. I tested several class D amplifiers and they produced 0 watts at 20HZ .They did not start producing any output until about 40 Hz and most of them at 50Hz.
A person with perfect hearing can hear from 20 Hertz to 20000 Hertz or 20KHZ.Octives of music are as follows 20HZ to 40HZ is one octave 40Hz to 80Hz is one 80Hz to 160Hz is one 160Hz to 320Hz is one 620Hz to 1240Hz 1240Hz to 2480Hz is one 4960Hz to 9920hz is one and finally 9920Hz to 19840Hz . 8 Octaves you can hear. An Octave of music contains all seven musical notes A B C D E F and G and their sharps and flats. WHEN AN AMPLIFIER CANNOT PLAY OR IS WEEK FROM 20hZ TO 50hZ You are as the listener are missing the entire lowest octave of music and part of the next one. Anyone listing can hear this.
I replaced a customers HiFonics 1000watt Class D amplifier with a little Rockford Fosgate Old School Punch 150. We were both amazed at how much more bottom and gusto it had with the much smaller 20 year old amp. It was like night and day.
I take broken down old school amplifiers and rebuild them bringing them back to life. I sell them using this website. Each one has a Rebirth Certificate which I take my signal generator and run the amp at 20Hz first for about 10seconds and I look with my Oscilloscope at the signal at clipping I measure the Voltage and the Current then to multiply them to determine the wattage. I go up an octave at a time and It makes a graph showing the wattage at the various frequencies drive all channels at the same time. You will get a more true reading than just running the amp at one frequency in the middle of the audio spectrum on one channel. I test the amps at the manufactures rated ohm loads using a speaker not a resistor sometimes I use lower ohms loads If the Power Supply and output transistors are built to take it.
I will have more to come on how each amp test out and my opinion about how it sounds on bass and midrange and highs..