Hi-Fi Tunig Fuses & Parasound A21
georgelofi 1,822 posts 11-16-2016 5:21pm geoffkait you are just a voodoo’ist, as is most of the stuff on your website. http://www.machinadynamica.com/ Real techs above are trying to tell you something, in a nice way, just incase you have something wrong upstairs. Cheers George Ouch! Very ouch! |
The idea that fuses and power supply components are not part of the signal chain is not entirely correct. Anything coming in from the A/C, power cables, fuses, rectifiers, regulators, or power supplies can all become part of the output signal. An operational amplifier circuit (whether discrete or monolithic op amp) will only pass through the actual signal if the signal is coming in on the inverting input of the op amp AND the negative feedback gain is unity gain (0 gain) or less than unity gain (i.e. it’s forcing op amp to de-amplify the signal). In this case, the waveform signal will actually route itself around the op amp using the negative feedback line as a pathway. That being said, even with unity gain, the type of op amp or power supply elements will still influence the character or sonic signature of the audio. If the negative feedback circuit is set to create a "gain" (or amplify), it increases the voltage of the waveform by using voltage from the positive/negative rails from the power supply (i.e. +/-15V). This additional voltage is sent through the output pin of the op amp. It this case, the fuse, power cord, A/C elements will contribute to the character of the waveform (in the sense of affecting how the op amp slews in relating to the input waveform, how far/fast it slews, character of the DC noise, etc.). In a power amp circuit, the output transistors have to create massive gain (turning a 1V input into something like 15-100 watts or more). It has to use the A/C power coming in to create this voltage, so your signal is actually something like 98% A/C voltage. https://www.youtube.com/watch?v=7FYHt5XviKc I’ve posted that link before, but it’s an excellent lecture on how op amps actually work. |
Actually, I perjured myself. On a unity or less gain, the input waveforms are, indeed, going around the op amp. However, they are getting sucked back into the output pin. The op amp is having to generate twice as much output voltage, since half of that is coming from the negative feedback. So, in all cases, the output of an op amp is always going to be based on positive/negative power supply current (i.e. fuses, regulators, A/C, etc.). Think of an op amp like faucet where you have to push down on a button to produce water output. The harder you push on the button, the faster water comes out. All op amps or transistors are variations of this idea, hence the old tubes being used to be called "valves". |
Auxinput, thanks for the explanation. After reading all the posts on how a fuse can or cannot interact and affect the signal path, your's has what seems to be the least amount of spin. It could very well be that due to my bias it sunk in but I've been temporarily swayed by arguments that go against what I actually hear only to come back to believing what I actually hear. :-) All the best, Nonoise |
