Amp/Preamp Asylum

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Oh the thump

Posted by airtime on April 13, 2017 at 07:18:20:
Well plate amps are made about as cheaply as possible. Some that thump on turn on or turn off are just either draining or rushing in a bit of DC current. In a stereo you would not get that thump because there is cap across the power button terminals, with speaker relay or blocking cap and large filter caps to block this DC. But in a cheap amp no relays, no large filter caps and no blocking cap = thump.

It's a miracle that plate amps last as long as they do. And they are getting even cheaper.

An example is I tried finding a new plate amp last month. The only "reasonable" plate amp I found uses jFET output transistors mounted on a grossly underrated cooling fin. After an hour it heats up and begins to hum. If you turn the plate amp over and "blow" on the fin the humming goes away. I mean what the f@#k. And people are buying these things for a grand or two. Subs are the biggest rip off in audio today.