Ughhh! There is no such thing as a "passive preamp". The two words are mutually exclusive, like "military intelligence" or "Geoff Kate".
Showing 4 responses by sleepwalker65
I'm in agreement with the notion that a wall wart will almost always be inferior to a well-designed power supply. In my case I've been using the similarity priced NAD PP2 phono preamp. There is substantial ripple voltage on the included wall wart. I don't have the measurements handy, but they were disturbingly high for the application. So, I went to my local electronics parts store and bought a nice (over-overkill) 100VA, 28v transformer, a 7824 regulator, 4,700uF 50v and 470uF 100v caps and assembled a dead-quiet 24VDC power supply for the NAD PP2. While at it, I upgraded the power connector to a 2 pin screw-lock type, and replaced the plebeian NE5532 IC op-amp with a Burson SV6 Classic discrete op-amp. The results were quite pleasing to the ears, with the faster slew rate Burson and oodles of clean power at its disposal. So, yes - a wall wart can be a limiting factor, depending on the application, and the quality (or lack thereof) of the wall wart output.
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Welp, SMPS are generally capable of producing more objectionable (irritating) noise than the 120Hz-ish ripple from a rectified 60Hz mains supply, but the economics and physical scale are in the favour of SMPS. Having said that, the manufacturing quality and sourcing of most SMPS wall warts and many SMPS modules is sketchy at best. |
You might disagree but you are still wrong. How can call something a preamplifier when does not amplify the signal? |