Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

Re:Build Your Own Professional-Grade Audio Amp on the Sort-O... by aidenn0 on Wednesday October 31, 2018 @07:54PM (#18350251)

There are cases where the difference is huge; particularly when you have very long runs between the preamp and the amp. This is on reason why you usually see XLR inputs to monitors. Any noise induced is amplified and a long unbalanced wire is a big antenna.

I've heard of cases where you could receive AM radio stations from such a setup; I lean towards "urban legend" for that though. While it seems theoretically possible (since many amplifier topologies can have resonance when fed signals outside their expected operating range), it seems a bit farfetched to actually end up with intelligible audio.

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Re:Build Your Own Professional-Grade Audio Amp on the Sort-O... by W-_-D on Wednesday October 31, 2018 @08:06PM (#18350324)

It's actually pretty common on older guitar amps. I've got a Marshall TMB replica which has this issue when the guitar isn't plugged in. If you turn it up loud enough, you can make out sentences clearly. I thought I was going crazy when I first noticed it.

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Re:Build Your Own Professional-Grade Audio Amp on the Sort-O... by rcxdude on Thursday November 01, 2018 @08:29AM (#18353274)

It's not as far-fetched as you might think. While you aren't likely to see the classic AM demodulator circuit appear in an audio signal path, the nature of AM is that any non-linearity will cause some degree of demodulation to occur, so it can appear in all kinds of places unexpectently (especially if a powerful transmitter is nearby).

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Re:Build Your Own Professional-Grade Audio Amp on the Sort-O... by tobyhinloopen on Thursday November 01, 2018 @03:42AM (#18351984)

It is absolutely not an urban legend. I experienced it myself with my Z5500 speakers! It was a bit soft but on max volume you could clearly make out what was being said

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