Quote Originally Posted by Mr Peabody
My LINN amp is Class D, 11 lbs and 125x5. Class D is what Panasonic calls their receivers. PWM to my understanding works as Feanor stated. Panasonic, and I assume others, claim this is a digital output, but it's hard to get used to thinking of a transistor output being digital. I was aware of PWM being used in power supplies but I didn't realize it went to the extent that it does in Class D.

This opens up a whole new way of thinking for me. If analog signals are converted to digital, will there be any difference noticed between better, best, analog equipment through these amps? I wonder if my LINN converts the analog input to digital before becoming PWM? If so, this means the processor converts digital to analog just to be converted back to digital again. Being some what OCD about my signal path, this hurts just thinking about it.
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I assumed in a typical receiver that the analog signals were preserved and bypassed the digital domain. I wonder if this is true? If not, I may be wrong in telling people they should notice differences in more expensive CD players using their analog outs into HT receivers. Will the better analog output sound be preserved in a conversion? I haven't done much study on analog to digital conversion up to now but this seems like it may become increasingly important.

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Mr. P, I believe it's very unlikely the the Linn converts to PCM before converting to PWM. (That is, assuming the Linn is a power amp only -- I don't know the Linn models very well.) Such a conversion seems point less: it would be easier to go directly from analog to PWM (or whatever PWM variant Linn uses).

Of course, it's different for an AV receiver where DSP is what you want. Many, but not all, AV receivers have a "bypass" mode where an analog signal can be sent directly from input to the output section without DSP, consequently skipping the ADC and DAC stages in most cases. The Panasonic XR25 that I have does NOT have a bypass mode, however, and always converts to PCM. Nevertheless it is a pretty good sounding amp.