In real life a 3 dB gain is not much (and you need to double the power to get it). 3 dBs is generally regarded as the minimum change most people need to hear a difference when playing music. Play around with an AVR with the volume calibrated in dBs. Go up and down 1 db on the dial. I doubt you will hear a difference. And when you are listening and someone asks you to "turn it up just a little" if you turn it up 1 dB they will look at you funny. People are way too hung up on watts. In most cases it is just a marketing ploy. Why would you buy a 100 amp receiver when you can get a 160 amp receiver? But what they don’t tell you is you will never hear that difference. Doing the calculation those 60 extra watts will only give you an extra 2 dBs when playing both amps at max volume (just before clipping). If you can hear that difference you have better ears than I do. An amp having an ample power supply and good reserves to power the peaks are way more important than published watts. From what I hear the OPs amp has a great power supply and reserves. I would prefer it to a 100 watt amp with an undersized power supply and cheap power caps. He should be fine. |
I could be wrong, but I thought the Pass Labs XA 30.5 was a true Class-A amplifier, and true Class-A amplifiers don't have headroom. elliottbnewcombjr179 posts11-08-2019 12:05pmtubes, transistors, transformers, capacitors, ... are all relative to the rated amount of power within certain specs. All are sized to achieve a price point. Other components are designed to deal with ... heat. If an amp truly could produce more power within specs, certainly the manufacturer would publish that capacity. It ain't so. Measured distortion prevents a larger rating. |
@atdavid, the Pass XA30.5, as well as the XA25 which I use, and I believe most or all other Pass XA amps, operate in class A up to and somewhat beyond their specified power ratings. (I say "somewhat beyond" in part because those ratings are specified very conservatively in terms of distortion percentages). But at higher power levels these amps transition to class AB, resulting in much higher power capabilities than are specified, as illustrated by the reference Twoleftears provided above. To provide an additional example, my XA25 is specified as having capabilities of 25 watts into 8 ohms and 50 watts into 4 ohms. Yet Stereophile measured 80 and 130 watts per channel into those impedances, respectively, at 1% THD + noise. Also, the paper by Nelson Pass on "Leaving Class A" that I referenced earlier in this thread may be of interest. Best regards, -- Al |
