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Post by jmasterj on Apr 28, 2016 16:37:13 GMT -5
On my small tube integrated amp I can switch from Class A to Class AB with the press of a button. I can hear an audible difference the Class A setting the music is more refined. In the Class AB setting the amp has double the power available in Class A so there is a definite change in the sound level it seems to be more dynamic and have a little more punch. I can't really tell if there is a temperature change in the amp because it's tubes are always hot, I prefer Class AB to Class A. But if there is a definite change in the volume when switching from Class A to Class AB, isn't that comparing apples to oranges? How can you separate what is due to the actual audio quality/character versus what is due to the change in volume? I can't separate what is due to actual audio quality/character versus what is due to change in volume. All I can do is say what I hear. That was the reason I mentioned the difference in available power I thought it pertinent to the conversation. As far as the sound quality in Class A it sounds more refined to my ears. |
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Post by geebo on Apr 28, 2016 17:44:49 GMT -5
But if there is a definite change in the volume when switching from Class A to Class AB, isn't that comparing apples to oranges? How can you separate what is due to the actual audio quality/character versus what is due to the change in volume? I can't separate what is due to actual audio quality/character versus what is due to change in volume. All I can do is say what I hear. That was the reason I mentioned the difference in available power I thought it pertinent to the conversation. As far as the sound quality in Class A it sounds more refined to my ears. But if the volumes are different you have things like the Fletcher Munson curves coming in to play. Our ears just don't respond in a linear manner to frequency at differing volumes. It's very important to match volumes precisely to make a valid comparison. |
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Post by Gary Cook on Apr 28, 2016 18:04:43 GMT -5
Anyone who claims they can "hear" when an amplifier switches from class A to class A/B must have precision calibrated ears. I have far from "precision calibrated ears" but there are certain parts in certain music from certain instruments/voices in my system at a particular volume where I can more often than not pick the difference (when someone else is flicking the switch). Generally in the mornings when my ears haven't been assaulted by daily activity. More volume, less volume, different tracks, different instruments/voices, more ambient noise and I can't pick it. The bottom line is that, given equal componentry, Class AB amps have gotten so good that any previous Class A advantage is all but gone. Cheers Gary |
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Post by leonski on May 7, 2016 19:00:45 GMT -5
I have a pair of XPA-1Ls driving my 90 dB sensitive mains, under normal listening conditions, and find that the amps never switch to AB. Out of curiosity, I turned up the volume to a level that I could only handle for one track, thinking it would probably switch to AB... and it didn't. Before I purchased the XPA-1Ls, I had this thought that I would need to enjoy my Class A music at whisper-quite levels, but not only is that not true, I can listen to them as loud as I want. Is anyone finding their XPA-1Ls switching to AB during listening? How do you KNOW it didn't 'switch' (wrong term) to A/B? It is NOT a brickwall 'barrier' which when passed results in sonic mayhem and speaker damage. It's a 'sliding scale', if you will. Don't forget, if you were CRUISING around at 4 watt steady state you'd have 40 watt PEAKS. Into A/B territory for sure. 4 watts would be 102db x 2 speakers MINUS your seating distance, which decays at 6db per 'doubling' of distance or maybe more? Line source speaker like my Maggies or the ever-popular Martin Logan decay much more SLOWLY with distance than 'box speakers'. If you start at 102db 1meter and SIT at 4 meters, you are down do about 90db. Correction must be made for 2 speakers. (add) In short? if you were cranking it pretty good, and could last thru 1 track, you were cracking well into the a/b range of the amp. Don't Sweat it. Nice amp. Before I went in a slightly different direction, I briefly considered 4 of 'em to biamp my panels. |
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