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Post by orthikon on Apr 23, 2014 9:35:12 GMT -5
big nick in emo sales dept told me that if the xpa 1 led are 1/2 way across the screen your using about 250 watts in 8 ohm mode 4 don't show.. what do you mean by the "...4 don't show" part above? I am using my xpa-1 gen 1 with Magnepan 3.6 (85 db sensitivity, dipole) and it does up the light up the LEDs halfway with if I turn it up especially those louder bass notes. I'll try to use my rat shack SPL meter and try to calculate the watts used backwards |
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Post by orthikon on Apr 23, 2014 9:37:33 GMT -5
Nice Cables! Received my XPA1's gen2 a couple of months ago and can confidently say that there is NO audible differences using A or B mode in conjunction with my 63 year old pair of ears. how loud and how far are you listening and what's the sensitivity of your speakers? I'm trying to find out if you are staying in class A or in AB. |
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Post by monkumonku on Apr 23, 2014 10:44:36 GMT -5
Nice Cables! Received my XPA1's gen2 a couple of months ago and can confidently say that there is NO audible differences using A or B mode in conjunction with my 63 year old pair of ears. If there really was any significant difference between the sound of an amp in class A versus class AB mode, wouldn't that then be an annoyance? Because you'd be listening to music in class A mode, and then when it switched, it would ruin the experience of enjoying the music. It would be like if musicians kept switching amplifiers or mics during a concert and you got a different sound character each time. So I would think that the goal should be to make the transition from A to AB as acoustically transparent as possible. However, in the audiophile world it seems that many people experience more enjoyment from being able to discern the transition point from class A to AB than they do from the music itself.  |
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LCSeminole
Global Moderator 
Res firma mitescere nescit.
Posts: 20,850
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Post by LCSeminole on Apr 23, 2014 13:23:00 GMT -5
Rickie, you are making entirely toooooo much sense!  |
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Post by monkumonku on Apr 23, 2014 13:32:45 GMT -5
Rickie, you are making entirely toooooo much sense! That's okay, I'll make up for it on my other posts that exhibit a lack thereof. (like always changing speakers...)  |
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Post by deltadube on Apr 23, 2014 15:35:47 GMT -5
Rickie, you are making entirely toooooo much sense! except that its class A switching to class AB.. cheers |
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Post by deltadube on Apr 23, 2014 15:38:14 GMT -5
big nick in emo sales dept told me that if the xpa 1 led are 1/2 way across the screen your using about 250 watts in 8 ohm mode 4 don't show.. what do you mean by the "...4 don't show" part above? I am using my xpa-1 gen 1 with Magnepan 3.6 (85 db sensitivity, dipole) and it does up the light up the LEDs halfway with if I turn it up especially those louder bass notes. I'll try to use my rat shack SPL meter and try to calculate the watts used backwards you will need to chat with an expert ... 8 ohm is only 500 watts eh.. 4 ohm is 1000 watts eh.. the led I was told is based on 8 ohm draw.. I have no idea if I understood correctly or not.. but 1/2 way is 250 into 8 ohm |
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Post by novisnick on Apr 23, 2014 17:39:12 GMT -5
what do you mean by the "...4 don't show" part above? I am using my xpa-1 gen 1 with Magnepan 3.6 (85 db sensitivity, dipole) and it does up the light up the LEDs halfway with if I turn it up especially those louder bass notes. I'll try to use my rat shack SPL meter and try to calculate the watts used backwards you will need to chat with an expert ... 8 ohm is only 500 watts eh.. 4 ohm is 1000 watts eh.. the led I was told is based on 8 ohm draw.. I have no idea if I understood correctly or not.. but 1/2 way is 250 into 8 ohm Purchase a Watt-O-Meter and you'll have your answer.I can tell what my amps are drawing with my meter on it. |
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Post by Jim on Apr 23, 2014 18:47:04 GMT -5
you will need to chat with an expert ... 8 ohm is only 500 watts eh.. 4 ohm is 1000 watts eh.. the led I was told is based on 8 ohm draw.. I have no idea if I understood correctly or not.. but 1/2 way is 250 into 8 ohm Purchase a Watt-O-Meter and you'll have your answer.I can tell what my amps are drawing with my meter on it. What you want to see is the output, however. I have a killawatt - I assume the way to meter is similar? It can only measure current, etc of the device plugged into it? I believe it's hard to correlate the output based on the input because he amplifier isn't 100% efficient. Most amps I've tested will draw 60-90W - when there is 0 output. Maybe if you can figure out the general efficiency - you can say X watts in means X out - but that would probably be with sine waves and I'm thinking that it may not be equally efficient at all wattages. This sounds like a Lonnie question. I've seen some speaker wattage meters but I think they tend to be inaccurate. |
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Post by deltadube on Apr 23, 2014 23:13:19 GMT -5
I will stick with led half way across the xpa 1 gen 1 amp is drawing about 250 watts into 8 ohm.... for further assistance talk to emo experts.. Im to busy listening to my music to really care cheers |
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Post by orthikon on Apr 25, 2014 19:40:02 GMT -5
I'm away from home too much so I have to spend my time theory crafting Well I took at my Radio Shack SPL meter and turned it up a bit to get 105 db peaks. Most of the time it was 90-95 (a lot of "quiEt" 75 db parts) dB which got uncomfortably loud at certain points of the guitar solo. I listened to Roy Buchanan's Live in Japan and Led Zeppelin's How The West Was Won and the LEDs were bouncing at halfway and for a very few moments, a third of the way but never red. So doing some calculations, (only taking into account speaker senstivity as I cannot measure the room gain factor) at 10 ft distance, with Magnepan 3.6 85db/watt/meter ~3 meter distance ~ 75bB/watt 1 watt power I get 75 dB 10 watts 85 dB 100 watts 95 dB 1000 watts 105 dB The other factors such as room gain, dipole radiation pattern, etc. probably accounts for the fact that I didn't hit red as the calculations show 1000 watts for 105 dB peaks. So the mention of LEDs in the 1/2 way 250 watt ballpark seem to be correct from my experience. And from those it seems that the 60 watt class A of the XPA-1 gen2 would be enough to sustain in class A for normal listening levels, but would switch to class AB when getting 10+ dB peaks (at least 10x the amp power). Nonetheless, I would still like to have the features mentioned before (calibrated meter, ala McIntosh and an LED indicator when leaving class A) but at this price point, I'm happy with my gen1's. I'll be patiently waiting for a pair of used gen2s BTW, listening to Nirvana's Live at New York with 95 dB peak, 80-85 average as I type this. Happy listening everyone! |
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