Excellent comments by Folkfreak, with which I agree entirely. Some further comments:
1)There are two ways in which cartridge output ratings can be defined, and unfortunately manufacturers usually do not indicate which one their spec is based on. See my post dated 7-4-2012 in this thread. The result can be a 3 db specification difference even for cartridges which in fact provide identical output voltages. And in addition, as Folkfreak indicated I wouldn’t count on such specs being particularly accurate either.
2)The reason for the differing gain recommendations you mentioned is that the KAB calculator indicates the gain required to boost a cartridge’s rated output to only 325 mv, while as you indicated Harley’s recommendation is based on boosting the cartridge’s rated output to 1 volt. 1 volt is 10 db more than 325 mv, which corresponds precisely to the difference between the two recommendations.
3)Both Stereophile and Soundstage measured the sensitivity of the LS50 as being about 84.5 db at 1 meter, for an input of 2.83 volts. In much of the mid-bass region, where lots of energy is typically required, the impedance of the speaker is not much more than 4 ohms. 2.83 volts into 4 ohms is 2 watts, which is 3 db more than 1 watt, so in that region the efficiency of the speaker is not much more than 81.5 db/1 watt/1 meter. In other words, very low.
4)Given also that the amp’s 4 ohm power rating of 100 watts corresponds exactly to the upper limit of KEF’s recommended range of amplifier power, it seems clear that the root cause of the issue, to the extent that it is an issue, is the Ragnarok’s overall gain of 26 db, which is very low for an integrated amp.
Regards,
-- Al
1)There are two ways in which cartridge output ratings can be defined, and unfortunately manufacturers usually do not indicate which one their spec is based on. See my post dated 7-4-2012 in this thread. The result can be a 3 db specification difference even for cartridges which in fact provide identical output voltages. And in addition, as Folkfreak indicated I wouldn’t count on such specs being particularly accurate either.
2)The reason for the differing gain recommendations you mentioned is that the KAB calculator indicates the gain required to boost a cartridge’s rated output to only 325 mv, while as you indicated Harley’s recommendation is based on boosting the cartridge’s rated output to 1 volt. 1 volt is 10 db more than 325 mv, which corresponds precisely to the difference between the two recommendations.
3)Both Stereophile and Soundstage measured the sensitivity of the LS50 as being about 84.5 db at 1 meter, for an input of 2.83 volts. In much of the mid-bass region, where lots of energy is typically required, the impedance of the speaker is not much more than 4 ohms. 2.83 volts into 4 ohms is 2 watts, which is 3 db more than 1 watt, so in that region the efficiency of the speaker is not much more than 81.5 db/1 watt/1 meter. In other words, very low.
4)Given also that the amp’s 4 ohm power rating of 100 watts corresponds exactly to the upper limit of KEF’s recommended range of amplifier power, it seems clear that the root cause of the issue, to the extent that it is an issue, is the Ragnarok’s overall gain of 26 db, which is very low for an integrated amp.
Regards,
-- Al