If you listen primarily to rock and or jazz a tube amp here is just a bad idea. If you want some tubiness use a tube preamp with a SS amp. Those frequencies at risk are the ones that provide the punch to the the music. The Focals cry out for a 100 watt/ch class A amp. There are amps in this category that are great at mimicking tube amps such as any Pass amp and the big Parasounds.
HELP advise PLEASE - Focal Sopra 2 Speakers - I want a tube amp but " Min 2.6ohm @ 104Hz "
HELP PLEASE advise bought a pair of Focal Sopra 2 Speakers that I absolutely love.
I want to use an integrated tube amp with them but the measurements worry me even though many Sopra owners say they happily use tubes with these speakers.
HERE IS THE ISSUE:
From HiFi News September 2015, lists Minimum impedance is around 2.6 ohms at 104Hz. Combined
with high impedance phase angles at low frequencies this results in a minimum EPDR (equivalent peak dissipation
resistance) of 1.1ohm at 85Hz – challenging to the partnering amplifier.
Can I used an integrated tube amp and hope for success?
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From HiFi News September 2015, minimum impedance is around 2.6 ohms at 104Hz. So the amplifier should be capable of approximately doubling its 8 ohm output power into at least 4 ohms and preferably again into 2 ohms.
Min 2.6ohm @ 104Hz. Focal claims 91dB sensitivity for the Sopra No 2 but our measured pink noise figure of 88.2dB falls almost 3dB short of this. Low impedance is a factor in achieving this figure: Focal specifies a minimum impedance of 3.1ohm (which would indicate a 4ohm nominal rating rather than the specified 8ohm) but we measured a dip to 2.6ohm at 104Hz. Combined with high impedance phase angles at low frequencies this
results in a minimum EPDR (equivalent peak dissipation resistance) of 1.1ohm at 85Hz – challenging to the partnering amplifier. The forward frequency response [Graph 1, below], measured on the tweeter axis, is essentially flat in trend with just a mild presence band dip.
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I want to use an integrated tube amp with them but the measurements worry me even though many Sopra owners say they happily use tubes with these speakers.
HERE IS THE ISSUE:
From HiFi News September 2015, lists Minimum impedance is around 2.6 ohms at 104Hz. Combined
with high impedance phase angles at low frequencies this results in a minimum EPDR (equivalent peak dissipation
resistance) of 1.1ohm at 85Hz – challenging to the partnering amplifier.
Can I used an integrated tube amp and hope for success?
____________________________________________________________________________________
From HiFi News September 2015, minimum impedance is around 2.6 ohms at 104Hz. So the amplifier should be capable of approximately doubling its 8 ohm output power into at least 4 ohms and preferably again into 2 ohms.
Min 2.6ohm @ 104Hz. Focal claims 91dB sensitivity for the Sopra No 2 but our measured pink noise figure of 88.2dB falls almost 3dB short of this. Low impedance is a factor in achieving this figure: Focal specifies a minimum impedance of 3.1ohm (which would indicate a 4ohm nominal rating rather than the specified 8ohm) but we measured a dip to 2.6ohm at 104Hz. Combined with high impedance phase angles at low frequencies this
results in a minimum EPDR (equivalent peak dissipation resistance) of 1.1ohm at 85Hz – challenging to the partnering amplifier. The forward frequency response [Graph 1, below], measured on the tweeter axis, is essentially flat in trend with just a mild presence band dip.
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