Infinity Kappa 7s and Jolida sj502a

P

pigneguy

Audiophyte
Hi,
just purchased a pair of Infinity Kappa 7s and unsure as to whether my Jolida sj502a amp will have enough power to feed them for extended periods. Should i upgrade my amp ?

Kappa 7 / 7A

Introduced: 1987
Dimensions: 94 x 43 x 31 cm
Bass: 1 x 30 cm
Mids: 1 x Kappa-Polydome
Highs: 1 x EMIT
Suggested for amplifiers with: 40-200 Watts per channel
Frequency range: 37 Hz - 45 kHz
Crossover frequencies: 800 Hz, 4500 Hz
Suggested price (pair): 1500 $


Nominal Impedance: 4 to 6 ohms
Power Rating: 40-200 watts RMS
Efficiency: 88 dB @1 watt, 1 meter
Crossover Frequencies: 800Hz, 4500Hz
Frequency Response: 37Hz-45kHz +/-3dB
Introduced in 1987
Discontinued 1989



Specifications: Jolida SJ502A

  • Maximum Power Output:85 wpc at 8 ohms, 1KHz Rated Output:60 wpc at 8 ohms, 25Hz to 60KHz Frequency Response:(at 1 watt into 8 ohms) 8Hz to
  • 130KHz + 1dB
  • Bandwidth:15Hz to 80KHz + 3dB; 0dB 60 W 1KHz
  • Distortion THD:Less than 1% at 20 V output, 28Hz to 15KHz
  • Circuit Type:Ultra Linear, Class AB
  • Input Impedance:100Kohms
  • Input Sensitivity:600mV at 1KHz for 60 watt output-
  • Output Impedance:4 ohms and 8 ohms Negative Feedback: Less than 5 dB Noise and Hum:85dB below rated output
  • Tube Complement:2 matched pairs (4) of 6550/KT88 power output; 2 pcs. 12AX7A/ECC83 pre-amplifier; 2 pcs. 12AT7/ECC81 power drivers.
  • Power Requirements:110V-120 VAC 60Hz 180 watts-standby, 450 watts maximum (220 VAC 50Hz option). Dimensions:17 inches (43cm) wide by 1 5 inches (38cm) deep by 7.5 inches (19 cm)
  • high.Weight:39 pounds (18 Kg)
  • Price $1100 new, average used $650-$700
 
rojo

rojo

Audioholic Samurai
Hi,
just purchased a pair of Infinity Kappa 7s and unsure as to whether my Jolida sj502a amp will have enough power to feed them for extended periods. Should i upgrade my amp ?

Kappa 7 / 7A

Introduced: 1987
Dimensions: 94 x 43 x 31 cm
Bass: 1 x 30 cm
Mids: 1 x Kappa-Polydome
Highs: 1 x EMIT
Suggested for amplifiers with: 40-200 Watts per channel
Frequency range: 37 Hz - 45 kHz
Crossover frequencies: 800 Hz, 4500 Hz
Suggested price (pair): 1500 $


Nominal Impedance: 4 to 6 ohms
Power Rating: 40-200 watts RMS
Efficiency: 88 dB @1 watt, 1 meter
Crossover Frequencies: 800Hz, 4500Hz
Frequency Response: 37Hz-45kHz +/-3dB
Introduced in 1987
Discontinued 1989



Specifications: Jolida SJ502A

  • Maximum Power Output:85 wpc at 8 ohms, 1KHz Rated Output:60 wpc at 8 ohms, 25Hz to 60KHz Frequency Response:(at 1 watt into 8 ohms) 8Hz to
  • 130KHz + 1dB
  • Bandwidth:15Hz to 80KHz + 3dB; 0dB 60 W 1KHz
  • Distortion THD:Less than 1% at 20 V output, 28Hz to 15KHz
  • Circuit Type:Ultra Linear, Class AB
  • Input Impedance:100Kohms
  • Input Sensitivity:600mV at 1KHz for 60 watt output-
  • Output Impedance:4 ohms and 8 ohms Negative Feedback: Less than 5 dB Noise and Hum:85dB below rated output
  • Tube Complement:2 matched pairs (4) of 6550/KT88 power output; 2 pcs. 12AX7A/ECC83 pre-amplifier; 2 pcs. 12AT7/ECC81 power drivers.
  • Power Requirements:110V-120 VAC 60Hz 180 watts-standby, 450 watts maximum (220 VAC 50Hz option). Dimensions:17 inches (43cm) wide by 1 5 inches (38cm) deep by 7.5 inches (19 cm)
  • high.Weight:39 pounds (18 Kg)
  • Price $1100 new, average used $650-$700
Your speakers are 88dB/w/m. Each time you double the wattage, you increase the SPL by 3dB. 2w = 91dB. 4w = 94dB. 64w = 106dB. That's per speaker. With both speakers playing together, add either 6 dB to the SPL or 1 meter to the distance.

Put another way, at 1/2 watt, sitting two meters from the speakers, your speakers are as loud as a vacuum cleaner (85 dB). The National Institute for Occupational Safety and Health claims you are at risk of noise-induced hearing loss if you're subjected daily to 94dB (4w with that amp and speakers) for more than an hour. At 97dB (8w) that time drops to 30 minutes per day. Your amp will easily drive those speakers to hearing loss levels.

As far as whether that 8Ω amp can handle the 4 - 6Ω nominal load, my guess is, probably. Just listen for harshness and back down on the volume if you hear impurity.
 
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