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Amplifier recommendations for 86 dB Sensitivity Speakers

Hi,

I’m considering a pair of Technics SB-G90M2, they have good specifications on paper; however, my only concern would be their 86 dB sensitivity. 

My current amplifier is Cayin A100t, which according to its specs, outputs 70 watts into 8ohms. the Technics are 4 Ohms; so, I assume my Amp could deliver 100-140 Watts into 4 Ohms. Unfortunately, I couldn’t find more accurate information about my amplifier, and it only shows the output power at 8 Ohms equipped with KT-88 output tubes (mine came with EL-34s), therefore, it’s unclear what the real output powerat 4 ohms is.

Wondering if this tube amplifier would be a good match for these more demanding 86 dB speakers? I’m aware of impendence fluctuations and I know the Amp can drive them just fine, but I am not sure if 100 watt per channel -assuming that’s what my Amp can deliver into 4 Ohms- would be enough for these speakers to make them sound as intended, meaning, good sound quality.

(I don’t nor am planning to listen at high volume but have a larger room with high ceilings).

Below are the specs.

Many thanks,

 

Technics SB-G90M2 Speakers 

  • Type: 3-way floorstanding speaker with bass reflex
  • Woofer: 2 x 16 cm
  • Midrange: 16 cm
  • Tweeter: 2.5 cm
  • Sensitivity: 86 dB
  • Impedance: 4 ohms
  • Frequency range: 33 Hz – 90 kHz (-10 dB)
  • Crossover frequencies: 500 Hz, 3400 Hz
  • Maximum power handling: 200 W
  • Recommended amplifier power: 40-200 W
  • Dimensions and weight: 111.4 x 29.2 x 36.6 cm / 35 kg

 

Cayin A100T Integrated Tube Amplifier 

Power output: 70 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 65kHz

Total harmonic distortion: 1%

Input sensitivity: 480mV (line)

Signal to noise ratio: 89dB (line)

Speaker load impedance: 4Ω to 8Ω

Valve complement: 8 x KT88, 2 x 12AU7, 2 x 6CG7, 1 x 12AX7

Dimensions: 440 x 210 x 397mm

Weight: 29kg

mamifero
oddiofyl's avatar
oddiofyl
4,219 posts
 

Agree that most tube amps that can comfortably drive a 4 Ohm speaker will have 4 Ohm speaker posts or the amp’s transformer has different internal taps to wire to the binding posts.   
 

My Quicksilver amps have 4 and 8 Ohm posts.  My 300b amp has 8 and 16 Ohm taps … confirmation that it’s not a good match with difficult loads.

Often times a tube amp will put out less power with 4 Ohm speakers connected to an 8 Ohm post.  
 

Just picked up a pair of 6 Ohm speakers. They are 88dB sen and 50 watts wasn’t quite enough.  100 was a good match. 
 

 

glennewdick's avatar
glennewdick
1,807 posts
 

your amp has 4ohm taps so just hook it up to those and you should be fine at low to moderate levels. 

mamifero OP
12 posts
 

Thanks everyone for your really helpful comments.

Indeed, the Cayin A100T has 8 and 4 Ohm taps, and I’m sure it can drive 86 dB speakers, however, since I couldn’t find information regarding its 4 Ohm output, I am not sure if it would have enough power to make those sound good and as were designed for; probably when they engineered these they had in mind those really advanced and powerful Technics amplifiers, or something similar. 

As a reference, I remember testing my old B&W 705 monitors with two different tube amplifiers. One was a 40 watt per channel and the other was this Cayin (70 watt per channel), and at the same volume level, the more powerful amplifier made a significant difference, it made the 705s sound more defined, in particular the bass was much better. So, I believe it might be the same with these Technics speakers, the Cayin will be able to output adequate power but I might be missing out their full potential. 

 

ozzy62's avatar
ozzy62
3,438 posts
 

the Cayin will be able to output adequate power but I might be missing out their full potential. 

Bingo!

glennewdick's avatar
glennewdick
1,807 posts
 

"Indeed, the Cayin A100T has 8 and 4 Ohm taps, and I’m sure it can drive 86 dB speakers, however, since I couldn’t find information regarding its 4 Ohm output,"

 

Tube amps do not increase power at lower impedances like SS amps do. The output transformer matches the output of the amp to match the speaker’s impedance so it’s still 70wpc out of the 4ohm tap. But this also functions to match the speaker’s impedance to the amp much better. I think 70wpc should be enough if you’re not trying to rock out at 100db. Technic’s recommended power is well within your amps power output. Recommended amplifier power: 40-200 W

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