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Paul Klipsch was right - What the world needs is a good 5 watt amplifier

For those who are questioning whether a low power high quality amp would be able to properly drive any speakers I've recorded a short video demonstrating very high SPL level from a speakers with average sensitivity. The video is of very low audio and video quality as its recorded from my smartphone. However, the microphone used for measuring the sound pressure is MiniDSP UMIK-1 and the software used is REW (Room EQ Wizard). During the tests the amplifier didn't show any hint of stress of distortion

The speakers used in this video are Sonus Faber Olympica II and the integrated amplifier is Pass Labs INT-25. According to some third party reviews the Olympica's are thought load for the partnering amplifier as their sensitivity is averagely rated (88db) and the impedance curve drops down to 3 ohms in the bass region with a estimated EPDR (the point where the impedance curve is intersecting with the phase angle) of 1.6 ohms. The pass labs is rated at 25wpc @ 8omh and is said to be stable down to 1 ohm doubling its power at 4 and 2 ohms. According to the manual it can deliver 200wpc @ 1ohm before the protection circuit is activated. 

So, the point of the video is to show that the Pass with its poorly rated power (25wpc) can drive even demanding speakers to insanely loud levels without any sound degradation. 

  

 

celestial__sound
atmasphere's avatar
atmasphere
11,784 posts
 

FWIW front row center at an orchestral concert can easily be over 100dB on peaks.

There are a lot of things that can cause harshness in a system when you try to run the volume at realistic levels.

Early side wall reflections are interpreted by the ear as harshness.

Higher ordered harmonics are interpreted as harshness.

Resonances excited by vibration in a turntable or vacuum tubes (microphonics) are interpreted by harshness.

Slap echoes in the room are interpreted as harshness.

Even if you don't play at +100dB levels, getting a handle on these things will result in a more musical relaxed presentation in the room even if 85dB is your maximum volume.

Of course you want your amp to have a good first watt!

limomangus's avatar
limomangus
1,426 posts
 

I have Polk Lsim707, they say their 88db,but I have read reviews there more like 85 db....well I had a lot of amps with 200 to 250 wpc to drive them...My Chinese made Cayin A50TP MK II with 16w Triode 35 w Ultra drives them with no problems what so ever...I have a big room 25 ×35 Cathedral ceiling  ,and I can play them Loud.....

dsper
663 posts
 

Hi All,

You all are much more knowledgeable than me, so I have a couple of questions if I may.

I bit the bullet and bought a pair of Klipsch Forte iv's in order to try a pair of high efficiency speakers. Listened to Cornwalls four or five times but felt, for me, the bass was better with the Forte's.

Played the Forte's with my McCormack DNA-500 amp, which is great with my Theil CS5i's, but not so much with the Forte's. 

Switched out to my old CJ LP66S tube amp and the sound greatly improved. In my space, 60 wpc is much more than enough. I think 30 wpc could be too much.

First question: does it make sense that the DNA-500 probably would not sound good with horns? Why?

Second Question: I recall reading somewhere that horns generally do not like amplifiers that use a lot of negative feedback. Is this generally true? Why?

Just trying to lay the groundwork to try a lower power tube amp or maybe Pass/First Watt?

Thanks for listening,

Dsper

 

 

 

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