2. amps-preamps
  3. 124313-2238

Not enough power?

Hi everyone,

I'm trying to sort through an issue with my system as I have it configured.  I've added a couple of pieces recently, and the results have been quite good.  However, there is one major problem - I don't seem to be able to generate reasonably high SPLs.  The system is as follows:

Source: VPI Traveler with Clearaudio Maestro V2 (4.2mv output)
Phono Stage:  LFD LE/SE (39db gain, not adjustable)
Integrated Amp: Sony TA-A1ES (80wpc into 4 or 8 ohms, switchable between the two)
Speakers:  KEF LS50 (84.5db sensitivity, 4 ohms min.)
Listening room 15x12ft.  relatively easy to pressurize.  

The system sounds fantastic.  However, I am using the volume of the Sony set between 70-80% of max, and I'm still only generating peaks of 80db (avg around 65db) at the listening spot (7 feet away).  If I push it much higher than that the sound starts to thin out quickly.  Interestingly, I had a similar problem a couple of years ago when I first tried the KEFs (and returned them) with a Hegel H80, which also puts out 80 watts per channel.  My initial thought is that the KEFs just need more power.  However, the various reviews of the LS50 use similarly powered amps with no comment about power problems.  

Don't know whether I should be looking at a more powerful amp.  The sliding class A sound of the Sony is phenomenal, but perhaps the topology just doesn't draw enough current?  Maybe the KEFs just need more kick?   I will be trying a pair of MM De Capo BEs, which in theory should be much easier to drive (although I just read a review where they were measured at just 86.7db sensitivity rather than their 92db as claimed).  

Any thoughts would be greatly appreciated.

Thanks, Scott
smrex13
smrex13 OP
423 posts
 
Thanks to everyone for your input.  Yes, I've quickly come to the conclusion that the Sony is not a good match for the KEFs (perhaps made even worse by a slightly lower than average 3.6mv output mm cartridge).  As I mentioned, I just picked up a pair of MM De Capo BEs, and the Sony can definitely drive those better (still need to have the volume at the halfway point for background listening, but it will get louder than the KEFs).  The De Capos are fascinating - I haven't heard anything with their clarity before - but I'll avoid jumping to conclusions before I give them a good listen over several weeks.  I think the Sony will be moving on soon for something with a higher current capability.

Best, Scott
Ag insider logo xs@2x
j_clark
4 posts
 
Smrex13

Check the speaker impedance switch on the back. Make sure it's set for the right setting for the KEF's. Also, the manual says to turn off the head phone impedance selector when listening to speakers. See if that helps. 

danvignau's avatar
danvignau
183 posts
 
When the sound "thins out", as you say, the power supply is not supplying as much juice as the output transistors could use. The bass goes first. Years ago, I bought my Dad a 90 wpc Pioneer receiver, which is now on my TV. At higher volumes, I lose the bass compared to a separate amp with 65 wpc.
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