Amp for LS50

I thought I’d go ahead and update the thread with what I ended up purchasing...

sooo, I found a good deal on a B&K Reference 4420 and a McCormack Micro Line Drive.  I paid $625 for both so I came in under budget and ended up with a system that should keep me content for a week or two ;)

This is my first B&K amp I’ve had and I’m enjoying it!  I feel like I stole it at $275!  Thanks Luis, I appreciate you!

Thanks for the input everyone!  I took long looks at everything suggested and learned about some new gear so Thank You!

Happy listening!!

@b_limo 

That's great. I bet the McCormack and B&K go great together, enjoy.

Cheers,

Scott

I wholeheartedly agree with tcatch on his position of using high quality amplification with the KEF LS50’s. Since these excellent speakers have a relatively low cost barrier, many people have typically paired them with mediocre amps and come away disappointed because all they get is mediocre sound quality. These speakers don’t require mega-buck amplification to sound their best, they just need high quality sources and power. 

I have used low power power amplifiers with my KEF LS50 speakers with the exception of my 150 watt Texas Instruments TPA3255EVM Class D DIY amplifier. My restored and modified Dynakit Stereo 35 6BQ5/EL84 push-pull tube amp and my Pass DIY Sony VFET Class A push-pull amp are only rated at 15 watts per channel, but coupled with my Audio Research LS7 tube line stage, my system can create smooth, room-filling volume that has a room response lower than 40 Hz. This is without a powered subwoofer. I partly attribute this to the high damping factors of each power amplifier and the 13dB gain and 200 ohm output impedance of my ARC line stage. The point is that these amps produce low distortion with a hearty dosage of second order harmonics. 

The LS50’s can present a difficult load for amplifiers to drive. For tube amps, you need really good output transformers to handle the large frequency vs. impedance response swings. For solid state amps, you need plenty of current and the ability to drive low speaker impedance loads. I built my Pass DIY amp with a beefy power supply using an overspecified 400 VA toroidal power transformer and 60,000 uF of power filtering capacitance per channel to handle transient peaks. That said, the amp’s massive heat sinks are only warm to the touch. 

Yes the ls50s definitely reward robust good quality amplification. 

Great combo, enjoy...