What is Tight Bass?

@clearthinker 1+. Having run large ESLs for decades not only do they hate making low bass (they will do it in a lumpy fashion) but it hampers them everywhere else increasing distortion and killing headroom. You are absolutely right about big power supplies but to that you have to add low impedance output stages or in other terms, a high damping factor to control a large subwoofer driver. A tube amp can have the power supply but unfortunately not the output stage. I had Krell KMA 100s for 20 years and they did make great bass and great everything else for that matter. I would still have them if one hadn't burned out. They gave me a love affair with Class A amps that I can not get away from. I understand why many love tube amps. I am considering buying a pair but, there are SS amps that will provide the same shimmer and effortlessness. The ones that I have heard are all Class A and I do not think this is psychological.  

@sandthemall , a good room and proper placement are essential for good bass but there are other factors that have to be considered to get the job done which is why achieving sota results are so difficult. This is compounded further by the use of subwoofers. Bass has a lot of energy. An explosion is a low frequency pulse. In medicine we use low frequency pulses to break up kidney stones. Put on a 30 Hz test tone and turn the volume up. Listen to your whole house rattle. This energy creates a lot of spurious noise which in simple terms is distortion. It starts with the enclosure the driver is in then multiplies with each surface and loose item. Totally accurate bass is something you can only dream of.

@mijostyn 

I am convinced you are utterly correct about the superior SQ of pure Class A.  I will never leave it.

My Krells are KRS 200s, the last reference before Krell were shamed into abandoning Class A because of the power consumption.  Mine draw more than 1kW per side continuous.  They are one of the very rare early pairs that were converted to deliver 400w/side and mainly suppied to Krell agents (where I got mine).  They are getting on for 40 years old now and I had them entirely refurbished (mainly caps) in 2011.  I also have a KSA 50 in another system - Krell's first product and glorious it is too.  That one continues to emit signal (albeit increasingly distorted) for nearly 10 seconds after it is powered down.  That's what I call a power supply.

IMHO you could do a lot worse than go back to Krell monoblocks.  I see a pair like mine, recapped, for $12,500 today.  In view of Class B amps in $six figures, this must be the bargain of the last two centuries.  I paid £6,500 in 1992.  List in the mid-80s was about £26,000 I seem to recall.  They are often cheaper than £12,500 but I paid £3,600 to refurb mine.

This is an interesting read.

"tight bass"

good luck with that. On the finest it is pretty convincing. To my ears, still a visceral level that can’t be reproduced. It is not about being LOUD.

Meanwhile, as this thread figures out what "tight bass is and how to get it...

Get up in that groove...

I am all about the effect of ports or sealed speaker construction as well as amplification, but the room resonance is the biggest deal of all. Not just by way of speaker/subwoofer placement, but whatever can be done to flatten the frequency and decay response will provide tight bass. 

Krell amps produce great bass because the power supply is so large, the damping factor isn't that high.