How can a 30 watt, 28 year old amp sound more

I recently connected a 30 watt NAD 3130 integrated to my 85 db efficient 8 ohm ATC SCM 12's. The amp it replaced was a 120 Watt high current and very highly rated amp. The sound I got was bolder, deeper, punchier and more dynamic. It took hold of the mid/woofers and whipped them into total submission. What the hell?

What would account for that? I always thought more watts, high current equals more dynamics and control. This proves me wrong. The NAD is also a high current design, but 30 watts??? is it damping factor? is it slew rate? the 120 watt amp has a damping factor of over 500 and is stable to 2 ohms. The spec on the NAD does not include damping factor or slew rates. It too is stable into 2 ohms.

Can anyone explains why in this case, watts did not matter? any idea what makes this 30 Watt integrated sound so bold, dynamic, and punchy?

So, what is the 120 watt amp?
Probably the power supply. Is the NAD appreciably heavier?
Might not be the amp,it could be the preamp you are using with the amp. Mismatch with amp? Need more info on what you have!
Without knowing the other amp, we can only guess. Its most likely that the NAD is just a better amp. There's no standard for measuring an amps power, so results like you are getting are not at all uncommon. Yogiboy is right as well. It could definitely be your preamp.
Years back I had a ML amp that needed to be repaired. While it was being repaired I used a 25wpc NAD unit to power my system. In a word, it was spectacular. It was easily 90% of what the ML was in terms of sound quality. Not long after the ML came back all repaired I sold it and have been chugging along quite happily for maybe 11 years with amps that have a quarter of the power the ML had. WPC ain't everything, and smaller and cheaper amps can be great.
This small NAD amp is very good...I too was totally surprised by its performance....Using it everyday with vintage IMF Supper compact speakers and always amazed on how good setup sounds...
more likely you get cleaner power, but not stronger dynamic drive. on top of above said the sound certainly different and adds another subject to your toys.
enjoy the tunes.
Well this throws all my pre-concieved notions out the window. From now on it's listen and decide, forget the specs :-)

I would rather not mention the brands of the pre and amp the NAD replaced as both are very very highly regarded and do sound great otherwise (less the dynamic contrast and punch). We're talking same class as Bryston's, Classe's, Odyssey's, Electrocompaniet, etc...

I guess just like Bruce Lee, Mini Coopers and well sometimes integrated amps, "Big" performance can sometimes come from "smaller" packages :-)

Another thought I have is "sweet spot": if I am using 10 watts from a 30 watt amp it is probably operating in its sweet spot for optimal performance, where as 10 watts out of a 120 Watt amp may be well before its optimal sweet spot kick in. Kinda like driving a high performance high HP car but keeping to the speed limit, the engine never really opens up. In the end who knows.

Thanks for all the valuable input.
Bokfudo, since the NAD has pre out and main in, you could try pre out from the NAD to the other amp, and also, the other preamp to main in on the NAD. This would help determine if the difference is really the amp. It may be the preamp.
I have an NAD 7225PE that I will never sell in a millions years. It just sounds awesome, and the only word I can use to describe its sound is "alive." I think that its sense of pacing is the key. It just makes me tap my foot and smile when I hear it, and it has run nearly continuously (with an occasional vacation) since 1991. When they designed this amp, they did it RIGHT.
I have an amp that would eat that NAD for lunch, but I would rather not mention the brand. Hope that helps.
NAD integrateds most-likely have passive line stage preamps so impedance match could be a problem.
Have a NAD 7140 that I have not used in over two years sitting on top of an excellent sounding Sansui AU 919.
Decided to run the 7140 for a while after playing with another recent find that surprised me.
I revived a thread I wrote about the 7140 in comparison to a Nakamichi Stasis 2 which it easily thumped, and had better build quality.
It's right up there with the Sansui on both power, and sound quality.
Using a pair of Yamaha NS 1000's with it.
Point taken Ddd1... I am not mentioning brands for the 120 watt amp and Pre as I may be selling them and would rather not give the impression that they are not great pieces.

I was only looking for input from the more "technical" folks as to what could give a good indication for control and dynamic punch with Amps. I always thought damping factor (higher equals more control), slew rate (ability to respond quickly) and wattage (power output) would give those indications. Now I'm not so sure...

A lot of it is synergy, matching the amp to whatever speaker is partnered with it. The 120W amp, whatever it is, might sound better with a different pair of speakers and suit a listener who plays music at louder levels and/or in a larger room. Years ago I used to own a NAD C370 integrated and enjoyed it very much in my system.
Ddd1 has hit the nail on the head - synergy - that component combination where the stars align and everything comes together.

Matching components is much more than watts, high current designs and efficiencies.

Each component impacts the other components it is connected too

It even includes cables - e.g. naim amps require (as stated on their web site) that the speaker cables be low capacitance.

I've read that they sound pretty bad if high-cap cables are used

Also, that 28 year old amp used exceptional components - andNAD had a great design and quality reputation back then. Once the bean counters take over then component quality often suffers.

Also - not all watts are equal - line up any number of amps with the same output rating in the same setup and you will get differing results in the system performance

When I bought my existing speakers I took my naim 5i amp and speaker cables to the store because of concerns about their ability to control them - turns out 50 watts (of naim power) was more than enough. Some brands my work better and some not as well - you have to hear them

When I first started this hobby, matching components was far more critical - things like input and output voltages had to be matched- then the manufacturers got together and settled on standard input and output specs, but even today other factors still come into play, which make certain component combinations excel in their performance - yours is one such case.

Unfortunately, there is no easy way to know what combinations excel, other than plowing through forums like Agon and soliciting advice and then try some options.

But bottom line - 28 year old NAD's were an exceptional design and a quality build.
After 28 years... maybe it's time to get the caps replaced?

If you think it's good now... get the caps upgraded to mundorf or even something even more exotic?

I re-cap'd my speaker crossover with mundorf - they now perform so much better than the originals
I think that after 28 years the NAD has finally broken in. The less patient than you will never know how good the amp is.

BTW, if you sell the amp on Audiogon anyone can quickly search your posts and find out that a lowly NAD amp sounds better than what you're selling, at least in your opinion.
Recently I came into possession of a Sansui receiver from the mid 70s, an HK integrated from about 82 and an Onkyo integrated from 85. They all had this in common, they were calibrated or voiced to work well with sources such as tape decks and turntables, both much less dynamic than the modern cd player.

For that reason they gave the impression with a CD player that was punchier and more dynamic. I'm sure the NAD is much the same. The more dynamic and higher voltage cd player made the difference. BTW, turntables sounded really nice on this old gear.
I think I agree with you Runnin, this NAD is definitely EQ'ed to boost certain frequencies...Just seems to work well with the ATC's...

"05-14-13: Ddd1
I have an amp that would eat that NAD for lunch, but I would rather not mention the brand. Hope that helps."

You are what you eat.
Thought it was a very silly response. Obviously you, and anybody else could.
The point is that the unit is surprising for what it is and what it can be had for.
I find it amusing you don't want to mention the brand let alone what model it is.
Another words you spent a lot of money and are getting diminishing returns and deciding you want to sell.

And yes the phono stage is great in the 7140.