Old NAD or newer high powered Denon?

Pryso...I know. I'm a tube guy also... it is amazing how a good tube amp can "open up" speakers..especially with multiple drivers and complicated crossovers....and how a 30 watt tube amp can sound as "big" as a 200 watt transistor sometimes. FYI I just had a ARC ST70-C modified/updated per Bill Johnson's 2004 memo circulating on the internet. I was nervous about touching this amp because it sounded great anyway. But WOW! the magic in the midrange is more transparent and both the top end and bottom end have been extended. I own several expensive tube amps and I am looking at this little old box and wondering why would I hook anything else up?? This amp easily plays my DQ10s and Infinity RSIIbs . . . 30 watts are you kidding me??? I've had Threshold and Sumo class A amps die on these speakers?? go figure. I think I will go fire him up...again

Thanks all. You have all been a great help. I'm gonna look for a garage sale st70. Wish me luck.

Hifibear, hopefully a good decision, but I must add some cautions.

Any ST-70 will be old. I built one from a kit in the late '60s as the foundation
for my first stereo system. It remained a current product up until the mid-
'70s I believe. Then a subsequent owner of Dynaco later offered a Mk 2
version for awhile. But they sold in huge numbers and a good many remain in
use. The first thing will be to check the tubes. Then, be sure the amp can be
biases correctly. If you suspect the amp you find is original it would be well
to at least replace the capacitors.

One reviewer suggested that ANY amp with EL-34 output tubes would likely
be pleasing and musical (assuming it was working properly). The ST-70
clearly stood the test of time since it remains popular 50 years later. But
while it may be one of the best amps for the money, no one should expect it
to be one of the best amps. Various brands mentioned in my first response
will outperform it, but they will all cost more.

Because the ST-70 was and remains so popular, many modifications are
available. The ARC ST70-C for example was a version designed by William Z.
Johnson, the man behind Audio Research. But those are not too common. I
think a clean, stock ST-70 example can be found for $200-400, depending
on your luck. One that has been modified by a reputable company/designer
may cost $500-800. Start with Audiogon ads.

If any of this sounds intimidating, you may be best to fall back on the Hafler
recommendation. If not, good luck to you.

I second the recommendation to try a used Hafler power amp - my choice would be the DH-220. I got mine on eBay for $150 about four years ago - they seem a bit more now, about $200, but still well worth it. I'm sure an ST-70 would sound very good, but it will be more money, and very possibly much more hassle. Same designer, btw.

My NAD 3020 is still going strong after 30 years, and powers my wife's kitchen system now.