Same watts at 8 and 4 ohms?

n80 OP

Get an amp like I said for your Aerial 7T's and you'll be happy. Your 7T at 84db and 4ohm "nominal" you need 100w-8ohm and close to 200w into 4ohms because you can bet they dive to 3ohm or less with epdr somewhere. 

From Keith Howards Measurement Labs https://ibb.co/7JrRXX8

This is the Wilson Alexia 90db and Wilson spec 4ohm nominal. You would think that just about any amp could drive it. But no.
The Wilson Alexia is said to be one of the hardest speakers ever to drive. And that because just in a small band of the low to mid bass it has an EPDR (combination of low impedance and high - phase angle) which to the amplifier seems like .9ohm!! and it sucks the life out of an amp.

And a 3000watt Behringer amp won't do it justice, but 25w ML2 will, to a certain volume level because they can double down to 1ohm, , it's all about the current, being able to double wattage 8ohm to 4ohm and 4ohm to 2ohm if you can do it for speakers like the Alexia and there are many like it.

Cheers George      

The NAD C388 will drive your speakers just fine if you don't play your music at rock concert levels.

But since you own/like a Levinson amp, which I think are all Class A/B, the NAD's Class D module may not make your speakers sing a tune you like.

Safer to buy a Class A/B amp like the Cambridge CXA81 (which has a decent DAC), which is 80/140 watts into 8/4 ohms, and is within your budget. I have heard that amp make a pair of Monitor Audio Gold 100 5Gs sing, which are only 86 db sensitive and dip at various points under 4 ohms. 

@georgehifi I have a Levinson, well, Madrigal, dual monaural amp

I would keep it, just have it serviced up to factory spec. Which model BTW?

Cheers George

@georgehifi,

Get an amp like I said for your Aerial 7T’s and you’ll be happy. Your 7T at 84db and 4ohm "nominal" you need 100w-8ohm and close to 200w into 4ohms because you can bet they dive to 3ohm or less with epdr somewhere.

The OP's new speakers are Aerial 6T’s;
manufacturer’s specs are 90dB sens, 4 ohm nominal with a 3 ohm low.
I couldn’t find independent testing or impedance curve. So, possibly sensitivity could be 88-89 dB. The amps being considered could drive these speakers.

While it is true that 'speaker sensitivity plays a role in required amplifier power, it is also true that amplifier power capability plays a role in distortion.  An amplifier will exhibit lower distortion at low output levels than at high output levels.  Distortion will often rapidly increase as the amp's rated power is approached.  Linearity is usually much better at small signal levels, hence lower distortion. This means that at a given output power level, well-designed high-power amplifiers typically exhibit lower distortion than lower-powered ones.

I run two channels of four Harmon Kardon Citation II tube amps each that, on the bench, deliver over 500 watts/channel with 0.05% THD at 1 kHz if line voltage is held at 120VAC.  This means at normal listening levels, each amp is operating at or close to small-signal operation.  Since the 'speakers driven by these amps are B&W 802Ds, I am glad I have the high-power capability.
Normally, solid state amps will deliver twice the power to 4-ohm than to 8-ohm loads.  However, power supply limitations can limit 4-ohm output.  Tube amps generally deliver the same power at 4- or 8-ohms provided the secondary winding of the output transformer has a tap to match the 'speaker's impedance.
By the way, at age 77, it is getting to be a big burden to carry a 60-pound tube amp from the first-floor listening room to the second floor test bench every time I have to change a tube.  I do so because I set the output tube balance for lowest THD.  If anyone wants to make an offer for 10 Citation IIs (I have four spares but want to keep a pair for other use), please let me know.

Norm