Amp/speaker recommendations

[Corey.wimberly]

I am sure this is a noob question, but I am having a hard time with the power specs on tube amps in particular.  The speakers I am currently looking to buy and or power are:  Magnepan 1.7i or Dynaudio Contour 5.4.  I understand these speakers can be “difficult” to drive.  The PrimaLuna Evo 400 has 70 watts per channel and my local dealer assured me the Evo would drive these speakers with no problem. 

Will the Stereomore or the Kaiju drive these as well?  I do want to get the most “bang for my buck” so if the Stereomore will do the trick, I would most likely purchase that one. I am very interested in building my own amp from the Bottlehead collection but want to make sure the amps can power the speakers I am considering.  Any help/opinions would be much appreciated. 

[Paul Joppa]

Those speakers are rated 86dB and 87dB respectively, but both are 4 ohms, so that's 83dB/84dB at 1 watt. You are going to want around 60 watts for fully satisfactory performance, about 10 times what 300B/2A3 SET amps can produce.

You can get quite nice sound for casual listening, or under particular conditions of room size, specific music, etc., but if you are a typical audiophile the limitations will always bug you with an SET. At least, that was my experience when I had such a system, many years ago.

Neither manufacturer provides information on the speaker's impedance as a function of frequency, so it's hard to say how "difficult" a load they may be.

[Corey.wimberly]

Thank you for the insight. Much appreciated.

[Paul Joppa]

The traditional approach has been to look for speakers with higher sensitivity or efficiency - around 93db/8ohms for 300B, 96dB/8ohms for 2A3. Such speakers are thought to have more synergy with SET amps than just the efficiency.

Here are a few alternatives:

Many people live in apartments with cranky neighbors, and have no use for concert-hall sound levels. Some may just not want to listen at high levels - for non-audiophile music lovers, a typical home loudness is around 10 dB less than Symphony Hall.

Small rooms do not need as much power to fill with sound. Dorm rooms are a common example.

Anther common approach is to use a tube preamp with a neutral solid-state power amp. This can provide much of the SET sonic character.