Art Audio Carissa Signature 845 or 300 b amp?

08-14-12: Mattzack2
I have Dali Helicon 800 speakers at about 90 db. No problem with the 845 at 16wpc. I need to sell my Carissa and get serious about a nice 300b amp.

The MkII version of the Helicon 800 is specified as 89.5 db for a 2.83 volt input at 1 meter, with a 4 ohm nominal impedance. A point to keep in mind is that that means its efficiency is 3 db less (86.5 db) for a 1 watt input. That is because although 2.83 volts into 8 ohms corresponds to 1 watt, it corresponds to 2 watts into 4 ohms.

That assumes particular relevance with a tube amp, which will not increase its power capability significantly into low impedances, as a solid state amp would.

Also, if you may be interested in a higher powered push-pull 300B amp, rather than a low power SET amp, you may wish to consider the VAC Renaissance series (the 30/30 or 70/70 models, which are in your price range). Research posts by member "Raquel" for lots of good information about them.

Good luck in your search. Regards,
-- Al

A P.S. to my previous post. Keep in mind also that many SET amps will not do well into a 4 ohm load, even apart from power capability/speaker efficiency considerations. The Franks, for instance, appear to only provide 8 ohm and 16 ohm output taps (Charles, correct me if I'm wrong).

My push-pull-parallel VAC Renaissance 70/70 MkIII, btw, has taps designated as "4 to 8 ohms," "2 to 4 ohms," and "1 to 2 ohms"!

Regards,
-- Al

90 db is okay, 4 ohms "could" be okay. Depends on how much (and where) the impedance flucuates to come up with the 4 ohm "average". The flatter the better.

Almarg makes a very good point.Mattzack2, as much as I admire my SET amplifier it`s not the 'ideal' choice for your Dali speaker. Al is right the Frankenstein does`nt have a 4 ohm transformer tap(8 and 16 ohms).The Frankenstein has an exceptionally stout power supply and premium over speced transformers. It`s asking a lot for this amp to drivr that speaker load and expect the best from the amp(or speaker) under these circumstances.

I agreed that the VAC REN amps are better suited for this Dali speaker and IMO would sound wonderful.As I mention in an earlier post amplifier-speaker matching is the key factor. To be clear I`ve driven 4 ohm speakers with my amp and it was a very good sound.I just believe the 300b push-pull VAC would handle lower loads even better yet(particularly with the lower sensitivity).

Mattzack2 if your speaker were more sensitive and had a higher ohms load I`d strongly recommend the Coincident Frankenstein without hesitation. For example my speaker is 94 db and has a 14 ohm load. the amplifier has complete control of this speaker and it just sings.
Regards,
Charles,

Agree with those who stated that 300B SET is for efficient speakers, not for the Dali. But I would not get a 300B push-pull amp. Use the Jadis, or acquire efficient speakers that will mate well with a 300B SET.