A "blind" speaker recommendation based on specs...

I currently have a box-stock Peachtree Nova that I purchased back in April. I purchased a separate unit at the same time and sent it off to Canada for MEGA-MODS! Basically a 5 month/$5k with all the bells, buzzers whistles. Burson op-amps, all new resistors, caps, high-end next-gen WBT jacks/posts, Furutech IEC inlet, new tube, tube base, internal wiring, volatage switching removed, internal shielding et al. The whole enchilada! And yes, I do know there were & are other options out there. Pardon if my choice wouldn't have been "your" 1st choice.

Now, without mentioning names I'm wondering if I should keep my existing speakers which were new in April or at least consider an upgrade I've been researching closely. In order to maintain some semblence of subjectivity I'll keep speaker proper names out of this and list specs only in an effort to keep things honest/objective.

The Nova is a hybrid integrated SS amp/tube preamp with an honest 80wpc into 6 ohms.

My current speakers are high-end (for a bookshelf) on factory stands, 8 ohm with 88db sensitivity. The speakers I'm considering are also bookshelf on their own 200lb stands, vulgarly spendy uber high-end 4 ohm with 87db sensitivity.

Disregarding getting into speaker-to-speaker sound quality, how much harder/hotter is the integrated/hybrid likely to run with the 4 Ohm/87db setup than it does with the 8 Ohm/88db setup? Significant? Dramatic? Negligible?


There is information lacking about the Nova and about the two speakers, specifically the Nova's power output into 8 ohms and into 4 ohms (not mentioned on the specs page of the Signal Path International webpage), and the two speakers' low impedance measurements.

Without these details, your question cannot be answered, IMO.
As an addendum to my previous post, in this Soundstage Review of the Nova there is a quote from David Solomon in which he states, "the Nova will be stable down to 4 ohms, as long as the speaker’s impedance doesn’t drop below that. If your speakers tend to drop below 4 ohms, he recommends you use an external power amplifier."

Based on this, I would not recommend the 4 ohm/87dB speaker since it's almost certain the impedance of this speaker drops below 4 ohms.
Me personally I learned a while ago specs don't mean a whole lot. Your ears should be the judge.
That being said I agree with Tvad regarding 4 ohm speakers with your amp.
Tvad has given you excellent advice. I would add that in the case of a 4 ohm speaker you have to be careful to note whether the sensitivity is specified relative to 1 watt input, or relative to 2.83 volts input (which is often the way sensitivity is specified, because 2.83V corresponds to 1W into 8 ohms).

If the spec is based on 2.83V, the sensitivity of the 4 ohm speaker is only 84dB for 1W input, which doubles the number of watts that are required to reach a given volume level, relative to what would be required with an 87dB/1W speaker.

-- Al
A couple of examples:
I have two very different standmount speakers that are both rated 86db 6ohm. My little 12/20wpc 8/4ohm t-amp makes nice open, full music with one pair, sounds anemic and shut in with another.
The Totem One speakers I used to have could make some 100wpc amps sound small. My friend who has them now powers them with a 25wpc class A Bedini and they sound huge.
Specs can be deceiving, sometimes there is no substitute for hands on experience.
As has Almarg (given you excellent advice, that is). You need to look the minimum impedence of the speaker and the way that the sensitivity was reported. Even with that, if the potential upgrade is "uber-expensive" I'd want a return policy.
Wow! $5K in upgrades for a Nova. Does that include the cost of the unit itself? Either way, for that kind of money you coulda bought yourself a real amp.
Thanks for all the responses/suggestions. I was hoping that given the 4 Ohm speakers would definitely, on occasion, drop below 4 Ohms that by never seeing even moderately loud volumes I could expect a relatively long amp service life.

BTW; 8 Ohm speakers I'm using now are B&W 805 Diamonds and the 4 Ohm upgrade I was considering is the Magico Mini II's but doesn't break my heart to stand pat and save the $30k for some other equally frivolous expenditure.

And thanks for the sole suggestion from one of getting a
"real" amp... that was most helpful! ;-)
even more important than impedance, at least to a stable amp design, would be the phase angle of the load.
B&W? Stereophile may have tested and measured these. Impedance mins at large phase angle indicate 'worse' load.

If the proposed speaker is better in this regard, at least electrically, it'll be a better match.

Example: Your amp would probably be OK with 4 ohm resistors, but NOT ok with an '8 ohm nominal' speaker with dips to 3 ohms, and 45degree phase angle at that frequency.