Naim and wattage

Plinius Hiato may be very powerful and diffferent in comparison to older generation Plinius amps. Nevertheless, based on my experience with the Plinius SA-100Mk3 Class A amp about 12 years ago, I would be wary if one is considering Plinius for Harbeth loudspeakers. The bass of my Harbeth SHL5 speakers sounded like mud when driven by the SA-100Mk3. The Harbeth sounds a lot better with Naim NAC202/NAP200 especially when pace, rhythm and timing (usually reproduction of bass transients) are important to the listener.

It’s not really a matter of power.

It’s more how the power is delivered, particularly how quickly the amp can change its output voltage (slew rate), how quickly it can respond to a change in current demand (current rise time) and how accurately It can reproduce transients without them affecting other parts of the music (transient distortion, particularly transient intermodulation distortion).

Do you feel the SN3 is also lacking in quality for the Harbeths or just power?

If just power then this would be a perfect example of where biamping is your economical friend. Even a NAP300 isn’t loads more powerful than a SN3. It’s a loads better power amp and if that’s what’s needed it’ll work. But if the SN3 is totally out of puff, something like a NAP200 to handle the just the bass units may be the lowest cost and most effective path forward.

Remember it takes near 10x as much power to get 2x the volume. 15w is a massive difference when you go from a 15w amp to a 30w amp. It’s not so much going from 80w to 95w.

In theory, that’s correct. Nevertheless, power still matters particularly with Harbeth speakers if they are required to perform dynamically. With solid-state amps, a 30W dual-mono design such as the Sonneteer Orton barely cuts it. An amp that’s less than 30W will likely not satisfy although it is capable of delivering the aspects that are mentioned above.

In real world, it’s the SN3 to something more powerful such as the separates, or biamping with another power amp would be the right thing to do. I’ve tried biamping before, 282/HCDR + NAP250DR and NAP200 driving the Harbeth. I can’t say the result of biamping is better than using the 250DR alone since the 250DR is already a capable amp on its own. The SN3 may be different ie. slightly underpowered when used with the SHL5 Plus.

The SN3 and 250DR have exactly the same power output (80W into 8Ω).
In practice, the difference between these power amps is the parameters I listed, not in their power output!

The SN3 will struggle a bit with the SHL5 Plus, the 250DR will do significantly better, even though it has no more power available!

Right, point taken that the SN3 and 250DR have the same power output. :grin:

The 250DR or perhaps the combination of the 282/HC/250DR is overall better than SN2/SN3.

Use the SN3 as a preamp and add a 250DR as the poweramp and it will still drive the SHL5 Plus better than the SN3 alone.
The ability to drive speakers well isn’t related to the preamp, and is more dependant on the power amp factors I quoted than it is on power alone (I know this from optimising my own power amp designs).

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Hi @Xanthe, the SN3 has a faster slew rate than SN2 due to some circuit changes - does this not put the SN3 closer to the 250? If so, perhaps a 250 would not help @Blackbird either (bi-amping aside).

Closer, but the SN3 is still an unregulated power amp.
The 250 is DR a regulated amp giving it a big advantage in respect of stability of current delivery and in its transient properties.

If you look at the internal images of both, you’ll see that the 250DR also uses a bigger transformer, and that helps its power supply to deliver more current than can the SN3 and to do it faster.

Many thanks for the clarification Xanthe but I thought that the SN3 was also DR?

The DR in the SN series is regulation of the power supply to the preamp only.

You stated in an earlier post some albums don’t sound good, is it the recordings on those albums, at what volume do you listen? What is your source?

And lastly, where are you located?

Scott

Ah, OK. Thank you. So there may be some improvement for the OP if he uses a 250 with his SN3.

So I can connect a 250DR to a SN3 and no need of hicap or external power?

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Yes, but I’d recommend considering a HiCap to power the pre-amp stage of the SN anyway, as that will free up current for the internal power amp. I think your solution lies in adding the 250DR, you can try either bi-amping, or just running it as a power amp. Then consider the HiCaP or swapping the NDS for the NDX2.

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