NAP 350 output configuration

With Naim amps and if power is not an issue. There’s a good video from an engineer at Esoteric where he explains exactly what the benefit is of passive bi-amping.

Oddly enough though, what we call biamping where one amp is in stereo driving either HF or just LF is simply called “wrong” in Japan. Here, (and the video I mentioned goes on to explain why), a proper bi-amped configuration has one amp dedicated to a speaker with one channel being HF and the other LF. And indeed most Japanese power amps have a switch on the rear for stereo, bi-amp, and BTL (bridged mono).

The rationale is twofold:

  • With a passive crossover, at the end of a bass transient, the cone will not stop immedietaly. The delta in time between the end of the transient signal and the end of the cone’s excursions is the period where the cone acts as a motor and generates a signal back to the power amp. That signal will reexit back out to the HF unit. But that return signal (noise) can’t cross channels. Ergo bi-amping rejects that noise.
  • Bi-amping should be done with one stereo amp per speaker because the current headroom lift on a stereo amp driving two LF channels is negligable.

I’m not declaring that the argument is correct. But I was sufficiently convinced and I don’t think the engineers at TEAC/Esoteric are morons. In their tests, that type of bi-amping always outperformed BTL. Though they mention high end exitic power amps do a better job of rejecting the described feedback noise.

I’ve held it as an article of faith that biamping provides no benefit where power handling is sufficient. But their argument successfully changed 30 years of belief and I’m both convinced now that how biamping is usually done is wrong and that it could be beneficial in some cases.

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If bi- not tri- , I would certainly do a single stereo amp on each speaker, if only because it is simpler and you can put the amps close to the speakers minimising speaker cable length. However that only applies where you have identical amps: With active speaker driving it is very normal to have higher power on bass than treble because far more energy is required at lower frequencies. (This assumes that sound quality of the amps are equal: if not then it needs trying both ways. Naim’s recommendation of the better amp on higher frequencies is based on sound quality, not on power requirements.)

I have extensively listened to 3x250.3 (new white light ones) vs a 500DR and the active combo is much ‘better’ to my ears. Hence I am sure 3x350s (6 mono blocks) will be ‘better’ again, but of course more £ and 3 more boxes/3 levels of Fraim…

and a lot more cables although I am still considering the 6 pack option with the Kudos crossover after it’s release.

Not sure what is happening with the Kudos crossover….should have been at Audio show east, earlier this year. Now…….some time away, still deciding who is going to make them……probably not many, after the initial rush?
Hope it works out for Derek and his vision.

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Yes I heard the same. It will be a terrible waste if RG’s design doesn’t ever make it to the dealers. I

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You’re gonna need (more) room treatment if you go this route :grin:

I’ve heard the much enhanced punch, albeit it’s tighter bass, from higher-powered amps. It’s quite something to behold, but it often delivers up complications in room management IME.

Yes I heard that your full statement are overwhelming in your room. But I have it in hand.

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Let’s just say that the level of percussion is several levels higher than you’ve ever heard before. I’m a fan of a visceral (front row) presentation, with some of the ills this can bring about if you listen to live music, but the benefits far outweigh the dis-benefits :grin:

Playing something like Castilian Drums from the Brubeck’s Carnegie Hall Live album from c.1962 is something else.

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I bet. I love that album which sounds great on my system so no doubt will on yours. My wife and I are planning to move home next year and I will ensure that the hifi rooms ticks as many boxes as possible. Dimensionally I want at least 14ft on the smallest wall and avoid a square. I won’t follow Peter Qvortrup’s advise next time either so the floor will either be concrete or I will stiffen up a suspended one with Joists at close centres and insulated between. Replacing the old floor bonding with 3/4” ply worked well in my last house also. Top that with all the Vicoustic room treatment and should be good to go active.

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I’m a big fan of Townshend’s Seismic Podiums, in the way they dislocate the 'speakers from the floor.

I just hunted this down on Qobuz. That was a real treat with the 250 and Ovators. I’m sure it’s remarkable with the 350s.

I will shortly listen to 3x350s active vs 3x250.3s active with an Exposure crossover and S1 Pre into 808s. Will let you know what I think…

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