Do I need bi amp?

I own a sn3+hcdr planning to go to 282/250dr with atc scm 19. When I will come back to my Home I plan to switch 19 with 40 or 50 according to finances. Now the question. Is 250dr able to drive 40 or 50 or will I need to move to a bi amp solution?

Just a thought. Why not go for 282/Hicap into ATC SCM40A?

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If you want to bi-amp you can only use passive biamping with the ATCs and Naim amps. Almost certainly better to use a 300 rather than two 250s passive.
ATC actives could be a good alternative.

Bi amping Naim amps is not so recommended by others here.


May '19

I have not heard this combo, but I have heard several ATC speakers with Naim and other amps. One general conclusion I have come to is that these speakers thrive on more powerful amps. I have extensively auditioned the SCM 19 and 40 driven by a 250 DR. To my ears, the 250/19 was a great match which I could happily live with, but although I enjoyed the 250/40 I could not escape the feeling that the 40s had more to give and would benefit from something like a 300. I guess this prompts me to recommend caution at least to the extent of auditioning SN2/19, perhaps comparing with SCM11s, before shelling out serious money.

However, perhaps more fundamental is why you want to put a SN2 between a Linn source and ATC speakers. Assuming you don’t want to go the DSM route, have you thought about an ATC integrated amp or, IMHO even better, an ATC preamp with active 19s? Or staying with Naim, sell your Linn DS to fund a used 272 which sounds splendid with active 19s. By the time you’ve budgeted for decent stands for passive speakers these options would cost about the same as SN2/ATC19s. Just a thought.


ATC ACM40 speakers work really well with a 250DR in my experience and a recent review here would agree with this

A Naim NAP250, of any type, can drive most things out there… :thinking:


I would not opt for a Bi-amp system. The returns are minimal at best. I did go this route myself and have switched to a better but single stereo amp. An amp spends most of its capacity and importantly current driving the lower frequencies it takes virtually nothing in comparison to drive high mid-high frequencies especially by the time one gets to tweeter levels.

Unless you have especially/seriously inefficient speakers a NAP250 will be more than enough.

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ATC50 really much better active

The advantages of multiple amps are only properly realised by using an active crossover in the small signal path in between the pre-amp and the power-amp; this way each amp has a direct connection to the voice coil of each driver with no passive components in the signal path. This allows the amps to get much better control of the drivers.
This setup is referred to as an active system.

An alternative is to connect a preamp to active speakers, i.e. speakers with amplifiers (= active components) within them.
This setup is a system with active speakers.

Using two power-amps and still keeping the passive crossover in the speakers negates most of the advantage. The relatively modest gains to be had this way are generally not worth the extra cost of the additional power amp, and much greater gains can usually be had applying the same funds to a better (single) power amp or to other parts of the system (such as source components or pre-amps).
This setup is referred to as a bi-amped system.

I would have thought that, but a couple of years ago I listened to a pair of SCM50As, then a pair of passive 50s driven by a 300DR. I preferred the passives.

SCM40 upwards are 3-way speakers, so tri-amping rather than bi-amping. However the bass amp has to be as capable as a single amp powering passively… Tri-amping is the icing on the cake, and of course you can do using 3 Naim power amps - but you also need an active crossover. I used to have an old ATC Active XO, the EC23, which undoubtedly could do the job, or of course there are a number of digital active crossovers around that can have other advantages, and it may be possible to use a Snaxo though I have no idea if its characteristics would match the needs of the ATCs.

If the 250 isn’t adequate, the question is whether to a) buy 2 more power amps and an active XO, b) change your amp for one better suited to the bigger ATCs, or c) go for the active version of the ATC, selling your power amp, and gaining tri-amping with its better control combined with amps perfectly matched to the specific needs of the drivers they are powering.

N.B I have ignored the concept of passive bi- or tri- amping, which in my view is pointless unless you happen to have spare amps with nothing to do with them, as any benefit is likely to be very small compared to the investment.

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I recently had ATC SCM40 with a Supernait 2 + HiCap DR. This combo did work well enough (very well in fact), but the 250 DR upgrade certainly made the speakers perform even better.

My understanding of the SCM40 speakers is that they will keep on giving as you feed them better sources and amplification. I guess that is true for most quality speakers, but somehow I feel this might be even more so in this case. So far they seem rock solid in their performance.

I’ve not done the comparison with ATC 50s, but the active 40s are something special: for me they give more musical pleasure than anything I have owned in over 50 years, including pricier setups. But I emphasise the “for me”, to stress that this is so personal. When I was going through a lot of auditions a few years ago, I spent a couple of hours comparing SCM 19s in active form vs passives driven by a 250DR. I much preferred the actives; they offered a more tangible and realistic experience of the musicians being there than the passives. But someone sitting next to me throughout the auditions felt the actives were too in-your-face. He reckoned they would be hard to live with and he would have opted for the passive setup. We were listening to the same music, in the same acoustic space, so this really brought home how much individual taste is a factor in hifi choice.

My recommendation to @piebia would not be to rush out and buy a set of active 40s. Rather, if it is possible were he lives, to give them a decent audition before investing in a power amp which would make incorporating actives more costly. If they float his boat the same as they do for me, they might just find a place in his new system.


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Just read a review of the ATC 40, in Soundstage ultra site. The review is by Jonathan Gorse , he uses a nac 82/ hicap / nap 250/ Ndx/ Gyrodeck / SME IV.
I feel the reviewer is among us, @JonathanG . Well done Jonathan !


Hey you found me frenchrooster!! Good spot - I’m going to savour my 15 mins of fame!! Hope you enjoyed the review - we’ve got plenty more interesting stuff in the works and the Soundstage guys are very pleasant and professional to work with. I hope that there’ll be opportunity to review some naim too in the future as it’s been years since I did the launch review on the NAC552 and SL2 for Hi-fi News.

I really love the way that Soundstage encourage reviewers to express their personality when reviewing the gear as that was always something that attracted me to the writing of people like Malcolm Steward, Ken Kessler etc. They also run features going behind the scenes and visiting the companies, interviewing the hi-fi designers, the record producers and studio engineers etc - it’s a really interesting website to write for and I just hope people enjoy it! Vinyl fans will probably enjoy what’s coming next!



Yes I agree, Soundstage and Soundstage ultra give interesting reviews. I enjoyed your review Jonathan :+1:


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