SCM40 question

Hi Peeps

Does anybody here run a set of passive SCM40s with either an Olive 250 or a pair of Olive 135s?

Would the 135s be a more manly partner for the 40s?

Many thanks


I don’t have any experience with an Olive 250 with the SCM 40s but have heard a Supernait 3 driving them fine. I think it’s more about the quality of amplification rather than absolute power - but the NAP 135s would offer more control I’m sure.

Lots of threads on here about the SCM 40 - the search engine is your friend.

Love mine by the way; and contrary to popular folklore don’t need to be driven at high SPLs to come alive.

I tried running 40’s with 300DR. The active 40’s were just better in every way in my room so went down that path.


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Different strokes for different folks,I guess. I was a bit disappointed by SCM40s driven by a 250DR and like Gary went for the active version.

For me, they do not necessarily need to be played loud but I do find that something just “clicks” at a certain volume. The sound comes into focus and the musicians are in the room. But the level that happens varies from recording to recording. That’s how I hear them, anyway.



Within the context of the OP’s question: in my experience 135’s are far superior to a 250 (having had both).

I would also agree that the actives really come alive with a little but of volume: in my case at about 9:30- 10 ish on the 52’s volume control.


I don’t have the exact same amps as you are considering but I’ll give you my experience that might be helpful.

I have a pair of passive SCM40s and have driven them both the the NC 250 and, more recently, a pair of the NC350 monoblocks. The 250 can certainly drive the SCM40s well and in my medium to small listening room I can play them pretty loud. If you have a big room then maybe you need something a bit more powerful to get the volume levels you like but I have no experience with that scenario. I got the 350s because they sound better than a 250 which, of course, they should do given the price difference.

I have a somewhat different theory as to why the SCM40s seem “open up” at high volumes. Consistent with their studio monitor heritage, ATC drivers are specifically designed to have low distortion so the distortion level stays relatively low as you turn them up. This means you can play them loud while keeping all the detail, soundstage etc… mostly intact. This seems somewhat unusual for speakers in the same price range and even somewhat above it.

Others have mentioned the active versions as an option they are really happy with. They are also a way of building a great system at a significantly lower cost than the SCM40 passives with separate Naim amplification. Active speakers do offer a technical advantage over passives. This is largely because the crossover characteristics, such a frequency and slope, can be controlled with greater precision before being fed into each of the power amps that drive each of the drivers. This is essentially because the crossover in an active speaker works on a low-level signal.

I use active monitors in my small studio so I think they are great. However, in my listening room I chose to use passives because I am a huge fan of the Naim “sound” so it becomes a bit of a balancing act between a “better” active crossover and the relative quality of the separate or “in the box” amps. I also have a bias in thinking that, given all the effort people put into isolating their amplifiers on Fraims or alike, inside a speaker cabinet is possibly the worst place to put an amplifier if you think isolation is important.

Coming back from that tangent: if you already have a 250 then I would start with that and see how you get on. A 250 with the passive SCM40s sounds really good so I regard the monoblocks as an upgrade option rather than being essential to drive the speakers properly.


Thanks for the replies.

As a note, Im not thinking for a minute of moving the Sibbles on…its just that SCM40s are such an absolute bargain at the moment! It would certainly be fun to try them out on my 250.
I dont have a particularity large room and dont play at outrageous volumes…I was intrigued to know if anyone had sensed a feeling of better grip using 135s over a 250,
…135s being my ultimate goal. I have heard it said that a 300 dr is better than either of the above but I would like to stay completely olive for the foreseeable future!


I understand “amps on the back of your speakers” challenge but trust my ears, the Actives are very good. I too love the name sound and I get spades of that through the 552/NDS/555 into actives.

Fond memories of my old olive system and have no doubts a set of serviced 135’s would drive the passive 40’s better than a 250 but If demoing then do your self a favour and listen to the active 40’s.


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Thanks Clive. The short answer to your question is that the monoblocks sound significantly better than the 250 but, in my opinion, that difference is not specific to driving the SCM40s which actually have a quite benign impedance as a function of frequency. They are relatively inefficient speakers but, as mentioned previously, the 250 has adequate power to drive them very well unless you have a big room and want to play quite loud. I agree with you that the SCM40s are great value for money even in the US. When I was auditioning loudspeakers I went to the ATC demo without knowing their price and was very surprised to learn that they were about half the price of the other speakers I had listened to.

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Thanks philiprst…thats really helpful. I know a 300dr is probably what I should be considering but just cant bring myself to mix boxes! The 52/SC is so aesthetically pleasing!


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Interesting, as an active fan with 135s, I’m talking to ATC about eventually downsizing.
It will be a hard decision.

TBH, I think it might be easier than you think.

I really rate my 40A’s; budget and space limitations precluded going for SCM50aslt, but if 50 users’ experiences are any guide, I don’t think they would disappoint.

Whilst going for the 40’s meant I changed speakers and power amps at the same time, I got a “better sound” for not much money in relative terms.

I haven’t nor want to hear more expensive ATC’s, but I don’t think you will be disappointed, and you will presumably still have your 52 for the Naim sound. I actually think I’m hearing much more what the 52 is about now.


`Thanks Gary. My comment about amps “in the box” was my rather weak attempt at irony about the contradictions that sometimes occur in how we view the high-end field. Personally, I doubt that putting the amp in the speaker cabinet produces any significant difference or issue. I also agree with you that everyone considering ATC speakers should listen to the actives as well as the passives.

Interesting… similar system here.
Had 250 o.80er before and now 135… do it! It’s great.
Also SBL mk1 - phantastic!
Was also thinking about passive or active atc 40s.
Finally gone for kudos 606 - low volume is pefect even with their lower sensitivity.

I am not convinced that a 300dr is better in every way than a 135.

Be prepared that it is hard to get rid of the SBL magic, even if the new speaker is better

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Oh I’m quite prepared for that drago! I’m a big SBLs fan boy!

Always wanted 135s too!




I never get anywhere near that on my 52.


The 135s will be a nice upgrade.

Darran or Naim will service them if required.

Higher or lower?

It’s possible that the unbalanced to balanced transformers I use on the Supercap’s output have changed volume levels vs position of the knob, albeit I did notice the volume rise seemed more “linear” for want of a better term, after Naim did the Pots-8 for ne.

Tell me of fanboy - used my SBL from 1990 till end of January 2024.
still have moments where I miss them.
It is different - some sounds are more prominent with the new one - some not.
But I can tell that the kudos have massive groove - that’s what I like a lot with SBL.

I listen on either low volume or very low volume, depending on what time of day it is, who is in, and what kind of mood I’m in.

If I want to blast it out, I go to 9 O’clock.

If I’m drunk, which almost never happens nowadays, I might max it out at 9:30 or so for a bit of Metallica, Led Zeppelin, Deep Purple or something of that ilk.

I have okay hearing at the age of 59, with just a bit of damage in the left ear, partly from a Robocobra Quartet gig in a small room in Manchester where the guy on the mixing desk I think didn’t like the band or the audience and deafened us all!

So it’s a combination of not wanting to wake my wife who sleeps in the room above the HiFi, and not wanting to damage my hearing…

…and maybe trying to make up for all the stupid things I did going to gigs and blasting very loud music into my ears for the first few decades of my adult life.

Therefore, I don’t think ATC are the speakers for me!