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ATC SIA2-100

I note the SIA2 -100 has power out put 100watts into both channels at 8ohms and 135watts into both channels at 4ohms. Is this new amp one of these amps which can drive and hold its own with difficult speakers like Naim amp or even the humble Simaudio Moon 240i can (much more to restrictive degree)?
 
The SIA2-100 has two transformers: one smaller toroid with multiple secondaries for preamp, DAC and logic functions and one larger toroid with two secondaries for each power amp.

No, the Grounded Source topology is not unique to us and you correctly identify that Hafler used it (quite extensively I think).

Our SIA2-150 Mk1, the current Mk2 and the new compact SIA2-100 all use a single transformer for the power amps but with separate secondary windings. It is not an absolute requirement that a stereo amp using grounded source output stages has seperate transformers for the LH & RH amps.

Having given it some thought yes separate secondaries on one transformer will work due to the very low impedance of the output stages which are being floated on the same transformer mitigating the coupling between them. It's not a topology you see very often! Separate transformers would be ideal though as with only one transformer the channels are linked by the leakage capacitance of the transformer.
 
I note the SIA2 -100 has power out put 100watts into both channels at 8ohms and 135watts into both channels at 4ohms. Is this new amp one of these amps which can drive and hold its own with difficult speakers like Naim amp or even the humble Simaudio Moon 240i can (much more to restrictive degree)?
Hi Romulus,
Based on the Simaudio Moon 240i specs (from their website), the SIA2-100 offers more power into both 8 ohms and 4 ohms. I can't really comment on, "Naim amp" unless you advise a model(s) you are interested in.

Edit.
I've found some good data on a comparable Naim amp, the Supernait 2 here:
https://www.stereophile.com/content/naim-supernait-integrated-amplifier-measurements
I don't know if this is regarded as being a good performer with 'difficult' speakers but it could be reasonable point of reference.
Stereophile measures the max O/P at 89W into 8 ohms and 140W into 4 ohms. So, our SIA2-100 offers slightly more into 8 ohms and slightly less into 4 ohms but, in reality, very very similar.
The Supernait 2 is more expensive at £3249.
 
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So, our SIA2-100 offers slightly more into 8 ohms and slightly less into 4 ohms but, in reality, very very similar.

Is the Amplifier section in the SIACD similar to that in the SIA2, they seem the same from the specs but it is difficult to know if that is the case?
 
Having heard the SIA2-100 recently I can vouch for it's performance. Sounded great in our big room (7m x 6m). Ours is on order and we cannot wait to get our dem unit in to experiment more. As with all of these things listening is the only option. Unless you have some very stubborn speakers it won't really be about power delivery, more which sound you prefer will be the biggest factor.
 
Having heard the SIA2-100 recently I can vouch for it's performance. Sounded great in our big room (7m x 6m). Ours is on order and we cannot wait to get our dem unit in to experiment more. As with all of these things listening is the only option. Unless you have some very stubborn speakers it won't really be about power delivery, more which sound you prefer will be the biggest factor.

Once you have experimented on your dem unit would you report your findings? I for one will be very interested.
 
Yes sure, I am hoping we get it in the next couple of weeks. We are heading to ATC next week for a factory tour so there should also be a detailed article on our web site that i will put a link on PFM for people to read if they wish..
 
The sound I heard from the SIA2-100 was dynamic very tuneful. it is great at unravelling what is really going on in a recording. Just hook up a streamer/music server and you have a system. I agree, shame black isn't an option.
 
Our new ATC SIA-100

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