FR10s driven by 25-50W Class A Vitus amps?

@Chris_Brunhaver – got a question for you regarding my new FR10s, which are now singing nicely in my room now that I’ve got their setup nailed down :)… at least until I start mucking with them again haha. I’ve recently procured a used but near-mint Vitus SL-102mk2 preamp and am loving it with my Pass X250.8. I’m considering some SM-011 monoblocks to replace the Pass. Here are their specs:

Into 8 ohms: 25W class A / 200W class AB
Into 4 ohms: 50W class A / 400W class AB

Do you think the above class A power will suffice to drive the FR10s? I usually listen at moderately-high levels during the day… medium to lower levels at night. Thoughts?

Thanks, Stew

The mono amplifiers should be completely sufficient for the small speakers. When things get loud, they switch to A/B mode and can deliver more power. If the amplifiers don’t make it, they wouldn’t be worth the money.:rofl: The question I ask myself is. Why you chose the FR10 speakers and then mention such amplifiers. Is the room small to medium sized? Then the performance will be completely sufficient. Greetings Andreas

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When those amps switch from Class A to AB they put out 200 and 400 wpc so yes more than enough power.


Welcome to the club!

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@Stier2704. Hi Andreas, I should have added in my original question, that the FR10 spec calls for 50-200W into 4 ohms. I only just learned that the SM-011 are, I have come to understand, similar in function to Pass X series, in that the first N watts are pure class A then the amp draws on class AB when the demand exceeds that. So, that does answer my question about these amps “compatibility” power-wise with the FR10s.

To your question about my choice of FR10s themselves. Like most of us, I upgrade my system a piece or two at a time, as finances allow. My room is small-to-medium-sized (12’ x 19’ x 8’, and the speakers “shoot” across the 12’ dimension). The FR10s are very revealing, I like their house sound, the bass is solid, they are perfectly sized for my room dimension and inline with my aesthetics. They also fit the pocket book :).

As for Vitus… I’ve always admired them and know they are considered very high end both in performance and price. When the SL-102mk2 came up for sale, the price and timing were right. It replaces a PSA BHK preamp and has taken my system to another planet entirely. Now, I may have a similar opportunity with SM-011 monos in the near future… I can build an all-Vitus amplified system for less than retail! I personally am so excited by this! The FR10s have so far been up to the task, revealing the differences/improvements from the Vitus and providing a very satisfying musical experience, so for now they are serving me well. As I climb the “upgrade” ladder, I’ll likely take the next step with upgraded speakers. But for now, the FR10s are making me happy paired with the disproportionately sophisticated Vitus :).

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Thanks! What do you have in your system?


Sorry if I may have written something provocative. The FR 10 are beautiful speakers. And size doesn’t always matter. The loudspeaker should form a harmonious connection with the room and correspond to your listening taste. I had an Einstein “The amp” for a long time. This one didn’t have the highest wattage. However, it is very current stable and could therefore also drive critical loads. In his work area he played in a very controlled manner where some other amplifiers would sweat. If you have a good opportunity to get components cheaply, it’s always worth considering. I think that the Vitos also runs very controlled and stable in its range of performance. A few months ago I heard Brinkmann mono power amplifiers. Small but solid structure. The sound was great and similar to my large AVM mono power amplifiers. Maybe a touch more delicate. In normal situations, on loudspeakers that are not too hungry, this is completely sufficient. Large power amplifiers have the advantage when even more power is needed. Most of the time you only need a little power. Maybe similar to letting a car just idle and not in the optimal speed range. If you listen to music on average with, for example, 10 watts, that would be 1/5 of the 50 watts. With my AVM it would be 1/100. One could ask which amplifier works better. Is the small one in the optimal range and with the large ones the input signal gets lost? What about the noise levels? I think the Vitos are a more than good choice for normal circumstances. Greetings Andreas

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Not provocative at all … at least not to me :). In fact good questions imho that delved into my thought process which I was happy to share. Hope my reply didn’t come across with any type of negative tone. If so that was not intended :). On the contrary I appreciate your questions.


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I think it was smart to resist the typical audiophile inclination to overload a room with too large of a speaker. With a short wall placement and the width of that room the FR-10 is the right choice from my perspective. I’ve been tempted to give one of the Aspen speakers a try recently. My newly constructed room is 9’x17’x26’ and I would stop at the FR-20. I have four Rythmik F-12’s for any bass augmentation that may be needed but will avoid any immediate overload issue. I’ve made that mistake in the past.