[Gary95762]

I have been very curious to try a first watt amplifier but have been reluctant with my Sonus Faber Amati's (90DB - 4 ohm) speakers in my 400square foot room. Id love to get opinions on how many watts I would need out of a class A amp to get the sound level I would get from a typical 200WPC McIntosh, something like the MA7900. Is it even possible?
I look forward to hearing any input.
Thanks!

[Bodhi]

Gary I think you'd be pushing it driving your Amati's with even the flagship FW 35w SIT-5 mono's. The minimum Class A power you'd want to drive those speakers is 50w, and preferably 100w. I don't know what your budget is, but here are two Dealer ads for Coda Class A amps which offer great build, sound & bang for buck. The ads are for open box and mint ex-demo examples respectively..

- https://www.usaudiomart.com/details/650251234-coda-s-55-coda-s-55-50w-per-channel-of-pure-class-a-bliss-outstanding-value/
- https://www.usaudiomart.com/details/650251233-coda-16-100w-per-channel-of-pure-class-a-bliss-sensibly-priced-reference-performance-amplifier-demo/

Terry London from Stereo Times has reviewed both of those amps (see links below)..

- https://www.stereotimes.com/post/coda-technologies-class-a-s5-5-amplifier-by-terry-london/
- https://www.stereotimes.com/post/coda-technologies-16-0-amplifier-by-terry-london/

Also you could look for a good pre-owned Coda Model 11 which is my favourite vintage class A amp. Though they rarely come up for sale these days. Hope that helps .

[toocool4]

Goto the link below, scroll down to Amplifier Power Required. Enter the details and it will give you the required amplifier power you need to have the desired SPL level at your listening position.

https://www.crownaudio.com/en/tools/calculators

[planet10]

My WAW are 4Ω at the bottom. My SIT-3 does just fine.

So does my ACA. And ACAmini.

dave

[seikosha]

No one will truly be able to tell you if it will work or not.  What one person thinks is loud could be completely unacceptable to another.  Everyone listens differently.  Toocool4 gave good advice.  Figure out your listening levels in db and run them through the calculator.

[AllanS]

No one will truly be able to tell you if it will work or not.  What one person thinks is loud could be completely unacceptable to another.  Everyone listens differently.  Toocool4 gave good advice.  Figure out your listening levels in db and run them through the calculator.

+1.  In my experience 90 dB 4 ohm Spatial Audio M4 Sapphires (~ 3 ohm excursions) , 300 ft^2 room, mid 70’s dB peak at 6’ from the speakers, 25 wpc Schiit Aegir sounds really good to me.  YMMV

[Bodhi]

+1.  In my experience 90 dB 4 ohm Spatial Audio M4 Sapphires (~ 3 ohm excursions) , 300 ft^2 room, mid 70’s dB peak at 6’ from the speakers, 25 wpc Schiit Aegir sounds really good to me.  YMMV

Your last comment is completely correct. I owned a pair of Infinity Reference 60 speakers for 16 years which are a 90db into 6 ohms. At the time I bought my speakers, the recommended amp to pair with the speakers by my Dealer was the Nakamichi Amplifier 1 integrated which is rated at 80w. So my estimation that the lower impedance Amati's would need atleast a robust 50w Class A amp marries up with my experience. And I note the minimum recommended power for those speakers is 50w.

[Rusty Jefferson]

You could use the F4 (my personal favorite) as balanced mono blocks if you have or get a balanced preamp that can swing 20 volts +/-. That would be 100 watts per channel of Class A and would likely be fine if you don't listen at concert levels.

Probably the best option is a big Pass Labs amp with maybe 40 watts of Class A and tons of headroom, though.

[Gary95762]

Thanks for that input. I will take a look at those calculations and go from there!

[RDavidson]

No one will truly be able to tell you if it will work or not.  What one person thinks is loud could be completely unacceptable to another.  Everyone listens differently.  Toocool4 gave good advice.  Figure out your listening levels in db and run them through the calculator.

Fully agree with this.

I’ve owned nearly all the First Watt amps and the “small” Pass amps at one point or another. And one thing that’s consistent is that the FWs all have limits ; Some of them have limits that aren’t hard to reach with mildly inefficient speakers (even in a somewhat near field setup). I think the F7 is probably the most versatile in terms of design/output/and overall performance.

However, without further info, I’d urge you to try the XA25. It is the most universal small amp in the entire Pass/First Watt lineup and has been my overall reference for many years. I think of it as a big First Watt amp more-so than small Pass amp. It has A LOT of the purity, tone, and texture of the First Watt amps, but has surprising grunt and density (despite the specs). It sounds excellent at low output and is very quiet. But it has guts FAR beyond the First Watt lineup, for those times you might feel like turning the volume knob up. It’s a masterpiece and deserves all the accolades and widespread praise it has received. They show up on the used market with some regularity too.

[Bill Baker]

I recently built an F5 for someone. At the time, the speakers I used were Linton 85’s at 90dB. My finding were you need a preamp with some decent gain to bring it alive as the F5 is a low gain unit. Sounded fantastic. As long as you have enough gain to properly feed the amp, you should be okay.

[mick wolfe]

No one will truly be able to tell you if it will work or not.  What one person thinks is loud could be completely unacceptable to another.  Everyone listens differently.  Toocool4 gave good advice.  Figure out your listening levels in db and run them through the calculator.

That's probably the most truthful response. Plus it will not only ride on efficiency, but the impedance curve a speaker presents. A speaker with a friendly impedance curve will be more of an asset than efficiency alone.

[Chazz5]

You're probably not going to get the loudest sound levels that a 200 watt McIntosh produces. But do you really know the loudest level you want for listening to music?

On the other hand, I've found that the typical formulas for Amplifier Power Required overstate the watts you need for the sound levels you really want.

The speakers have a good sensitivity rating but they are 4 ohm boxes. So you need to pay attention to the 4 0hm power rating of the amp, not its 8 ohm rating. Some Nelson Pass amps deliver more watts at 4 ohms, some deliver less.