Amp angst: STR or 2 AHB2s?

[ex audiophile]

I'm looking to upgrade my stereo amp (Anthem MCA225) that pairs with my STR preamp. The matching STR power amp retails for 6K, lots of power (400/ch) and appears to have very good measurements (Audioholics https://www.audioholics.com/av-preamp-processor-reviews/anthem-str-preamp-power-amplifier/p2). We of course are familiar with the superb measurements of the AHB2 done by Amir. Two of the latter cost 6K so, which to choose? My gut tells me there would be no audible SQ difference driving Focal Spectra towers. Hell, I could even get one AHB2 and the power would likely suffice but what fun would that be? The STR is a cosmetic match and has cool watt meters but is heavy compared to the AHB2.
I have believed that there is little difference in SQ between quality amps, but I recently moved a Mac 312 stereo amp into my surround system to drive the mains and it was truly an OMG moment. The speakers sounded much livelier and clearer, but of course that is just a subjective opinion. I will point out however, that when I first turned on the system with the new amp I was not "listening" for any change. I was simply checking to see if all the cables were connected and if the system would make any sound, so i believe my bias meters were at zero. The initial sound seemed such a dramatic improvement that I immediately started the search for a new/better amp for my STR preamp in a two channel setup.
As always, all comments welcome as a "what would you do" kinda thing.
Happy new year, and if you haven't seen Gene DellaSala's newest video on snake oil and his personal experience with a trade show it's worth a listen.

 

[Mtbf]

I don’t know what the sensitivity is of your Focals, but one AHB2 most probably will be enough. For me my AHB2 has been my best buy amplifier ever, and I have yet to see the AHB2’s clipping indicators lighten up.

 

[ex audiophile]

I don’t know what the sensitivity is of your Focals, but one AHB2 most probably will be enough. For me my AHB2 has been my best buy amplifier ever, and I have yet to see the AHB2’s clipping indicators lighten up.

Thanks. The Focals are 90ish so I agree one is likely enough. Did u hear a distinct difference with the ahb2?

 

[vitalii427]

Focal Spectra towers

I’ve found only Focal Spectral

If it is actually the right model than

Specs sensitivity: 91dB 2.83V/1m
But from measurements: 87.82dB

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

 

[ex audiophile]

I’ve found only Focal Spectral

If it is actually the right model than

Specs sensitivity: 91dB 2.83V/1m
But from measurements: 87.82dB

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

Yes, that's the right speaker, I was going by the 91 cited in the owner's manual. Thanks for the link

 

[vitalii427]

https://myhometheater.homestead.com/splcalculator.html

Take one more)

One AHB2 100w/8ohm at 88dB sensitivity is not enough for my taste. It depends on your room size.

I would get 2 Purifi Monoblocks from @March Audio. I like the enclosure design very much.

 

[Sparky]

Yes, that's the right speaker, I was going by the 91 cited in the owner's manual. Thanks for the link

Did you make a decision on this?

 

[ex audiophile]

Did you make a decision on this?

Yes, I have had the STR for a week or so. I didn't want to continue to wait on Benchmark; they are unable to get a part they need for their amp so production is still delayed. I also liked the cosmetic match with the STR pre and of course to be honest, could we hear differences between these two fine amps? Thanks for the inquiry

 

[Sparky]

Yes, I have had the STR for a week or so. I didn't want to continue to wait on Benchmark; they are unable to get a part they need for their amp so production is still delayed. I also liked the cosmetic match with the STR pre and of course to be honest, could we hear differences between these two fine amps? Thanks for the inquiry

Good choice! All amps are meant to sound the same anyway...it's the preamp that adds the flavour.

I'm almost at the purchase stage for the STR Pre....I use an RME ADI2 DAC at the moment and I'm sure the RME has better specs but it's only small measures. You just can't beat the STR Pre for functionally, design and of course, room correction...

 

[ex audiophile]

Good choice! All amps are meant to sound the same anyway...it's the preamp that adds the flavour.

I'm almost at the purchase stage for the STR Pre....I use an RME ADI2 DAC at the moment and I'm sure the RME has better specs but it's only small measures. You just can't beat the STR Pre for functionally, design and of course, room correction...

I'm sure you'll be delighted; I believe the STR Pre is a unique piece in the marketplace. If you stream digital music i'd enjoy hearing what source you come up with (I'm using a Sonos Port). And if you run two subs let me know what you think of mono vs stereo application.

 

[Sparky]

I'm sure you'll be delighted; I believe the STR Pre is a unique piece in the marketplace. If you stream digital music i'd enjoy hearing what source you come up with (I'm using a Sonos Port). And if you run two subs let me know what you think of mono vs stereo application.

I think so too, it seems like a very useful bit of kit! The fact that Audioholics have measured and confirmed it's abilities, SNR and THD+N figures sealed the deal for me really.
I use an Innuos Zen Mini Mk3 as my Source/Server/ROON Core & TIDAL HiFi which is connected via Asynchronous USB to my current DAC.

I use two subs yes but they're not ideally positioned so will be interesting to see how ARC deals with that one!

Exciting times....

 

[peng]

If you need reference level you should go with two AHB2a unless you sit close enough. Your OMG moment re the MC amp may be due to other factors than just "amp" sound signature but that's a never ending debate that I didn't mean to start.

 

[ex audiophile]

If you need reference level you should go with two AHB2a unless you sit close enough. Your OMG moment re the MC amp may be due to other factors than just "amp" sound signature but that's a never ending debate that I didn't mean to start.

I'm not sure what you mean by reference level, both amps measure so well that there would be no audible distortion or noise in either. And I agree, we certainly don't need to start the discussion of the "sound" of amplifiers! I've already purchased the STR amp in any case.

 

[peng]

I'm not sure what you mean by reference level, both amps measure so well that there would be no audible distortion or noise in either. And I agree, we certainly don't need to start the discussion of the "sound" of amplifiers! I've already purchased the STR amp in any case.

I meant 85 dB average 105 dB peak from your listening position. The Spectra 40's sensitivity is 91 dB/2.83V/1M, nominal impedance 5 ohms, dip to 3.1 ohms minimum and recommended amp power 40-300 W.

If you sit 4 M from them, 100 W will get you about 102 dB peak, or 82 dB average. That's still very loud for a lot of people, I don't prefer anything louder than 75 dB average but some people like it loud.

So 100 W is likely enough for you but I think it is always good to have 2X (or more of course) of what you need. The STR's pre out voltage spec is 3.3 V RCA, 6.6 V XLR at <0.1% THD of 0.1% THD would be considered horrible for Amir, but that's him. IIRC, the STR did measure (By AH, or HTHF I think..) much better than specs so that shouldn't be a concern. I just thought it is still better to pair it with higher gain amps than the AHB2, all else being equal. If you bridge two AHB2s then you would only need half the pre out voltage from the STR and that would mean lower THD at the same output level from the STR preamp. Whether that would make any audible difference or not is a different story. I don't know about the Spectra, but I can tell you even my 1028 Be has high enough resolution that I find it less tolerant to distortions than my other speakers.

 

[ex audiophile]

I meant 85 dB average 105 dB peak from your listening position. The Spectra 40's sensitivity is 91 dB/2.83V/1M, nominal impedance 5 ohms, dip to 3.1 ohms minimum and recommended amp power 40-300 W.

If you sit 4 M from them, 100 W will get you about 102 dB peak, or 82 dB average. That's still very loud for a lot of people, I don't prefer anything louder than 75 dB average but some people like it loud.

So 100 W is likely enough for you but I think it is always good to have 2X (or more of course) of what you need. The STR's pre out voltage spec is 3.3 V RCA, 6.6 V XLR at <0.1% THD of 0.1% THD would be considered horrible for Amir, but that's him. IIRC, the STR did measure (By AH, or HTHF I think..) much better than specs so that shouldn't be a concern. I just thought it is still better to pair it with higher gain amps than the AHB2, all else being equal. If you bridge two AHB2s then you would only need half the pre out voltage from the STR and that would mean lower THD at the same output level from the STR preamp. Whether that would make any audible difference or not is a different story. I don't know about the Spectra, but I can tell you even my 1028 Be has high enough resolution that I find it less tolerant to distortions than my other speakers.

Thanks very much for the detail. There are a couple reasons why I agree that 100 watts is marginal in my case. The spectra 40s were measured by NRC to have a sensitivity of 88

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

I'm listening at about 15 feet and although most listening is in the 70s I do get above 80 often, and when I had a mac MC312 connected to the system the watt meters would swing between 30 - 300 watts routinely (closer to 30!). Benchmark had suggested that I try their amp in stereo mode and if I was displeased I could always buy another and that was a reasonable suggestion. So far I'm happy with the STR power amp and the Focals. Thanks again, it's folks like yourself that make this forum a great resource.