Decision between CA azur 851w and Parasound A23+ for low volume

[Oscarshock]

I plan to replace my current amp (Denon pma 600ne) with one of the two amps in the title because I no longer need all the functions that the Denon provides, e.g. DAC, BT, preamp etc, and I am looking for a pure power amp. I only need the amp to drive a bookshelf speaker, namely, Elac dbr 62 and since it is for a bedroom setup I am most concerned with low volume. These two amps appear in my local used market with the prices differing by 500 CAD (~400 USD) for which the CA is cheaper. They seem to work in similar mechanics with one claim to be biased A/AB and another to be XD, however, IMO it seems to be just a matter of difference that after X watt in class A, it turns to class AB. Inspecting from the spec, 851w seems to draw higher maximum power (2400w) in contrast to A23+ (800w) so I assume maybe the 851w would work further into class A before turning into class AB. But besides that, they have similar specs with A23+ output in 160w @ 8o and 851w output in 200w @ 8o. In addition, 851w was released in 2013 and A23+ was released in 2019 to anyone who is concerned with their launch day.

I am looking for advice between these two, or your experience with either one of the amps or both. The preamp I am using is a tube preamp and has an output impedance 450 ohm, so it seems to be very easy to match either one of the amps. Forgot to mention, that the A23+ has a gain adjustment on both channels while the 851w has a bi-wire option.

 

[CharlieAudio]

The speakers are specified with 86 dB sensitivity. That is somewhat power hungry, but for a bedroom or similar size listening space, the amp probably needs to be rated at only 60 watts.

For comparison, my Spendor A1 speakers are rated at only 83 dB sensitivity, but in a similar listening environment and with similar liking for moderate volume, my 25 watt amplifier is more than adequate.

 

[Oscarshock]

The speakers are specified with 86 dB sensitivity. That is somewhat power hungry, but for a bedroom or similar size listening space, the amp probably needs to be rated at only 60 watts.

For comparison, my Spendor A1 speakers are rated at only 83 dB sensitivity, but in a similar listening environment and with similar liking for moderate volume, my 25 watt amplifier is more than adequate.

Ye, I have read that the elac is somewhat power hungry as it is rated in 86db @ 2.83v in 6ohm. This is part of the reason why I want to replace my current amp. And you are right with Denon which is rated in 45w @ 8o, it have already produced enough SPL for my room. Both amps are indeed very powerful, and I know it is a bit odd to drive the bookshelf with either one of them. However on one hand I can't find an amp that is rated lower power and cheaper, and also has a well quality, on the other hand, I simply want to play with another amp and see how does it sound like.

 

[krautmaster]

I own an A23+ with P6 preamp- plenty of power (lots of current on tap) they are in my family room driving a set of either old Dynaco A25's or new Monitor Audio Bronze 2 bookshelf speakers (depends on the rotation which ones are in use) The A23+ has plenty of power/current to drive the bass on an inefficient speaker like your Elac dbr 62s at any volume level.

 

[UncleAng]

Inspecting from the spec, 851w seems to draw higher maximum power (2400w) in contrast to A23+ (800w) so I assume maybe the 851w would work further into class A before turning into class AB

The idle bias plus overall configuration determines class A operation not maximum draw. The A23+ idles at 75 watts so it most likely is in class A for the first 3-5 watts.
The Azur 851W uses their proprietary XD technology which purportedly keeps the amp in class A for a longer period before switching to A/B; however they don't publish idle specs or how many wpc in class A prior to switching. However, from Stereophile testing....

Before performing any measurements on an amplifier, I run it for an hour at one-third its specified maximum power, which, thermally, is the worst case for an amplifier with a class-B or -AB output stage. I cut short this preconditioning with the Cambridge 851A after 30 minutes, however, because its case was getting very hot—the top-panel grille over the internal heatsinks was too hot to touch, at 148.4°F (64.7°C)—and I was concerned that something might break. I don't believe this will be a problem in normal use, as long as the amplifier is given plenty of space for ventilation.

Buy the A23+