The new Coda S5.5 amplifier: It's a "Petite Beast"!

@aolmrd1241 

       Does this sound like a correct interpretation based on your recent post and my discussion with Doug. In a sense the S5.5 is a 50 WPC at 8ohm  Class AB amp (it may be even slightly higher) except the first 50 watts are Class A; so it's a genuine 50WPC Class A amp for 8 ohm impedance. I am saying this because of how the No. 16 amp is rated in the manual as follows "150 WPC Class AB at 8 ohm (first 100 watts are Class A". For the S5.5, the doubling to 100WPC at 4 ohm and 200WPC at 2 ohm is not Class A but rather Class AB.  None of these power specs  matter much though because what does matter is how well  the amp is producing phenomenal audio. For the S5.5, at 4 ohm impedance the Class A WPC rating would therefore indeed  be less than 50WPC  (40 WPC Class A is reasonable) and at 2 ohm's even less wpc for the given output voltage of the amplifier. 

Again, the power ratings don't really matter. The S5.5 manual states only the key spec (50 watts into 8 ohm Class A). The sound the amp produces is what matters. The S5.5 is certainly looking like a phenomenal Class A amp and a true great value.  

Color me confused?

I have never had a class a amp.  I had the Parasound A21+ which was class A up to a certain point and then switched to AB.

But if I was going to buy a class A amp and was interested in its power rating (not including current) would I want to know (?):

Watts at 8, 4 and 2 ohms class A

As well as:

Watts at 8, 4 and 2 ohms class AB

@aolmrd1241 Thanks for that! Very helpful.

FYI based on a recent email (today) with Doug at CODA, at minimum any S5.5 manufactured in 2023 is also "current spec" parts and topology. He did not choose to elaborate on precisely when the current S5.5 spec was introduced. 

As for the Class A envelope into 4/2 ohms, my guess is the S5.5 topology is "sliding bias" so 25/12.5 watts in Class A, given the lack of heat (never more than 90 degrees F) generated by my S5.5 even after hours of high DB playback.

But as others have mentioned, does it matter really ? when even with very challenging loads like my B&W 804 D4s, the amp remains cool and "sweet" sounding. I detect zero hardening even with crap recordings. 

@jetter

I have reviewed specs of countless amps and haven’t found one yet, no matter if it is called a Class A amp or Class AB that gives you the information you are asking for; rather you will get what each manufacturer decides to give you as your guide. And power is not always the best gauge to sound quality or speaker drive capability.

Best explained maybe by a few examples. PASS Labs calls their INT-25 a Class A integrated amp and it’s rated at 25 amps Class A into 8 ohms. That’s all the power spec you get; yet it does transition into AB beyond that 25 watt limit or at lower speaker impedances (but is doing it AB even if it isn’t stated). The same PASS Labs calls their INT-60 a Class AB integrated amp, with a single power spec listed as 60WPC AB into 8 ohm. That’s all. But that amp is Class A for the first 30 watts into 8 ohm. There are countless examples. The bottom line is a Class A SS amp is going to have some region where it performs as AB and vice versa, just as you mentioned is the case for your Parasound amp. There is no apparent requirement for any manufacturer to give you the data you want to know. Yes it can be confusing at times. It becomes complicated though to know what the power ratings boil down to in terms of the WPC at various impedances for both Classes. So the specs manufacturers give are often limited, but serve to tell you something about where the component’s strength resides. And for the S5.5 it starts with 50WPC Class A in 8 ohms. Where it finishes though is at your ears and from all the reviews posted in this thread, it finishes in 1st place, by a wide margin.

This probably hasn’t helped your confusion on this but is an attempt to explain that you are not likely to find answers to the questions you ask in your post and even if you could, they won’t always relate to how good the component is going to perform.

It was explained earlier that the lower power side of the S5.5 allows the use of some unique transistors which are the reason behind the stellar sound being reported by everyone who has purchased the S5.5 amp on this thread, and these are critical listeners. The eye opening accurate reports of Terry London and all these users carries far more credence than any thorough list of power specs could ever convey (imo). Hope this helps some and any confusion on power ratings is understood and shared by many; however, in rare cases such as this Coda S5.5 thread, there just may be a more accurate criterion to focus on. Like who is winning all the races.