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

@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.

I FINALLY got my Coda S5.5 going today. (I have been without the rig since December 2023!) It was quite an ordeal because yesterday when I got it connected there was distortion! It took me all day of fruitless trial and error. I narrowed it down the the Legacy Wavelet II so I emailed them this morning. (Ed at Legacy is great and answers me quickly every time) It seems that since my Dinafrips Venus II DAC XLR’s were into the Wavelet the gain was too high causing the distortion. Ed suggested I use the dip switches to take the input down and I did -3db then -6 Db then -12Db and that cleared it up! It took some trial and error to get the right dip switch settings. right, I ended up at -6 Db. So now it is finally sounding sweet and burning in. Yesterday I spend hours trying to troubleshoot the problem, trying cables, different configurations to isolate the issue, what an ordeal fearing it was my new amp. I am so happy now! I will report back after I get 100 hours on the rig. It sure shows great potential! Sidebar comment: I also needed some adapters from Silversmith to fit my Fidelium speaker wires into the posts, so I had to use some old heavy gauge Monster cable just to get it going, holy cow when I got the Silversmith speaker cables back in it later today what a revelation! Solid copper isn’t the answer in my case. The change was HUGE! I can already hear the same attributes previously noted in others impressions of this amp. I am transitioning from all tubes to all solid state so a big leap.

@firefly627s 

Thanks for your well thought out explanation, it helps me to understand manufacturer thought processes rating amps.

My rather limited understanding of amp watt ratings was that a true class A amp would run in class A at all impedances.  As you mention, this amp is a class A amp at 8 ohms.

So by my way of looking at things which I believe you are confirming this is a class AB amp once speaker impedance falls below 8 ohms.

No indirect criticism here as I agree what matters is sound and I have only owned class AB amps.