question to Plinius Amp owner

Just curious to know what is the sounding difference you experience when you switch between class A and class AB? I guess this comparison might be more objective since the rest of circuit is the same except the bias. Can you confortably draw the conclusion that class a mode is better in every aspect ?
In my opinion, after a few minutes of additional use I hear additional extended highs, better mids and deeper more robust bass slam.
to my ears, the plinius in class a, is absolutely wonderful. perhaps close to the best characteristics of both tubes and solid state, but then, i may be a bit biased.
Lak & Danderson,
I'm not questioning your opinions but just a little bit confused. If what you said are ture, then it makes me wonders why Plinius bother to add a AB mode switch there ?
Easy, AB mode = less heat and less electrical comsuption, AB mode is fine for casual listenings, for example.
I usually listen to AB also however if I'm doing critical listening I always use A.

AB= cool to the touch.
A= hot to the touch.
There also seems to be more PRAT associated with A.
In class A the Plinius it dissect the inner detail
of the music,more emotions,instrument sounds more
palpable,soundstage opens up and more.I agree with
Lak and opinions above.Remember it takes an hour
to hear the differrence between Class A and ClassAB.
Class A in the morning, I can cook my eggs and bacon while listening to music without going back and forth to the kitchen.

Sorry, it's a snowed in kinda day here.
because of this 1hour I usually hear in AB....because there's so little time to here to music, unless I left on class A for 1hour and then listen..(why not ?)
to answer your question IMHO the diffence in AB is it sounds like a very good 2 channel system playing in your room, in class A it sounds like very good musicians are playing in your room.
So to get the best what we do guys ?
Leave the Plinius always on o.k. ?
with signal for 20 minutes in AB then turn the bias in A for 1 hour ???
or give signal directly in class A and wait for 1 hour ?

please share your opinions, so we can all get the optimum from our Plinius !
Thanks for the responses !
Let me try summarizing and adding as follows:
1. A well designed class AB is still not as good as a well designed class A, looks like the difference is not trivial
2. the above might be applied to dynamic biased class A
3. based on my experience, it takes 45 minutes to 1 hours (depending on the environment temperature) for Class A amp to reach the thermal equilibrium where it is designed to operate at.
4. "always on" might not be appropriate unless you do not pay the electricity bill
I leave my Plinius on AB 24/7. When I want class A it only seems to take a short 5 minutes to start soundind better. 20 minutes it's good to go!
The owners manual says to leave it on. That is what I do. When you want to listen critically switch to class A. I usually start listening right away and the sound just keeps improving.
UPDATE: I leave my amp on class AB, 24/7. When I flip it into class A, it takes a good 30 minutes to really stand out and become very dynamic.
In class A the sound is slightly more palpable than in class AB thus rendering the music to be more enjoyable to listen to. However, in my findings, extensive and prolonged listening sessions in class A will render the sound quality to be almost similiar to class AB when switched back to AB. Hence in order to appreciate the benefits of class A over AB, I mostly listen in class AB and only switch to A when I am really into the mood for some critical listening session.
I have a Plinius SA-102 amp purchased in 2003. Class A mode makes a lot of difference specially when kept on for one hour.
Few weeks back, I observed that the heatsinkls were not as warm as it used to be earlier in Class A.
Please note that over a certain period of time after usage, "Bias" voltage may come down and need re-adjustments. If you feel that the heatsinks are not getting enough heated, then consult your local dealer for re-adjustment
The hotter the amp runs, the more bias drift you can get. Couple that with a low-feedback design and you will need readjustments pretty often.
Old thread, I know. But I could (and others who listened) detect the difference that class A made on my legacy (old, retired, sold) Martin Logan Summits over class a/b.

What I always remembered was that in class a, the voices/imaging were tighter with less fuzz around the imaging. It was very evident and easily detectable.

And this was within about 5 seconds of switching.
Caveat to my statement above... Could hardly tell with less responsive speakers like sonus faber Cremona 1... Could not tell.

But on the summits.... Nearly instant I could tall we were in class a. I'd get up and turn the switch then sat down . As I sat down the sound just physically changes and in 5 seconds I'm in full class a.