What are the weak points of Pass amps and pre-amps ?

cowan217, agree about all the great pass reviews.  But a lot of us call whatever we have as the best thing ever.  Then out next purchase is the new best thing better than what we had before.  Its good to know if there is something not perfect about an item to see if that "thing" is a deal breaker or not of consequence to us personally. 

I have never heard a pass, but I think that other than the heat I would love to have one.  

@jetter 

Gotcha, really looks like a whole lot of useless space and words to me.  No idea what it has to do with Pass Labs...

I have owned a number of Pass Amps and pre-amps, as well as several First Watt Amps.

Right now I have a xa30.8, and x20 pre and x10 phono.

Every Pass amp and pre amp I've owned has sounded a bit different, but they've all sounded excellent.

The people at Pass are great to deal with, as is Mark from Reno Hi-Fi ( where I've purchased all my Pass equipment).

I suppose there is better equipment, but I would say that if you are not satisfied with the sound of Pass then you will likely not be satisfied with anything.

Of course this is just one man's opinion, but I think it's a valid one.

I remember running a Yamaha 1970s CA 1000 integrated amp with 15 watts Class A switch.  It got rather warm but it did sound superior to the Class A/B 70 watts (about).  The 15 watts sounded more musically involving, smoother and quieter than Class A/B.  

I own an EAR 890 which is 70 watts Class A.  It gets burning hot on the chassis and transformers after 30 minutes. 

I now use a pair of monoblock 130 watt tube amps running Class A/B.  It is a voltage regulated design which runs so cool that after 2 hours, you can place your hand on the transformers which are merely warm.  Plus the sound is superior to the EAR 890.  

I don't think there is an advantage running Class A over Class A/B, depending on design.  The cost of powering Class A and the heat are definitely a consideration.

Are Pass amps somewhat 'lazy', not quite fast and dynamic enough ?