Do I esentially have a class A amp?


I have a Krell KST 100 which has class A/B topology but it runs in class A up to 50 watts or half power before sliding over to class B. At most I may use 10 watts and at that very rarely when I drive my Vandersteens. So my question is do I essentially have a class A amp?
128x128digepix
Ruunin and Digepix,
I think both of you are listening to class A power most of the time if your listening levels are usually in the mid 70-80s db range C weighted.You`re often using less power than you realize.
Digepix, I understand that you consider class A better sounding, otherwise you wouldn't care. It should be better sounding if it is designed that way. Class AB has to use more of negative feedback to counteract nonlinear operation of output transistors. This negative feedback improves everything: THD, IMD, Bandwidth, Output impedance etc. but unfortunately can produce Transient Intermodulation (TIM) - basically overshoot of fast changing signals (signal fed back is late because amp introduces delay) that in frequency domain shows as addition of odd order harmonics. Since it can make sound unpleasantly bright designers try to keep amount of negative feedback to minimum. 30dB gain of power amp represent voltage gain of 30 but amplifier will most likely have gain of 300 in class A and 3000 in class AB before feedback that brought gain back to 30 was applied. Class AB needs more feedback (and therefore initial gain) not only to linearize non-linear operation of output transistors but also to reduce "gm doubling" effect. Gm doubling (trans-conductance doubling) is simply gain difference between two (class A) vs one (class AB) transistors operating at given moment.

Since your amp has both - nonlinear region of transistors and gm doubling it has to use more gain and "damage" was already done. This whole issue is very complicated and it was even shown that increasing bias in typical SS amp can actually increase THD distortions (overbias). I'm sure Krell engineers know what they're doing and this amp can sound better than class AB amp but it is not as good as equivalent class A amp at any loudness level.

I understand you need to know what you really got for your money but I would pay more attention to system synergy and overall sound and less to classes of operation, specifications etc. Often amp with poor specifications has wonderful sound.
Kijanki-Wow!! Thanks for all the information. I'll be honest, the Krell was a freebie so it doesn't hurt my feeling one way or the other. It sounds good even though the KST series of Krell amps get no love. I'll tell you from a pure synergy perspective I haven't heard a better amp than my Music Reference RM-10 through my Vandersteens. Sure 35 watts won't tear the walls down but for me it plays loud enough. When Roger Modjeski designed this amp he used my Vandersteen's and a pair of old Quads to voice the amp with. I always loved el-84 amps, my first amp was my Dad's Harman Kardon Ballad integrated and ever since I've been hooked. I'm sure my amp doesn't offer the best specs but for me it offers the best sound.
35W won't tear the walls but don't forget that 350W (that tears the wall) is only 2x louder. Also 3dB more sensitive speakers will give you same as doubling the amp power.

So, how your 35W amp compares with good 140W amp driving 3dB less efficient speakers? 140W amp will be only 22% louder.
People often ask if it is better to buy 200W or 100W amp. In spite of amp's power being useless specification IMHO, I would always choose 100W because for the same money I can buy better amp.