Amp draw, Class A vs AB, oh my?

I had to do some repair on my KSA50 today. I thought the Thermistor had failed but it just turned out to be a loose screw on the patch panel. As I was buttoning it up I noticed my WattsUp meter sitting on the table so I thought I would hook it up and see what the Krell was drawing. Oh my, at 123V AC it was drawing 3.4A. this got me wondering so I hooked up my Symasym. It draws 0.42A. My three channel ESP P101 only draws 0.64A. Does this seem right? I had no idea that Class A amps were so inefficient.

Thanks, Terry
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
I wouldn't say my KSA50 clone sounds better than my Symasym. Different, but not better.

Amp alone doesn't produce sound. There is synergy between amp and speaker and there are compromises in speaker design. For this reason it is not always easy to say which amp is better.

But if you want to find out what to expect from a class-A amp, focus on the enjoyment aspect, the ability to produce non-fatiguing sound. This is the most important benefit from class-A amp, but not many people are "trained" to listen to such parameter.
 

SUZTEK

Member
2005-09-27 7:42 am
I have all components for assembly of Jean Hiraga 20 w class A amplifier complete with regulated power supply, but i am undecided about pursuing the project. Can anyone out there convince me that the effort and expense is worthwhile. My speaker is based on the transmission line design, maybe that could be a dawback regarding efficiency.
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
I have all components for assembly of Jean Hiraga 20 w class A amplifier complete with regulated power supply, but i am undecided about pursuing the project. Can anyone out there convince me that the effort and expense is worthwhile. My speaker is based on the transmission line design, maybe that could be a dawback regarding efficiency.

If you have no experience with class-A amps and are worry about power, remember that the issue with low power amplifiers in general is that they are incapable of delivering short term high power. A class-A amp OTOH, as long as the power supply is capable of 6A or above, you will usually notice as if the amp power is higher than it's rated power.

High power class-B amps often have unusable power due to its high distortion before you can open the volume to maximum opening. With class-A amps OTOH, we can often fully open the input in order to get maximum power and the amp still sing.
 
Amp alone doesn't produce sound. There is synergy between amp and speaker and there are compromises in speaker design. For this reason it is not always easy to say which amp is better.

But if you want to find out what to expect from a class-A amp, focus on the enjoyment aspect, the ability to produce non-fatiguing sound. This is the most important benefit from class-A amp, but not many people are "trained" to listen to such parameter.

I really dont buy into the synergy crap peddled around to sell bad equipment and yes i have heard Ok equipment shuffled around to produce good sound on specific recordings ..

A good speaker will sound good on a good amplifier , it will never sound bad and require synergy to sound good , yes it will sound better if feed better amplfication but never bad, in regards to amplification , load tolerant amplifiers at a bare minimum and 20 watts is not enuff , but best if that 20 watt amp delivers [email protected] ohm ...

Regards
 

SUZTEK

Member
2005-09-27 7:42 am
Thanks Jay for your input, i have never heard the sound quality of a class a amp and from what i have read it seems that these amps are really good for great and clear sound reproduction. My only concern is the efficiency of these amps if used with transmission line loudspeakers. Do not know if 20 w will be sufficient to drive them.
 
I really dont buy into the synergy crap peddled around to sell bad equipment and yes i have heard Ok equipment shuffled around to produce good sound on specific recordings ..

A good speaker will sound good on a good amplifier , it will never sound bad and require synergy to sound good , yes it will sound better if feed better amplfication but never bad, in regards to amplification , load tolerant amplifiers at a bare minimum and 20 watts is not enuff , but best if that 20 watt amp delivers [email protected] ohm ...

Regards
I used to believe in system component synergy.
The dealer could swap around purportedly good equipment. Often you came away convinced that ONE combination sounded better.

Now that I know more, I suspect some of the equipment was misbehaving when terminated with a poorly matched cable/source/load.
It was possibly a quirk of selecting a group of badly behaved and unusual terminations that suppressed the bad behaviour, to allow JUST that ONE combination to sound right/better.

A set of proper and honest measurements would have shown clearly what was going wrong.
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
I really dont buy into the synergy crap...

and 20 watts is not enuff...

I used to believe in system component synergy...

Now that I know more, I suspect some of the equipment was misbehaving...

To clarify things, my point was not about amp-speaker synergy, but about things that would make it difficult for people to judge properly the quality of 2 amps.

And one of those things is the "synergy", either because 20W is "not enuff" or the equipment is "misbehaving". And it takes a very very very experienced person to know the exact location of the bottleneck simply from listening.