Do Class 'A's do Slam?

Just wondering what people's views are on this one. I've always liked low/no feedback class 'A' power amps.

Can they do bass slam, PRAT, groove, etc. or are we mainly talking mid-band bliss, clarity and space?

What are your experiences?

 

Well to me mid band is vital, hence my desertion. I can get slam from a sub, however I really am now seeking only the tangible presence a horn or similar can give, with an amp with just 2 valves in the signal path.

my current parallel sets are no feedback, and they go deeper than a michell alecto. they are a different quality, I wouldn't call them loose, just fruitier, plummier bass. Its not as tight, but very hard to describe. The sheer vibrancy and life make more than compensation for me.

 

Of course they do.. a 100watt class a amp will give as much if not more slam than a 100watt class B.

However if you are only thinking of valve amps then I'd probably say they do slam, but to a lesser extent as compared to other valve amps.

 

tbh, the one thing I have learned is you can't have it all, its one or the other.
oddly some things do one thing, yet are deficient in the other. Its like there is some strange force at work that only allows either great bass or mid, but not both at the same time.
You have to see what gives you what you seek and seek the stuff that gives you it.

 

are you referring to any Class A,or just valve?

I have the A21,and the bass is fabulous,not arse-rumbling or window rattling,but tight,deep,controlled and just plain "right".So in my case,with the Audio Physic Sparks,no they don't slam,in that sense,but the effect hits you where you want it to,musically,sensually,and not just loud for the sake of it.But if there is bass to eek out it gets to it,in such a seductive way,you dont over-analyse,you just enjoy.I would say Class A ss is Placido' s culture to Pavarotti's brashness.

But they go loud,far louder than you would thing 25 watts has any right to,in fact,it goes far louder than i enjoy listening music too.I had The Kings Of Leon on today,loud,and if the bass slammed anymore than it did the music would have been unbalanced,the thing just rocked

I hope i am making sense,i am still on lesson 1 of HIFI speak

 

Steve, are you thinking of an amp to control your subs? or just a general open question?

Ive heard plenty of class A amps that thwack (to use tone-o-speak).

One of the best ones I heard for low end grip was the CJ MF2300. See below link.

http://www.conradjohnson.com/It_just_sounds_right/classic-products.html

For myself, I never got past the question ''what sounds the best''? which for me has always proven to be a class A valve amp.. everything else faded into insignificance when I had the answer to that..

each to their own of course

Chris

 

Steve,

those Pro-ac's at Heathrow were powered by Sugden mono's masterclass, you tell me
Pass X350 great power superb mids, slam??? humm dunoo about that

 

Steve,

If you are looking for bass slam and control you really should try the Crown K series Class D amps.

I'm seriou, they eat big Class A monoblocks for breakfast

 

86db w/m? Blimey, it drives those at just 25wpc??? I was given the impression that you need something more like 89db w/m sensitivity for something low powered like that.

But then I've got a DPA Renaissance (class A, not sure about power output) on the way, and thats got to drive my good ol' Swordsmans at 87db w/m!

 

indeed it does,average 6ohm load and they never dip below 4,according to a test,and in a 20ft lounge they go beyond what is comfortable to listen to without really pissing the neighbours off.:JPS:

 

No, just a general open question. I'm already looking at class 'D' for my subs.

I don't hold very strong views on which amps are 'best'. My own personal taste is for class 'A' valve with my full-rangers. Within class 'A' I tend to prefer neutral to oversweet and as much detail as possible without getting hard. Border Patrol suit me just fine.

I like the class 'A' theory too. Well, it stands to reason - no crossovers in speakers, no crossover in waveform. A bit of extra heat output? No bad thing at all in the UK most of the year.

I've heard good and bad amps of all sorts. Actually what I enjoy is listening to different flavours and trying to get into what different people listen for.

 

What's 'slam' sound like?

All this anthropomorphic theorising about feedback and 'class' is so much bollocks.

Paul

 

For heaven's sake Paul! We live in Britain. If we cannot talk about class differences what have we become as a nation?

 

Steve, I couldn't agree more, my 300b PSE mono's have heated my lounge for the last two nights, I scoped a MF A1 once and that bend is horrendous.

Stuart

 

Need a slam-o-meter.

 

Completely opposite end of spectrum to SET Class A, but I am trying to understand whether the Krell kav-400xi really is a 200W Class A design (400W into 4 Ohms). This just doesnt make sense to me, I thought even a 100W Class A amp would be massive and produce enormous amounts of heat. Have I missed something?

 

Greg,

You are right, theres no way it could be 200W fully class A otherwise it would be massive and very hot. Its probably class AB with the first few watts Class A.

 

specs are tricky things. a lot of transistor amps run class a for the first few watts (or even 10's of watts) and then transfer to class b for really big demands. bigger krells (and other amps too) do not have a fixed biasing current (which determines how many watts are class a) the krell system responds to demand so if a demand for 50 watts comes along then it ups the bias to allow for this from then on. after the amp is unused for a while the bias current falls back to a standard lower level to save power. not sure if the 400 uses this system though.

given that most of the time an amp is outputting less than 10 wpc anyway it means that most of these amps will be running in class a unless some big transients come along and kick them into class b along with lots of crossover distortion and a wilting psu. maybe this is why some amps 'time' and some don't - just a thought.
cheers



julian

 

Well, ATC active speakers use amps that are class A for the first 2/3rds of their output, anything from 180-250 watts depending on speaker model, and they're small enough to fit inside the speaker cabinet, so I think the size thing is mostly related to the efficiency of the heatsinking arrangement. Having said that, the ATCs idle pretty hot, even with some chunky heatsinking; if the Krell is both small and runs cool, that probably indicates it runs in class A/B I'd guess. Does it use case fans?

Edit: what Julian said ^^^

-- Ian

 

Ah reread here and there and it is the pre-amp stage which is fully class A (AFAICT).