| AudioREVIEW's Forum Archives - Amplifier-Preamplifier |
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|   OK, time for me to learn something | jbangelfish
Nov 6, 2003 11:52 AM | | I have class A components, class A/B components and I guess, class B. Just what makes class A better than B? What determines these designations? Thanks,
Bill |
| re: OK, time for me to learn something | RGA
Nov 6, 2003 7:09 PM | | Are you referring to Stereophile's ratings? If so then in their opinion class A is the top end products money can buy out of what they have heard.
Everything they review gets a recommendation...and they don't list the componants that didn't make the cut. I have heard a lot of stuff for a lot less money that are better than their class a and b and c etc designations.
They may have heard it too and disagreed. In the end their and yours may not be the same...or I should say their preference and yours may not be the same. Sometimes I agree whole heartedly as I do on the Sennheiser HD 600s at other times I think they've really missed the boat - like the Paradigm Atom.
Do not go solely by reviews. Try and get a smapling of reviews from Europe and the States and try and find reviewers who are not afraid to tell you about the weaknesses. For instance lots of products that do well in Stereophile get ripped to shreds in other magazines.
So if you go solely by reviews then get a consensus.
If you're referring to class A, A/B and B amplifiers this is an engineering approach to the design of the amplifiers. Generally you want to find Class A or Class A/B amplifiers - and get a good one within these two based on your needs. |
| nope, not reviews or opinions | jbangelfish
Nov 7, 2003 7:59 AM | | I've written in some other posts that I haven't subscribed to a stereo magazine in many years. It seemed that everything being made got great reviews, no matter what it sounded like so I quit paying attention. If I read a review, it will be here or on other audiophile sites. These reviews come from owners' opinions and should be more honest. Some people are biased to certain brand names but you just have to try to read between the lines and make note of what else is in their system to form your own opinion.
My Parasound PLD2000 preamp is rated "pure class A". I know this relates to the circuitry but in what way? What makes it better than A/B or B? I have two Parasound HCA2200II power amps and they are rated A/B. My Cary PH301 Phono preamp is also rated "class A" and it is a tube component. These ratings all come from the owners' manuals. Just wondering what they mean as they seem to imply that it is superior. Why? Thanks,
Bill |
| re: OK, time for me to learn something | skeptic
Nov 10, 2003 5:11 PM | | I posted extensively on tubes versus transistors and class A versus class A/B recently. I will not try to rewrite all of it here. Read my recent postings to see some explanations an my views.
Briefly, All preamplifiers are class A. Most power amplifiers are class A/B, a few are class A. Class A or class A/B has to do with the way tubes or transistors draw current from the power supply when there is no signal present. Class A and class AB can be made from either tubes or transistors, comparing them is apples and oranges.
Class AB amplifiers can be made more powerful because they are more efficient. Read my analogy to two men sawing down a tree with each one working a handle at his own end versus a single individual with a hand saw working by himself. This is the closest analogy I can think of. Afficionados of class A power amplifiers say that they are more musical but cannot prove it by any rational measured performance specification. That doesn't mean that it isn't true but that doesn't mean that it is either. Generally class A power amplifiers are; tube units, very expensive, low powered. For this reason, they restrict the loudspeakers they can be used with successfully to very efficient models.
It is not rational and is not corroborated by experience that transistors are automatically worse than tubes, that class A/B amplifiers are automatically worse sounding than class A, that the use of negative feedback makes amplifiers sound worse, not better, that low efficiency loudspeakers are no good. This comes from a small segment of audiophiles who believe that vinyl phonograph records are automatically better than cds, that moving coil cartridges are automatically better than moving magnet types, that direct driven servo controlled turntables are not as good as belt driven models, that expensive audio cables are superior to inexpensive ones.
I'm not getting into this debate right here. It is too broad for one thread and besides, we have been debating this recently as was pointed out ad nauseum. Refer to the recent postings on this and other bulletin boards. |
| re: OK, time for me to learn something | FLZapped
Nov 7, 2003 9:37 AM | | That's been covered. Perhaps you should now try a forum search.
-Bruce |
| Was there an article on this or something??? | topspeed
Nov 7, 2003 10:59 AM | | Why is this the third time this has been asked in the last, what...10 days? Like Bruce suggested, do a quick forum search or just pan down from here. This was discussed ad nauseum just a few days ago and should answer your question.
Happy reading! |
| no article, found the argument, er discussion | jbangelfish
Nov 7, 2003 11:46 AM | | No, nothing other than my own curiosity caused me to pose the question. Having components of all the different class ratings over the years, I decided to find out what the hell it meant. Didn't realize that there had been such a big discussion of it so recently. Had to read through alot of heated debate to actually find the answer but it was there. Thanks |
| no article, found the argument, er discussion | RGA
Nov 7, 2003 5:06 PM | | There is no real debate. A properly designed class A amp is best period end of story.
The poster who was debating the point with me was arguing i favour of buying Krell instead of the class A amps I was suggesting...trouble is Krell also operates in pure class A. Almost all preamps operate in class A = so it's hardly a selling point.
And onemust note the words "properly designed." I prefer a lot of class A/B designs to say some of the amplifiers that Musical Fidelity makes.
Generally you will get more power from Class A/B but you also get certain types of distortion some people get aggrevated by. If you're not such a person then it won't matter if you are you might.
You simply cannot assume that a class A amp is going to sound better...but generlaly speaking the very elite or best of the best stuff operate all in class A. Most tube designs, Cary, Audio Note etc, and the top SS stuff Krell, Sugden the list goes on and on operate in class A.
But many of these make very accompished high end A/B designs as well. The reason should be pretty clear. Class A usually has less power...so if you want class A and you have sensitive speakers then a $1500.00 Sugden is your cup of tea perhaps. If you have an 82db speaker and you want class A then you'll need the 200 watt per channel class A amps from Krell at $20,000.00.
Which is why IMO it makes a LOT more sense to buy a very good sensitive easy to drive speaker than it does to buy a power hog. It takes more work and generally a LOT BETTER materials to make a high sensitive good sounding speaker however - poor high sensitive speakers can sound honky. And most hard to drive speakers sound boxy and lifeless because they NEED so much power that even 200 watts don't always provide.
The difficulty with hard to fdrive speakers aside from power is that you continually try to improve..."if only a I buy 400 watt monoblocks etc." I have found that such speaker makers are hiding poor sound. They always claim you need "More power" to make them sound good, whereas other good designers building easy to drive speakers don't have to tell you that because a good amplifier at 20 watts will get all there is or would ever be needed out of the speaker.
There are exceptions of course...but 89db 8 ohms can be driven quite well off 10 quality watts.
12 watt tube amps with the right speakers can rattle glass and walls...so can a 3 watt amp for that matter. a speaker rated at 105db sensitive achieves that with 1 watt(and 108db total). To get 108db from an 82db speaker requires 516 watts. To get 108 db for a speaker with a rating of 85db requires roughly 250 watts. And if you look at many speakers rated at 82db or 85db they can't handle much more than 100Watts....so the first set-up will be far far louder and cost you far far less money in amplification and the distortion you do get is even order(much superior than the typical transistor version). |
| Debate seemed tube vs ss | jbangelfish
Nov 9, 2003 6:38 PM | | From what I read but I also read other debates. I'm not sold on nor against tubes, they do some things very well and some things not so well in my observation. Overall, I'd have to call myself more of a ss fan than a tube fan. The only tube component that I've ever owned is my Cary phono preamp and I consider it to be a very good one. I've also used a Conrad Johnson preamp (PV3) and was not overly impressed with it.
Anyway, I don't doubt that quality class A is the way to go whether tube or ss. The point about preamps and class A makes sense and probably doesn't give any bragging rights as it's the most logical way to do it and most fit the class. They still like to claim it.
With the explanations given, I have a very rudimentary understanding of the various class ratings. Thanks for all the info. My understanding of them is not limited by the explanations but by my knowledge of the inner workings of the components.
As I have stated in the past, I have always been a big power nut. I've always liked the most power that my speakers could handle and with absolute minimal distortion ratings. Within the systems that I have owned, I was able to appreciate to a great degree what the lack of power caused in my stereos, it caused clipping and distortion. Also as stated, I have never met a receiver that I liked and have been sold on separates since the early 1970's.
I always found that if I had lots of clean power available that I could play the system very loud and not hear distortion or clipping. This was good enough for me. I have probably not had many efficient speaker systems over the years as my likes led me to powerful amplifiers which would be too much for many speakers. This could certainly be the wrong approach but it was the one I chose.
Can you tell me what is different about the old Crown DC300A power amp? Doesn't it do something different with direct current? I don't know what class it is as the owners manual makes no mention of A or B and trying to decipher the circuits only confuses me. I still believe it to be a helluva well made old amp and has great specs. Only rated at 155wpc 8 ohm, it is individually tested to 185wpc with .05 distortion with distortion at rated output at .002, not bad for a power amp. It still works perfectly after 28 years of use.
Some friends have class A amps and are in love with them. One has a GAS Son Of Ampzilla and runs AR9's with great results. Another has Crown M1000 or M10,000 mono class A, (can't remember which) and he says he would use nothing else. Says he could cook eggs on them after use but no ill effects as this is the way they are. I bought the Parasounds from him and he said that he preferred the Crowns. I probably would too but the Parasound amps are very decent AB amps.
Bill |
| Debate seemed tube vs ss | RGA
Nov 9, 2003 9:50 PM | | It's been way too long for me to comment on Crown...though the ones I heard seemed to be grainy. But they were more beat-up because they were used as tools. They're not made anymore to the audiophile crowd if they ever were.
I was watching the meters of a tube amp last year where the sound was shaking the place and it never passed 12 watts.
rarely is an amp going to get past these points.
If you're interested in volume level sensitive speakers are far more important than the amp. Insensitive speakes then watts play a much bigger factor.
The design SS or tube or Class A or A/B has to be judged on its own merits. I bought a class A/B SS Sugden over a Class A tube amplifier.
My argument was that not all tube amps are rubbish...Good tube amps have an ear for music, many SS have an ear for analytical etchiness. The Sugden didn't produce that SS etchiness but had the beloved tight bass and overall beat the Tube amp I was thinking of.
Sounds like you're happy with your system...so that's all that matters. |
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