I am looking for a new receiver. I currently have a sony str-k84op I am looking at the Yamaha - 525W 5.1-Ch. A/V Home Theater Receiver Model: RX-V465 Can someone shed some light if I am making the right choice
That model Yamaha looks like it should be a good choice. I had a Yamaha awhile back. It was the HTR-5940. It was pretty decent for a cheap receiver. It was 6.1, had plenty of inputs, and sounded good. But then I got my Onkyo. I like my Onkyo much better, personally. My Yamaha didn't decode the new HD audio, but didn't matter at the time. I didn't have a BD player anyway. I didn't like the amber light in the receiver window. I heard the new Yamahas don't use the amber light anymore. Mine also didn't do an OSD (on screen display). Had to read everything in the tiny window of the receiver. I hated that! Looks like the 465 don't have it either. Maybe it won't bother you as much as it did me. Other than that, it looks like a great little receiver. Good luck!
I too am a big fan of Onkyo. I've had mine for over five years now and it has never let me down. Over the years I also have had receivers from Sony, Yamaha, and Denon. All four of those manufacturers make good quality products, but Onkyo would be my first choice.
Before purchasing your new rig, may I suggest finding out the type of amplifier is in the receiver (this may take a call to the customer service dept of the manufacturer) I prefer class A/AB or AB alone Unfortunately many receivers (nowadays) are made with some variant of class D, which I am not fond of. I believe djscoop would agree
yeah absolutely check the specs before dropping down money on a receiver. class A and B are good circuits. Class D was originally used in automobile amps, and are slowly finding their way into home systems because they are less expensive. I'm pretty sure that most higher end manufacturers like Harmon/Kardon, Onkyo, Yamaha, and Carver still use class A or B circuitry, but make sure before you buy. Good point iluvendo, I didn't think about that...
http://stason.org/TULARC/entertainm...ifier-Class-A-What-is-Class-B-What-is-Cl.html To get true Class A you will have to spend a small fortune. Well well.
From the article: You are correct in your comment about the speakers. True Class A amps are likely out of reach for the regular consumer and can only be found in 10% of the high end market. Pure Class B amps are nonexistent so most amps are sort of "hybrid" Class AB. Like the article said Class D amps may have already caught up in quality. To the untrained ear and with low to mid level speakers one may not even hear a difference. Plus Class D amps draw less power and are thus more environmentally friendly. You lower you carbon footprint - if you're into that sort of thing.
there are really high end amps that do use class A circuits, McIntosh is one I believe. We've been talking about different amp class circuits recently on another thread about subwoofers, so its funny this topic came up again. I definitely recommend a AB class amp over a class D amp. Here is what I posted earlier today on the other thread about the classes: The class D amplifiers are much more energy efficient. Class A and AB circuits are very inefficient. only 10 to 20 percent of its power consumption is actual signal output, the rest is heat. Class D circuits use a different type of transistors. I won't bore you guys with the super technical details, but basically class D transistors are either on or off. when they are on, the current draw is at the max but voltage is zero. when they are off, the current is zero but the voltage is at max. basically that means that a minimum amount of current is drawn when the transistors require a large load, and vice versa. the downside of class D circuitry is that signal quality is much less than that of other classes of amplifiers. They implement pulse width modification to convert the input signal to a sequence of pulses which makes the transistors as efficient as they are. I would have to disagree. There is a very good reason why the majority of the class D amplifier circuits are still used only in subwoofer amps and car audio. The quality just still isn't there compared to the A and AB classes. Perhaps one day when the different processes it uses to convert the signals and sequence the push pull effect improve, then there will definitely be a good competition between class AB and class D.
I guess that day is already here with the Rotel RSX-1560 Receiver. http://www.hometheatermag.com/receivers/rotel_rsx-1560_av_receiver/index2.html I got a chance to listen to the 1560 driving a pair of B&W series 7's and I must say I agree with the review.
I'm sure the rotel sounds great, but that wasn't the point I was trying to make. The rotel is almost a $3000 receiver. Of course any receiver of that build quality and price is going to sound good. if not, no one would buy it. the fact that it takes a high end company to build a $3000 receiver to be able to say that the class D circuitry sounds good it pointless. To me, that means its still not readily available on a consumer level. When companies like Sony, Denon, and Onkyo can produce class D receivers for the same price as the AB ones, but have the same quality, thats when the technology will be here.
Although the article is somewhat dated, the basic electrical engineering design principles are still valid. The limitations of Class D If Class D were perfect, it would have swept the world and there would be no other class in common usage. I'll tell you about the three major problems of Class-D amplifiers in a moment, but first, here's a question: how do you make an efficient radio transmitter? Answer: start with a Class-D audio amplifier. Yes, the high frequencies involved in Class-D amplification readily propagate as radio waves, potentially causing interference with radio receivers and other equipment. You might think that the solution would be to enclose the amplifier in a substantial steel housing. But that's not where the problem manifests itself — it's in the cables. The filter that is supposed to remove the high-frequency components and leave only the audio signal is quite shallow in slope — 6dB or 12dB per octave — so there's quite a lot of RF energy still getting out. Clearly, manufacturers take care to improve the situation and remain within allowable limits, but it is a problem inherent to Class D. The second problem of Class-D is that the last thing the signal sees before it reaches the loudspeaker is the filter. A passive filter made from capacitors and inductors expects to see a certain load on its output. Even just looking at the resistance of a loudspeaker and ignoring its capacitance and inductance, loudspeakers come in 2(omega), 4(omega) and 8(omega) nominal impedances, and the filter will work differently according to the impedance of the loudspeaker. Taking capacitance and inductance into account, the impedance will vary according to frequency. So the filter design is suddenly very much more complex: an amplifier that performs differently for different speakers is going to be a problem. Thirdly — not finally, but enough for now — a Class-D amplifier has a relatively poor damping factor. The damping factor is the ratio of the impedance of the loudspeaker to the output impedance of the amplifier (it's a little more complex than that, but let's not get bogged down with details). In simple terms, it's a measure of how well the amplifier can control the movement of the diaphragm of the loudspeaker. A good amplifier doesn't just give it a push and hope for the best; it senses where the diaphragm is from moment to moment and controls its position. To do that, a high damping factor is desirable, and, as mentioned above, a simple Class-D amplifier has a low damping factor. Clearly, advanced technology can be applied to ameliorate these problems, but because of them Class-D amplification is used mainly in applications where efficiency, weight and small size are important. These include live sound, in-car audio and compact portable systems. Top of page That's not all, folks Clearly, there is more to know. For instance, it's important to know that the switching frequency must be very high to achieve the necessary resolution. A switching frequency of around 300kHz, which is around 15 times the highest audio frequency of general interest, is typical. The dynamic range and signal-to-noise ratio of the Class-D amplifier are controlled by the switching frequency — the higher the better. Clearly, the greater the rate of pulse generation, the more closely the pulse width will be in proportion to the instantaneous signal level. However, the drawback of increasing the switching frequency is that the amplifier will be less efficient. Optimum efficiency would be achieved if the transistors could switch instantaneously, so that they were in either their fully on or fully off states, where almost no power is consumed. But in the real world it takes a little time for the voltage to swing, and during that time some power is dissipated. So the more often the swings take place, the more opportunity for waste. Even so, the efficiency of a practical Class-D amplifier can be better than 90 percent, which is significantly better than a Class-AB design (78.5 percent at best and typically closer to 50 percent). Coming full circle, because a Class-D amplifier is more efficient than the conventional Class-AB one, it can be lighter. And that, in a nutshell, is the reason for Class D's existence. Lighter also leads to smaller, and to achieve the high switching speeds necessary, the circuitry has to be physically small. Look inside a Class-D amplifier and you'll find a transformer. Look hard enough and somewhere in there you'll find the circuit too! http://www.google.com/url?sa=t&sour...w0pjefh1jBEEqRGUw&sig2=jk4AfRwyVW-fQumUOCjgNQ
