In rereading this thread, I don't understand the rationale for Colbalturbo's contention in the 1/31 post that "with a projector you will need a retractible screen for 2 channel." Colbalturbo, do you believe good 2 channel sound can only be achieved with sound treatment on the wall behind the LR speakers? If you believe that, can't you envision panels that can slide or swing away for viewing?
db |
Classe is an AB amp. I have one and as long as you are not going to be putting it in an enclosed cabinet I see no problem with heat. The sound is fantastic. |
Cobaltturbo-
I realize that the Arcam is Class G, but it is highly biased to run in Class A for the first 20 watts. I believe that information is on Arcam's website and if it isn't it is definitely on the review of the Arcam AVR600 by Peter Moncrief at the IAR80 review page and at Widescreen website review.
Most manufacturers only use a single voltage rail, but the higher and lower voltage rails on the Arcam AVR600 classify it as a Class G device. But Arcam chose to bias the first 20 watts (where the vast majority of music resides) because it sounds far better than a regular A/B bias, which doesn't follow the full wave pattern as Class A does. The use of Class G (higher and lower voltage rails)by Arcam allowed them to have a considerable heat savings which permitted them the luxury of using those savings for a large amount of Class A biasing (which emits far more heat than the classic A/B that is used in most receivers).
But Arcam's brilliant engineering allowed them to use this tremendous heat savings with the addition of Class A.
All other receiver manufacturers use a single voltage rail system, which must be on all the time. Arcam employs a higher and lower voltage rail (Class G), with the lower rail using far less power and emitting far less heat than the higher voltage rail. Since most music doesn't require the higher voltage rails, Arcam is able to utilize the substantial heat and power savings by biasing heavily into Class A.
I have bought a Panasonic V25 65" Plasma which made me have to place my sofa at the rear wall. This means I must employ a 5.1 system, as opposed to being able to use a 7.1.
Greg |
>I realize that a Class A multichannel amp would put out a
>lot of heat. Maybe I should consider a Class A/B with high
>bias into Class A.
You just described the Pass Labs X5 or X3 multi-ch. amps. They are no longer made but a decent piece of equipment for HT used. It works real well for HT. Still, I'd use class-A for the mains and a powered SW. |
Another option is to take a look at Butler audio. There is an amp for sale here on this site. |
As an owner of an avr600, there is little that is actually better for multichannel. Even in two channel it sounds great. However the Arcam av888 paired with the matching p777 sounds excellent as well. It definitely sounds better, but the only concern I have is the price. It costs more than twice as much as an avr600. I don't think it sounds twice as good. Cost of diminishing returns I'm afraid. I would say it sounds about 20-30% better. When you look at what other pre/pros are available, the av888 is cheaper. I've heard the classe pre/pro (can't remember model). It sounds really good, but didn't hear it side by side with an arcam (different dealer, but same speakers). The classe was more money as well. If I had to pick though I would go the arcam route. Thats just me though. |
Cobaltturbo, I hope the original poster takes our subjective remarks and suggestions for what they are, subjective.
When I suggest going with a 7.1 system I usually mention room size is not an issue and regardless of the quickly growing amount of available 7.1 media that simple 5.1 productions on both disc and broadcast can sound much more surrounding when matrixed through a capable 7.1 system. The LCR somehow become more discrete in locating on screen audio queues than with 5.1. I can't speak of the actual way the matrixing is accomplished other than to say the side channels seem to bridge the left and right channels with the rears widening the screens sound stage and creating a rear that's more peripheral. The effect is amazingly uncanny and far more fun than 5.1. Another variable I can't speak of is just how much the quality of the room correction being used plays into the success of matrixed 7.1.
When auditioning for my current HT I too found the Arcam to provide a very nice audio presentation. Ultimately, I passed on Arcam. When pushed to more realistic volume levels its output became somewhat congested similar to the Integra unit I was replacing. It also lacked a comprehensive automatic time, EQ, and volume balance room correction program in favor of Dolby Volume processing and gain management. |
The Arcam AVR600 is a class G amplifier.
Class G
The Class G topology is a modification of another
Class of amplifier (normally Class B or Class AB)
to increase efficiency and reduce power dissipation.
Class G takes advantage of the fact that musical and
voice signals have a high crest factor with most of
the signal content at lower amplitudes. The Class
G topology uses multiple power supplies, operating
from the power rail that provides the optimum
combination of headroom and power dissipation.
Th e Class G topology improves amplifier efficiency
by optimizing the power supply. A Class G device
uses a minimum of two different supply rails. Th e
device operates from the lower supply until output
headroom becomes an issue. At this point the device
switches the output stage to the higher supply
rail. Once the output signal drops below a predetermined
level, the device switches back to the
lower rail. Power dissipation is greatly reduced for
typical musical or voice sources. Figure 3 illustrates
a simplified Class G implementation with a split
supply Class AB output stage.
I am currently using an AVR600 in my home system and have nothing but praise for it. Outstanding sound superior to most anything else I have heard for HT including Classe` and other high end HT receivers.
In 2 channel mode using Dali helicon line of speakers it sounds remarkably good. Although it is difficult to set up a system that sounds good for both HT and 2 channel. This will be a challenge especially with a projector you will need a retractable screen for 2 channel. So unless you need one system to do both which I recommend against I would think the need for Class A amps in a HT are not necessary.
The need for 7.1 seems to be overrated since so few BD discs are actual 7.1 and 95% of the time you will be listening in 5.1 EX. I have to admit there is a huge difference between the 2 and if more discs were supplied in 7.1 I would say spend the extra on the speakers . For now you might consider wiring your room for 7.1 and seeing what happens in the future of these discs if more 7.1 content is released. |
Classe' amplification products are generally considered higher end than the others on your short list. Classe' room EQ adjustability may require a different process which you should check into.
Unless your attempting to assemble a high quality two or multi channel system that will also support HT then quality amplification components may be considered critical by some. If, on the other hand your assembling a primarily HT system the level of quality amplification may not be as critical.
Personally, in a primarily HT system I would forgo some quality in favor of a 7.1 HDMI system. Depending on your viewing habits an HT system can be in use far more that a music only system which would demand far more running time from an amplifier. High quality switching amplifiers are far more efficient for this purpose requiring less wattage, less in standby, less heat, and more economical. |
I realize that a Class A multichannel amp would put out a lot of heat. Maybe I should consider a Class A/B with high bias into Class A. I heave heard that Earthquake Cinenova makes one that can be biased up to 20 watts into Class A.
I also wonder if the Arcam multichannel amp is biased highly into Class A, such as their AVR600 is. I have heard that the AVR600 is also biased to about 20 watts into Class A and that is what gives it its great sound. One would hope that Arcam would have put that same technology into their new multichannel technology, but I see nothing to that effect on their site.
When the OPPO BDP95 comes out in March I might purchase it and move my OPPO BDP93 into my bedroom system.
Is the Integra DHC 80.2 processor considered good? Or would it be smarter to get an Anthem or a Classe processor. Also, are the Classe multichannel amps good?
Greg |
Allchemie, you heed a multichannel preamp, NOT a pre/pro, for your expensive system. I have and love a c-j MET1; McCormack and others also make them. With an analog preamp, the player does all the decoding and bass management and you use the player's analog outputs to the preamp.
. |
Due to what Roscoeiii describes, I found the best alternative for my Coincident theater. I'm using a Mac 7106 which is 100 x 6. Mac is clean, crisp, detailed and a little on the warm side. Since I only need 5 channels, I bridged 2 channels to give extra power to the center. Conquest R&L, Triumph center, mini Triumph rears. The only other amp I would consider for this theater in my price range is the Cary. |
Be aware that a multichannel Class A amp will put off a LOT of heat. I'd imagine that because of heat it is rare to put more than two Class A channels in one chassis. |
If you have the money you cant beat the Anthem D2V, its room EQ is outstanding and its extremely adjustable in both audio and video settings. You could always go multi amp and get a couple class A amps for mains and surrounds and mono one for center as it gets alot of use anyway.
I use Classe multi channel amps that are limited class A then A/B but they sound great. |
