Information and or help required.

[Fincave]

Having recently upgraded my speakers the weakest link in my system is my receiver (Yamaha RX-V640). My new speakers have a sensitivity of 85db whereas the previous ones were 89db, ie really need to crank the volume up to achieve the same listening volume, also have installed acoustic panels which also requires a bit more volume to achieve the same levels. The store where I make all my purchases suugested that I would need a more powerful amp/receiver to drive the speakers (Amphion Argon2's) and that their full potential can not be achieved with the Yamaha. Two recommendations were Harman Kardon and Marantz. My speakers are accurate and I suppose could be called bright especially in relation to my previous JBL's and so a warm sounding amp/receiver should fit the bill nicely, researching via the net Marantz has been described as warm and so it is on my list of listen to and possibly demo at home. As music is more importanat to me I have thought about getting a stereo amp (later also updating the receiver) but am not too sure about connection possibilities to my receiver, the Yamaha's manual does mention that an external amp can be connected but it is rather scanty on the details, there are output jacks for main (L&R), rear, centre, rear centre and subwoofer. Even though I listen to stereo music only I do use a subwoofer and have a BFD, how would I connect up a stereo amp or can I even connect it up as I would like to continue using the sub as the speakers are bookshelf and do not extend very low. Am I correct in assuming that a stereo amp will provide better SQ over a receiver especially as the budget for a stereo amp would be about $500 and I really do not want to spend more than $1000 on a receiver. (Budget is not that strict as prices here in Finland do differ from the US prices.) Hopefully this post makes some sense. I have done a lot of reading on the net but somehow just seem to get more confused. Any suugestions as to what I should look for and any assistance will be much appreciated!!

[Sonnie]

85 watts per channel is rather mild for speakers with that sensitivity, I would think anyway.

I have a Denon 3806 which has about 120 wpc, a little more with my 4 ohm speakers. I use it as a pre-pro for my mains and center and only use the amp section in it to power my rear surrounds. I feed the pre-outs to an Earthquake Cinenova Grande 5, using three of those channels to power my frontstage. It runs about 600 wpc. I'd say you could probably do something similar. If you are more into 2-channel then look at some of those amps, or maybe a 3 channel amp for when you do watch movies. To stay at $500 though, I suspect you may have to go used, but if you are talking $1500 for an amp and receiver, maybe you could keep your receiver and look for an amp, and $1500 would open the door to all kinds of possibilities.

[Fincave]

I still need to do some research and probably increase my budget. Am toying with the idea of keeping the Yamaha for movies and buying a stereo amp with subwoofer connection for music, Harman Kardon have one that fits my budget quite nicely. Watts per channels gets confusing sometimes: Harmon Kardon specs for receivers are start at about 50w per channel and go up to 65w or so, my Yamaha specs are 85 according to the manual though everyone that I have spoken to says the Harman is the more powerful.

[Sonnie]

I just don't think you are going to notice that much difference going from the Yamaha to a HK. Their AVR 7300 is rated at 110 wpc but it retails for $2400... their AVR 635 is rated at 75 wpc and retails for $1300. HK might be more conservative but I kinda doubt it would be that much difference.

I don't remember your sub off the top of my head... is it powered?

EDIT: Okay, I just noticed you got the BK Monolith... is it powered?

[Fincave]

My sub is a BK Electronics Monolith, powered, 300W continous discrete mosfet amplifier http://www.bkelec.com/HiFi/Sub_Woofers/monolith.htm The store where I do all my purchases recommended HK but am open to all suggestions. NAD is another prospect but there do not seem to be many distributors here in 'tropical Finland'. Am quite happy to keep the Yamaha for now and go for a stereo amp which should in my understanding give me better SQ for music? I can get a new HK 970 (2X75W) for about $400, another option is Cambridge Audio Azur 640 Intergrated amp for the same money, also new and with the same rating. At a later stage I would then also update the receiver (after I win the lottery!)

[Sonnie]

All you really need would be the 2 channel amp for stereo music listening. Have you considered NuForce that NLAV sells? Those are supposed to be ever so sweet.

http://www.nuforce.com/

You could continue to use your sub pre-out on your Yamaha.

[Fincave]

Everything I have read about Nuforce has been spectacular to say the least, unfortunately cannot find anybody in Finland that stocks them. I suppose they could always be ordered from Sweden but I really would like to audition at home first.

[Sonnie]

Maybe Andrew could work something out with you. I'll ask him to stick his head in over here.

[Fincave]

Found a store that stocks Nuforce! Will have to have a closer look at their products and also try and get one home to listen to. Would their intergrated amp, IA7 serve my purposes, kind of pushing the budget but hey, already spent too much so what is a little bit more, right? (Bit fuzzy on the terms stereo amp, intergrated amp, what is the difference?)

[Sonnie]

I believe NuForce rates their amps very conservatively, so the IA7 might just do it for you. An audition would answer that for you though, if you can work it out.

An amp is strictly power while an integrated amp will usually have a volume control and possibly an input selector with inputs for components.

[Fincave]

Intergrated amp seems to be the path down which I am heading. Advance Acoustic is another name that has come up recently. Does anyone have any first hand experience of their products, in particular the MAP303 Integrate Stereo Amplifier

These are the specs that I copied off a friends website, they do not mean much to me, I just want a nice sound and value for money.
The MAP 303 has been created by Advance Acoustic to offer music fans an affordable amplifier of remarkable achievements.

It is fit with one toroidal transformer, accurate resistances and input switching through relaying.

Neutrality, clearness and power make of the MAP 303 a unique amplifier.

Output power: 2 x 100 W / 8 Ohms
Output power: 2 x 160 W / 4 Ohms
Bandwidth: 15Hz-100kHz (+1/-3dB)
Frequency response : 10Hz-100kHz
Distorsion: <0,1%
S/N Ratio: >100dB
Channel separation: >70dB
Input Impedance: 20K
Input Impedance phono: 47k-100
Input level (CD-Aux): <400mV
Input Phono MM/MC: 2,5mV & 0,2mV
5 inputs: CD, Tuner, AUX1, AUX2 and Phono MM or Phono MC
Pre-Out to be used with external power amplifiers MAA-405, MAA-705, etc...
Main IN to be used with external sources in direct mode.
Remote control IR

Dimensions (L x P x H): 45 cm x 43 cm x 15 cm
Weight: 18 kg

[JCD]

I just wanted to throw something into the mix..

The change in sound level from an 85watt amp to a 100watt amp is not even 1db. Granted, I'd say the Advance Acoustic (or Nuforce) amps are probably conservatively rated and the Yamaha is exaggerated, but even if the "real" comparison were a 65watt vs. a 120watt, the increase would still only be ~2.7db's which wouldn't make up for the 4db's you "lost".

One caveat:
I know that sensitivity is the spl at 1 meter when the speaker is supplied with 1 watt. What I don't know is if the 4db difference between your old speakers and your new ones would be the same at 10watts or 25watts.

I'm not trying to downplay the improvement you may hear by upgrading to the 100watt amp, I just wanted to give you a heads up that a 100watt amp might not get loud enough for you. I'm a big proponent for in-home testing, so I'd check with your retailer to see if you can try an in-home audition of the amp to see if it fits your needs.

One final note fwiw: you mentioned HK and Marantz as possible alternative receivers -- I've personally had problems with the HK in the past. They may have fixed their quality control problems over the last few years, but I'm still leery of their products. I don't think I've heard anyone complain about Marantz.

JCD

[brucek]

Intergrated amp seems to be the path down which I am heading.

So, this means you're going to also add a new set of speakers to attach to this new integrated amp? If not, how do you intend to integrate the Yamaha and the integrated amp together for both HT and stereo duties?

Your Yamaha has good reviews on its pre-amp/processor section. Why not simply add a stereo power amp? Is your sub active when you select 'stereo' on your Yamaha?

brucek

[Sonnie]

BINGO! Look for something with 200-300 wpc and know you'll have plenty of power too.

[brucek]

It's quite easy to add an external power amp to your receiver since it has pre-amp outputs.

Simply remove the speaker connections on your Yamaha (for the left and right mains) and connect them to the new stereo amplifiers left and right mains speaker outputs.

Then connect two RCA interconnects from your Yamahas left and right mains pre-amp outputs to the stereo power amps left and right inputs.

See below:



This assumes that your subwoofer output is active in 'stereo' mode on your Yamaha, so that you'll have sub when using the new power amp......

brucek

[Wayne A. Pflughaupt]

Fincave,

To reiterate what brucek and others have said, adding an amp to the Yamaha is the best path. An integrated amp or an “amp with a subwoofer output” is only going to complicate things tremendously. As brucek’s excellent diagram shows, it’s easy to connect an outboard amp to the Yamaha – it has the L/R output jacks you need. It will be easy to switch back and forth between movie modes and stereo for music.

I also agree, you’ll want to get a fairly substantial amp. The rule of thumb when upgrading amplifier power is that you have to at least double what you had before, so I’d say at least 200 watts per channel is what you want.

Regards,
Wayne

[Fincave]

Sonnie, Wayne, Brucek, JCD, a big thank you! I now have an idea of what I should be looking for. Thanks for the great diagram as well.

I am not really looking to increase the volume, the Yamaha can achieve the volumes that I listen at, my aim is to improve the SQ, especially for music.

The Advance Acoustic that I mentioned in a previous post can be used as a 'power amp' according to a friend/acquaintance who sells it. It is also supposed to put out quite a bit more than the specs. I will try and get it home to audition, also try and get a Marantz as they are supposed to have that 'warm' sound. Will also have to look into Nuforce as well, so many options!!

I really really like the diagram, nice and simple and something that I can understand at a glance.

[Sonnie]

Just from what I can gather... if you are simply looking for SQ... NuForce!

[Fincave]

Ok, this is what I am going to get home to try out. Read good things about it powering Amphion Xenon speakers so will give it a go with the Argon2's. It is however really really ugly!

Advance Acoustic MAA405

Specifications
Output power / 8 Ohms : Classe AB - 2 x 150 W - classe A - 2 x 40 W
Output power / 4 Ohms : Classe AB : 2 x 260 W - classe A - 2 x 60 W
Frquency response : 10Hz - 100kHz (+1/-3dB)
Distorsion : < 0,03%
S/N Ratio : > 100dB
Channel separation : > 90dB
Input level : 1,2 v
Input impedance : 20K
2 input : 1 balanced - 1 Unbalanced
Dimension (L x D x H) : 44 cm x 43 cm x 15 cm
Weight : 19 kg

Any pointers as to what the Class AB and Class A specs differences mean will be much appreciated.

[JCD]

If you're asking what what Class A amps are vs. Class AB, I got the following information from here. Now, I'm not sure if this really answers your question exactly, or if it confuses, but here it is fwiw.


Class A
This is the most linear of the classes, meaning the output signal is a truer representation of what was imputed. Here are the characteristics of the class:

The output device (transistor) conducts electricity for the entire cycle of input signal. In other words, they reproduce the entire waveform in its entirety.
These amps run hot, as the transistors in the power amp are on and running at full power all the time.
There is no condition where the transistor(s) is/are turned off. That doesn't mean that the amplifier is never or can never be turned off; it means the transistors doing the work inside the amplifier have a constant flow of electricity through them. This constant signal is called "bias".
Class A is the most inefficient of all power amplifier designs, averaging only around 20.
Because of these factors, Class A amplifiers are very inefficient: for every watt of output power, they usually waste at least 4-5 watts as heat. They are usually very large, heavy and because of the 4-5 watts of heat energy released per watt of output, they run very hot, needing lots of ventilation (not at all ideal for a car, and rarely acceptable in a home). All this is due to the amplifier constantly operating at full power. The upside is that these amps are the most enjoyed of all amplifiers. These amps dig out musical detail, since the transistor reproduces the entire audio waveform without ever cutting off. As a result the sound is cleaner and more linear; that is, it contains much lower levels of distortion.
They are the most accurate of all amps available, but at significant cost to manufacture, because of tight tolerances, and the additional components for cooling and heat regulation.

Class B
In this amp, the positive and negative halves of the signal are dealt with by different parts of the circuit. The output devices continually switch on and off. Class B operation has the following characteristics:

The input signal has to be a lot larger in order to drive the transistor appropriately.
This is almost the opposite of Class A operation
There have to be at least two output devices with this type of amp. This output stage employs two output devices so that each side amplifies each half of the waveform. [li Either both output devices are never allowed to be on at the same time, or the bias (remember, that trickle of electricity?) for each device is set so that current flow in one output device is zero when not presented with an input signal.
Each output device is on for exactly one half of a complete signal cycle.


These amps run cooler than Class A amps, but the sound quality is not as pure, as there is a lot of "crossover" distortion, as one output device turns off and the other turns on over each signal cycle.
This type of amplifier design, or topology, gives us the term "push-pull," as this describes the tandem of output devices that deliver the audio signal to your speakers: one device pushes the signal, the other pulls the signal. They can be less expensive, because one can use two cheap output devices instead of one high-quality one in the design.

As I mentioned before, the input signal has to be lot larger, meaning that from the amplifier input, it needs to be "stepped up" in a gain stage, so that the signal will allow the output transistors to operate more efficiently within their designed specifications. This means more circuitry in the path of your signal, degrading sound even before it gets to the output stage.

Class AB
This is the compromise of the bunch. Class AB operation has some of the best advantages of both Class A and Class B built-in. Its main benefits are sound quality comparable to that of Class A and efficiency similar to that of Class B. Most modern amp designs employ this topology.

Its main characteristics are:

In fact, many Class AB amps operate in Class A at lower output levels, again giving the best of both worlds
The output bias is set so that current flows in a specific output device for more than a half the signal cycle but less than the entire cycle.
There is enough current flowing through each device to keep it operating so they respond instantly to input voltage demands.
In the push-pull output stage, there is some overlap as each output device assists the other during the short transition, or crossover period from the positive to the negative half of the signal.
There are many implementations of the Class AB design. A benefit is that the inherent non-linearity of Class B designs is almost totally eliminated, while avoiding the heat-generating and wasteful inefficiencies of the Class A design. And as stated before, at some output levels, Class AB amps operate in Class A. It is this combination of good efficiency (around 50) with excellent linearity that makes class AB the most popular audio amplifier design.