A little disappointed with todays receivers - Page 3

uhm the law should require nothing other than passing a safety standard. To have government regulate stuff is bad.......the industry it's self must come up with a standard...

y'know... i thought the same thing when pio came out with the sc... i figured other cem's would follow and then class d would begin to trickle down to lower units...

still haven't seen it yet, so i'm guessing the a/b solutions are still cheaper to implement...

besides, there's a vocal group who decries the usage of anything but a/b (or even better to them, pure class a space heaters )...

The whole design is clearly implemented as simple as possible, presumably to keep cost and use of space down.

Let's find this schematic.. yes, a 100W (approx.) amp made using 9 transistors.
This circuit is actually also a bit more exotic than the simplest one I saw.

The input stage is a single differential, which feeds a second differential, this is the voltage gain stage.
The use of a differential stage here is what makes it more "exotic", they could have used only one transistor here.
The differential stage may be a better choice because it may be possible to achieve better linearity.
The pre-driver and driver stage does not exist, only a darlington complementary output.

It is not symmetric (using complementary transistors in all stages), does not have any isolation between the U-stage and the output stage, it is not dc-coupled, does not use dc-servos, no cascode, and the input stage and the U-stage runs on the main psu rails as far as I can see.

So, it is simple, but that does not necessarily mean it is so bad that it is useless.

Nelson Pass has made many minimalist designs using very few transistors, and they all have reputation for outstanding good sound.
In audio design it is often a goal to make it so simple as possible, because it may be easier to control the nonlinearities.

It is also the specific implementation of this circuit topology that determines this particular amplifiers performance.
I am sure they have used lots of hours to fine-tune this circuit, so that the end result is as good as it can be.

It is also debated whether different amplifiers actually sound any different, as long as they have a flat frequency response and reasonably low distortion.

What I would suspect first with this design is lacking capability to run more difficult loads, such as speakers with an impedance curve that goes rather low in some frequency range.
Because when the amplifier can not deliver more current, it will clip the signal, with excessive distortion as a consequence, and that will be clearly audible.

I would not try to improve this design.
Changing parts of the circuit will most likely cause unpredictable and undesired results.
I am quite sure the designers have done a great job, the constraints given.

I would rather replace it with a totally new design.
And that is what people actually do when they use external power stages.

I guess the A/B versus Digital will be CD versus Vinyl delima.
The future is digital and I have embraced it with open arms.

From a historical perspective, the Federal Trade Commission got involved many years ago because manufacturers were making wild claims about power output of amplifiers and receivers. Manufacturers still do it today for things like car stereo amps since they were not covered by the rules (didn't exist at the time). The FTC basically said that if you are going to make a claim in the advertising that your amp had so much power, then that power had to be measured the same way and specified the same way in the advertising (and manuals). That way the consumer could make proper comparisons from one model to another.

I've seen ads for a 100w amp that were 100w into 1ohm at 1kHz with 10% THD in the small print. I've seen another 100w amp that was 100w into 4ohm from 20Hz to 22kHz +-1db with 0.01% THD. Cost a bit more but at least one could tell that this one wasn't going to sound like crap when you turned it up.

No point in forcing this problem through the nail eye some sort of ideological litmus test and then.....suddenly stopping halfway.

Efficient markets require efficient flow of information aka truth in advertising. Particularly so when you have a small handfull of technical companies selling opaque technology to ordinary consumers.

Clearly the market regulator's role must include setting advertising standards. Otherwise said market attracts charlatans and will tend not to reward producers of high quality product. Which benefits no one - neither the consumer nor the manufacturers. And hey, that's exactly what is going on in this market. Waiting for the industry to self-regulate? Are you joking? Said industry is busy consuming itself.

It's all going to crap - precisely because the regulator is AWOL.

I agree with everyone's concerns on manufacturers stated power output stats. While probably 100% true they are 100% misleading and aimed at snagging the under informed consumer. Always read the fine print & do your homework before you fork over your hard earned money on a product!

Anyway that said, I too have wondered how could an AV receiver weighing in at 24# have what it takes to drive speakers through the full spectrum from 20 Hz - 20 kHz? In my mind, compromises in sound quality must have been made.

I was very happy with my last 2 AV receivers, Denon 4802 & NAD 773 (still have). Both are quite robust and I enjoyed their sound quality, but I thought I wanted a bit more power in my system. I was also tired of the chasing the ever changing codecs. I was able to purchase an AudioControl Pantages amp (customer return) below cost, I picked up a display model processor. Last year I purchased the OPO BDP-95 & run analog out to the processor, letting the the OPPO do the work, awesome sound!

Sorry, kind of long winded but while the codecs are changing rapidly amplifier technology does so much slower. I found an amp that I can live with both sound & $, the other parts can then be replaced if I want. My processor is old by technology standards but it sounds great and has (2) 7.1 inputs and everything else I need. I am a happy old dog!

considering that there are VERY few speakers that can reproduce that spectrum, that would be irrelevant...

and if someone does have speakers that will do that, i think it's unlikely they are considering a low to middle end avr...

I agree completely then it most definitely would require separates and probably an amp capable of delivering at least 500 watts per channel most of those few speakers that could span that were 86ddb 1w/1m and dipped down to 2 to 3 ohms around 100 Hz in impedance and still rolled off a couple of db at 20 Hz.

The in-between stuff is relevant, and there is a difference in what most external amps can deliver throughout the frequency range versus almost any AVR these days. I think that was his point, based on his own experience.

Most people are probably happy enough with their AVR performance and, if they never try an external amp, they will likely not know what they are missing. Ignorance is bliss, as they say.

^^^

i'm not speaking from an "ignorance is bliss" position...

Sometimes we perceive what we choose to believe whether fact supports it or not I used to belong to the separates are always better crowd but since then I don.t play at reference levels anymore do to age and I want to keep my hearing. Todays upper end receivers can deliever a clean and distortion free sound as long as you don't try to play rock concert levels in which case you might want to look for that amp and a local audiologist.

I agree that listening at reference level at almost any age is a bit crazy, but my point about the improved dynamics with an external amp really has nothing to do with how loud one plays. I think anyone with full range speakers (not those baseball sized satellites) would benefit from an external amp.

The best analogy would be acceleration (ie dynamics) vs speed (ie volume). Most cars can hit 100 mph these days but it's how you get there that makes things exciting. An external amp will have better control and will be more responsive troughout the dB range, like comparing the dynamics of a Corvette (external amp) to a Cavalier (typical AVR). Bottom line, if you have made a significant investment in speakers, why would you short change them with a wimpy AVR ? I think a good rule of thumb is that you should spend about the same for an AVR or pre-amp/external amp combo as you do for your speakers, sub not included.

my 59TXi - still weighs a tonne and sounds sublime ... wait a minute ...

As I said if you invest in a good quality AVR and played at a reasonable level or at least my ears there was no noticeable difference .
But if I cranked it up yes the story changed the external amp was a lot cleaner.
The amp I had was when Yamaha used big VU meters and it was playing along at somewhere between 5 and 10 watts with dynamics hitting 125 watts and it was loud and that was a 200 watt per channel rig.
So my point is if you have an AVR that can output at least 100wpc into 8 ohms and somewhere close to 200 into 4 ohms full bandwidth with low distortion you will have what 90% of the people want and it will sound great and some of the new digital amps seem to provide that.
Some purists will say the class A/B people don't know what Hi-Fi is and will
not have anything short of pure class A so take your pick.

I also still use a Denon 5800 as I just use a Lumagen XD video processor for the video switching and use the ext-ins for the dts hdma from blu-ray player to Denon. Are the options in the new receivers like the audssey feature worth it to warrant an upgrade in receivers?

Thanks,
Mike

I was super pissed I had to buy a new receiver just because the plugs changed, and the 5800 is a fantastic piece of equipment, but I will say that the benefit from XT32 is truly remarkable. I thought I would be disappointed taking a step "down" from a 5 series to a 4 series and I was convinced Audyssey was just snake oil until I tried it. I am very happy with the 4311 and it sure is nice just running one cord from everything into the receiver and then one into the TV. The modern GUI is awesome as well.

Thanks for your perspective since you have the 5800 and the 4311 as that is the one I would get as the 5802 is just an ungodly price. I'm going to try and wait until I get my tax money before I purchase but it might be hard to pull the trigger as I think I have had the 5800 for 10 years or so and it has always worked flawlessly.

Thanks,
Mike

I know what you mean, as I am still a little sentimental about my 5800. But I am really happy with my 4311 and the new tech that came with it. The 4311 is a bargain at its current street price for what you get.

http://www.avsforum.com/avs-vb/showthread.php?t=1388717