Amps or Recievers Postulate or Question

[surveyor]

Here are some of my thouhghts (questions) on Amps vs. Recievers.

1. If a person has a decent quality AV reciever and has more than one subwoofer or speakers with built in subwoofers, is there really any sonic advantage to seperate amplification?
1a. Only low frequencies near DC require, or use high power (WATTS)?
1b. Subwoofers must be tuned into your system, not easy but always possible!

2.Speakers are the most influential elements in a good audio system!!
2a. Spend a good share of the budget speakers!

3. Decent quality sources DVD, Multi Disk players are also important.
3a. Cheap DACS etc. are telling with good speakers!

4. On interconnects follow this sites recommendations!!!

In closing, I would have serious doubts, if the above criteria were met that seperate amplification would have any sonic advantages?

 

[Doug917]

Where's the mule when you need him?

 

[t3031999]

Amps can drive the speakers louder.
They usually have a lower noise floor than their receiver couterparts.
And most amps have a higher damping factor than the amps in receivers.

Other than that there is little difference.
And besides getting louder I'm not sure how much the other 2 would affect sound.

 

[mulester7]

Where's the mule when you need him?

.....right here, Doug....not to worry, these guys have a bad case of White Men Can't Jump....one says, "I'm not sure", and the other says, "I would have serious doubts"....does either of those say experience with?......

 

[surveyor]

.....right here, Doug....not to worry, these guys have a bad case of White Men Can't Jump....one says, "I'm not sure", and the other says, "I would have serious doubts"....does either of those say experience with?......

But Mule what about Larry Bird?
Well, give us a definite answer!

 

[mulester7]

But Mule what about Larry Bird?
Well, give us a definite answer!

.....well, Surveyor, Larry Bird is a different story....he was born to play the round ball game called basketball....he could jump plumbed out of the gym....at home, Larry has amps everywhere....just like our man Peng....would I lie?......

.....guys, I'll say this....some don't need amps....some can't get as deeply involved with their music....some wouldn't know if the music got cleaner and came to life at gunpoint....most would, but some wouldn't....plain and simple....no shame involved....we're all different....amps for me.....

 

[mtrycrafts]

Amps can drive the speakers louder.]/b]

That depends on a few other factors.

They usually have a lower noise floor than their receiver couterparts.

Maybe yes, maybe no. In either case, the issue of room noise floor has an input on audibility of that noise.


And most amps have a higher damping factor than the amps in receivers.

Totally irrelevant. SS amps have sufficient DF, period.

 

[Snap]

.....well, Surveyor, Larry Bird is a different story....he was born to play the round ball game called basketball....he could jump plumbed out of the gym....at home, Larry has amps everywhere....just like our man Peng....would I lie?......

.....guys, I'll say this....some don't need amps....some can't get as deeply involved with their music....some wouldn't know if the music got cleaner and came to life at gunpoint....most would, but some wouldn't....plain and simple....no shame involved....we're all different....amps for me.....

You Crack me up Mule!

 

[mulester7]

And most amps have a higher damping factor than the amps in receivers.

Totally irrelevant. SS amps have sufficient DF, period.

.....climb out of that hole you're in.....

 

[mulester7]

.....look at me, acting like I actually know anything about these surround receivers....here's what I need to do when the insides of surround receivers comes up.....

http://pg.photos.yahoo.com/ph/mulester77/detail?.dir=b724&.dnm=b8c9.jpg&.src=ph

 

[mtrycrafts]

.....climb out of that hole you're in.....

You think I am in a hole? Or just a perception of a hole

 

[MacManNM]

You think I am in a hole? Or just a perception of a hole

Judging your knowledge of linear power supplies (and amps in general) I'd say you were in a hole.

 

[mtrycrafts]

Judging your knowledge of linear power supplies (and amps in general) I'd say you were in a hole.

You should read the response from Jneutron. Maybe you have some problems.

And, how was this a 'value added' comment? Remember your pet phrase?
Best if you worry about your own holes.

 

[MacManNM]

You should read the response from Jneutron. Maybe you have some problems.

And, how was this a 'value added' comment? Remember your pet phrase?
Best if you worry about your own holes.

I did read it. It proves that I am correct, and you have absolutely no knowledge of electronics.

 

[mtrycrafts]

I did read it. It proves that I am correct, and you have absolutely no knowledge of electronics.

It does??? News to me. Worry about your holes.

 

[mulester7]

It does??? News to me. Worry about your holes.

....Mtrycrafts, I'm disappointed others besides you and me don't ask more questions....don't they have a desire to learn?.....

 

[MacManNM]

It does??? News to me. Worry about your holes.

Yes it does. He is speaking of a full wave rectified power supply, I used a half wave unit for my example.

 

[Buckeyefan 1]

A lot has to do with how you are using your system. Do you utilize the sub with music? ie do you enjoy listening to music in 2.0 mode? How sensitive are your speakers?

A mid level receiver (for the most part) is more than enough with HT usage, a powered sub, and bass management. But when you introduce music into the mix, with preferences, there becomes an argument for external amplification.

External amps quite often offer lower THD ratings when compared to receivers of similar power. The larger chassis of an amp allows manufacturers to locate sources of noise, like the amp's power supply, far from the other amplifier circuits. Designers can use upgraded components, like bigger power supplies, capacitors, and heat sinks — all elements that combine for better performance.
When a preamplifier, power amp, and tuner are housed in separate components, each has its own enclosure which isolates the low level audio signals of the tuner and preamp from the large magnetic fields of the power amp. It's debatable whether most can hear this low level noise.

Flagship receivers have extremely heavy duty power supplies and large amounts of internal shielding that minimize signal interference. Analog and digital signal paths are kept separate, and video signals are well controlled. The performance levels of the best AV receivers are intended to seriously challenge separates.

 

[WmAx]

External amps quite often offer lower THD ratings when compared to receivers of similar power.

You can get more power for lower $$ from a reciever in many cases. The only time recievers seem to have a fault most of the time is when unusually low impedance loads are presented to them; in that case a low cost professional audio type amp can be used, which will handle just about any load.

The larger chassis of an amp allows manufacturers to locate sources of noise, like the amp's power supply, far from the other amplifier circuits.

If there is a 'noise' problem it will be audible as hiss or hum during normal use. There should not be many brand name devices today with such problems, even at the low price point. It's easy enough to detect. No test equipment required.

When a preamplifier, power amp, and tuner are housed in separate components, each has its own enclosure which isolates the low level audio signals of the tuner and preamp from the large magnetic fields of the power amp. It's debatable whether most can hear this low level noise.

Either you can or can't hear the noise. If you hear audible hiss or hum in quiet parts of music that bother you, then obviously one needs to try a different product.

The performance levels of the best AV receivers are intended to seriously challenge separates.

The performance levels of many low or mid end recievers should 'seriously' challenge seperates today. Even some audiophiles have accepted that today, which is evidenced by the surge of popularity of the Panasonic XR 'low end' recievers to use in so-called 'hi-end' systems, as can be witnessed on the king of nutjob boards, audioasylum.com. But audible performance is rarely evaluated in a fair manner [such as level matched blind testing], so I guess it's to be expected that many inaccurate opinions will persist.

-Chris

 

[jneutron]

Yes it does. He is speaking of a full wave rectified power supply, I used a half wave unit for my example.

This is correct. What I was wondering, is why in the world is anyone talking about half wave rectification supplies for any type of power amp. It has been known for decades that this significantly increases the eddy losses in the core, the ripple power losses in the caps, and the peak diode junction temperatures. You should have stated up front that your examples were not consistent with currently accepted amplifier design practices..

Comments on the following...note that I did not copy all of the correct postings, but some that are interesting..

3db is twice as loud.

Incorrect. It is twice the power..10dB is twice as loud.

you are speaking of what the ear perceives. Just because your ear is a nonlinear device doesn’t mean that 3db isn’t twice as loud, it is. Please don’t tell me I’m wrong when you are comparing your apples to my oranges. How do you know that he isn’t sitting 70ft away from his speakers and the average SPL at his position is 85dbm, so an increase of 3db would be measured as twice as loud, and perceived as twice as loud. 3db is twice as loud period.

3 dB is indeed measured as twice as much power. But it is not perceived as twice as loud, no matter what the relative distance or level is. It requires 10dB increase of power at any power level, to be perceived as twice as loud.

Again, you don't know what the levels are at his listening position, so you can presume what you like. It doesn't matter to me, but 3db is 3db no matter how you slice it.

See the last statement. The relation is intensity independent.

If you read the article it basically says that the ear is nonlinear. At higher levels the responsivity changes. It totally depends on the ambient noise and the spl at the listening position. So in reality we are both right, just I'm a little more right. it is all a matter of perspective.

No. it is 10dB, it is not a matter of perspective.

The poster said he wants the neighbors to hear his system, since they are in the far field the 3db gain is going to seem much greater to them moreso than to the person sitting in front of the TV.

No. See above.

You don't buy it because you don't understand it. The recovery time can't be any faster than 16ms (20 ms if you live across the big pond). Now, if your peak is 60 Hz or lower they won't recover in time.

Incorrect for modern power amps. However, included here for continuity, as the statement half wave has since been introduced.

: I thought that is recitified and DC is fed to the caps, hence, the line frequency is irrelevant.

Incorrect. Line frequency plays a big role in how long the cap has to wait until the transformer voltage starts to exceed the voltage the capacitors were discharged to.

No, I am not mistaken, the limiting factor of a WELL designed amp is the input line current,frequency. The things that Dan are talking about happen well after the capacitave reserve runs out, so, the more capacitance you have, the better.

All are tradeoffs. Good amps with small caps are possible as well as large caps. Most designers do not understand well enough e/m field theory to design extremely good amps with small cap banks. A limit to a power amp is of course the input current, as ya can't get more than what the breaker will allow..for long.

It is rectified but it is pulsed DC. The caps are what make it line level DC

Correct,

The AC is rectified. Caps charge by DC so there is no crossing, just DC and the RC time constant is in play on charging time.

Incorrect. The caps at the primary supply are fed by rectified sine, with the current occuring near the peak of the voltage wave.

Then, by your logic, if you played a 10kHz sine wave to check the RMS power output, those caps would never recharge and would be depleted in a hurry as you are discharging faster than you can recharge it? .

Incorrect. The cap voltage will decay between charge pulses based on the average current that is drawn from the cap. It will rise up, riding the ac, when the ac exceeds the voltage of the cap at the instant. If there is insufficient power capability for recharging, the cap voltage will start a downward trend, looking like a sawtooth of sorts, until the conduction angle reaches equilibrium where the power input matches the power draw.

An interesting point here. The 10 Khz ripple will be on the supply capacitors, and when the diode conducts to recharge the cap, this ripple voltage will be superimposed on the transformer secondary, and through to the primary, where is will go into the AC power line. Under no circumstances, is this ripple current considered when discussing line cords..given that this is 166 times line frequency, what prevents this from coupling to the input ground loop..remember, the faraday coupling constant is proportional to frequency, if you have hum at a 1 millivolt level, you will have 10K freq at 166 mV..audible..no?

One must also remember that the DC line voltage is usualy somewhere around .707 x the rectified peak voltage, usually a little less though. This means it will take a good portion of the waveform to charge them. Also depending on the size of the power supply (size of the caps), it may well take several cycles to charge the caps completely.

As was pointed out, it is 1.414, or 1/.7071.

Cheers, John