I have an old amplifier ,a small gift from a friend of mine, he said that he doesn't have any specifications regarding this amplifier. All I know is that its 15 years old Integrated and in good condition. I looked behind the amplifier and saw that it had 160watts printed down.

Does this mean that the amplifier delivers all that power ?
If not why ?

(The amplifier does not have anything written down in front face)

That is the maximum power draw from wall circuit. A Sansui amp I have here has 320 watts listed on back plate near power supply cord. Power maximum is 140 watts according to display in front. You may be able to gauge yours from these numbers.

xen-uno

There's nothing written but i'll try searching it with google !

Thanks for the help !

My guess is (from the huge number ) that it is a peak power it can deliver.
I'm unsure if I translated the term correctly thought...
EDIT: BTW, if it is old and huge, it can be a row power output too, consider you lucky, then. You can estimate it when looking at output transitor cascade - it usually consist of two huge transistors with radiators. If you can see them - check catalog for power they can transfer...

What do you mean by this ?


Where can Imlook for the transistors ? (inside it ?)

If it could pump out 160 watts as printed on the power suppy then its the right rating ,isn't it ?

Does an amplifier consume power for any other reason exept for the speakers ?

Thanks

Yes, some of it is converted to heat.

Power Amplifier Efficiency Explained (Just used google and skimmed it)

Sorry for fast post. To clarify it a bit.
There are very many "powers" that can be mentioned when speaking about amplifiers.
Most common examples:
1. Consuming power - max power amplifier consume from the el. net for operations.
Usually is printed in manual and near power supply unit.
If your 160W (btw, usually they print it not in W, but in VA) is this power, then your row output should be ~15W for class A, ~35W for class B amplifier. But it can vary much because of thousands of implementations possible...
2. Peak power - maximum power amplifier can deliver to output in defined period of time (usually in msec). Then average power output can be estimated as 1/12 - 1/7 of peak power... It also can vary much.
3. Row (or average) power - average power amplifier could output (during long period of time). This is one of the elements loudness of your speakers is based on.
In my previous post I mean you are lucky if you got old powerfull amplifier with average power output of 160W (or 160/1.41 = ~110W if they measured it for special test signal). I once have lamp amp with 90W output - it easily could be used for diskos at the street. Alas lamp electronics are hard to maintain
P.S. Sorry for crap english...


As upNorth already mentioned, good class A amp output ~10% of consumed power, class AA - about ~3%...

1. What are lamp electronics ?
Why are they so hard to maintain ?



2. I heard about class A amps but not of clas AA, are they easy to find ?



I didn't say this was just an average power output, but more than this its more likely to be the total consumption of the amp.

3. What i'm trying to tell you is apart that the amplifier transfers power to the speakers,and looses some becase of heat generated does it use any of its power for any other kind of reason ?

4. BTW I have red about some differences between class a b c amps, somehow the author said that a class a amp would be very inefficient ,agreed, so what amplifier should I choose then ?

5. What I think is that a class a amplifier would need alot of power, would loose power (heat) but eventually output more power than any other class b and c amp.

Do you agree ?

To clarify what amp class mean.
Any amp is based on transistors. (or other semi-conductor device)
Transistor is a non-linear device. See it pass-throught characteric - it is a complicated curve.
Class a amps are working on a small range of this curve, that is virtually linear
Class b working on a "mostly" linear part of the curve.
Class c usually operates in a large current range that obviously has no linear pass-throu characteristic.
When we are working on a non linear range - we will get non-linear distortions in an amplified signal. That is bad.
But linear part of the curve is very small, so amp is always a tradeoff of non-linear distortions alowed and power consumed by transistor itself. Amplification cycle has many cascades (usually you should have at least 2 to maintain U amplification in common emmitter scheme and I amplification in common collector scheme wich should stabilize output resistance) so with every cascade you will loose power.
So, to resume: A class amp has best quality. C class amp has best power perfomance.

To explain non-linear distortions:
ideal characteristic would be a line:
out = in*k; where k is an amplification coeficient.
For example k = 3;
So, when input signal is (taking it at some points) 1,2,3 then output will be 3,6,9.
But in real life formula will be:
out = func(in)*k; Where func is a complex function. So, your output will be, for example 3, 6.4, 8.7. This means non-linear distortions. Also, this function is usually a function of frequncy too, making out = func(in,f)*k which makes things even worse
Hope this helps.

>>1. What are lamp electronics ?
Hmm ? Did you ever see electronics based on electronic lamps, not on semiconductors ?
>>Why are they so hard to maintain ?
Lamps can burn. You need to replace them.

EVERY element in el. scheme will consume power for it's operations. That's simple. That's real life

Lamp Amp = Vacuum Tube Amp

i thought class B was the more efficient one, and the typical amps we see in consumer electronics was actually class AB, or even class H, which are sort of hybrids of A and B.

if you want to know the power output of this amp, try typing it's model number into eBay.com. that's how i found out my Yamaha A-520 was 65 watts per channel (390 off the mains, and it measured watts, not volt-amps. these two measures are basically the same, except for a few details about inductance/capacitance and the effects it has on power consumption. my brother once explained it to me, but my maths has got rusty in the 5 years since highskool).

does anyone have a good explanation of volt-amps vs watts?

The most eficient aplifier is the class D, she Amplifiers for a aclaration of amplifier classes minuc C class. in reality modern class D intagrates amplifiers has eficiency up to 94%.

Thanks for the link !
Some years ago when I was involved in radioelectronics we have the next classification here AA, A, AB, B, C. All the hybrid schemes have had no index...


As I remeber: W are for DC.
VA are for AC and usually it also means ideal sinusoid signal it is measured for...


Thanks for correcting me. My english is really bad sometimes

Therfore a class amp would consume alot of power, to deliver the best sound quality. Whilst class C amps would consume the same amount of power but will use it to deliver higher power output but with minimal sound quality.

Is it so big the difference in quality and power management between the class a and c amps ?

A class c amp would be therfore adequate for discos ,pubs etc.



What is the advantage of having a Vacuum Tube Amp over a standard amp ?
IS there a difference in price, quality and power managment ?

There is none...in fact...I would call it a disadvantage. Tube amps output quality varies over time due to tube aging. Reliability and longevity are suspect. A good solid state amp has it all over a tube type in virtually all respects (disclaimer: IMO). Which type sounds better is akin to the various Digital vs Analog or CD vs Vinyl debates. Do some googling on "vacuum tube vs solid state amps" and you'll find gold.

There is some advantages to a tube type...if an H bomb goes off near you, it may continue to run whereas the solid state type will crap out due to intense radio waves and other EMR.

xen-uno

What would you choose between those two ? why ?

Are there any other type of amplifier excluding the ones mentioned above ?

Is the tube amp also known as the valve amp ?

Solid state all the way...for reasons mentioned in my last post.

Vac tube, solid state, and hybrids of the two are it AFAIK.

Valve tag looks like it is applied to vac tube amps (like guitar). Both vac tubes and transistors regulate (current) flow just like a valve does with water...so there may be more to it.

xen-uno

They are

In pure theory tubes have very (extremely, I must say) small internal (or own) noise.
And can operate in radiated environment easily
Semiconductors have relatively large internal noise.
So specialists CLAIMS that el tube amplifiers are better. But for music listening purposes I do not see a difference, IMHO.
But as already wrote - it is really hard to maintain... But funny - lamps are really lamps. They shine

Usual semiconductor amp. More convinient...

Seems that YES

Thanks to all your help ,

BTW I have tried searching the amp mentioned in the begining of the thread and didn't find it. IMHO I would say that if the amp get supplied 160watts it will perhaps feed 130watts to the speakers the rest would simply be used for other operations. With this I would conclude that a manufaturer would list down 130watts in the amp's specs since this would be the actual power transmitted.

I think you're being way to optimistic.

My amp consumes 800VA and sends 85W/channel, according to the official specs (Arcam Diva A85).

800VA ?? How much would they be converted to watts.

And the fact that I am optimistic does this mean that I wouldn't gain 130 watts from a 160watts ps.

800 Watts = 800 VA

Evereux's amp draws 600 watts max per ...

http://www.stereophile.com/amplificationre...516/index3.html

I would guess yours is in the 50 to 60 watt per channel range (peak)

xen-uno

FYI edit: Excellent conversion site here...

http://www.onlineconversion.com/

This is the fact I can't understand the power consumption output.
If it has 160 watts and as you said it uses just 60 watts of it, what will the other 100 watts be used for ?




Isn't supposed a class AA amp be more less efficient than a class A ?
Does this mean that a class A amp delivers better sound quality than a class AA ?

800VA is not 800W but it is 800W in some cases in AC ,

VA = V*I

W = V*I*cos(fi)

fi= phase diferenci betwen current and tension, wen they are in fase fi = 0 and cos(fi) = 1, in this cas VA = W.

normaly 800VA is betwen 800W and 400W and les in very extrema cases

800 volt ampere = 800 watt



This is the fact I can't understand the power consumption output.
If it has 160 watts and as you said it uses just 60 watts of it, what will the other 100 watts be used for ?





Isn't supposed a class AA amp be more less efficient than a class A ?
Does this mean that a class A amp delivers better sound quality over a class AA ?

Wen I studied for tecnic in electronics, I learned the diference betwen Watts and VoltAmperes, Wats is the real power and its definition is 1 joule/second an their formula is Volts * Amperes * cos(a) but VoltAmperes is the aparent power and is Volts * Amperes, a parctical case is in may UPS it can deliver up to 1000VA but only can deliver 800W in this case for optain 800W and 1000VA the "a" need to be equal to 37º or -37º. On a forum i found a interesting response about the diference and is this Watts vz VA I reproduce it here:

What would be cos(a) ?




Therfore VA = WATTS thus the same

http://www.onlineconversion.com/power.htm
Check this out !

"a" is the absolute value of the phase diference betwen curent and tension, the capacitor oposes to any change in tension and it make a phase diference, the coils and their derived components oposes any change in current and it make a phase diference but the resistor don't produce any phase diference. the conbination of this components can make any phase diference betwen -90º to 90º ( it can have sception but in some extreme cases and fore some strange aplications ), tipical "a" is arround 37º and its cosinus is 0.8



its has a error, VA is the aparent power need to get a effective power.

shaw this please:
Some Basic Electricity
ALLIED'S ELECTRONICS DATA HANDBOOK page 32
Shedding New Light on Electrical Fundamentals

I didn't mean to be disrespectful but that how the website works on that kind of conversions.

The reality it isn't posible to convert betwen VA and W without know the phase diference, but for this is need to use a specific devices to know the phase diference and this pashe can varie with the time and the load, for this many people asumed than W = VA for analogi of the power in DC that is V * I and this is only the maximun power consumition posible for a device in AC at that VA but if the uncorrected industrial estandar of cos(pashe diference) is 0.8 we can asume than W=VA*0.8 and it is the tipical medium consumition case, in the other hand this is not the most frecuent formula for the people but is the most correct formula. the sait is simply wrong whith the conversion but they error is not much important for give a idea of the power, if they are using a conversion ratio of 0.7 they can be in a total mess but they asume teh conversion ratio of 1 is wrong, but for the previous mentionet is not very important thsi mess.

Is there a way of converting VA to WATTS correctly

eg : 238 watts into VA ?

Don't exist any way to conver t it correctly only with Wats or VA, I normaly use the expresion W = VA*0.8 , in conventional power supliers the error is betwen 5% , in swichted power supliers the error tend to be near 24% with minumun load and it decreses with at medium load up to less than 15% at maximun load the error tend to be less than 5%., but depends on the cuality of the suplier, in a good quality swichted power supli the error tend to be biger tan a normal swichted power suplier, I have a power suplier on one of my pcs than it consumes 315VA and 300W at normal load the error is in this 19% whith my formula(its a 550W redundant power suplier and cost 450€) in the other pc the power suply consumes about 340VA and 280W the error is 3% whith my formula( thsi is a 340W power supliaer and cost 50€).

PD teh load i have in the redundant power suplier is divided into the two units than make it redundnats, max power of the sistem 550w+550w = 1100W maximun peack power whithout any unit damaged, the load is 300W*0.9(eficiency of the conversion) = 270W, it is has a oberal load about 24.5% the other machine has a load abouy 280*0.9 = 252W and it has a overalload about 74%

Which formula are you talking about and how did you find the 3% error ?



I would like a little suggestion from you do you find this sound system fit together ?

The amplifier I'm interested too Is an NAD 372

Its feature list includes:

2 x 150W Minimum Continuous Power into 4/8 ohms
220W, 340W, 460W IHF Dynamic Power into 8, 4 and 2 ohms, respectively
PowerDrive™
High Current Holmgren™ Toroidal Power Transformer
Bridgeable to 400W Mono (8 ohms)
A/B Speaker outputs with remote switching
7 Line Inputs, including Two Tape In/Outs
Main-amp input & 2 pre-amp outputs
Bass and Treble Controls with Tone Defeat Switch
Relay Input Switching
All Discrete Circuitry
Gold plated RCA Connectors
Short signal path from input to output
NAD Soft Clipping™
Headphone socket
IEC Detachable Power Cable
12V Trigger Output
IR Input/Output
NAD SR-5 Full System Remote Control

Subwoofer specs:

http://www.onlinecarstereo.com/CarAudio/Pr...ProductID=14066
Speakers 8ohms 200watts pair.

I'm talking to this formula W = VA*0.8 and the error is the absolute valor of 1 - (stimated power)/(real power) but this is one mode of the error using the real power as reference, I use a ACpower meter that thell you the Voltage, Amperes , Voltampers, Watts and the pashe diference, to obtain the real values.

Toroidal tranformer, the amplifier is using a standard power suply, an the the error can be betwen 5%. And now the AB amplifier eficiency is betwen 70% at maximun power and 20% at minimun power.
with thsi condition I predict aproximated maximun consumition with the 2ohms wofer using the two chanels of 1340W ant it has a 1640VA +-5% ( btewen 1558VA and 1720VA ), I use this (Power impu)=(power output)/(efficiency) , VA = ( Power imput) / 0.8 , now the interval of VA is: VAmax = VA * (1 + error/100) and VAmin is VA*(1 - error/100), I asumed a tipical error of 5% but if you like to be more secure you can use a erro of 10%

W = VA*0.9 I will use this. Do you think its right ?


And what do you tink about my speakers specifications ?
Do they fit together ?



How do you know its a class AB amp, isn't it a class A amp.

The mayority of AudioPowerAmps ar class AB or derivates ( E , F... ), for they specification y can se that is in reality a derivated clas AB amplifier, look at this: http://www.nadelectronics.com/hifi_amplifi..._closerlook.htm ,
the preanps in it are clas A but they need to be a class AB derivated, in the othar thsi this drivated don't have much great performance at maximun power, but it hass greater performance at low to medium power for thsi I use the eficiency off clas AB, but they eficiency can be a liter better.
I use the W=VA*0.8 for a simple reaseon, is the standar used for the elctronics manufacturers, for this i think hat is a better aproximation. they speaker can fit, but you are using thiferent aplifier for the woofers and speakers? in thsi cass they fit very well.

Is it calss A or class AB then ?




What do you mean by this ?

For this te last etape in the amplifier need to be a class AB derivated. if you have a poweramop with 2 or more etapes and the fisrt is class A and the last is class AB the amplier is a class AB amplifier.

My second sentence is due to my very bad english. pelase anwer ne: what is the configuraion of the speakers?

1.What are etapes ?



Can you help with this ?
2. I have red about the large variety of crossovers but can't figure out the difference and effect in sound there would be between a crossover of 1.5 kHz and a crossover of 10.80kHz can you help ?


SUBWOOFER
SPEAKERS

Sorry for my bad english, but for etape im refering to stage. but wy tipe of corssover, exist 2 tipes of primary crossover, low pass, high pass and 2 tipes of derived crosssover, band pass, and band rejecter. their function is simple they only alow to pass a certain frecuencies.
Low pass, only allow frecuencies under their frecuenci limit
High pass, only allow frecuencies over their frecuenci limit
Band pass, only allow frecuenci in the range of their frecuenci band
Band rejecter, only allow the frecuencies than are out of their frecuenci band

the efects aren't in the crossover, the efects are in the speakers, the diference is in the frecuencies than are played by the speakers conected to the crossover, wat if you send a Low frequency to a tweter or a high frecuency to a wofer, the crossover alow the speakers to receive only their band response frecuencies, for this telling about a crosover are cluesless without telling about the speakers conected to it.

this is a very good explanation over crossovers: http://www.carstereo.com/help/Articles.cfm?id=52

SUBWOOFER
SPEAKERS

Here are my audio specs you have previously asked,do you think they will fit toghether ? (Amplifier specs further up)


So you mean that there will be no difference in the sound between a crossover of 1.5 kHz and a crossover of 10.80kHz , its just a question of the speaker type.

Is that right ?



Thanks Elohe

Not exactly
Every speaker has a range it normally operates in. This means low distortions in this freq. range and ability to reproduce it correctly.
For example 1KHz-12KHz speaker.
A crossover will feed only the needed freq. to selected speaker thus providing better quality output.
As example - if you feed 500Hz frequency to the special hi-freq speaker which operates on >10KHz range this does not mean that you will hear nothing. You will hear "something" But not what you wanted.

What would I hear then ?

And can you state the frequency ranges we humans are capable to hear ?

Up to 16Khz usually...

What about decibels ?

750USD for a Subwoofer?. Wow. That must quake the earth. With that kind of money you can buy the best stereo system in the shop I visited a few hours ago, plus 10 CDs. Obviously nothing fancy or anal-audiophile-proofed ("just" a Sony). But 1000 times better than my system
Obviously the power of this system was nowhere near 1000W....2x220W IIRC.

Sorry for not contributing with anything interesting

That Subwoofer is a professional design any home amplifier would struggle to handle a nominal power of 1000watts. In my opinion I should have seen something else, because this subwoofer is meant for real competion.

Sensitivity: 87 dB
Recommended RMS Power: 1000W
Peak Power Handling: 2000W
Impedance: dual 2 ohms subwoofer wiring options

I would personally prefer this woofer instead of a home stereo, it could be used for anything you like, even for home surround.

What do you mean by anal-audiophile-proofed ?


Can someone help with this ?

Most amplifers I've seen had LCD display showing the current decibel power, the stange thing I have noticed is that the more you open the volume the more the decibel goes down -6, -8 etc ?

Whats all after this ?
What is the minimum and maximum a human can hear ?

They don't show the ouput decibel power, they express the ouput power or the amplification in decibles, they try to express the power in the mode to eras sense it. the amplifiers are linear componets but the eras sense the sound in a logaritmic scale and the decibels are the representation of this logaritmic escale for this the amplifier represent the output power or the amplification using a decibles scale.

the hears can hear from 0 DBA to +125 DBA ( this level is dangerous for the ears ), but DBA(deibles audio) is not the same as DB(decibles) but they are related.

What is the difference then ? Can you make a small comparison between the two.

Thanks