What is preamplifier? How important it is in the stereo music system?

[ukjeyaraj]

Was trying to understand about preamplifier and its role in a stereo music system? Did some googling and also read some old threads in HFV forum

This is what I understood (may be right/wrong)

1) Preamplifier does gaining
2) Preamplifier does impedance matching (dont know what does this mean)
3) Preamplifier has something to do with volume adjustment (is it same as gaining)
4) There are two different preamplifiers Active and Passive ??!! (courtesy:googling)
5) Every integrated ampliifer has in-built preamplifier

Would like to know something more

1) Whether any source (CD/Casette Player/WalkMan) containing volume control does have in-built preamplifier?
2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?
3) Does all integrated amplifier contain active preamplifier?
4) Is pre-amplifier(separate) is always active preamplifier?
5) Is Pre-Power separate always better than integrated amplifiers (This could be very subjective)?

Thanks in advance

 

[Audio_Freek]

Was trying to understand about preamplifier and its role in a stereo music system? Did some googling and also read some old threads in HFV forum

This is what I understood (may be right/wrong)

1) Preamplifier does gaining
2) Preamplifier does impedance matching (dont know what does this mean)
3) Preamplifier has something to do with volume adjustment (is it same as gaining)
4) There are two different preamplifiers Active and Passive ??!! (courtesy:googling)
5) Every integrated ampliifer has in-built preamplifier

Would like to know something more

1) Whether any source (CD/Casette Player/WalkMan) containing volume control does have in-built preamplifier?
2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?
3) Does all integrated amplifier contain active preamplifier?
4) Is pre-amplifier(separate) is always active preamplifier?
5) Is Pre-Power separate always better than integrated amplifiers (This could be very subjective)?

Thanks in advance

UKjeyaraj,
Before moving to the questions its better to explain the reproduction of sound.

Music is stored in CD\tape
A DVD player or Cassette player reads the source and retrieve those frequency and convert it as Audio frequencies

A Pre-amplifier receives those Audio frequency and boost the audio frequency.

Integrated amplifier or power amplifier or Amplifier ( it could be called i any name of these three) Receives the gained frequency and convert them to e played in Speakers

B]Would like to know something more[/B]

1) Whether any source (CD/Casette Player/WalkMan) containing volume control does have in-built preamplifier?Not necessarily- Coz in CD\DVD it jus controls the output level which its capable of and does not increase or decrease the strength of frequency out of it level.
2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?
3) Does all integrated amplifier contain active preamplifier?
Pre-amplifier just strengthen the frequency, But Integrated amplifier can even play the low strength frequency EG: ur amp can ply the ouput from DVD which runs in 20 volts also from your Mobile (You can understand how far the Mobile power usage is low compare to dvd PLAYER)
4) Is pre-amplifier(separate) is always active preamplifier?Its not clear sorry,active means to?
5) Is Pre-Power separate always better than integrated amplifiers (This could be very subjective)?


20 volts DVD getting connected to 500 volts amplifier never sounds good, as the amp would need to pull the frequency hardly and produce output,more over you cant expect the full performance of amp or speaker i this case

20 volts DVD getting connected to 500 Volts amp then to 500 volts Amp\power amp,, this gives the better peformance..

DVD delivers the thread, Pre amp strengthen the thread to rope and Integrated amp is the person who is use to pull a small chair (volume), so imagine, the performance of pulling the chair with thin strong thread is easy or with rope.. At same time if you have small pin (small speakers with 5-10 watts)then its okie to pull with thread itself instead pre-amp..


Conc- high power speakers needs a preamp and integrator set-up
Little speakers just need just a integrator amp, as the power handling of speakers is going to be less.



If you still ve any doubts pls PM me, let me make you clear in other possible ways

 

[2chFreak]

UKjeyaraj,
Before moving to the questions its better to explain the reproduction of sound.

Music is stored in CD\tape
A DVD player or Cassette player reads the source and retrieve those frequency and convert it as Audio frequencies

A Pre-amplifier receives those Audio frequency and boost the audio frequency.

Integrated amplifier or power amplifier or Amplifier ( it could be called i any name of these three) Receives the gained frequency and convert them to e played in Speakers

B]Would like to know something more[/B]

1) Whether any source (CD/Casette Player/WalkMan) containing volume control does have in-built preamplifier?Not necessarily- Coz in CD\DVD it jus controls the output level which its capable of and does not increase or decrease the strength of frequency out of it level.
2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?
3) Does all integrated amplifier contain active preamplifier?
Pre-amplifier just strengthen the frequency, But Integrated amplifier can even play the low strength frequency EG: ur amp can ply the ouput from DVD which runs in 20 volts also from your Mobile (You can understand how far the Mobile power usage is low compare to dvd PLAYER)
4) Is pre-amplifier(separate) is always active preamplifier?Its not clear sorry,active means to?
5) Is Pre-Power separate always better than integrated amplifiers (This could be very subjective)?


20 volts DVD getting connected to 500 volts amplifier never sounds good, as the amp would need to pull the frequency hardly and produce output,more over you cant expect the full performance of amp or speaker i this case

20 volts DVD getting connected to 500 Volts amp then to 500 volts Amp\power amp,, this gives the better peformance..

DVD delivers the thread, Pre amp strengthen the thread to rope and Integrated amp is the person who is use to pull a small chair (volume), so imagine, the performance of pulling the chair with thin strong thread is easy or with rope.. At same time if you have small pin (small speakers with 5-10 watts)then its okie to pull with thread itself instead pre-amp..


Conc- high power speakers needs a preamp and integrator set-up
Little speakers just need just a integrator amp, as the power handling of speakers is going to be less.



If you still ve any doubts pls PM me, let me make you clear in other possible ways

oppsss.... check those figures again ..

with those values, it aint a preamp or audio anymore, its low-voltage electrical engineering .. :yahoo:

 

[mbhangui]

The primary job of a preamp is to boost the voltage from the source to a sufficient value so that it can be fed to a power amp. A preamp boosts mainly the voltage. The current will be so less that if you cannot drive a heavy load like a loudspeaker. The job of the power amp is to amplify the power (V x I).

A preamp is a terminology. You can do all the amplification stages (voltage gain, current gain) amplification in one unit and call it an integrated amplifier. Or you can do pre-amplification separately. This allows you to mix and match pre-amps and amps from different manufacturers. Also allows you to upgrade the preamp separately or the power amp separately. So having a separate preamp, power amp may give you a perceived flexibility. This can be an advantage if you are in the habit of frequently changing stuff as per your liking.

Most of the sources (tape head, Phono Cartridge, Microphone) produce electricity in few millivolts. These need to be boosted as close to the source so that any noise that gets picked on the way will be very small as compared to the actual audio signal. A preamp provides voltage gain (from few millvolts to around ~ 1 volt). A Preamp provides voltage gain only with almost no current gain and hence it does not have sufficient power to drive speakers. However if these are fed to a power amp, the power amp can provide the necessary current gain also and have enough power (V x I) to drive loud speakers.

A good preamp will boost the feeble input power with as low noise as possible. Lower the noise, higher the signal to noise ratio (SNR). Once you have boosted the power with very low noise, even a long cable of 1 m or so will not affect sound quality that much since the actual audio signal will be quite high compared to noise picked up by the cable (interconnect). Remember that each and very cable, wiring, copper lines on the pcb can act as an antenna and pick up stray RF from the surroundings. Also if you have boosted a voltage enough, you can put a potentiometer to reduce the voltage to be fed to the power amplifier.

The preamp also serves to give your music a sound signature that is very subjective from person to person. Hence you will find people going ga-ga over a tube preamp. Remember that if you want to hear the source exactly as it was sung, you need to have all equipment neutral. This requires the preamp, amp to have a linear gain throughout the audio frequency spectrum. Since nothing in nature is perfect, no tube or transistor can every give a perfect linear amplification. Hence you will find people saying that such-and-such amp is bright and such-and-such amp is mellow, etc

Preamps can also be used for impedance matching (though this need not be the primary function). Impedance is the opposition by a system to the flow of energy from a source. Maximum power transfer happens when the impedance of the load equals the complex conjugate impedance of the source. Usually phono preamps do impedance matching. The source impedance will be ~ 47k for mm cartridge for example. You will find folks changing this to match it with their specific cartridge.

Audio is a very personal journey. You will discover more myths than facts as you go along. Nothing will beat your own personal experience. Don't get bogged down by technical jargons. The important thing is to listen as much as possible with various equipments, demos, etc and let your ears decide.

This is what I understood (may be right/wrong)

1) Preamplifier does gaining
Yes usually voltage gain. The power is still negligible to drive heavy loads.

2) Preamplifier does impedance matching (dont know what does this mean)

http://en.wikipedia.org/wiki/Impedance_matching

3) Preamplifier has something to do with volume adjustment (is it same as gaining)

volume adjustment is just feeding the audio output to a potentiometer to reduce the output fed to the next stage. It is just a simple voltage divider.
http://www.varesano.net/blog/fabio/...ey are how they work and how use them arduino

4) There are two different preamplifiers Active and Passive ??!! (courtesy:googling)
http://www.rothwellaudioproducts.co.uk/html/the_truth_about_passive_pre-am.html

5) Every integrated ampliifer has in-built preamplifier
Yes. If it does not have, it will be called a power amp

Would like to know something more

1) Whether any source (CD/Casette Player/WalkMan) containing volume control does have in-built preamplifier?

Yes. And in addition they do some equalization. Some frequencies are boosted and some lowered. This is because the reverse happens during recording.
http://en.wikipedia.org/wiki/RIAA_equalization
http://home.comcast.net/~mrltapes/equaliz.html

2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?

The output from such a preamp can be fed directly to a power amp. It can also be fed to any audio input on an integrated amp. One should not again feed this to an input like "Phono input" on an integrated amp else double equalization will happen.

Preamps in integrated amp provides convenience. You don't need to have two units.

3) Does all integrated amplifier contain active preamplifier?
Yes

 

[mbhangui]

UKjeyaraj,

20 volts DVD getting connected to 500 volts amplifier never sounds good, as the amp would need to pull the frequency hardly and produce output,more over you cant expect the full performance of amp or speaker i this case

20 volts DVD getting connected to 500 Volts amp then to 500 volts Amp\power amp,, this gives the better peformance..

oppsss.... check those figures again ..

with those values, it aint a preamp or audio anymore, its low-voltage electrical engineering .. :yahoo:

With 500 volts on the output, you don't need a loudspeaker. One can hold two wires of the speaker cable in each hand and "Dance to the Music"hyeah:

Anyway, just joking, I know you tried your best to explain the OP in terms as layman as possible and thanks for that. Appreciate that

 

[omishra]

Any small amplifier with little voltage gain (not a power amplifier) or no gain ( called buffer) which is in between source output and power amplifier, is termed as preamplifier.
1. All sources have some output stage which is added to avoid loading signal generating source. There is some kind of volume control which is not preamplifier. It there to control its own output.
2. Roll of preamplifier in above chain is to match impedances, bump signal voltage and control frequency curve, if any.
3. A preamplifier wherever it is, inside or outside, separated or integrated, function remains same as step 2.
4. I have separate preamplifier which is no gain buffer with source selection and volume control only.
5. Separate is preferred (by audiophiles) as preamplifier handles low level signal. Any high level signal or related high power supply can induce any noise into low level signal. Integrated preamplifier inside power amplifier has limitation for low quality implementations.

 

[ssf]

Can one use a pre-amp with an integrated and if so, what are the benefits ?

 

[ukjeyaraj]

2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?

The output from such a preamp can be fed directly to a power amp. It can also be fed to any audio input on an integrated amp. One should not again feed this to an input like "Phono input" on an integrated amp else double equalization will happen.

Preamps in integrated amp provides convenience. You don't need to have two units.

Does it mean whenever we connect any source to integrated amplifier using connection(like tape/aux/tuner) other than phono input, it bypass preamp section of the integrated amplifier?

 

[venkatcr]

Music is stored in CD\tape
A DVD player or Cassette player reads the source and retrieve those frequency and convert it as Audio frequencies. A Pre-amplifier receives those Audio frequency and boost the audio frequency.

Huh? Frequency? Let me understand this. Let us say the source has a 100Hz signal and that is fed to a pre-amplifier. You mean to say the pre-amplifier converts that to a 200Hz signal? And, I am at a complete loss to understand what a 'frequency' is and what an 'audio frequency' is.

Cheers

 

[ssf]

2) If yes, when they are connected to integrated amplifier, what is the role of preamplifer in source and integrated amplifier?

The output from such a preamp can be fed directly to a power amp. It can also be fed to any audio input on an integrated amp. One should not again feed this to an input like "Phono input" on an integrated amp else double equalization will happen.

Preamps in integrated amp provides convenience. You don't need to have two units.

I missed that, thanks.

 

[venkatcr]

Can one use a pre-amp with an integrated and if so, what are the benefits ?

Why would you want to do that? The integrated would already have pre-amplified the signal. Why pre-amplify it again? Some units do have what are called 'pre-outs'. Here instead of using the internal power amp, you can route the signals to an external power amp.

If you do not like the pre-amplifier of an unit, you must route the original source signal to a different pre-amplifier.

Cheers

 

[ssf]

Can one use a pre-amp with an integrated ?

Why would you want to do that?

To add a bit more gain, perhaps. I do feel on occasions that my Topping TP60 could benefit from a bit of a gain or boost of the source signal to better drive the Quad 12L2's.

 

[sachu888]

To add a bit more gain, perhaps. I do feel on occasions that my Topping TP60 could benefit from a bit of a gain or boost of the source signal to better drive the Quad 12L2's.

Hi,
You can use a separate preamp or replace your existing preamp of your amp.Some HFv members have done that with Norge .They are using SSP and results are great.

Regards,
Sachin

 

[mbhangui]

Huh? Frequency? Let me understand this. Let us say the source has a 100Hz signal and that is fed to a pre-amplifier. You mean to say the pre-amplifier converts that to a 200Hz signal? And, I am at a complete loss to understand what a 'frequency' is and what an 'audio frequency' is.

Cheers

No. 100 Hz will remain 100Hz. The normal human audible audio frequency spectrum consists of waves having frequency from 20Hz to 20 KHz. Abnormal humans like me can hear frequency range from 20Hz to 15KHz only. Dogs can hear frequencies even higher than 20KHz

A neutral amplifier will convert 1 mV of 100 Hz to 1 V of 100 Hz, 0.5 mV of 2000 Hz to 0.5 V of 2000 Hz, 2 mv of 2000 Hz to 2V of 2000 Hz and so on. It will not alter the frequency. Hence a preamp or amp increases only the amplitude of a wave and not the frequency. The gain I am giving in this example is hypothetical. In real life you cannot have a amplifier with the same gain for each and every frequency in the audio spectrum. That's why amplifiers from different brand will sound different.

 

[mbhangui]

Does it mean whenever we connect any source to integrated amplifier using connection(like tape/aux/tuner) other than phono input, it bypass preamp section of the integrated amplifier?

Not necessarily. The integrated amp mostly likely can have a preamp (with much lesser gain) before the volume control. This pre-amp will not do any equalization (like the phono input).

In some of the integrated you can break the connection between the power amp and the preamp by removing the short interconnect at the back. Look at the below picture to see how the integrated Pre and Power are connected using a short connector.

 

[omishra]

No. 100 Hz will remain 100Hz. The normal human audible audio frequency spectrum consists of waves having frequency from 20Hz to 20 KHz. Abnormal humans like me can hear frequency range from 20Hz to 15KHz only. Dogs can hear frequencies even higher than 20KHz

A neutral amplifier will convert 1 mV of 100 Hz to 1 V of 100 Hz, 0.5 mV of 2000 Hz to 0.5 V of 2000 Hz, 2 mv of 2000 Hz to 2V of 2000 Hz and so on. It will not alter the frequency. Hence a preamp or amp increases only the amplitude of a wave and not the frequency. The gain I am giving in this example is hypothetical. In real life you cannot have a amplifier with the same gain for each and every frequency in the audio spectrum. That's why amplifiers from different brand will sound different.

In short you are mentioned all input voltage is multiplied 'N' times irrespective of source frequency. N is amplifiers voltage gain.
Output Voltage = Gain X input voltage, whatever frequency is. That is flat frequency response.

 

[venkatcr]

No. 100 Hz will remain 100Hz........

The question was meant for Mr. Audio Freek who freaked me out with his answers.

I have read your posts and they are correct.

Cheers

 

[ukjeyaraj]

All source signals have to be be pre-amplified, irrespective of where it is done.

CD, Tape, and TT (phono) provide different signal strengths, and that is why you have different inputs in a pre-amplifier. Phono outputs usually have very low signal strength, and the gain added to this is usually higher than that of the CD or Tape. Remember, a pre-amplifier has to provide a steady 2V to the power amplifier. But what does it do when the inputs signals are (say), 200 millivolts, 400 millivolts, and 500 millivolts? It just add the exact amount of gain needed for each to give a steady output of 2 volts. That is why you have different inputs to each source in a pre-amp. Each source goes through a slightly different circuit that defines how much gain is to be added.

If you connect a TT to a CD input, because the pre-amp will be adding lesser gain, the power amp will struggle to amplify that as it is not receiving the 2 volts it is expecting.

Cheers

So, irrespective of whether the source(CD/TAPE/TT) has pre-amp built-in, when the signal reaches integrated amplifier, the pre-amp section in the integrated amplifier will gain the strength suitable enough to the requirement of power amp. Depending on the connection chosen it will accordingly add the required gain.

 

[omishra]

So, irrespective of whether the source(CD/TAPE/TT) has pre-amp built-in, when the signal reaches integrated amplifier, the pre-amp section in the integrated amplifier will gain the strength suitable enough to the requirement of power amp. Depending on the connection chosen it will accordingly add the required gain.

I think you are getting impression that at certain volume level you will get equal sound level for all sources. This is incorrect. Rather than you will headroom for increasing input for power amp, thanks to preamp. For TT phono stage adds extra but fixed gain to cartridge output.

 

[Audio_Freek]

The question was meant for Mr. Audio Freek who freaked me out with his answers.

I have read your posts and they are correct.

Cheers

The frequency doesn't change its original form.. I.e 100 Hz needs to be 100Hz whether its been sent to 10 watts speaker or 100 watts speaker..

If you play a 100hz with 1 volt to a speaker the DB will be low compared to playing 100hz with 10 Volt..



If you dont agree with this then hold the wire of head phone connect to the mobile with volume turned to full, you never feel the shock, but if you hold the speaker wire from 300 volts amplifier with full volume surely you will feel a bit shock...

"In general to increase the DB of an frequency we need some extra power/volt"

Pre-amp ads the voltage for the frequency so the Integrated amp can use that volts to increase the DB of the frequency

Hope all here know the difference between DB and frequency


anyways Sorry for using a term "Audio Frequency" i should have made this in initial thread itself...

Its a forum and not the argument to justify, Hence please correct me if am wrong