ultra high current amp

[raghupb]

Output voltage is based on the gain and input signal. Amplitude, amplifier, tada ..
When this is presented to the speaker, a continuous complex impedance (simplified to R in ohms) kicks in.
Can the power supply hold the voltage at the impedance that instant, before compression or clipping?
High current capable amps can; some call it high, some call it ultra high.
E.g. an amp capable of 20A peak is a good one; higher this number goes better it can handle demanding loads.

Most of the demanding speakers misbehave in the LF region of sound spectrum.
Their impedance variations (from nominal) are the greatest say below 500Hz or so.
Have heavy bass, impedance can dip and strain the amp.
One solution, get a higher powered amp and/or add a sub-bass unit to augment.

Cheers,
Raghu

 

[marsilians]

If you take high fidelity amplifier and have massive transformer and capacitor then it will even sound good in tonality and precision has nothing to do with high current infact when you drive hard in order to hold the precision of localization of instruments the current should be delivered as demanded and in low current capable amplifiers they precision is lost when the power supply unit cannot deliver the demanded current its as simple as that.

You are introducing a new term called high fidelity amp. Could you pls explain what that means?

Wish the instrument separation was that simple as you are stating...there are other key variables including the damping factor, speaker impedence and the gain or volume one is listening at.

Here is another video by Harbeth about how much amplifier power do you really need? Here when you observe the video you will not believe how much power does your speakers demand.

https://www.harbeth.co.uk/library/movies_hug/HAL-HV0515-01a_Power.mov

I will clarify a few things here

50V x 10Amp is 500W
25V x 20Amp is 500W
10V x 50Amp is 500W

So even in the above video its the current which is being demanded by the speaker now at situations you need 50Amp of instantaneous current hence you can also see in the above video that its the current demand not the voltage demand.

I would take what Alan suggests with a grain of salt. BTW I am not questioning his brilliance as I own a pair of compact C7s. It’s more on how he messages when it comes to managing other equipment around his speakers. For eg., he states his speakers can be placed on cheap IKEA stools and it should sound absolutely fantastic but then in all the retailers and few shows I have been to, Harbeths have been on Skylan, foundation or Tontrager stands. Similarly around amps for his speakers, I have very diverse results with Tube, Class D or class AB amps with these speakers. I feel he doesn’t want to show his preferences as clearly as others do as it might limit some people purchasing his speakers. He tends to tow the middle road very consistently. Again my personal views and based on how I have seen his products in use.

 

[sandyjhyderabad]

I would take what Alan suggests with a grain of salt. BTW I am not questioning his brilliance as I own a pair of compact C7s. It’s more on how he messages when it comes to managing other equipment around his speakers. For eg., he states his speakers can be placed on cheap IKEA stools and it should sound absolutely fantastic but then in all the retailers and few shows I have been to, Harbeths have been on Skylan, foundation or Tontrager stands. Similarly, around amps for his speakers, I have very diverse results with Tube, Class D or class AB amps with these speakers. I feel he doesn’t want to show his preferences as clearly as others do as it might limit some people purchasing his speakers. He tends to tow the middle road very consistently. Again my personal views and based on how I have seen his products in use.

I can't get onto all the fundamental concepts of what is fidelity or precision or soundstage etc. Im really exhausted on that aspect sorry for that.
Impedance dips happen very badly when the speaker cone moves dynamically and it demands certain high current at that instance. If that current is not delivered into the load the voltage at the load drops resulting in lower cone excursion than the actual required excursion.

Sonic signature comes from the amplifier architecture and the materials used in power supplies and components.

Power equation is standard for any power amplifier.

V=IR
Voltage will be current multiplied by resistance.

Doctor Saab I wish I could learn engineering from you.

Power = V x I
Power = V^2 /R
Power = I^2 x R

here R is resistance but speaker load is reactive so-called as Impedance and the resistance varies with frequency.
Let us not make it mathematically complex here.

 

[prateekatasniya]

Doctor Saab I wish I could learn engineering from you.

Power = V x I
Power = V^2 /R
Power = I^2 x R

here R is resistance but speaker load is reactive so-called as Impedance and the resistance varies with frequency.
Let us not make it mathematically complex here.

Power demand ain't going to vary with frequency?

 

[sandyjhyderabad]

no it has nothing to do with frequency there is another term called as Duty Cycle or Duty Factor. I guess you can check it on that. You mean to say lower frequency needs more power than higher frequency? take the full range driver and drive it and measure how much power its consuming in the spectrum.

If you have impedance peaking then infact you need more power to overcome that impedance. Very deep concept but yes when you do frequency sweeps on the driver and also measure the impedance across the entire spectrum you will find more answers.

 

[raghupb]

no it has nothing to do with frequency there is another term called as Duty Cycle or Duty Factor. I guess you can check it on that. You mean to say lower frequency needs more power than higher frequency? take the full range driver and drive it and measure how much power its consuming in the spectrum.

If you have impedance peaking then infact you need more power to overcome that impedance. Very deep concept but yes when you do frequency sweeps on the driver and also measure the impedance across the entire spectrum you will find more answers.

You mean impedance bottoming. Lower impedance at certain frequencies in the audio spectrum.
Cheers,
Raghu

 

[sandyjhyderabad]

dynamic impedance is different from the static impedance

 

[ravikumar-rotel]

Well, if you have both the Amps, then i think you should try it and let us know which one drives better.

Theoretically, both should be able to drive 6 ohms with ease ! The Denon is likely to have used its two Transformers in this way - one for Pre section and other for Power Section. So the Rotel with high power rating is more likely to move your speakers better.

Please note this is a purely theoretical calculation based on specs given by products. This has no relevance to how the Amp sounds in real.

Denons use both the transformers for power section.. there is a separate transformer for the pre section...

Should he have mentioned a plane or something?

May be a s1000RR, zx10R, gsxR, Cbr1000RR. Lol.

Output voltage is based on the gain and input signal. Amplitude, amplifier, tada ..
When this is presented to the speaker, a continuous complex impedance (simplified to R in ohms) kicks in.
Can the power supply hold the voltage at the impedance that instant, before compression or clipping?
High current capable amps can; some call it high, some call it ultra high.
E.g. an amp capable of 20A peak is a good one; higher this number goes better it can handle demanding loads.

Most of the demanding speakers misbehave in the LF region of sound spectrum.
Their impedance variations (from nominal) are the greatest say below 500Hz or so.
Have heavy bass, impedance can dip and strain the amp.
One solution, get a higher powered amp and/or add a sub-bass unit to augment.

Cheers,
Raghu

20 Amps???? the power cables will burn up....

 

[raghupb]

20 Amps???? the power cables will burn up....

Not on the input power side. This is requirement on output side towards speakers.
If a high enough voltage after amplification is to be maintained at low impedance, instantaneous current capability is required.
Cheers,
Raghu

 

[ravikumar-rotel]

Not on the input power side. This is requirement on output side towards speakers.
If a high enough voltage after amplification is to be maintained at low impedance, instantaneous current capability is required.
Cheers,
Raghu

Would that improve dynamics and provide a better headroom?

 

[raghupb]

Would that improve dynamics and provide a better headroom?

Headroom yes it; it is directly related to electric theory.
Dynamics is subjective. Some feel it does, some don't notice the difference.
Having high (ish) current capability means little to no chance of clipping of output signal.
Cheers,
Raghu

 

[johnmicheal]

Jeff Rowland model 5 is one of the classic example of High current amplifier. It remains stable at very high current demand from speaker.

 

[magma]

Ultra high current amps are those that recommend the user to get life and fire insurance before you buy them

 

[surfatwork]

A lot of terms being bandied about, but there seems to be a lot of wrong info.
An ideal amp is a constant voltage source. The max voltage at the speaker Terminals is +/- Vcc, less a few volts. If you feed the amp an input signal Vin, then it will produce an output voltage of Vout = Vin x Gain. If Vout is more than +/- Vcc, the amp will clip. It has nothing to do with the current capability of the amp.
One of the posts mentioned 8000Amperes. That's ridiculous. 8000Amperes into an 8ohm speaker, no matter how momentary, needs thousands of volts at the speaker outs since I=V/R. I can guarantee that no amplifier delivers 1000s of volts at the speaker Terminals.
An amplifiers current delivery capability is required to deal with the varying impedance presented by a speaker. If the speaker impedance is low, then at some point the amp will not be able to sustain the same power output. That will be because either the power supply can't supply anymore current, or the output device max current capacity is exceeded and the device fails. Most decent amps have protection circuitry to prevent this well in advance.
Do note that excessive current demand can cause the power rails to sag, and hence cause clipping. But again, it's because Vout is more than +/- Vcc.

 

[abeyaby]

Should he have mentioned a plane or something?

Seriously...