Amps for Usher BE 718 speaker

[AMITNOIDA]

Hi Amit,
I would tend to settle for a compromise of the following kind: tonality and clarity followed by microdynamics are the most important traits, at least for the predominant variety of music I listen to. I am not ready to compromise with these things too much and may let go other desirable traits to some extent. Of course, if I had the budget of a dinyaar, I would not mind having more powerful amps, because I would know at that budget fewer things will be compromised.

To comment on the Quad 909 power amp: Yes, I have heard that at a lengthy (3 hour long) audition. It is a decent amp, and its strengths are absolutely fabulous mid-range resolution and dynamics, but in terms of clarity, it is not the best available for the price. I would personally prefer a much cleaner amp. My Leben CS300 is simply a class apart from all these amps that I auditioned (detailed in my amp thread).

Regards.

Asit you are absolutely right. I don't have budget for going to region of fewer compromise. I have to live with some compromise due to budget. Leben is a good amp. I had personally listened BE-718 with Leben CS600. But you know, it is simply beyond my budget. I think, considering all the feedbacks, Jaton Operetta with Lyrita pre is going to be the choice available to me within my budget. Regarding Operetta you, Cranky, ROC, Sridhar and Dinyaar all have given good opinion.

Also, I will be happy to include at least one component from Viren. I have big respect for him.

But I have to go to Bangalore once more to listen BE-718 with Operetta and finally decide. Thank you all for your overwhelming response and suggestion.

 

[dinyaar]

1 watt into a 93dB/w speaker will produce 93 dB at 1m.

The exact same watt into a 85dB/w speaker, will produce 85dB, roughly (in perception) one third the volume level.

You never listen to watts, though the amplifier produces it. You listen to sound pressure. A speaker converts electrical input into acoustic output, and its sensitivity is a measure of how much sound pressure it creates for a given power. Use the analogy of how much light a CFL with 20 watts produces as compared to an incandescent 200 watt bulb, and you begin to get an idea.

Another thing is the calibration of the volume control. It is possible to have an amp that is gain-calibrated to a 150mV source (most commercial amps are designed to reach max output with around this much level) but in fact most CD sources are 2V, which is why almost all amps max out at about 1 o'clock with such sources (and people complain of why portable players need the volume to be turned up).

The best volume control is none at all, but that's hardly practical. All kinds of control schemes (including attenuators) attain maximum performance at 0dB attenuation, which equates to maximum volume.

To answer your question, when the volume knob is turned, the amp creates more voltage. You cannot create current. Current flows when there is a voltage, the magnitude of the current is not within your control, it depends on the impedance of the load. So for a given load, the power will be different even if the volume control is at the same position...

Mahiruha, Volume level is not an indicator of amp power.

Cranky, i believe some amps now are really taking on the problems of the volume pot.
An example is ANALOG VARI-GAIN AMPLIIFER MODULES. The operation principle of this control is totally different from conventional controls using resistors. In AVA the music signal is weighted into stages (In accuphase its 16 stages) and a current switching circuit serves to select the signal, thereby changing the volume level.
Hence when the volume is turned up or down its position is detected by the adjustment circuit and the current switches automatically set to on or off accordingly. Seems complex!!!! I have a detailed mail from Accuphase with some illustrations explaining all the 16 stages but frankly its going over my head
If the speaker is sensitive a faint clicking sound can be heard when u turn up the Vol. but on most moderately sensitive speakers its a non issue.

Amit, i dont think the quad 909 is the best amp for this speaker. It will naturally drive the speaker but IMO a veiled presentation. Look for a used Primare /Bryston Integrateds, will work well.
Rgds

 

[mahiruha]

1 watt into a 93dB/w speaker will produce 93 dB at 1m.

The exact same watt into a 85dB/w speaker, will produce 85dB, roughly (in perception) one third the volume level.

You never listen to watts, though the amplifier produces it. You listen to sound pressure. A speaker converts electrical input into acoustic output, and its sensitivity is a measure of how much sound pressure it creates for a given power. Use the analogy of how much light a CFL with 20 watts produces as compared to an incandescent 200 watt bulb, and you begin to get an idea.

Another thing is the calibration of the volume control. It is possible to have an amp that is gain-calibrated to a 150mV source (most commercial amps are designed to reach max output with around this much level) but in fact most CD sources are 2V, which is why almost all amps max out at about 1 o'clock with such sources (and people complain of why portable players need the volume to be turned up).

The best volume control is none at all, but that's hardly practical. All kinds of control schemes (including attenuators) attain maximum performance at 0dB attenuation, which equates to maximum volume.

To answer your question, when the volume knob is turned, the amp creates more voltage. You cannot create current. Current flows when there is a voltage, the magnitude of the current is not within your control, it depends on the impedance of the load. So for a given load, the power will be different even if the volume control is at the same position...

Hello Cranky,
thanks for your explanation. I kind of understand your point. The amp is producing electrical energy which gets converted into sound energey in the speakers and how efficiently the conversion is done is dependent on the efficiency of the speaker. Now my amp specification states 15 watts per channel into 8 ohms. does it mean that the internal circuitry of the amplifier has a resistance of 8ohms and the when the volume knob is turned to max it will create maximum potential difference to create maximum current flow to deliver 15 watts per channel ??Is it possible to vary this resistance for the amp to deliver more power. But how much spl will be created by this 15 watt entirely depends on the speaker and efficinency to convert electrical energy to sound energy. In a way it is always pointless to state the power of an amp without knowing where this power is delivered to. My amp has only one control which is the volume knob then other than this how one can explain the power of the amp??
Thanks.

 

[suri]

so why come nobody is saying nothing about 'damping factor' in these amplifiers being discussed.

after all, the tiny-dancer (with the 8948A 7" paper cone that is has), needs lots of damping to show off it's best (especially in the lower frequencies).

good luck trying to mate these with 'tube amplifiers', but then one would be missing that certain palpability to the music, i am sure.

that said, i would certainly like to hear these with tubes at the home of the braveheart who will sign the cheque (soon, it appears) for such a combo!

 

[odyssey]

Damping factors while having some truth to the whole story can be fudged - e.g. with a small amount of negative feedback, one can have damping factors running into a 1000, you will find people on both sides of the camp. Simple R is taken instead of true impedance, Phase lags are not considered.

cheers

 

[AMITNOIDA]

Damping factor is not an issue, but the speakers really like voltage and are not distressed when cranked hard (lesser speakers start distorting like crazy due to over-excursion, even Dynes), so you can turn the volume to 11 and still enjoy the presentation. That is the real benefit of the super-low distortion (~.1%) speakers like these.

But the vol at 11 is really difficult in my smallish (15 ft x 12 ft) room. I think I will not be able to get the real benefit of the super low distortion of this speaker.

 

[suri]

zilch i know theory about this, but-

i have seen (both with the scanspeak midwoofers and the said usher midwoofers) that these cones move with the slightest air pressure applied to their surface - for example, a high speed bajaj fan rpm'ing above them can move the cone - extrapolating, the surround and the spider are very pliable, but with good memory.

in such a system, surely, the voice coil (with it's extreme range of movement) will induce currents more than other systems, and if the amplifier has anything but the lowest output impedance, the damping will not be good, and therefore, control in the lower frequencies will be inadequate (the cone will continue to oscillate), and the bass will not be tight and will not be able to "start and stop on a dime".

sure that "Massive Attack" will be un-listenable via a tube/tiny dancer combo

but, this is instinct talking!

 

[suri]

Actually, if they were a little more sensitive (~90dB/w), they would be perfect partners for low-powered tube amps.

i have observed this - the more sensitive the (cone) loudspeaker transducer, the less the range of excursion it is allowed - i suppose these low-excursion drivers do not produce (relatively) significant back-current, and therefore, partner well with tube amps with highish output impedances.

the cones of midwoofers, by the very nature of work allotted to them, have to have large excursions = significant back-current= need for low-output-impedance amplifiers.

No, Panjabis should marry Panjabis, and Tamilian brahmins should marry Tamilian Brahmins ( so as to make beautiful music together!!)

a thousand pardons for unintended offense caused, or mistaken inferences!

 

[suri]

But the vol at 11 is really difficult in my smallish (15 ft x 12 ft) room. I think I will not be able to get the real benefit of the super low distortion of this speaker.

Amitnoida,

you, really, will get the benefit of a low-distortion speaker in any room and at any volume (but especially volumes that preclude polite conversation!)

 

[reignofchaos]

Whatever you do, please don't get the Quad 909. I found the amp to sound very lumpy and the top end was totally rolled off. The Jaton is a far far better amp. You can check the odysseys and usher's own amp too. I personally use a mccormack with it and never found a lack of drive or dynamics with it. Its slightly reserved at the top but its not bad at all.

While the Lebens sound supremely clean and sounds really nice, they definitely don't have the grunt that a 150W solid state amp does. So depending upon what you are looking for, you may have to choose!

 

[Asit]

Hi
I like vocals, soft instrument, indian classical etc. No heavy metals kind of music.

Is there a big "grunt" necessary in the above taste? I do not think Amit needs a big grunt from his equipments.

RoC, I do not think Amit is going to get the Quad, because there are much better amps available for the money. As I indicated in the first of my posts in this thread, I personally think the combination of Lyrita pre and the Operetta power appears to be one of the strongest candidates for the budget he has indicated. BTW, excuse my ignorance, what is lumpy in the characteristics of an amp? Do you mean a lack of smoothness? In the midrange too?

What do you think of the Lyrita pre and the Odyssey power amps (Khartago and Stratos) combo? You volunteered to do that test when I was looking for my amp, but I never got the results. Now if you have some time and are willing to take the trouble of carrying out this exercise, please let us know and people like Amit, Pratim and several others may benefit from it.

Regards.

Regards.

 

[anm]

cranky - where did you learn all this?

regards

QFT.

Nobody likes anything with high distortion. When you start lowering the distortion levels, you open up new dynamic possibilities that were simply not reachable with poorer equipment.

That still doesn't mean you can't enjoy them at lower levels. It's just that they will play a lot louder and a lot cleaner than most similar speakers, but even at lower levels, they will shine.



This is true for the most part, but it's not just excursion, it's also cone damping. A more linear cone will use different geometry and materials and usually be a little heavier (if it's not metal, which is a different ball of wax), requiring a more powerful motor and suspension, which reduce its sensitivity. This has less to do with back EMF and damping, which is more a product of the VC impedance/inductance and its location in the magnetic field. As long as some part of the coil is within the field, the back EMF remains controlled. It's a bit complicated to get into and will derail the thread, so I'll say no more on this.

You may run into problems with very inductive, multilayer VCs such as found in Dynaudio, Dynavox and Morel speakers (for example). Most reasonably specified speakers do not have these issues. Generally, fussy speakers like these require amps with super high-current outputs, which automatically mean super-low output impedances and high damping factors (before NFB).

 

[Asit]

Hi anm,

Long time ago, I asked a senior Dutch physicist (who is the inventor of the field I work in): "Where have you learnt all this from?". "Just by trying, Asit", he answered.

From many informal discussions, I gathered Cranky has acquired all this knowledge just by trying. He confessed he started by breaking open radios from around the age of ten.

Whatever I know about Physics, music and anything else, I have found that first you love something so much that you search for answers almost like a mad man. Books and things like that help you, but by trying incessantly on your own one day you start getting some answers.

Regards.

 

[suri]

Hi anm,

Long time ago, I asked a senior Dutch physicist (who is the inventor of the field I work in): "Where have you learnt all this from?". "Just by trying, Asit", he answered.

From many informal discussions, I gathered Cranky has acquired all this knowledge just by trying. He confessed he started by breaking open radios from around the age of ten.

Whatever I know about Physics, music and anything else, I have found that first you love something so much that you search for answers almost like a mad man. Books and things like that help you, but by trying incessantly on your own one day you start getting some answers.

Regards.

that is so true!

passion lights the candle that shows one the way (on an unknown journey) and as one progresses, the light gets brighter, until, at one stage, the entire object of that passion is lit by 10,000 w Osram floodlights!

 

[srramanujam]

Amit

I listened to Usher BE 718 with Operetta amp (roughly 60K) at Surrealstix's place last tuesday.

He has a fairly expensive preamp (about a lakh and a half) and uses his PC with a DAC. The room is music only (also HT) and has a lot of treatment.

The whole set up sounded quite nice, especially the soundstage and the details. There was a song that Surrelstix played (cant figure out which one). It feels like a singer is sitting next to you with a mouth a foot wide.

Ram

 

[AMITNOIDA]

Amit

I listened to Usher BE 718 with Operetta amp (roughly 60K) at Surrealstix's place last tuesday.

He has a fairly expensive preamp (about a lakh and a half) and uses his PC with a DAC. The room is music only (also HT) and has a lot of treatment.

The whole set up sounded quite nice, especially the soundstage and the details. There was a song that Surrelstix played (cant figure out which one). It feels like a singer is sitting next to you with a mouth a foot wide.

Ram

Thanks Ram. In fact after getting your PM, the veil on BE-718 got removed and I started this thread. I started recollecting my experience of listening BE-718 at Bangalore.

Thank you for removing my dilema again on BE-718 and Operetta combo. But before taking final decision I will perhaps go for one more audition of BE-718 this time pairing with Operetta at Bangalore.

 

[AMITNOIDA]

Please dont mind, I am asking a very basic question. What's the difference in max. power consumption between an amp with 70 wpc and another amp with say 125 wpc?

Is there any thumb rule about the standby power related to its wpc power rating?

 

[pratimbayal]

Hi Amitnoida

I have already decided to add operatta power amp with my BE 718 based on feedback from Sridhar and Roc (obviously supported by excellent freinds like Cranky and Asit) . This thread adds more strength to my decision. I have decided . Hope you will find answer quickly.

Good Luck
Pratim

 

[suri]

Please dont mind, I am asking a very basic question. What's the difference in max. power consumption between an amp with 70 wpc and another amp with say 125 wpc?

Is there any thumb rule about the standby power related to its wpc power rating?

hi amitnoida,

this is the thread-

http://www.hifivision.com/amplifiers/6285-power-consumption-audio-amps.html

 

[AMITNOIDA]

Hi Amitnoida

I have already decided to add operatta power amp with my BE 718 based on feedback from Sridhar and Roc (obviously supported by excellent freinds like Cranky and Asit) . This thread adds more strength to my decision. I have decided . Hope you will find answer quickly.

Good Luck
Pratim

Hi Pratim,
It is always encouraging to know that somebody has already decided the combo, which I am going to select. Did you listen to BE-718 with Operetta? Which pre are you going to use?


If you don't mind, may I know about your room size and type of music.

Thanks
Amit