power and amplification

[nandac]

i have a pair of sonus faber concertos powered by a rotel 1062 integrated (350 watts) hooked to a rotel 1072 cdp.

till 9 O'clock the sound is good. nice and smooth.

but past 9, it kind of gets harsh.

mind you that there is no audible distortion. but at some imperceptible level there is a harshness which you can feel.

one of my prime concerns is the power supplied to the amplifier. i wonder if the amp is getting the necessary power it requires.

i have little or no knowledge of how electricity works in such contexts so if the below questions are stupid, pls bear with me.

the rotel 1062 was bought in the usa. so i use a 500 watt raksha step down convertor to hook it up. could the convertor possibly be the issue - in that it is not supplying the necessary power to the amp?

from the wall socket i have a belkin multi plug thing to which all the electronic equipment is connected. the belkin according to its literature is the one to use for home theatre equipment etc. not sure if that is causing the issue.

the step down convertor was initially hooked up to the belkin and i felt the sound was kind of getting stifled at some level. then i hooked up the convertor directly to the wall socket. it seemed to open up the sound a bit.

we have an invertor installed in our home (due to the endemic power cuts in bangalore). could the invertor be a reason that power is not flowing freely (if that's really the issue)?

also i note that for our microwave and certain other equipment we have a kind of different bigger wall power socket in our home. is that supposed to pump in more current? if so would that help the amp?

appreciate any insights.

 

[avidyarthy]

Are these the Grand Pianos? If so, then the 1062 is seemingly underpowered.

 

[GeorgeO]

On the face of it 250 w is a lot of juice and more than i enough for the SF speakers. The inverter( assuming that it is not a pure sinewave UPS) should only provide power when the mains is not coming through and at that time you should shut the system down.

 

[nandac]

by 350 watts, i mean the consumption. the amp's output is 60w per channel.

 

[Bluu]

Agree with avidyarthy. The Rotel seems under-powered. Try listening to the speakers with a more powerful amp.

 

[nandac]

the concertos are bookshelves. they are the older model.

 

[GeorgeO]

what dB sensitivity?

 

[nandac]

SYSTEM:
13 lirtres two way system front reflex port TWEETER:
Sonus faber design,neodymium ultra
dynamic linearity drive, 26 mm silk dome ferrofluid, magneticaly shielded FREQUENCY RESPONSE:
40-20.000Hz, tuning port included
CABINET:
construction with decoupled side panels for resonance control CROSSOVER :
first order attenuated cross-point 2.5 KHz FINISH:
combiantion of black leather and solid walnut or black piano lacquer
MID-WOOFER:
Sonus faber design,ultra dynamic linearity driver,180 mm fiber glass multicoating cone,magnetically shieded IMPEDANCE:
6 ohms nominal DIMENSIONS:
240 x 320x 360mm(W D H)
9 1/2 x12 1/2 x14 1/4in (W D H)
SENSIVITY:
88 dB/1W/1M POWER HANDLING :
30/200 W. withot clipping
WEIGHT:
18 Kg pair without packing
22Kg pair shipping weigh

 

[avidyarthy]

Quite possible the Rotel is causing 'clipping' beyond 9'O clock. 60W x 2 at 8 ohms could be less even with toroids inside.

Try out a heavier power amp ..... @ 120W x 2 at 8 ohms ... that should do the trick.

 

[jaudere]

I had 2 questions
1)what is your room size?

2)Do you cross 9 o clock position just for the sake testing or you need it to get adequate loudness?

If you are getting adequate volume at 9 oclock or less,then pushing it beyond that will give you unbearable loudness.

Similar thing happens with my marantz which is 45w RMS. Most of the times when volume is adequate at 9 o clock and if i turn it up further, it is unbearable because of sheer loudness even though there is no distortion. However,some discs have low volume. These discs (and my PC) need a volume knob at 10 oclock or higher to provide adequate volume. At such times the sound remains good. No distortion. I have not tried anything beyond 12 oclock.

The issue may be just the interpersonal variability in auditory sensitivity. I feel that 60w should be good enough especialy when the brand is standard like Rotel and is less likely to give fake specs.

 

[square_wave]

Lose the Rotel.

The sonus faber concertos deserve better. And SF speakers like quality power.

Depending on your budget, there are many worthy candidates in the market. Look around.

In the process you will get rid of that converter also. That will improve the sound quite a bit.

 

[nandac]

Depending on your budget, there are many worthy candidates in the market. Look around.

can you suggest some?

i am already looking at musical fidelity 3.2/3.5

anything else in that price range?

 

[GeorgeO]

88 dB speakers can very comfortable by driven by much less power than you are now using. I use a 60 wpc amp with an 87 dB speaker and it is very loud.

 

[square_wave]

@George,

I was meaning quality power as opposed to adequate power. I hope that clarifies.

@ nandac

Many budget amplifiers especially the mass produced ones have adequate power on paper. But what one hears is very much dependent on how the amp behaves when it is driving the speaker. The amp speaker combination is a constant feedback system wherein the good designs circumvent manifold problems and are able to create music with self-confidence and composure. The really good ones are extremely transparent and provide a very clear window into the music. The extremely good ones can even give you insight into the musicians intentions. Such amplifiers are very rare.

I do not know your budget. But some options which are not very costly:-

1. Odyssey etesian integrated
2. Odyssey Khartago/ stratos + a passive preamplifier
3. Exposure amplifiers (they are available with the Bangalore dealer)
4. You could even look at some cayin or primaluna tube amps. I am not sure about the Indian dealers. I am sure they are available.
5. Pick up an arcam integrated and then a power amp and bi-amp the speaker. This is a very popular method to use arcam amps since they are not exactly very powerful but works well in this manner
6. A Naim or plinius integrated amp from the used market

 

[jaudere]

88 dB speakers can very comfortable by driven by much less power than you are now using. I use a 60 wpc amp with an 87 dB speaker and it is very loud.

+1 to that. In fact, through my observations, for a listening distance of 8-10 ft (regardless of room size) , speaker sensitivity of 87dB And above,with regular CDs and cd player (and normal ears ), anything above 35w rms/ch is more than enough for music. That is why amps like Marantz pm 5003/4 are bought. However For movies with lot of LFE, this may not be adequate.
So the issue over here does not seem to be the amp power.

I know that I am contradicting myself but here is A wild guess why higher powered amp may be better. Higher the power for a class AB Amp, more will be the initial watts coming as class A(constant current). So a 200w
Amp may have some 20w class A power while 60w amp may have just 6 to 10w watts of class A power. These are absolute wild guesses of a non techie. Experts please comment.

If this guess is right then it makes sense in buying a more powerful amp otherwise 60w is enough.

 

[soundofmusic]

+1 to that. In fact, through my observations, for a listening distance of 8-10 ft (regardless of room size) , speaker sensitivity of 87dB And above,with regular CDs and cd player (and normal ears ), anything above 35w rms/ch is more than enough for music. That is why amps like Marantz pm 5003/4 are bought. However For movies with lot of LFE, this may not be adequate.
So the issue over here does not seem to be the amp power.

I know that I am contradicting myself but here is A wild guess why higher powered amp may be better. Higher the power for a class AB Amp, more will be the initial watts coming as class A(constant current). So a 200w
Amp may have some 20w class A power while 60w amp may have just 6 to 10w watts of class A power. These are absolute wild guesses of a non techie. Experts please comment.

If this guess is right then it makes sense in buying a more powerful amp otherwise 60w is enough.

There are only few Class AB amplifiers which work in Class A for first few watts. The SF needs Quality and not Quantity. Even a Hi quality 50 watts is more then sufficient.

@Nanda: I have used the MF A 3.5 and the power of 150watts from the amp is less then 50 watts from Naim or the Cyrus. Dont look at the RMS rating. The MF will not drive the Concertos. Sell the Rotel and get a decent amp like what Square wave suggested. Just my opinion.

regards

 

[square_wave]

+1 to that. In fact, through my observations, for a listening distance of 8-10 ft (regardless of room size) , speaker sensitivity of 87dB And above,with regular CDs and cd player (and normal ears ), anything above 35w rms/ch is more than enough for music. That is why amps like Marantz pm 5003/4 are bought. However For movies with lot of LFE, this may not be adequate.
So the issue over here does not seem to be the amp power.

I know that I am contradicting myself but here is A wild guess why higher powered amp may be better. Higher the power for a class AB Amp, more will be the initial watts coming as class A(constant current). So a 200w
Amp may have some 20w class A power while 60w amp may have just 6 to 10w watts of class A power. These are absolute wild guesses of a non techie. Experts please comment.

If this guess is right then it makes sense in buying a more powerful amp otherwise 60w is enough.

Completely agree with you but it all depends on the design of the amp

There are 50 watt amps which start sounding harsh and losing composure when pushed beyond 40 percent of its max volume.

Then there are 50 watters which can be pushed to the absolute maximum without even a hint of harshness.

There is a world of difference between such amps.

You get 50 watters for 20k and also for 300k.

 

[avidyarthy]

Budget permitting ........ you can also consider a Krell S 300i integrated amp.

 

[reignofchaos]

Completely agree with you but it all depends on the design of the amp

There are 50 watt amps which start sounding harsh and losing composure when pushed beyond 40 percent of its max volume.

Then there are 50 watters which can be pushed to the absolute maximum without even a hint of harshness.

There is a world of difference between such amps.

You get 50 watters for 20k and also for 300k.

So very true - you can get a 50W Einstein and a 50W Nad which are obviously not comparable. The former probably has more available dynamic power than the top of the line 200 odd watt nad.

 

[jaudere]

The thread is educating me about the names which had not heard before.
Has anyone heard an indian company called 'nine'. It is from pune. They claim to produce amp producing completely flat response.
The cost of a 35w amp was quoted around 25k to me. Now that is a huge cost for unknown brand. They told me that they are more into custom installations.