Roksan Kandy BT , Rotel RA 1570 or other?

[davedotco]

They go down to 3ohms. I wouldn't even think about integrated for these.

Really...... :doh:

Assuming you are right, nasty.

Who on earth thought that a good idea for modestly priced speakers?

It is not that they are trading ease of drive for size etc, these are full size speakers, no excuse really.

 

[Vladimir]

Sensitivity: 88dB

Nominal impedance: 8ohms (3ohms minimum)

Recommended amplifier power: 30W - 150W into 8Ω on unclipped programme

http://www.bowers-wilkins.com/Downloads/Product/InfoSheet/ENG_FP300741_CM8_info_sheet.pdf

In 3 ohms the amplifier may need to deliver bursts of 450W RMS per channel continuous unclipped 20Hz-20kHz, less than 0.1% THD.

And when a manufacturer says its 3 ohms minimum, be prepared to deliver power for 2 ohms.

Here is an unlucky chap that bought Cyrus 8vs for his CM8 and got stuck with the lack of power and drive.

http://www.canuckaudiomart.com/forum/viewtopic.php?t=22317

 

[davedotco]

Sensitivity: 88dB

Nominal impedance: 8ohms (3ohms minimum)

Recommended amplifier power: 30W - 150W into 8Ω on unclipped programme

http://www.bowers-wilkins.com/Downloads/Product/InfoSheet/ENG_FP300741_CM8_info_sheet.pdf

In 3 ohms the amplifier may need to deliver bursts of 450W RMS per channel continuous unclipped 20Hz-20kHz, less than 0.1% THD.

And when a manufacturer says its 3 ohms minimum, be prepared to deliver power for 2 ohms.

Ridiculous spec for a £1200 full size floorstander.

Not a B&W fan, this does not help.

 

[Esra]

I read sometime xxx speaker will drop to xxx ohm at xxx Hz so an xxx ohm amp would suit best.What does that mean,since i can´t see in the specs x amp is 4,6,8,ohm?!Some orientation needed here.

 

[Vladimir]

Again, the specs are there for everyone to read. However, we keep playing Hi-Fi astrology based on echoic memory (scientifically proven to be less than 4 seconds long).

Will the Creek run the B&Ws? Yes. Will they clipp? Yes. Will you notice? Maybe not, considering if your room acoustics boom anyway.

 

[hifikrazy]

And yes, all solid state amps of decent quality sound the same when level matched in double blind test. The sound quality differences are imaginary due to differences in loudness and FR.

Seriously?! If that's the case you shouldn't be saying that Marantz sounds boring and sweet in comparison to your Roksan in the other thread. Both should sound the same, and your opinion of the Marantz's sweetness must be purely imaginary.

Questions regarding which amp to choose would become much simpler to answer..."It doesn't matter because they're all the same. "

 

[Vladimir]

I read sometime xxx speaker will drop to xxx ohm at xxx Hz so an xxx ohm amp would suit best.What does that mean,since i can´t see in the specs x amp is 4,6,8,ohm?!Some orientation needed here.

When a speaker drops impedance (resistance) it gets closer to a short circuit. 0 ohms impedance is like when you connect the speaker terminals on your amp together. It will either shut down, explode or just arc like a welder if its something monsterous like a Krell.

Each time speaker drops impedance an amplifier needs to deliver more voltage and current. The Creek Evo 50a delivers 85 Watts into 4 Ohms. It is a small amp for running easy florostanders and grumpy insensitive bookeshelf speakers. Not quite the CM8 territory.

Krell s300i

Output voltage: Peak to peak 138 V

Output power: 8 Ohms 150 W, 4 Ohms 300 W

Transformer: 750 VA

Power consumption: max 1800W

Weight: 19.1kg

There is an amp for every speaker out there.

 

[Vladimir]

And yes, all solid state amps of decent quality sound the same when level matched in double blind test. The sound quality differences are imaginary due to differences in loudness and FR.

Seriously?! If that's the case you shouldn't be saying that Marantz sounds boring and sweet in comparison to your Roksan in the other thread. Both should sound the same, and your opinion of the Marantz's sweetness must be purely imaginary.

Questions regarding which amp to choose would become much simpler to answer..."It doesn't matter because they're all the same. "

Those are not actual qualitative differences but subjective impressions from differences in loudness and frequency response. Quality is more in the spectrum of low distortion, clean output without clipping etc.

If one amp has brighter sound and another has warmer sound, neither is better based on that. If one is louder earlier on the volume knob than the other, it is not better, just louder sooner on the knob.

 

[hifikrazy]

And yes, all solid state amps of decent quality sound the same when level matched in double blind test. The sound quality differences are imaginary due to differences in loudness and FR.

Seriously?! If that's the case you shouldn't be saying that Marantz sounds boring and sweet in comparison to your Roksan in the other thread. Both should sound the same, and your opinion of the Marantz's sweetness must be purely imaginary.

Questions regarding which amp to choose would become much simpler to answer..."It doesn't matter because they're all the same. "

Those are not actual qualitative differences but subjective impressions from differences in loudness and frequency response. Quality is more in the spectrum of low distortion, clean output without clipping etc.

If one amp has brighter sound and another has warmer sound, neither is better based on that. If one is louder earlier on the volume knob than the other, it is not better, just louder sooner on the knob.

But when you say all solid state amps of decent quality sound the same, then one amp should not have brighter sound and another has warmer sound. They should sound exactly the same as long as their levels are matched. I believe that's what's meant by "sound the same".

 

[Vladimir]

But when you say all solid state amps of decent quality sound the same, then one amp should not have brighter sound and another has warmer sound. They should sound exactly the same as long as their levels are matched. I believe that's what's meant by "sound the same".

That is my mistake, I worded it badly. I meant when you level match amps you eliminate the loudness bit that gets mistaken for resolution, punch, PRaT etc. and only thing left is just FR variation, brighter, warmer etc. Ideally there shouldn't be any coloration but people like their flavors, I know I do.

 

[hifikrazy]

That is my mistake, I worded it badly. I meant when you level match amps you eliminate the loudness bit that gets mistaken for resolution, punch, PRaT etc. and only thing left is just FR variation, brighter, warmer etc. Ideally there shouldn't be any coloration but people like their flavors, I know I do.

OK, I get what you mean now. :cheers:

Yea, I for one don't think the best measuring amplifier with the lowest distortion readings is necessarily the best sounding one, although "best sounding" is very much subjective. It's true that we like our colouration, otherwise valve amps and turntables will have no place in hifi.

But I wouldn't get caught up with the measurements either, otherwise this with a THD of <0.1% (20Hz to 20kHz)...

will sound worse than this with a THD of <0.01%...

 

[Cynic-al]

Creek 50a and Exposure 2010 for B&W CM8? Are you joking Dave? These are flea amps for those speakers. They are superior in absolutely nothing. The speakers will be underpowered and uncontrolled. The CM8's want monoblock power, even the Rotel and Roksan integrateds are compromises.

I've got a budget of £1300 for amp and DAC together, surely there must be an amp in this price bracket that can drive these speakers with conviction.

I can't imagine anyone driving the CM8's off a pair of monoblocks!

I'm going to compare the Roksan and Rotel in the coming week and report back.

 

[Vladimir]

THD bellow 1% is really difficult to hear so both amps are good from that perspective.

Where we hear the differences is the FR as it changes depending on how the amp and speakers react to eachother while playing music. Specs are all manipulated by manufacturers and are mostly some tone bursts in easy 1kHz loads. They are basic guides but they don't even scratch the surface of what goes on when you play music with different amps and speakers. Specs used to be a buyers aid to help with system matching but during 80's specs wars they became just marketing borchures with brag numbers. But this doesn't mean we should ignore specs for system matching, but learn to filter the rubbish.

The D'Agostino amp looks alien submarine technology for interdimensional travel, but under the shell its still just an SS amp very similar to the CA. They both make small signal into big signal. However, they are similar like Citroen Saxo is a car and Ferrari F1 is a car.

It all depends on the speakers they are driving. Use both amps with a pair of cheap Sony bookshelf speakers and you will not apreciate the differences between the amps. Plug them in a pair of Focal Utopia's and you will hear the difference. While the CA will do an impressionist painting of the small signal fed into it, suffocating while trying to push the huge Utopia's, the D'Agostino will paint a stunning camera obscura like Caravaggio and frame it.

 

[Esra]

:doh: :rofl:

btw. thanks for explanation but how do you know what ohm a amp is?

 

[Vladimir]

Creek 50a and Exposure 2010 for B&W CM8? Are you joking Dave? These are flea amps for those speakers. They are superior in absolutely nothing. The speakers will be underpowered and uncontrolled. The CM8's want monoblock power, even the Rotel and Roksan integrateds are compromises.

I've got a budget of £1300 for amp and DAC together, surely there must be an amp in this price bracket that can drive these speakers with conviction.

I can't imagine anyone driving the CM8's off a pair of monoblocks!

I'm going to compare the Roksan and Rotel in the coming week and report back.

That's what sucks with speakers like B&W CM8 or Linn Isobariks. You will spend way more for amplification than for the actual speakers. This is why some people just praise easy to run efficient speakers (90dB above and nominal 8 ohms).

 

[BigH]

Creek 50a and Exposure 2010 for B&W CM8? Are you joking Dave? These are flea amps for those speakers. They are superior in absolutely nothing. The speakers will be underpowered and uncontrolled. The CM8's want monoblock power, even the Rotel and Roksan integrateds are compromises.

I've got a budget of £1300 for amp and DAC together, surely there must be an amp in this price bracket that can drive these speakers with conviction.

I can't imagine anyone driving the CM8's off a pair of monoblocks!

I'm going to compare the Roksan and Rotel in the coming week and report back.

That's what sucks with speakers like B&W CM8 or Linn Isobariks. You will spend way more for amplification than for the actual speakers. This is why some people just praise easy to run efficient speakers (90dB above and nominal 8 ohms).

But most standmounts are less than 90db at 8 ohms.

 

[Robdespy]

Hi, actually my first post here and I'm no expert but I'm running cm8s of the rotel and to me it sounds great. Music taste isn't hugely dissimilar from the kind of bands you've mentioned and everything sounds great to me!

 

[Vladimir]

But most standmounts are less than 90db at 8 ohms.

1) Compact size

2) Large dynamic output

3) Easy to drive

Pick only two.

 

[BigH]

But most standmounts are less than 90db at 8 ohms.

1) Compact size

2) Large dynamic output

3) Easy to drive

Pick only two.

What?

 

[Cynic-al]

Hi, actually my first post here and I'm no expert but I'm running cm8s of the rotel and to me it sounds great. Music taste isn't hugely dissimilar from the kind of bands you've mentioned and everything sounds great to me!

Thanks Robdespy, did you compare the Rotel with anything else?

 

[Robdespy]

Naim (I forget which one) and the older roksan kandy that didn't have a dac. Rotel clinched it for me due to the included dac (not relevant to your decision) and how close it seemed to sound to monitor mixes when you're listening to tracks back in a studio. I did also try a cheaper rotel, ra12 perhaps? That didn't sound as good, presumably because that really was underpowered.

 

[Vladimir]

But most standmounts are less than 90db at 8 ohms.

1) Compact size

2) Large dynamic output

3) Easy to drive

Pick only two.

What?

Hoffman's Iron Law

or 'You Can't Have Your Cake and Eat it Too'

http://sites.psu.edu/speakerdesign/2013/01/24/hoffmans-iron-laws-of-speaker-building/

You can never have all three at the same time: speakers that have large output with thunderous bass, compact size and easy to drive. If the speakers are compact like the CM8 and have large output and dynamics, they will be difficult to drive. If you want large output and easy load, then clear some furtniture because you will need huge boxes.

A speaker designer is always faced with this law at his desk. If he solves the size and the output, he has to push the problem with the difficult load to the amplifier designer. Bass sucks 90% of the power delivered by the amplifier.

If you live in a small living room with not much space for large speaker, you will naturally go for compact size. If you want loud music with speakers maintaining their composure, you will have to get ready to buy more capable amp. If you don't care for loud output, you can go for more lightweight speakers easy to drive but don't shake the room.

Something like that.

 

[Cynic-al]

Naim (I forget which one) and the older roksan kandy that didn't have a dac. Rotel clinched it for me due to the included dac (not relevant to your decision) and how close it seemed to sound to monitor mixes when you're listening to tracks back in a studio. I did also try a cheaper rotel, ra12 perhaps? That didn't sound as good, presumably because that really was underpowered.

Thanks for expanding. Actually having the DAC built in is a big deal for me. I think more manufacturers should follow suit,look how popular the new NAD D amps have become on these pages. It sounds like this Rotel has plenty of clarity then, I'm looking forward to hearing it.

 

[Reijer]

Maybe you can check out NAD C375BEE with optional MDC DAC ( http://nadelectronics.com/products/hifi-amplifiers/C-375BEE-DAC-Stereo-Integrated-Amplifier ).

NAD is great. 2 x 150 watt continuous power per channel at 8 ohm. See the specs for yourself.

I borrow a 30 year old NAD 3020 with 2 x 20 watt continue for mij 685 s2. Powerfull enough. Maybe I buy his little brother for myself, the C356BEE but I don't know that for sure yet.

 

[BigH]

Naim (I forget which one) and the older roksan kandy that didn't have a dac. Rotel clinched it for me due to the included dac (not relevant to your decision) and how close it seemed to sound to monitor mixes when you're listening to tracks back in a studio. I did also try a cheaper rotel, ra12 perhaps? That didn't sound as good, presumably because that really was underpowered.

Thanks for expanding. Actually having the DAC built in is a big deal for me. I think more manufacturers should follow suit,look how popular the new NAD D amps have become on these pages. It sounds like this Rotel has plenty of clarity then, I'm looking forward to hearing it.

Why buy an amp with a Dac if you already have one or don't need one, thats just wasting money. sounds like the NAD dac is not much cop anyway.