[Voley]

   
Great post. It is a genuine question because the ability/quality of pre-amplifiers to drive a power amplifier varies greatly and people are willing to pay a lot for one that is better than another. I am genuinely interested in the experiences of people who pair the Cavalli with a Mojo and use the combination as a pre-amplifier.
 
At the end of the day, whatever your philosophy is, the sound you like is a personal preference. That is one of the tough parts of this hobby. You can read as many reviews of a component as you like. You can however never really tell how much you are going to like it until you actually give it a listen.
 
With respect to driving headphones, that has already been covered, don't you think? I wonder how loud your headphones would be with 4 Watts? What headphones are you using?
 
My speakers have a 175 Watt power handling but I am using a 25 Watt amplifier to drive them. Why? Because I love the sound.

Ah - apologies! I've never used the Cavalli as a pre-amp, so can't be a lot of help there, but I know it sounds great with my headphones and a Mojo (as you say, a personal preference - I like warm sound signatures and strong bass / mids). I have the LCD-2s, and yes we've covered driving headphones and volume, but I admit I'm still puzzled. I've spent quite a while in the last week or so trying to get to the bottom of how/why/if different headphones need to be matched to different power outputs of amplifiers. I haven't found a definitive answer - which surprises me (I'm a professional research scientist, and am used to being able to find the answers to what should be pretty simple questions like "does an amplifier's power have any benefit beyond just providing more volume to headphones"). From the fragmented bits I've uncovered on various forums the answer to my question is probably "yes" - my understanding is that power to provide an average volume is one thing, but amplifiers also need headroom to meet surges in headphones' demands when the music spikes, even for a few milliseconds...and if they can't then this has perceptible consequences. So that might explain why I hear a bigger soundstage with the LC. Or it could easily be a placebo / simply what I want to hear having shelled out for an amp . As I say if there's a definitive article on this I'm yet to find it.
 
And in general I'm rapidly concluding that this hobby is in desperate need of a lot more properly controlled testing of gear and preferences to separate the snake oil from the facts. It would be pretty hard to argue with a randomised blind trial of people's preferences for DACs, for example - imagine we took 500 audiophiles and played a variety of music, blind, through 20 leading DACs to see if a) they could reliably, and repeatably hear any difference between different DACs and b) if there were any consensus on preference. That would help consumers but upset the manufacturers, I suspect...
 
But yes, I agree entirely: it all comes down to personal preference, and I've found a combination I love at the moment!  Phew...sorry that turned into an essay.

 

[felix3650]

In audio applications an amp has two main purpouses: adding the power to drive (be it voltage swing or current) and the ability to control the driver (of speakers and/or headphones). I own a Mojo and I'm driving a ZMF Eikon out of it right now (my LC is out for repair). It sounds very good but it feels a bit lacking. Mojo's output stage is a simple I2V converter and doesn't provide the voltage swing the LC outputs in balanced mode. Plus driver efficiency refers to the power required to reach a certain loudness, but it's not an indication of how good that loudness is interpreted by the brain. Hugo's power output is higher than Mojo's and that's why it sounds more expansive and more "airy". Another example, a Dave would not benefit much from a LC or another amp (except for a very linear one) as its output stage is sufficient and very well designed. And we know how a Dave is regarded sound-wise

 

[x RELIC x]

In audio applications an amp has two main purpouses: adding the power to drive (be it voltage swing or current) and the ability to control the driver (of speakers and/or headphones). I own a Mojo and I'm driving a ZMF Eikon out of it right now (my LC is out for repair). It sounds very good but it feels a bit lacking. Mojo's output stage is a simple I2V converter and doesn't provide the voltage swing the LC outputs in balanced mode. Plus driver efficiency refers to the power required to reach a certain loudness, but it's not an indication of how good that loudness is interpreted by the brain. Hugo's power output is higher than Mojo's and that's why it sounds more expansive and more "airy". Another example, a Dave would not benefit much from a LC or another amp (except for a very linear one) as its output stage is sufficient and very well designed. And we know how a Dave is regarded sound-wise

No.

Hugo and Mojo share the exact same power output, both are classA, both have a Current delivery of 500mA, and both have an output impedance of 0.075 Ohms, but the Mojo's THD performance is better than the Hugo. The Hugo TT has largely the same power specs but with higher Current bias for the TT. Rob has confirmed this many times. The differences are down to the WTA filter and tuning of the Mojo vs the Hugo (again, confirmed by Rob Watts). There's' a lot of misinformation being spread around on this thread, including perpetuating myths about max power requirements.

I have the Mojo and used to own the Liquid Carbon(1.0). I found the differences down to the tuning and sound signature of the Liquid Carbon vs the Mojo at all volumes, but both have great quality. The Liquid Carbon has a wider soundstage with more warmth but less depth, the Mojo is a little cleaner with better depth and transients to my ears. Both can drive my LCD-2.2, ETHER Flow and Utopia very well IMO.

Quite simply, loudness=power. Preference and quality=tuning and implementation. I'd say distortion, impedance, crosstalk, channel separation, slew rate, etc., have more of an impact than max power if you aren't overdriving the gear. The 'control' of the headphone has a lot more to do with the gear's implementation than just the power specs, as your false comment about Hugo1 and Mojo's output power highlight. I've heard powerful amps sound terrible and low powered amps sound sublime. Power is not the only yardstick.

I now own the DAVE and Liquid Gold. The Liquid Gold, with 9x the power output, is not better than directly out of the DAVE. The Liquid Gold is a good amp with a sweet sound but the excess of power doesn't make it better.

 

[Voley]

Ah - thanks both for your thoughts. So to conclude there IS no benefit to power beyond just providing enough volume if I've understood correctly? I'm glad to have this cleared up - somewhere, as I say, there should be a definitive explanation for us lay people (=noobs in my case). And so the wider soundstage on the LC (which as far as I can tell isn't a placebo - it really sounds wider) is unlikely to be anything to do with increased power, as opposed to different implementation of that power resulting in different degrees of channel separation, crosstalk etc?

 

[x RELIC x]

Ah - thanks both for your thoughts. So to conclude there IS no benefit to power beyond just providing enough volume if I've understood correctly? I'm glad to have this cleared up - somewhere, as I say, there should be a definitive explanation for us lay people (=noobs in my case). And so the wider soundstage on the LC (which as far as I can tell isn't a placebo - it really sounds wider) is unlikely to be anything to do with increased power, as opposed to different implementation of that power resulting in different degrees of channel separation, crosstalk etc?

Yes, more or less. Keep in mind that quality of power is very important. Also enough Voltage and Current varies from amp to amp so it's not as easy as just saying power. Headphone requirements differ as well so, generally, while planar magnetics will benefit from more Current than a dynamic driver, a dynamic driver with high impedance will better utilize more Voltage. That's where design comes in, and enough is not as simple as enough.

The amp designer needs to find the balance between power output, noise, tuning, etc.. It's not as simple as power=quality and more does not always mean better is the point being made. As an example, not enough power seems to collapse soundstage, but so does impedance mismatches in certain cases. It's complex and more to do with design than just raw juice, after a certain point.

 

[felix3650]

No.

Hugo and Mojo share the exact same power output, both are classA, both have a Current delivery of 500mA, and both have an output impedance of 0.075 Ohms, but the Mojo's THD performance is better than the Hugo. The Hugo TT has largely the same power specs but with higher Current bias for the TT. Rob has confirmed this many times. The differences are down to the WTA filter and tuning of the Mojo vs the Hugo (again, confirmed by Rob Watts). There's' a lot of misinformation being spread around on this thread, including perpetuating myths about max power requirements.

I have the Mojo and used to own the Liquid Carbon(1.0). I found the differences down to the tuning and sound signature of the Liquid Carbon vs the Mojo at all volumes, but both have great quality. The Liquid Carbon has a wider soundstage with more warmth but less depth, the Mojo is a little cleaner with better depth and transients to my ears. Both can drive my LCD-2.2, ETHER Flow and Utopia very well IMO.

Quite simply, loudness=power. Preference and quality=tuning and implementation. I'd say distortion, impedance, crosstalk, channel separation, slew rate, etc., have more of an impact than max power if you aren't overdriving the gear. The 'control' of the headphone has a lot more to do with the gear's implementation than just the power specs, as your false comment about Hugo1 and Mojo's output power highlight. I've heard powerful amps sound terrible and low powered amps sound sublime. Power is not the only yardstick.

I now own the DAVE and Liquid Gold. The Liquid Gold, with 9x the power output, is not better than directly out of the DAVE. The Liquid Gold is a good amp with a sweet sound but the excess of power doesn't make it better.

OK. I stand corrected on the Mojo & Hugo output stage. I'm not as informed as you regarding that (didn't bother to read through those threads till the end). I thought Mojo/Hugo did use different power (thus voltage) output. No need to say that I'm spreading false information...it's just one post and you cleared that one for me. I know you guys love Chord's product (and I do too otherwise I wouldn't have bought the Mojo) but no need to stress so much about it

If it's down to power=loudness then why build an amp at all when a DAC can simply sound loud enough. Let's edit the files and increase their volume on the PC side and make them louder. It won't increase Mojo's output power. A sound wave has an energy that varies over time. The control it's got to do more about adapting to the energy required by the loudspeaker to reproduce that sound, when you can provide the right amount at the right time it will be percieved as sounding "right". I know those amp specs define in part an amp's signal output, but power plays a very important role. It's the power the main objective of the amp. Crosstalk, intermodulation, internal heat, efficiency are all unwanted effects (distortions) which differ from amp to amp and some manufacturers use them to create harmonic distrotions that affect the sound in a different way. I'll make an analogy, GPUs. An integrated vs a dedicated card. Both output pixels but some complex scenes require more processing power that an integrated one can't provide. And what do they differ basically? Power draw. An amp is basically the same, on complex music parts it can provide more energy. Both the Mojo and LC can drive your headphones but if the music requires a certain amount of energy, who can provide it more easily? I can also add that voltage controls how much a speaker can displace from its quiet state and current with what intensity (acceleration).

I didn't state that power is the ONLY factor. Otherwise I would have said "Hugo's power output is higher than Mojo's and that's the only reason why it sounds more expansive and more "airy". Maybe I should have added that "from what I know..."

Also some headphones behave better when driven with a higher current/voltage (consequently a higher power offered by the output stage of the driver).

And I said the same: the Dave has a sufficient output drive that amping is mostly not required except for innefficient headphones like the HE6, in which case an amp (and a very linear one) would work better.

My thoughts

 

[x RELIC x]

OK mister. I stand corrected on the Mojo & Hugo output stage. I'm not as informed as you regarding that (didn't bother to read through those threads till the end). I thought Mojo/Hugo did use different power (thus voltage) output. No need to say that I'm spreading false information...it's just one post and you cleared that one for me. I know you guys love Chord's product (and I do too otherwise I wouldn't have bought the Mojo) but no need to stress so much about it

If it's down to power=loudness then why build an amp at all when a DAC can simply sound loud enough. Let's edit the files and increase their volume on the PC side and make them louder. It won't increase Mojo's output power. A sound wave has an energy that varies over time. The control it's got to do more about adapting to the energy required by the loudspeaker to reproduce that sound, when you can provide the right amount at the right time it will be percieved as sounding "right". I know those amp specs define in part an amp's signal output, but power plays a very important role. It's the power the main objective of the amp. Crosstalk, intermodulation, internal heat, efficiency are all unwanted effects (distortions) which differ from amp to amp and some manufacturers use them to create harmonic distrotions that affect the sound in a different way. I'll make an analogy, GPUs. An integrated vs a dedicated card. Both output pixels but some complex scenes require more processing power that an integrated one can't provide. And what do they differ basically? Power draw. An amp is basically the same, on complex music parts it can provide more energy. Both the Mojo and LC can drive your headphones but if the music requires a certain amount of energy, who can provide it more easily? I can also add that voltage controls how much a speaker can displace from its quiet state and current with what intensity (acceleration).

I didn't state that power is the ONLY factor. Otherwise I would have said "Hugo's power output is higher than Mojo's and that's the only reason why it sounds more expansive and more "airy". Maybe I should have added that "from what I know..."

Also some headphones behave better when driven with a higher current/voltage (consequently a higher power offered by the output stage of the driver).

And I said the same: the Dave has a sufficient output drive that amping is mostly not required except for innefficient headphones like the HE6, in which case an amp (and a very linear one) would work better.

My thoughts

Lol, no stress about Chord products, and I could care less if anyone else likes them or not. I was just clearing up something that, unchecked, usually turns in to myths and falsehoods that become perpetuated. It was just your comment that more power is why the Hugo was more expansive and 'airy' that triggered my response. If it was any other gear I was knowledgable about I would have done the same thing.

Most DACs have a very high output impedance to match the high impedance of an amps input so most DACs would be terrible for directly driving headphones (typically very little Current output as well). Increasing the loudness in the digital domain of the files would result in clipping so that's also a terrible idea. Obviously you are just making a point and in the end I feel we are really saying the same thing. What I am stressing is that if there is enough power then other factors have MUCH more influence on the quality of the output.

I've been reading a lot lately on Head Fi about just power, power, power. One poster in the Elear thread said his amp's 18W of power made all the difference in quality. Rubbish, it was the amp's design that made the difference because the headphone's only received a tiny fraction of that power at reasonable SPL. My assertion is that if there is ENOUGH power to cover the needs of the headphone to reach one's desired listening level and to cover the dynamics in the track (usually under 3/4 max volume for safety) then the rest of the quality is down to implementation. Most headphone gear meets that requirement already and many would be surprised how much 'enough' power is actually needed.

Look at the Woo WA8 (350mW max@45 Ohm) and ALO CDM (125mW@32 Ohm balanced). There are many reports that they both can drive full sized cans like the he1000 very well, yet they have much lower power output than something like the Liquid Carbon, and less than the Mojo/Hugo. It's frustrating to read that better quality automatically means that the gear is more powerful. It simply isn't a given. So, while I quoted you specifically for the info between the Mojo and Hugo1, the rest was basically a rant on what I've generally been reading as misconceptions in many threads.

 

[felix3650]

Lol, no stress about Chord products, and I could care less if anyone else likes them or not. I was just clearing up something that unchecked usually turns in to myths and falsehoods that become perpetuated. It was just your comment that more power is why the Hugo was more expansive and 'airy' that triggered my response. If it was any other gear I was knowledgable about I would have done the same thing.

Most DACs have a very high output impedance to match the high impedance of an amps input so most DACs would be terrible for directly driving headphones (typically very little Current output as well). Increasing the loudness in the digital domain of the files would result in clipping so that's also a terrible idea. Obviously you are just making a point and in the end I feel we are really saying the same thing. What I am stressing is that if there is enough power then other factors have MUCH more influence on the quality of the output.

Lol yes. You are saying that when power requirements are covered an amp's distortion reshapes its sound. I'm saying that if power is not enough sound won't be perceived the same as in your case. Basically it's the same thing from 2 points of view. In the way that I expressed myself it would seem like power is the only factor (I'm italian and sometimes I tend to think in italian and write in english so it causes a bit of confusion lol). I apologise for that.

My mistake was assuming Hugo & Mojo's power output difference with the ability of Hugo to provide better when needed (and be perceived as better by the brain). Mojo has a Xilinx Spartan 7 and I thought Hugo too, and the main difference between them was the output stage and extra features of Hugo (not considering different firmware). Corrected!

I've been reading a lot lately on Head Fi about just power, power, power. One poster in the Elear thread said his amp's 18W of power made all the difference in quality. Rubbish, it was the amp's design that made the difference because the headphone's only received a tiny fraction of that power at reasonable SPL. My assertion is that if there is ENOUGH power to cover the needs of the headphone to reach one's desired listening level and to cover the dynamics in the track (usually under 3/4 max volume for safety) then the rest of the quality is down to implementation. Most headphone gear meets that requirement already and many would be surprised how much 'enough' power is actually needed.

18W would blast the heck out of your ears, if the driver's coil doesn't melt or becomes loose. 18W means, if the driver needs it it's there to tap to but not that it gets fed ENTIRELY all the time. Why add volume knobs then? lol

Look at the Woo WA8 (350mW max@45 Ohm) and ALO CDM (125mW@32 Ohm balanced). There are many reports that they both can drive full sized cans like the he1000 very well, yet they have much lower power output than something like the Liquid Carbon, and less than the Mojo/Hugo. It's frustrating to read that better quality automatically means that the gear is more powerful. It simply isn't a given. So, while I quoted you specifically for the info between the Mojo and Hugo1, the rest was basically a rant on what I've generally been reading as misconceptions in many threads.

I moved from Mojo to Mojo + SR-71B to finally Mojo + LC to tweak the sound and make it more pleasing to my specific taste. I'm well aware of that. Mojo is driving alone my Eikons right now and it sound very good. I definitely expressed myself badly

 

[x RELIC x]

No worries Felix. I was just making sure that there was no confusion in the end. Not trying to be a prat about your post specifically and I apologize for dragging your post in to my rant.

Spoiler: Last OT comment about the Hugo/Mojo

Funny thing about the Mojo and Hugo is that the analogue stage is almost identical (a difference of 3 large transistors in Hugo vs 6 small transistors in Mojo but with the same performance) and it's the FPGA / WTA filter and Pulse Array DAC where the fundamental differences are. Hugo's FPGA is the Spartan 7, Mojo's FPGA is the Artix7 75T

 

[Voley]

Guys, I really appreciate all this info. As ever it seems to be more complex than I'd first thought, but what you say makes a lot of sense to me, in the context of my (limited) experiences. I feel like I'm a LOT better informed now, which I guess is the point of these threads. Thanks for taking the time!

 

[Hooster]

I think we would be better off if people only wrote long posts about things that they actually know about. Thanks for the effort though.

 

[Voley]

I agree - but there's a difference between writing a post giving a subjective impression of sound with certain gear (which everyone is entitled to do, being as qualified as they need to be - ie having ears and a preference), and long explainers based on an incomplete grasp of the facts (which I agree aren't helpful unless the writer is honest about their lack of knowledge and uses it to ask for more info).

 

[bronzboy]

I'm listening to the new TajMo album with my Elears through the LC2. The LC2 is broken in and sounds high and tight and I love the sound.

 

[thecrow]

Not wanting to go too OT i have been enjoying reading this page can someone answer me a dew naive questions about power/current

When i see something like as mentioned above for the alo cdm 125mw@32 ohm does that mean that that is the (maximum) amount of current/power transferred when the volume is at maximum (with a 32 ohm hp)? And gain has nothing to do with that?

How does gain affect total max power or does it not at all? Thats just getting to the maximum quicker on a higher gain?

TIA

 

[Hooster]

When i see something like as mentioned above for the alo cdm 125mw@32 ohm does that mean that that is the (maximum) amount of current/power transferred when the volume is at maximum (with a 32 ohm hp)? And gain has nothing to do with that?

How does gain affect total max power or does it not at all? Thats just getting to the maximum quicker on a higher gain?
TIA

Max power is simply the amount of power that the device can produce at a given level of distortion (it does not seem like alo has seen it fit to publish that). You can probably get more power out of it, but it will most likely sound scratchy/distorted. It has nothing to do with volume at max or gain. Gain has no effect on the total power. The max power of an amplifier depends on the power supply and the output stage.