[commtrd]

The LCD4 doesn't need that much power in my experience, more to do with synergy. In fact, of more than about 10 amplifiers I have tried with the LCD4, the one that sounded best to me (other than the Egoista 845) was one of the least powerful ones of the lot. The closest specs I can find are at 300ohms where the CMA800R is rated at only 180mW, the GSXmk2 for comparison is rated at 1W at 300ohms (the watts will be a bit higher for 200ohms). Using my balanced DAC, volume is between 12 to 1 o'clock so not even close to using max power (single ended it is at 2 o'clock, pot goes to 5 o'clock). I like to listen fairly loud too.

Some great points made. Probably most peeps do not listen to their stuff at ear-bleed levels most of the time (hope not for preserving hearing safety) so max power discussions should necessarily include synergy and SQ considerations as being at least equal to if not more important than the raw horsepower available. Also differentiation between balanced and single-ended outputs and net effect on SQ etc. For example my setup in use currently is single ended thru and on the lower end for available power so that was the reason I decided to go with the 4z instead. So I really don't know if the chain could have adequately driven the LCD4. Someday do intend to build out a much more substantial system, but even so I suspect that the chain of components I have is providing fairly good mid to upper tier performance, well within the range of generally highly-regarded systems which are still affordable.

I know from spending tens of thousands of hours listening to headphones over several years that what I am hearing is really special and at the end of the day that's what really matters anyway. Having the flexibility to go with the i4 when I do not want the full headphones on, and then going with 4z when I really want to get into some serious listening BUT having either option still in the range of absolutely sterling performance is worth a lot too. On the other hand, there is still that ever-present desire to experience the absolute best SQ we can which inevitably leads to a battered and bruised wallet. BUT so worth it...

 

[mlxx]

The CMA800R is a monoblock amp with a stereo mode. I only have one amp so it is always single ended. Just to be clear, I meant a balanced DAC input so 4V and single ended DAC input so 2V, into the one amp using the same DAC, the CAS192D. I did try both monoblocks but couldn't reliably hear that much difference to justify the cost. With 2 monoblocks, that is four times the power of one. However, adding the Questyle preamp to control the monoblocks volume (ie. the full gold stack) did clearly improve things maybe another 5%. So again more to do with synergy than power.

I found the LCD4 to be picky, it sounded different with everything I tried. Nothing was actually bad sounding except the Mojo put everything in my face which I didn't like. It is hard to know if something will be a special pairing with the LCD4, the LCD3 was a lot easier, mostly all sounded similar.

 

[MacedonianHero]

The LCD4 doesn't need that much power in my experience, more to do with synergy. In fact, of more than about 10 amplifiers I have tried with the LCD4, the one that sounded best to me (other than the Egoista 845) was one of the least powerful ones of the lot. The closest specs I can find are at 300ohms where the CMA800R is rated at only 180mW, the GSXmk2 for comparison is rated at 1W at 300ohms (the watts will be a bit higher for 200ohms). Using my balanced DAC, volume is between 12 to 1 o'clock so not even close to using max power (single ended it is at 2 o'clock, pot goes to 5 o'clock). I like to listen fairly loud too.

I find the differences quite profound especially with the DAVE as the source and high rez music. The added power help the LCD-4s come alive. Definitely worth the extra power in my experiences.

 

[silversurfer616]

Totally agree with the synergy comment. Went through a lot of amplifiers and 'more' is not always better. Furthermore I came to realise that the quality of the source/dac is probably the most important part of a system.
This is mainly the reason why we hear negative comments about TOTL headphones...they are just not 'fed right'.

 

[mlxx]

I find the differences quite profound especially with the DAVE as the source and high rez music. The added power help the LCD-4s come alive. Definitely worth the extra power in my experiences.

No doubt it needs adequate power but... "when properly driven...more than say 3W amp into the LCD-4"... not too many headphone amps can even get close to that. The GSXmk2 certainly can't, I know you like that as one of the best. I think that the actual power needed is closer to 0.5w but it doesn't hurt to have extra power up your sleeve I guess. Certainly a great source is mandatory at this level. BTW, the 4z is only 1db more efficient than the 4, but its 15ohms is more amp friendly, where most amps make most of their power.

 

[commtrd]

Can someone relate "efficiency" to input impedance of a load? If the LCD4 has input impedance of 200 ohms, but equal efficiency as the LCD4z which has input impedance of 15 ohms, how does that work? Within the bounds of ohms law...

 

[x RELIC x]

the 4z is only 1db more efficient than the 4, but its 15ohms is more amp friendly, where most amps make most of their power.

It’s interesting that Audeze lists the LCD-4z at 98dB/1mW and 116dB/1V sensitivity, but for the LCD-4 it lists 97dB/1mw and 95dB/1V... which doesn’t add up for the LCD-4. The LCD-4z seems accurate (well, close enough) but the LCD-4 seems to be quite off. I’ve commented to the rep from Audeze on the 4z thread before regarding the SPL/mW vs SPL/V rating discrepancy on their website and they’ve changed it accordingly. I just wonder why the discrepancy for the LCD-4 as well. Another reason why I don’t trust marketing regarding power requirements.

 

[x RELIC x]

Can someone relate "efficiency" to input impedance of a load? If the LCD4 has input impedance of 200 ohms, but equal efficiency as the LCD4z which has input impedance of 15 ohms, how does that work? Within the bounds of ohms law...

Current vs Voltage. Lower impedance (resistance) draws more Current. Higher impedance (resistance) needs more Voltage.

 

[seamon]

Can someone relate "efficiency" to input impedance of a load? If the LCD4 has input impedance of 200 ohms, but equal efficiency as the LCD4z which has input impedance of 15 ohms, how does that work? Within the bounds of ohms law...

Headphone Efficiency is measured in dB/mW. For eg. LCD 4 efficiency is 97 dB/mW. Decibels is a logarithmic scale so 107dB is 10 times louder than 97dB. So, it would take 10 times the amount of power(10mW) to reach 107dB on the LCD 4.

Since the LCD 4 has an impedance of 200 Ohm, an amplifier driving the LCD 4 must be capable of providing 10mW at 200 Ohms to get to 107dB.
Now, the LCD 4Z has an impedance of 15 Ohms, so if it has the same efficiency, an amplifier driving it must be capable of providing 10mW at 15 Ohms to get to 107dB.

For most solid state amplifiers, it's much easier to provide 10mW at 15 Ohms than at 200 Ohms. That's why even though both headphones have same efficiency, LCD 4Z is easier to drive.

 

[x RELIC x]

Headphone Efficiency is measured in dB/mW. For eg. LCD 4 efficiency is 97 dB/mW. Decibels is a logarithmic scale so 107dB is 10 times louder than 97dB. So, it would take 10 times the amount of power(10mW) to reach 107dB on the LCD 4.

Since the LCD 4 has an impedance of 200 Ohm, an amplifier driving the LCD 4 must be capable of providing 10mW at 200 Ohms to get to 107dB.
Now, the LCD 4Z has an impedance of 15 Ohms, so if it has the same efficiency, an amplifier driving it must be capable of providing 10mW at 15 Ohms to get to 107dB.

For most solid state amplifiers, it's much easier to provide 10mW at 15 Ohms than at 200 Ohms. That's why even though both headphones have same efficiency, LCD 4Z is easier to drive.

You can’t really mix the dB SPL rating with the resistance. The Ohm rating will determine the amount of Voltage push vs the amount of Current draw. The sensitivity is a measure of what overall power is required to move the transducer to produce a specific loudness. The resistance will determine what kind of Voltage / Current balance is required, but for the same sensitivity the TOTAL power will be the very close between the two.

You are correct on the logarithmic scale, which means a 1dB change will be 20% difference in power required, and a 3dB difference requires double the power.

Edit: Here is the power required using 15 Ohm and 200 Ohm. It’s very close for the TOTAL power, but notice the difference between Voltage and Current required between the two.

15 Ohm with 98dB/mW


200 Ohm with 98dB/mW

 

[mlxx]

You can’t really mix the dB SPL rating with the resistance. The Ohm rating will determine the amount of Voltage push vs the amount of Current draw. The sensitivity is a measure of what overall power is required to move the transducer to produce a specific loudness. The resistance will determine what kind of Voltage / Current balance is required, but for the same sensitivity the TOTAL power will be the very close between the two.

That is correct assuming amps operated the same at 15 and 200 ohms which they don't.
The Dave can run speakers but not the LCD4. It will run out of current for low impedance and run out voltage for high impedance before getting to power needed.

 

[x RELIC x]

That is correct assuming amps operated the same at 15 and 200 ohms which they don't.
The Dave can run speakers but not the LCD4. It will run out of current for low impedance and run out voltage for high impedance before getting to power needed.

True regarding operation at different impedance for different amps, but the DAVE has 0.5A Current (500mA), more than most headphone amps. I wasn’t speaking about the DAVE but just clarifying in general the power requirements. Plus, I disagree with running out of Voltage. The numbers tell a different story, depending on listening levels of course.

 

[mlxx]

The DAVE has 0.5A Current, more than most headphone amps.

Umm.. at what impedance?
That is the point.

 

[seamon]

You can’t really mix the dB SPL rating with the resistance. The Ohm rating will determine the amount of Voltage push vs the amount of Current draw. The sensitivity is a measure of what overall power is required to move the transducer to produce a specific loudness. The resistance will determine what kind of Voltage / Current balance is required, but for the same sensitivity the TOTAL power will be the very close between the two.

You are correct on the logarithmic scale, which means a 1dB change will be 20% difference in power required, and a 3dB difference requires double the power.

Edit: Here is the power required using 15 Ohm and 200 Ohm. It’s very close for the TOTAL power, but notice the difference between Voltage and Current required between the two.

15 Ohm with 98dB/mW


200 Ohm with 98dB/mW

Of course, of course. I was just trying to lay it out in simpler terms. If they have similar efficiency, the power drawn for a specific loudness will be similar but the current drawn / voltage required will be smaller for the headphones with lower impedance.

 

[seamon]

That is correct assuming amps operated the same at 15 and 200 ohms which they don't.
The Dave can run speakers but not the LCD4. It will run out of current for low impedance and run out voltage for high impedance before getting to power needed.

True, but the DAVE has 0.5A Current (500mA), more than most headphone amps. I wasn’t speaking about the DAVE but just clarifying in general the power requirements.

Yes, that's what I meant in my original post. Amps don't have the same power ratings for different impedances. Solid State Amps tend to fall in their ability to supply power as the Impedance of the headphones increases.