[ZeroAtlas]

Clear as a rain. Thank you for your knowledge. I was under the misimpression that a higher impedance automatically meant more power needed. My only experience with high-ish impedance phones were the HD600's and those were finicky with amps. Made the mistake of correlating the two. I'll be sure to keep your rule of thumb when considering future purchases.
cheers.
 

  
 
 
Quote:

I keep seeing the assumption that high impedance cans are somehow "hard to drive" but a comparably low Z amp can also be very "hard to drive."  It really depends more on efficiency than impedance, until you are at very high or very low impedances.  Efficiency is correlated to how much power is required.  Because calculating power using actual impedance is complex, I'll simplify and discuss as if the headphone was a simple resistor to make the math more obvious.
 
Efficiency is measured in dB/mW, or decibels per milliwatt and milliwatts are a measure of power.  
 
In a purely resistive load (assuming an ideal resistive instead of reactive headphone, to simplify the math) the formula for Power is:  P = VI (Voltage x Current).  
 
Since V = IR, where R is resistance, P = V x V/R or or P = I x I x R.  From this you can see that power can be considered either by looking at current or voltage.  If the device is very inefficient and has high impedance, you need a lot of voltage but not much current to reach peak sound levels.  If the device is very low impedance then you need a lot of current (and also low amplifier output impedance so all the power isn't lost as heat in the amp).
 
Since every 3dB of efficiency decrease requires twice as much power to generate the same volume, you can see why "high impedance" phones will make amps run out of voltage quickly if the headphone is not efficient.

This is not the only way to determine "best fit" for an amp/phone impedance match, but it's a good rule of thumb that I use.  
 
IF:
 
1) Phone is efficient (e.g. IEM) very little V or I are needed to generate enough P to make your ears bleed
 
2) If Phone is not efficient and has HIGH impedance than you want an amp with a lot of voltage swing, but maybe not much current
 
3) If Phone is not efficient and has LOW impedance, you need an amp with strong output current capacity and low output impedance
 
Hope that is as clear as mud.
 
 
 

 

[mrspeakers]

Sure, no prob...   It seems to be what everyone thinks. 
 
I am listening to some 650's right now, driven by the DACPort, and it has more than enough juice to drive them to a louder level than I would listen to, and the power is just a bit higher than the D6 spec.   
 
I think the D6 will be similar, in that for a portable it has a lot of power and relatively high potential voltage swing, so it should support both High Z and Low Z phones pretty well, as long as they aren't really inefficient.  The 650's are 103dB efficiency at 1mW, the JH16s are 118dB and only 18ohms, if memory serves.  Both should be easy loads for the D6.
 
An Audeze LCD-2 would still probably play though much depends on the buffer quality and current capacity.  With efficiency of only 91dB, they'd require about 8x as much power, so the current output would have to be about 3x as high.  A swag says this would still be in easy spec to take to 103dB, and for average but not peak levels, that's really loud.  Love to hear from the D6 owners how a low efficiency low impedance load drives, as I have two phones that fit that bill.  

 

[jamato8]

Well the D6 drives the LCD-2 with no problem. I don't hear any distortion and space remains, it does not compress on louder passages. Every time I listen to the D6 I am struck by how transparent it is. It has to be one of the most transparent amps I have ever heard. 10 o'clock gets me into loud and 11 is about my limit. No clipping or distortion on the LCD-2. 

 

[paulybatz]

Did some brief listening, had to share time between this and the PB-2....kind of feel like a polygamist...want to make it equal time with these girls...but Ill steal a quote from Jam here: 
 
"Every time I listen to the D6 I am struck by how transparent it is."
 
Out of the box this thing is a monster little amp, Ill have to do some more listening but this (and the PB2) are really top tier products...Im awestruck ...and man she looks great in matte black!

 

[Madpierrot]

A few more question before I make my decision on the D6 or D12.
 

• If I go from my soundcards optical out to the D12, is the DAC on the D12 still being used or is the D12 now acting purely as an amp?
• Does the above mean that my 24/96 is now being rendered by the D12's 16/48?
• Does the above also allow my soundcard to still apply effects when necessary (EAX etc) or is it just a passthrough?
• Is there a differences using usb, optical, coaxial or are these just options?

 
I think the D6 is what I want, but the D12's input options is alluring. Thanks in advance to answering these!
 

 

[estreeter]

Quote:

Well the D6 drives the LCD-2 with no problem. I don't hear any distortion and space remains, it does not compress on louder passages. Every time I listen to the D6 I am struck by how transparent it is. It has to be one of the most transparent amps I have ever heard. 10 o'clock gets me into loud and 11 is about my limit. No clipping or distortion on the LCD-2. 

I am going to stir the pot further, not because I have a dog in this fight, but simply because Skylab is specific about the three amps he tested in his final comparison and their ability to drive the LCD-2. Apologies to those who have already read the following in Rob's thread, but I dont want to simply take a sentence out of context.
 
---------------------------------------------------------------------------------
Bass:

L3 > SR-71B > Stepdance

Again reminding that this is the performance in single-ended mode, I found that the SR-71B lacked a little weight and impact compared to the other two, and the L3 had the best weight, impact and depth combination.  This was with the L3’s variable bass control set to flat.  All of the amps had outstanding bass performance, but the Stepdance had just a tiny bit of trouble bringing the LCD-2’s bass prowess out to full measure.
 
------------------------------------------------------------------------------------
 
I want to make it perfectly clear that, for the majority of us, the ability to render bass to 'full measure' on something like the LCD-2 is probably a lot less important than how well an amp does everything else *with less demanding cans*. That said, if you are trying to drive orthos, this may be an area where the big numbers of the latest round of iBasso amps **might** get you over the line. Merely quoting the opinion of two (long-standing) members of Head-Fi doesnt make it so, but I felt that this was a rare opportunity to put the two impressions alongside one another, given that they refer to the same pair of headphones.
 
In the interests of clarifying Rob's comments re the tonality on the Stepdance, I asked him whether it was his pick for best-bang-for-buck amp of his 'Top 3':
 
Absolutely and unequivocally.  The Stepdance is THE bargain here for sure, being about 50% of the price of the other two, and basically as good sounding.
 
Finally, I'm not trying to start a 'Stepdance vs iBasso xxx' derailment - simply marrying up two impressions in the interests of highlighting one area where 'on paper' specs might just make a difference. To my knowledge, there simply hasnt been a direct 'Stepdance vs D6/P4' comparison from someone who has both amps (or all 3 !) - happy to hear otherwise. My gut feeling is that many of us would be happy with any of the above, but my gut and my wallet are no longer on speaking terms.

 

[78tball]

Will the D4 topkit be the recommend kit for the D6? Or are there plans for a different D6 topkit? If so, any availability and pricing info? You had mentioned in the D12 thread that the opa637bp being a nice setup for the D12. Would that configuration improve on the stock D6? Any buffer changes required for opa637bp in a D6?

Regards.


Quote:Originally Posted by HiFlight 
For those who also have the D4 Topkit, you can safely use it with the D6 despite the higher supply voltage.  They both share very similar amp sections so the same Topkit will be used for both models. 
 

 

[HiFlight]

The same Topkit will be used for both D4 and D6.   The 637 sounds OK with the battery voltage, but is underpowered with USB power.  The Topkit outperforms the 637, IMO.  While it does sound good, it's greatly overpriced for what you hear. There are better choices at much less cost. 
 
Quote:

Will the D4 topkit be the recommend kit for the D6? Or are there plans for a different D6 topkit? If so, any availability and pricing info? You had mentioned in the D12 thread that the opa637bp being a nice setup for the D12. Would that configuration improve on the stock D6? Any buffer changes required for opa637bp in a D6?

Regards.


Quote:Originally Posted by HiFlight 
For those who also have the D4 Topkit, you can safely use it with the D6 despite the higher supply voltage.  They both share very similar amp sections so the same Topkit will be used for both models. 
 

 

[Jalo]

Quote:

Did some brief listening,..but Ill steal a quote from Jam here: 
 
"Every time I listen to the D6 I am struck by how transparent it is."
 
Out of the box this thing is a monster little amp, Ill have to do some more listening but this (and the PB2) are really top tier products...Im awestruck ...and man she looks great in matte black!

Given the about statement, can either Jam or Pauly comment on how the D6 compare to the PB2 in terms of transparency and any other aspect between the two?  I am kind of into balance now , I have the DB1 and wanted to know how the PB2 compares to the D6.  Thanks much.

 

[paulybatz]

Ill do some A/B over the weekend!
Quote:

Quote:

Did some brief listening,..but Ill steal a quote from Jam here: 
 
"Every time I listen to the D6 I am struck by how transparent it is."
 
Out of the box this thing is a monster little amp, Ill have to do some more listening but this (and the PB2) are really top tier products...Im awestruck ...and man she looks great in matte black!

Given the about statement, can either Jam or Pauly comment on how the D6 compare to the PB2 in terms of transparency and any other aspect between the two?  I am kind of into balance now , I have the DB1 and wanted to know how the PB2 compares to the D6.  Thanks much.

 

[HiFlight]

If I didn't need USB input, I would choose the PB2.  (After listening to both with a variety of genres.  No rock though)  From the SE output of the PB2,  they are very close, depending upon opamp configuration. 

 

[Jalo]

Quote:

If I didn't need USB input, I would choose the PB2.  (After listening to both with a variety of genres.  No rock though)  From the SE output of the PB2,  they are very close, depending upon opamp configuration. 

Yes, I didn't need the USB input because I have the DB1 with Coax/Toslink/USB input.  So you are comparing the D6 and the PB2 straight from SE output?  and they are very close?  Wow, that mean if used in balance mode the PB2 could improve further with its SQ.  Great!  Just for confirmation, HiFlight, at least from what I can see, the PB2 right now is the most powerful amp from the Ibasso lineup with up to 2500mW (is that per channe?) is that right?  the D6, or P4 has only around 600 to 650 mW per channel.  That is a hugh difference.

 

[jamato8]

With the PB2 in balanced, it is the most powerful portable that I am aware of. 25 volts of swing and 2.5 watts into 32 ohms. With it plugged into the AC to DC converter/charger, the voltage swing goes up to 32. 

 

[Jalo]

Jam, thanks for the tibits. Are you planning on upgrading to the PB2?  I am just interested a comparison between the PB2 and SR71B also.

 

[Train]

How much would running off the 5V USB affect the D6's output power? And is it even possible to get the full 12.6V using the wall charger while operating the USB DAC?