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Objectively "Good" Amps and DACs

post #1 of 88
Thread Starter 

 

Now that I have a headphone with great measurements (LCD-2), I think it's time to give my source and amp the same treatment. I want to do it right this time, and not rely on subjective reviews. I figured this was the best place to ask and, to keep thing "on-topic", I want to open discussion to measurements of amps and DACs of all shapes, sizes, and prices.
 
First though, this is what I'm looking for. I want spend between $500 and $1000 total, but if I don't sacrifice anything by going cheaper so be it. I am open to all solutions, including internal soundcards. Obviously the amp needs to be powerful enough for the LCD-2. The more power the better, in case I ever get any other headphones. I want as neutral a setup as possible from 20Hz to 20kHz, with inaudible noise, crosstalk, distortion, maybe even low jitter (because why not right?). The DAC only needs to be 16/44.1 because 99% of my music is CD quality. Any more is just a bonus.
 
Originally I thought I would be buying a Schiit Asgard or Lyr with the Bifrost DAC. The amps put out plenty of power. However, I'm not sure if the amps are colored or not. I'm also losing interest in the Lyr because I would prefer a solid state amp for minimal distortion and maintenance. On the other hand, the Asgard has no better THD (both at 0.1%). The fact that they are made in the United States is a small plus, as is how powerful they are at competitive prices. I really wish I could see some more measurements though.
 
A recent favorite of mine is the CEntrance DACmini. I imagine the 1.5W (750mW per channel) output would be plenty, and the specs given by CEntrance look very promising. The subjective reviews of it, in particular when paired with the LCD-2, support the choice as well. The fact they use a 10 Ohm output by default because it sounds more "musical" is a concern, and makes me lose a little faith in CEntrance. That brings the price to $900, since I would probably want the 1 Ohm mod. Surely I could get something better for that price?
 
I was going to mention a specific DIY amp project by a specific blogger, but another thread was just made about it which appears to have been deleted so I dare not anger the moderators confused.gif
 
For standalone DACs, thanks to a promising bunch of RMAA measurements by MrGreen, something in the Echo Audiofire line would be nice. I wouldn't use any of the recording features like multiple inputs/outputs, so perhaps I could get something cheaper? What is the cheapest model that can be used as a standalone DAC (as in, can output an unamped analog signal to a separate amp)? Are there DACs built for standalone use that measure as well for affordable prices?
 
Obviously feel free to ask questions. And feel free to discuss objectively well-made amps and DACs outside of my price range and needs, but warn me first wink.gif
post #2 of 88

Have you considered the PS Audio GCHA headAmp?

 

http://www.musicdirect.com/p-7416-ps-audio-gcha-headphone-amp.aspx

 

I love the sound of that amp.  Seems very neutral to me, puts out a couple watts per channel, dead silent, etc.

post #3 of 88
Thread Starter 
Quote:
Originally Posted by kwkarth View Post

Have you considered the PS Audio GCHA headAmp?

 

http://www.musicdirect.com/p-7416-ps-audio-gcha-headphone-amp.aspx

 

I love the sound of that amp.  Seems very neutral to me, puts out a couple watts per channel, dead silent, etc.


Has anyone taken extensive measurements? I don't even see basic specs on that site, which isn't a good sign, not to mention the fact the instruction manual recommends an aftermarket power cable. I'd like to keep this discussion to objectively neutral and silent equipment.

 

post #4 of 88
Quote:
Originally Posted by Head Injury View Post

Has anyone taken extensive measurements? I don't even see basic specs on that site, which isn't a good sign, not to mention the fact the instruction manual recommends an aftermarket power cable. I'd like to keep this discussion to objectively neutral and silent equipment.

It's completely up to you, but you might objectively consider to do a google search for "PS Audio GCHA" and read the reviews and about the company.
 

 

post #5 of 88

Sorry, can't discuss or link to banned users activities.

TIA

post #6 of 88

I questioned fiio about the high output impedance of the smaller jack which is 43ohms, I have a set of soundmagic Pl11's which are 8ohm i plugged them in the small jack with the 43ohm output impedance i expected the frequency responce to change but it didn't, and fiio said

 

"The reason is that the loader is not " pure resistor ", the real headphone/earphone includes resistor, capacitor and inductance.

 

A resistor connect to a capacitor or inductance will change the frequency response.

 

BTW , the 10 ohms resistor is the design request by the TI. it is for safe.

 

What I means is consider the headphone/earphone as a pure resistor."

 

The higher output impedence only seems to effect balanced armature IEM headphones.

post #7 of 88



 

Quote:
Originally Posted by JRG1990 View Post

I questioned fiio about the high output impedance of the smaller jack which is 43ohms, I have a set of soundmagic Pl11's which are 8ohm i plugged them in the small jack with the 43ohm output impedance i expected the frequency responce to change but it didn't, and fiio said

 

"The reason is that the loader is not " pure resistor ", the real headphone/earphone includes resistor, capacitor and inductance.

 

A resistor connect to a capacitor or inductance will change the frequency response.

 

BTW , the 10 ohms resistor is the design request by the TI. it is for safe.

 

What I means is consider the headphone/earphone as a pure resistor."

 

The higher output impedence only seems to effect balanced armature IEM headphones.


This just isn't accurate.  The combination of resistance, capacitance, and inductance in a line creates impedance; which is the opposition to current flow in an AC circuit.  This will drop voltage across the output section no matter what.  With a set of IEM's like the soundmagics you mentioned, your headphone impedance can vary a lot across the frequency response range, giving you varying amounts of voltage drop across the output section of the headphone amp.  This variation is worse with both a higher amp output impedance and a lower headphone impedance.

 

Now you may have some changes based on the phase angle created by the capacitive/inductive reactances (the equivalent resistance created by a reactive load) that will change how current and/or voltage is consumed (because it will "consume" voltage/current on quarter cycles and "release" voltage/current on quarter cycles of the AC waveform).  However, you will still have the overall opposition to current and resultant voltage drop no matter what the reactive elements of the load are doing, that phase angle will only tell you how much real load is being applied to the headphones.

 

Furthermore, because of the relatively high output impedance you talked of (43 ohms), you will be forced to turn the volume up higher than normal, which will result in more noise, distortion, etc... being passed through the amp (this is due to an overall higher closed loop gain), all of which can degrade sound quality.
 

 

post #8 of 88

To the OP, if you've found a good DIY project, go ahead and build it.  Those can be very rewarding!!

post #9 of 88
Thread Starter 
Quote:
Originally Posted by SpaceTimeMorph View Post

To the OP, if you've found a good DIY project, go ahead and build it.  Those can be very rewarding!!


It's not my DIY project, but will apparently be marketed as one through a future retailer. I think I will try it if it isn't too complex. It'd be my first time redface.gif

 

If anyone's interested in the project I'm talking about, PM me. The inventor was banned, so apparently I can't discuss it publicly (though I'm not sure where that is in the TOS). Am I allowed to discuss it via PM?

post #10 of 88
Quote:
Originally Posted by Head Injury View Post


It's not my DIY project, but will apparently be marketed as one through a future retailer. I think I will try it if it isn't too complex. It'd be my first time redface.gif

 

If anyone's interested in the project I'm talking about, PM me. The inventor was banned, so apparently I can't discuss it publicly (though I'm not sure where that is in the TOS). Am I allowed to discuss it via PM?

You are not encouraged to discuss this individual even in PMs.  Why not use his blog site and forum facilities for that?
 

 

post #11 of 88
Thread Starter 

I'm in a DAC mood right now. Does anyone have any knowledge of the performance of these (beyond published specs)?

 

  • Cambridge Audio DacMagic (Upsamples frown.gif Balanced outputs too, but I won't use them)
  • HRT Music Streamer II or II+ (about the same except 99 vs 115 S/N and 25 uV vs 4 uV noise floor)
  • CEntrance DACPort LX
post #12 of 88

@ Head Injury:

 

There's nothing wrong with upsampling, the Benchmark does it too.  The DacMagic measures very good for the cost in line with the DAC1 save USB.  I've gone from a much more expensive DAC down to the DAC Magic with no problems.  I imagine I could get an even lesser DAC and still be happy, but I got mine for a better than average price new.

 

 

post #13 of 88
Since you are looking for a piece of gear that measures very well, why not just buy a Benchmark DAC1, the Audio Precision measures are quite extensive and complete, finally, I think the basic version still sells for $999, just inside your budget envelope. It still is a bit expensive, but IMHO, you would be totally sure that the spces are "state of the art", unless you spend $4000 for an Invicta.

The headphone out should deliver plenty of power with very low distortion:THD is -106 dB, 0.0005% into 30 Ohms at +18 dBu

NB: Complete specs of the Benchmark here: http://www.benchmarkmedia.com/sites/default/files/documents/DAC1%20HDR%20Manual%20RevE.pdf
post #14 of 88
Thread Starter 

Quote:
Originally Posted by khaos974 View Post

Since you are looking for a piece of gear that measures very well, why not just buy a Benchmark DAC1, the Audio Precision measures are quite extensive and complete, finally, I think the basic version still sells for $999, just inside your budget envelope. It still is a bit expensive, but IMHO, you would be totally sure that the spces are "state of the art", unless you spend $4000 for an Invicta.

The headphone out should deliver plenty of power with very low distortion:THD is -106 dB, 0.0005% into 30 Ohms at +18 dBu

NB: Complete specs of the Benchmark here: http://www.benchmarkmedia.com/sites/default/files/documents/DAC1%20HDR%20Manual%20RevE.pdf


About an hour ago I was thinking of that. The basic version is $999, you're right.

 

I don't know, though. I mean, I do want better-than-inaudible specs for peace of mind, but I think a DAC1 might be overkill. Like Shike said, the DacMagic isn't that much worse, and the difference should be inaudible. They both even offer balanced output, if I ever choose to go that route. If I buy/make the DIY-which-must-not-be-named, I'd probably be about $300-400 under budget with the DacMagic or a similar $500ish DAC.

 

And actually, until you mentioned it, I forgot it had a headphone amp built in. It's sounding more tempting by the minute...

 

Now that I've mentioned the subject, is balanced worthwhile? LCD-2's removable cables would make it a relatively painless transition.


Edited by Head Injury - 7/30/11 at 8:56pm
post #15 of 88
Quote:
Originally Posted by Head Injury View Post


About an hour ago I was thinking of that. The basic version is $999, you're right.

 

I don't know, though. I mean, I do want better-than-inaudible specs for peace of mind, but I think a DAC1 might be overkill. Like Shike said, the DacMagic isn't that much worse, and the difference should be inaudible. They both even offer balanced output, if I ever choose to go that route. If I buy/make the DIY-which-must-not-be-named, I'd probably be about $300-400 under budget with the DacMagic or a similar $500ish DAC.

 

And actually, until you mentioned it, I forgot it had a headphone amp built in. It's sounding more tempting by the minute...

 

Now that I've mentioned the subject, is balanced worthwhile? LCD-2's removable cables would make it a relatively painless transition.


I've yet to seen a real reason to go with balanced for headphones myself, and I think there's been past discussions about it on this sub-forum worth searching for ;)

 

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