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Is a DAC enough to drive 250 Ohm headphone? - Page 2

post #16 of 32
Quote:
Originally Posted by autumnholy View Post

But why tube amps? Does it make the headphone sound better?

They are a low cost way of outputing a lot of voltage, for high Ohm headphones.

post #17 of 32
Quote:
Originally Posted by autumnholy View Post

 

But why tube amps? Does it make the headphone sound better?

 

You are opening up a can of worms...

 

No, tube amps sound worse. Cheap class A tube amps on ebay are especially bad. People think they sound "warm" because they glow and give off heat. We are stupid like that.

I like tubes in guitar amps because they distort when I turn them up loud. A stereo meant to represent a musician's recording accurately should not do this.

 

 

Quote:
Originally Posted by PurpleAngel View Post

They are a low cost way of outputing a lot of voltage, for high Ohm headphones.

 

Did you read the original post? He says that the DACport LX drives his headphones loud enough. That means it already has enough voltage.

And opamps are way cheaper than tubes.


Edited by Eisenhower - 9/18/12 at 12:49am
post #18 of 32
Thread Starter 
Quote:
Originally Posted by Eisenhower View Post

 

 

LOL, okay then...

I wonder how it amplifies his music, and drives his headphones?

 

 

A "buffer" means what I said earlier, that it has a fixed gain/volume. It was designed to be paired with an external amplifier with a dedicated volume control. It is made to drive up to "line level" which is a standard voltage/current typically sent between stereo components (e.g. a DAC into an amp).

However, a headphone out can also be used to send line levels: http://www.sweetwater.com/expert-center/techtips/d--10/26/2000

Maybe you have plugged in your ipod's into a car stereo or speaker setup through it's headphone out? This is the same thing.

 

Now what you are talking about is doing the opposite: using a line level to drive a pair of headphones. Usually the difference is that devices with line level outs have very high output impedances (sometimes thousands of ohms), much too high for most headphones. However the DACport LX has only 10 ohms, which is exactly why they call it a low impedance buffer. It just so happens that a low output impedance is a requirement to be a decent headphone amp, since most headphones don't have that high of an impedance. Thus, you're DACport LX can drive headphones.

 

If you're DACport LX was distorting or coloring the sound, I don't see how putting an amp in front of it would fix anything. It might make it worse..

Some people in this thread think the LX actually sounds better without an external amp: http://www.head-fi.org/t/615548/do-the-dacport-and-the-dacport-lx-really-sound-different

This is due to the volume potentiometer adding flaws in the signal, or something like that.

 

Anyways, if you really want to put your mind at ease, borrow an amp or buy a cheap cmoy or FiiO and see if you like it more. Do a blind listening test with the volume levels matched as best you can.

 

Thanks. That's very helpful as I get to know more about Dacport and how DAC-Amp works.

 

Anyway, I've personally tried the setup of Dacport LX->Fiio E7. But i noticed that in the track: Mambo No. 5, in the beginning few seconds, the bass is over bloated. I wonder if it's the limitation of E7 or something wrong somewhere. I was kinda interested in the E9 pairing too, but many people held me back, saying that it isn't worth spending. I was also in doubt when seeing the 10 Ohm Output impedance and also the absence of RCA input.

post #19 of 32

I suspect you're looking for a computer based rig where the transducer (the headphone) is the beyer t70.

 

A full audio system would go like this:

 

Digital audio file -- asio4all/Wasapi and foobar -- usb -- Digital to Analogue Converter (DAC) -- Amplifier -- T70

 

The dacport LX does NOT have an inbuilt amplifier, unlike the original dacport. There are so many ways you can go about getting both a dac and an amp- notice I said both. You need both, believe me! (and 99.99% or other experienced/half experienced headfiers). Now say you were to plug the t70 into your computer's headphone output. That 'full audio system' would be satisfied as the laptops headphone output uses the internal sound card or processor which has a DAC and amplifier built in. Needless to say, there are different levels of quality in the dac and amp world and not many folks here are big fans of pc headphone outputs, put it that way.

With the dacport LX you should be sorted in terms of DAC choices- it must be a great dac (judging by reviews- it doesn't sell for a fair price in the uk so I never bought one myself). I haven't had experience with high impedance beyers, but there must be plenty of amps out there fit for purpose. It's up to you what to do- get rid of the dacport lx and get a dacport? I don't know, but any choice is yours which would, I would guess, depend also on your budget.

 

You say you're looking for scientific reasons why an amp should be used at all. That's almost like going to a supermarket and asking the manager why should I buy food? Or like going to a physics lecture and asking the professor why nothing in physics makes any sense to me?

Maybe you ended up at the wrong address sir!.....

 

...An amp is not primarily about volume. For me its never, yes never been about volume. Yes, I know, in some forums it is with the very cheap fiio e6 and others which are designed to overcome design flaws in ipods, but these are not the amplifiers were talking about here. The amplifier provides the correct voltage the correct amperage and thus the correct drive for your headphones to be driven, to work as intended. It's a piece of electronic equipment remember so these things are important. The difference between a suitable and unsuitable amp (inc no amp) can be very significant with effects pervading through entire sonic characteristics of headphones including soundstaging, imaging, speed, tonality, detailing, frequency response and so on. The differences between two 'suitable' amps for a specific headphones are generally small, sidesteps as it were. Of course, deciding what is suitable and what isn't is a challenge sometimes, but with the wealth of good info available on these forums, it shouldn't pose too much of a problem.   

post #20 of 32
Thread Starter 
Quote:
Originally Posted by PurpleAngel View Post

They are a low cost way of outputing a lot of voltage, for high Ohm headphones.

 

Yup. It's kinda cheap to afford. But I heard a headphone store owner said that Beyerdynamic T70 is tuned to be balanced, and therefore pairing it with Tubes aren't that suitable. Maybe I'll try some Tubes around to check with my own ears and experience them when there's a gathering around.

 

Thanks for your help tho. It's better for me to listen to more opinions as I'm learning.

post #21 of 32
Thread Starter 
Quote:
Originally Posted by CantScareMe View Post

I suspect you're looking for a computer based rig where the transducer (the headphone) is the beyer t70.

Yup. Cheaper than going all-in on CDs, although that's my latter plan.

 

A full audio system would go like this:

 

Digital audio file -- asio4all/Wasapi and foobar -- usb -- Digital to Analogue Converter (DAC) -- Amplifier -- T70

That's what I read somewhere too, and also my initial setup until I wonder if my amp is suitable or otherwise (technically suitable, not the -sound good, must be suitable- kinda thing).

 

 

The dacport LX does NOT have an inbuilt amplifier, unlike the original dacport. There are so many ways you can go about getting both a dac and an amp- notice I said both. You need both, believe me! (and 99.99% or other experienced/half experienced headfiers).

Okay, I'm listening...

 

Now say you were to plug the t70 into your computer's headphone output. That 'full audio system' would be satisfied as the laptops headphone output uses the internal sound card or processor which has a DAC and amplifier built in. Needless to say, there are different levels of quality in the dac and amp world and not many folks here are big fans of pc headphone outputs, put it that way.

Yup, not a fan of PC on board soundcards as replacing them would be a headache. And heard that (scientifically hearsay) it'll introduce more noise.

 

 

With the dacport LX you should be sorted in terms of DAC choices- it must be a great dac (judging by reviews- it doesn't sell for a fair price in the uk so I never bought one myself). I haven't had experience with high impedance beyers, but there must be plenty of amps out there fit for purpose. It's up to you what to do- get rid of the dacport lx and get a dacport? I don't know, but any choice is yours which would, I would guess, depend also on your budget.

My initial plan on going for Dacport LX is the flexibility to switch between amps later. I was told, and personally felt that (albeit with the lack of proper explanation on why) it's not suitable to go for Dacport as to avoid double amping (unsure of what's the right term, which means amping the signal twice in serial order), since Dacport doesn't have aux out, although I'm fully aware that it's a budget method.

 

 

You say you're looking for scientific reasons why an amp should be used at all. That's almost like going to a supermarket and asking the manager why should I buy food? Or like going to a physics lecture and asking the professor why nothing in physics makes any sense to me?

Maybe you ended up at the wrong address sir!.....

Haha. Maybe the way I put it makes it sounds so naive. Anyway, I really lack of the proper knowledge about why's and how's in the audio world, that's why I frequented SS forum more than any other places in head-fi.

 

 

...An amp is not primarily about volume. For me its never, yes never been about volume. Yes, I know, in some forums it is with the very cheap fiio e6 and others which are designed to overcome design flaws in ipods, but these are not the amplifiers were talking about here. The amplifier provides the correct voltage the correct amperage and thus the correct drive for your headphones to be driven, to work as intended. It's a piece of electronic equipment remember so these things are important. The difference between a suitable and unsuitable amp (inc no amp) can be very significant with effects pervading through entire sonic characteristics of headphones including soundstaging, imaging, speed, tonality, detailing, frequency response and so on. The differences between two 'suitable' amps for a specific headphones are generally small, sidesteps as it were. Of course, deciding what is suitable and what isn't is a challenge sometimes, but with the wealth of good info available on these forums, it shouldn't pose too much of a problem.   

Thanks to you and also the other forumers as well. I'm thinking, well, to go with the E9, stick to my current amp (Govibe Peak) after it's repaired, do nothing, or find something else which the measurement fits my current setup, or to go with the amp-with-no-name. I'm all about budget for this one until I learn enough, and experience enough in audio knowledge before I invest heavily in the black hole.

post #22 of 32
Quote:
Originally Posted by autumnholy View Post
Yup. It's kinda cheap to afford. But I heard a headphone store owner said that Beyerdynamic T70 is tuned to be balanced, and therefore pairing it with Tubes aren't that suitable. Maybe I'll try some Tubes around to check with my own ears and experience them when there's a gathering around.

Thanks for your help tho. It's better for me to listen to more opinions as I'm learning.

As the DACport LX has a low impedance of 10-Ohms, there should be no impedance problem with plugging the T70s into it.

 

More "ideas".

The O2 (Objective 2) headphone amplifier ($155) is a well like solid state amp..

NFB-12.1 DAC ($215+shipping) gets lots of positive feedback

post #23 of 32
Quote:
Originally Posted by CantScareMe View Post
...An amp is not primarily about volume. For me its never, yes never been about volume. Yes, I know, in some forums it is with the very cheap fiio e6 and others which are designed to overcome design flaws in ipods, but these are not the amplifiers were talking about here. The amplifier provides the correct voltage the correct amperage and thus the correct drive for your headphones to be driven, to work as intended. It's a piece of electronic equipment remember so these things are important. The difference between a suitable and unsuitable amp (inc no amp) can be very significant with effects pervading through entire sonic characteristics of headphones including soundstaging, imaging, speed, tonality, detailing, frequency response and so on. The differences between two 'suitable' amps for a specific headphones are generally small, sidesteps as it were. Of course, deciding what is suitable and what isn't is a challenge sometimes, but with the wealth of good info available on these forums, it shouldn't pose too much of a problem.   

 

Oh man...

post #24 of 32
Thread Starter 
Quote:
Originally Posted by PurpleAngel View Post

As the DACport LX has a low impedance of 10-Ohms, there should be no impedance problem with plugging the T70s into it.

 

More "ideas".

The O2 (Objective 2) headphone amplifier ($155) is a well like solid state amp..

NFB-12.1 DAC ($215+shipping) gets lots of positive feedback

 

Thanks. That oxygen amp. There's a forumer selling it around my place. Just that as a new user, I'm rather skeptical if the DIY unit is as good as the original plan of voldemort, or what JDS/Epiphany produced. I'm really interested in getting one to see what's the hype is about

 

Regarding NFB, I'm not really sure if I'd want another dac/amp combo. I think the Dacport LX does its job pretty well already.

post #25 of 32

Fair enough, I guess that's the best way to learn- ask. I learn something new on the forums all the time I visit headfi. Never ending pursuit really. 

 

I want to stop short of recommending good amps because nearly all of my experience lies with 32-50ohm closed headphones, that would inherently perform with amps differently to 250ohm ones. But what I will say is that there's plenty of amps suitable for 'most' types of headphones. If you want to keep your dacport LX, then it's best to look for an standalone desktop amplifier as that's the best for value and performance generally speaking. A matrix m-stage is often recommended for a range of headphones as well as, well there's plenty more. Oh yea, also consider the actual physical size of the amp. I mean, it'll look funny to have a 25kg beasty amp being fed with the tiny dacport LX!  

post #26 of 32
Quote:
Originally Posted by PurpleAngel View Post

As the DACport LX has a low impedance of 10-Ohms, there should be no impedance problem with plugging the T70s into it.

 

 

While you probably can safely plug a headphone straight out of this dacport lx, it's very likely to not be ideal. I'm not sure what the output stage stands as, but this item is advertised on centrance's website as a dac only.

post #27 of 32
Quote:
Originally Posted by PurpleAngel View Post

As the DACport LX has a low impedance of 10-Ohms

 

Does that apply to the line output of the DACport LX, or only the headphone amplifier, which is only on the DACport (not LX) ? The manufacturer's specifications suggest the latter.

The T70 is fairly efficient, and does not need much current, or even voltage (despite the impedance). It might be one of the headphones that actually sound better from a high impedance source (such as Beyerdynamic's own A1 amplifier), since one of the most common complaints about it is its bass light sound. However, if the DACport LX is not designed to drive headphones at all, then the T70 might still be a too low impedance load for it, causing high distortion and/or other problems.

post #28 of 32
Thread Starter 
Quote:
Originally Posted by stv014 View Post

 

Does that apply to the line output of the DACport LX, or only the headphone amplifier, which is only on the DACport (not LX) ? The manufacturer's specifications suggest the latter.

The T70 is fairly efficient, and does not need much current, or even voltage (despite the impedance). It might be one of the headphones that actually sound better from a high impedance source (such as Beyerdynamic's own A1 amplifier), since one of the most common complaints about it is its bass light sound. However, if the DACport LX is not designed to drive headphones at all, then the T70 might still be a too low impedance load for it, causing high distortion and/or other problems.

 

stv014, can u please tell me about the relationship between low impedance T70 and distortion/problems? I haven't the knowledge to fill the missing link. Thanks!

post #29 of 32
Thread Starter 

Speaking of which, I just tried this setup:

 

Digital source -> Dacport LX -> Fiio E7 -> Beyerdynamic T70 and also Shure SE535 SE.

 

I cranked the foobar 2k volume to max and use the E7 digital volume control.

And I noticed that some songs have distorted bass / altogether distorted sound.

 

In Mambo No. 5, the low bass was distorted (both T70 and SE535)

 

In All the right moves (using SE535), the sound was distorted all along.

 

I wonder if:

1. it's the source problem and all these while I was suppressing the volume so that the distortion wasn't audible, or that

2. I have a faulty E7, or

3. it was a bad setup and I didn't know the science behind.

post #30 of 32

The line input of the E7 can only handle a limited voltage (less than 1.25 Vrms) that is lower than the 2 Vrms standard level that the DACport LX probably outputs. Therefore, to avoid clipping, you need to reduce the level using software volume control on the PC.

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