Need to buy a DAC with amp
Sep 17, 2012 at 4:15 AM Post #17 of 24
I haven't heard HE-400s so can't comment on those, but it's also all personal preference.

I think you're right about Audio-gd being more specialised in headphone amps, and you can still roll OPs. Apparently the Moon OP is very good (if memory serves).

It looks like Asus is an awesome PC-oriented option while Audio-gd is a great general hi-fi option that also does PC very well.
 
Sep 17, 2012 at 6:48 AM Post #18 of 24
Quote:
Originally Posted by Loquah /img/forum/go_quote.gif
 
I'm basing this on the maths that 7V rms (the HPO rating of the Asus) equates to 7mW at 1000 ohms. Many of the best cans are 250-300 ohms. If you divide 7mW by 0.3, you get 23.33mW. Given that I have my NFB-5.2 volume at 50% to drive my 300 ohm HD650s, I can only assume that this equates to significantly more than 23.33mW as max power output from the NFB-5.2 is 300mW into 300ohms.

 
These calculations are completely wrong. 7 Vrms into 1000 Ω is 7 * 7 / 1000 = 49 mW of power, not 7. Even taking into account the 10 Ω output impedance of the Essence One, a 300 Ω load allows for a maximum power of slightly more than 150 mW. With the HD650, that should be more than enough for anyone who does not want to go deaf.
You cannot simply calculate the actual power from the position of the volume control, there are variables that would need to be taken into account but you do not know, such as the taper function of the volume control and the gain of the amplifier. "50% volume" can really translate to anything.
 
It is a rather snobbish assumption that an Audio-Gd product is automatically better because the company is "specialized in headphone amps". There are many poorly designed and overpriced devices that are sold by small boutique audiophile companies. It may be better or worse than the Asus, this can only be found out by testing both.
 
Sep 17, 2012 at 6:54 AM Post #19 of 24
Thanks everyone for the input, I have ordered from Audio-gd. Just that they do not have the 5.2 anymore, instead, they offered me the 5.32 for $10 more, they said the USB chip is better or something.
 
After all it was only USD 396 including delivery, which was a bit cheaper than I expected.
 
Next I will try it out with the DT-990 first, will go for the HE-400 if I can get a good price in Australia.
 
Sep 17, 2012 at 7:36 AM Post #20 of 24
Quote:
 
These calculations are completely wrong. 7 Vrms into 1000 Ω is 7 * 7 / 1000 = 49 mW of power, not 7. Even taking into account the 10 Ω output impedance of the Essence One, a 300 Ω load allows for a maximum power of slightly more than 150 mW. With the HD650, that should be more than enough for anyone who does not want to go deaf.
You cannot simply calculate the actual power from the position of the volume control, there are variables that would need to be taken into account but you do not know, such as the taper function of the volume control and the gain of the amplifier. "50% volume" can really translate to anything.
 
It is a rather snobbish assumption that an Audio-Gd product is automatically better because the company is "specialized in headphone amps". There are many poorly designed and overpriced devices that are sold by small boutique audiophile companies. It may be better or worse than the Asus, this can only be found out by testing both.

 
Thanks for clarifying. I knew I was doing sandpit maths, but didn't realise I was so far off. My understanding was that 1Vrms = 1mW into 1000ohms and V=IR so V/R=I, therefore 7/0.3=23.3mW. Where does the 7 x 7 come from? (i.e. can you help me understand? and sorry Bob for hijacking your thread with a maths/physics question)
 
In relation to my assumption about the Audio-gd being better, I didn't intend to make wild statements, but have found that while my Creative products are great, they are at a very different level to any dedicated headphone amp in terms of ability to drive high impedance headphones. I admit the transfer from Creative from Asus is probably not 100% fair, but it wasn't a random fleeting statement as it might have sounded.
 
Sep 17, 2012 at 7:37 AM Post #21 of 24
Quote:
Thanks everyone for the input, I have ordered from Audio-gd. Just that they do not have the 5.2 anymore, instead, they offered me the 5.32 for $10 more, they said the USB chip is better or something.
 
After all it was only USD 396 including delivery, which was a bit cheaper than I expected.
 
Next I will try it out with the DT-990 first, will go for the HE-400 if I can get a good price in Australia.

Good one! I'm pretty sure you'll be happy and we'd love to hear your thoughts on the NFB-5/5.2 (and now 5.32) appreciation thread.
 

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