[Gwarmi]

Quote:

I'm not saying it's a perfect match. I'm saying that's plenty of power, and all power determines is peak volume, so there's not much point in quoting a power figure if you're talking subjective preference. I'd need to see some in-depth graphs of distortion, noise, phase, crosstalk, channel balance and other sorts of things to say it's a good match or not 

 I suspect the HD800 likes a lot of voltage swing but it's a difficult call considering few manufacturers publish their figures
 ~ end of the day, it might be a crude approach, but I just go about what my ears are telling me, taking note of source used,
 material and the amp in question.
 
 From there it's just an expressed subjective opinion that some may or may not agree with.

 

[Head Injury]

Quote:

 I suspect the HD800 likes a lot of voltage swing but it's a difficult call considering few manufacturers publish their figures
 ~ end of the day, it might be a crude approach, but I just go about what my ears are telling me, taking note of source used,
 material and the amp in question.
 
 From there it's just an expressed subjective opinion that some may or may not agree with.

It does need a lot of voltage, all high impedance headphones do. The HD800 as measured by Tyll needs about 2.4 Vrms for 110 dB. That 152 mW is sqrt(0.152 x 300) = 6.75 Vrms (though for the headphone Tyll measured it would actually be about 7 Vrms, because he measured 320 ohm impedance at 1 kHz). Voltage swing, if you mean peak-to-peak, is 2 x Vrms divided by 0.707, but that's not really as useful.
 
You don't need the manufacturer to publish voltage swing if they publish power output into a given impedance. P = V^2/R, where P is power in watts, V is Vrms, and R is resistance in ohms. Likewise they don't need to publish current, since P = I x V, I being current in amperes. Even if you take a subjective approach to audio, these sorts of equations might come in handy in determining whether or not an amp will give you enough volume. Plus it clears up some of the mysticism surrounding all the different terms and how they relate.

 

[Gwarmi]

Quote:

It does need a lot of voltage, all high impedance headphones do. The HD800 as measured by Tyll needs about 2.4 Vrms for 110 dB. That 152 mW is sqrt(0.152 x 300) = 6.75 Vrms (though for the headphone Tyll measured it would actually be about 7 Vrms, because he measured 320 ohm impedance at 1 kHz). Voltage swing, if you mean peak-to-peak, is 2 x Vrms divided by 0.707, but that's not really as useful.
 
You don't need the manufacturer to publish voltage swing if they publish power output into a given impedance. P = V^2/R, where P is power in watts, V is Vrms, and R is resistance in ohms. Likewise they don't need to publish current, since P = I x V, I being current in amperes. Even if you take a subjective approach to audio, these sorts of equations might come in handy in determining whether or not an amp will give you enough volume. Plus it clears up some of the mysticism surrounding all the different terms and how they relate.

 Here's a nutcracker for you ~ I've always been baffled why the SPL Phonitor sounds fairly average with the T1
 and absolutely dreadful with the DT990 in 600ohms.
 
 Might check some of those figures but it's a head scratcher, make no mistake ~ it's a shocker with the DT990.
 
 Both the DT990 and Phonitor play nice with other gear so it's definitely not a case of defective operation.

 

[Head Injury]

You don't like the sound of the T1 with whatever brand of coloration (if any) the Phonitor imbues. It has nothing to do with power, voltage, or current. The DT990 is quite a bit less efficient (I think about 6 dB less per mW, so it needs twice the voltage for the same volume), but as long as they're both playing at sufficient volume (and obviously you're volume matching accordingly!) then it's not a power issue.
 
I think we've had this discussion before.

 

[Gwarmi]

Quote:

You don't like the sound of the T1 with whatever brand of coloration (if any) the Phonitor imbues. It has nothing to do with power, voltage, or current. The DT990 is quite a bit less efficient (I think about 6 dB less per mW, so it needs twice the voltage for the same volume), but as long as they're both playing at sufficient volume (and obviously you're volume matching accordingly!) then it's not a power issue.
 
I think we've had this discussion before.

 I've got figures of 102dB for the T1 and 100dB or 96dB (no specific reference to whether it's for the 32,250 or 600)
 for the DT990-600ohm. Anyway, it's something for the Head-Fi X-files..
 
 Volume is not the issue, it's just really congested.

 

[Currawong]

The design of the amplification circuit would have everything to do with it. Amps aren't just power output, impedance and distortion figures.

 

[Head Injury]

Quote:

The design of the amplification circuit would have everything to do with it. Amps aren't just power output, impedance and distortion figures.

That's certainly debatable, but this isn't the place for it 

 

[Duckman]

I think it's cool that Tassie Devil has his 800s plugged directly into the analogue outs of the DAC, not using the HP out. I'd love to hear how that sounds.

 

[Tassie Devil]

Well I like a bit of volume but have ever found the DAC9 lacking for the Sennies.  It opens up with a LED readout of 50 and I find myself listening at around 40 - 10 db less than the mid range setting.
 
And I tried out my friends HDP before passing it on - not as articulate as the DAC9 but surprisingly good.  The HDP/AKG 701 combo he is happy with would suit most people.  It is only nutter like some of us here who spend 5X or more for that little bit extra!
 
Bottom line, it depends on how good is the signal; going in.  GIGO works here like everywhere else!!
 
John

 

[Tassie Devil]

Quote:

 
 Keen as mustard to get my grubby hands on this Nuforce DAC 9 next week ~ speaking to someone in the industry ~ he
 reckons this DAC 9 eats the Audiolab MDAC for breakfast - will see if the superlatives translate into actual listening.
 
 Doubt the headphone amp section is on par with the Class A unit in the MDAC but then again, who buys a $1999AUD
 DAC to use as their main head amp?

Damn!  I had just about finished posting a reply on the iPad when the rotten thing vanished & couldn't be found - anyway back on the PC to try again.
 
Have you got your DAC 9 yet?  I'll be very interested to read your findings.
 
A footnote on all this discussion:
 
I have read crits of the Sennheiser HD800s as sounding harsh, lacking bass, ... and there is a similar lukewarm comment about the DAC 9 on the net.  IMHO this reflects poor input which the Sennies and DAC 9 are faithfully passing on.  GIGO applies with a vengeance with items of this caliber.
 
I have been living with the Sennies for over 18 moths now and have been listening to the FLAC files from the Sooloos system for 16 months so my appraisal of the audio quality is not a reflection of the first joy of ownership.  I have never heard such high quality audio, first via the modded Benchmark DAC1 and then via the NuForce DAC 9 which really did surprise me as being better.  And I'm increasingly impressed with the AKG 702s so am investigating making up different cabling to see if the small gap between the Sennies & AKGs can be narrowed even further.  Not sure how much the balanced capabilities of the Sennies might account for the differences as it does not seem the AKGs can be wired that way to make the comparison more valid.
 
John (having fun playing with his headphone toys)

 

[Gwarmi]

 
 
Hey John,
 
I posted up some brief impressions when it rolled into the store here
 
http://www.head-fi.org/t/549887/nuforce-dac-9-dac-9-new-high-end-all-in-one-solution
 
No time as yet to give it a go with the HD800, the other dilemma being that this particular unit developed
a particularly nasty fault whereby it would just drop out, necessitating that it be switched off, switched back
on and the USB cable unplugged and plugged. Bit frustrating The supplier is looking into it for a replacement.
 
Anyway, as per my micro impression in that thread ~ the DAC-9 is certainly one of the most colourful, musical
DAC's I've ever heard to be honest, it makes my Rega by comparison sound a little restrained on the straight
and narrow. For personal tastes, It would make my short list ~ however, for this unit I'm helping a local store
evaluate whether it could be a keeper for them ~ at this stage, knowing full well how so many regulars like
a neutral source, I'm a little hesitant to recommend it to the store.
 
Still it's a big, long thing - nice remote control, pre amp volume control and touch button LED is interesting.
 
Such a shame, only 10hrs or so old before it just went silent.
 
I understand now why you're running it out of the pre-outs or with the on board head amp ~ heaps of gain
present on these two!
 
 
 

 

[arcamman]

Hi there. Don't know if you could help but i am considering buying a Nuforce dac 9 for hifi listening mainly maybe occasional headphones but possible pre amp duties straight into a valve power amp. I can buy the Benchmark dac1 PRE for almost the same money. Would you consider the Dac 9 to be a better quality dac & in what way. I like a smooth musical sound but with good detail.
 
Many Thanks.