[HeadphoneAddict]

Quote:

Originally Posted by A_Dying_Wren /img/forum/go_quote.gif How many volts would a good desktop headphone amp be rated at or is the comparison meaningless? Can't quite get a grasp of where 5v or 9v lies on the grand scheme of things. Can't wait for your review. Thanks a lot. Just in general, can you plug a proper amp into the D4 at a later stage and use the D4 just as a DAC? Sorry if this is rather obvious.

Some desktop amps run on 12v like Square Wave XL vs 24v like the Travagans Red - yet the Sq Wave XL is slightly more powerful. Some run on 18v like the EF5 which is even more powerful than those.

I'm not sure the input voltage is always an indicator of power in a desktop amp, but with the portables the 9v 3MOVE is a little more powerful than the 8.4v Pico or XM5, which is a little more powerful than the 5v Predator or P-51 or D10 (which may be 3.7 - 4.2v internally). Some 5v portable amps might use a voltage boosting technique internally, as the vivid V1 and TTVJ portable Millett both are charged with a 5v charger and yet have as much power as the 9v amps.

 

[HiFlight]

Yes, one can use the D4 as a DAC only by using the Aux output to feed a downstream amp. No battery power is required.

 

[tonho_rp]

Is there anyway that the 9V battery section can be powered by a usb port, or even two ?
So I dont have to worry about recharging the batteries, since Ill be mostly using it with my laptop, and I DO need to use 9v + 5v since Ill be driving Hd650s.
Is there any adaptor like this ? Usb to 9v, or so, i dont know.
Thanks

 

[tonho_rp]

Also,
Anyone here know how does it compare with the new TTVJ portable dac amp.
Looks like they would be even more suitable for driving the HD650s.
Am I wrong ?
Thanks

 

[kunalraiker]

The chip can can be powered by a maximum of 10V, you can either use the 9V from the battery or the 5V from the usb,can't use both.
9V should be enough to drive your HD 650s on high gain,there is something called as voltage multiplier which I know some amps use, not too sure if its available for USB power.

 

[tonho_rp]

I was told that I could power the dac section with 5v usb , and the amp with 9v batteries.

 

[kunalraiker]

You are right you can ,but you can't combine the two to hace a higher voltage then 9V to the amp.

Therefore 9V for amp and 5V for DAC is what you will get to use, and this should be good reasonably good for HD 650.

 

[HeadphoneAddict]

The DAC runs off 5v no matter what. The amp section can run off the 5v USB or 9v battery. When plugged into USB the DAC is still using the 5v USB, even if you flip the 9v switch to give the amp more power. With no battery installed the amp will default to the 5v from the USB, just like the DAC section. And, it can be used as a line out DAC with just the USB and no battery installed, as well as an amp via USB with no battery.

But, when plugged into USB, the D4 demands you use the DAC as the source. So you can't use the 5v USB to power the amp but feed an iPod into it to run at 5v - this is because whenever the USB is used the D4 turns the analog input into a line out. And, when you plug a cable into the line out, the headphone out shuts off. For an iPod your only choice is the battery power.

The only thing I haven't checked is if using a wallwart 5v power supply instead of USB will power the amp but not switch on the DAC, since it wont sense data. If that is the case, you could set it up at the bedside with an iPod and 5v wallwart and run it forever on 5v without running down the battery.

 

[tonho_rp]

Will the JJTV Portable amp + DAC or the Iqube V2 drive the HD650s better than the D4 with topkit and stock buffers and 9v battery plus 5v for the dac section ?

I read that the JJTV is able to drive any cans up to 600ohms withouth a problem.


Which one of these three has more power to drive the Hd650s, if the price wasnt a concern.

The other thing to consider is that the D4 dac looks better than both of the Iqube v2 and the TTVJ portable.

Please helpme headfiers, Im really lost.

 

[A_Dying_Wren]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif The DAC runs off 5v no matter what. The amp section can run off the 5v USB or 9v battery. When plugged into USB the DAC is still using the 5v USB, even if you flip the 9v switch to give the amp more power. With no battery installed the amp will default to the 5v from the USB, just like the DAC section. And, it can be used as a line out DAC with just the USB and no battery installed, as well as an amp via USB with no battery. But, when plugged into USB, the D4 demands you use the DAC as the source. So you can't use the 5v USB to power the amp but feed an iPod into it to run at 5v - this is because whenever the USB is used the D4 turns the analog input into a line out. And, when you plug a cable into the line out, the headphone out shuts off. For an iPod your only choice is the battery power. The only thing I haven't checked is if using a wallwart 5v power supply instead of USB will power the amp but not switch on the DAC, since it wont sense data. If that is the case, you could set it up at the bedside with an iPod and 5v wallwart and run it forever on 5v without running down the battery.

Oh right. That's a shame. Its almost definitely always going to be a DAC for me. Gonna have to give this some deeper thought.

Does it really matter though if I listen to music at rather soft levels? I don't even raise the volume to max listening to the HD650s straight out of the sansa clip+.

Thanks a lot for clearing that up HPA.

 

[HeadphoneAddict]

Quote:

Originally Posted by A_Dying_Wren /img/forum/go_quote.gif Oh right. That's a shame. Its almost definitely always going to be a DAC for me. Gonna have to give this some deeper thought. Does it really matter though if I listen to music at rather soft levels? I don't even raise the volume to max listening to the HD650s straight out of the sansa clip+. Thanks a lot for clearing that up HPA.

Well, if you use re-chargeable 9v batteries you can still power the HD600/650 with D4 in 9v mode without breaking the bank, but you have to charge the 9v externally like with the 3MOVE (which also has enough power for HD600 in 9v mode).

The Pico and Vivid V1 have just about enough power for HD600 (more than most other 5v USB DAC/amp), and they have internal rechargeable batteries so you don't need a separate charger like the D4 and 3MOVE. The Pico uses a 8.4v lion dual cell. The V1 must use an internal voltage multiplier or something, because it is only charged with 5v but it still manages to get some pounding bass and high volumes out of the HD600. I think the TTVJ portable Millett might have had enough power for the HD600, and it was another amp that is charged by a 5-6v wallwart, but it has no DAC.

 

[trentino]

You folks using the D4 portable, are you satisfied with the battery life?

 

[jamato8]

I get an easy days use with the D4 and the HD650 on one battery. It powers them fine with solid bass and more volume than I would ever want. I have the volume pot around 12 oclock or 1 for loud passages but after that it is too loud but without distortion.

 

[kunalraiker]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif I get an easy days use with the D4 and the HD650 on one battery. It powers them fine with solid bass and more volume than I would ever want. I have the volume pot around 12 oclock or 1 for loud passages but after that it is too loud but without distortion.

Its really cool to know John that you are happy with driving the HD 650 from D4,wouldn't this be the ultimate test for any portable amp.

As per the battery lifer for my D4 I use alkaline,must be having about 6 hours on it, still no signs of running out of battery.

 

[jamato8]

Yes, the 650's can take some power to get to the volume some people, including myself, like to have. But more volume, shorter run times. I use the Li-Poly 500mA rechargeable and under normal use get around 11 or 12 hours of run time.