[warubozu]

Yeah, they are upside down in that pic.

 

[gaijin]

Anyone had the chance to audition this amplifier and care to give some impressions ?

 

[Vic]

I believe StevieDVD has ordered one a few weeks ago; I hope he shows up in this thread, or you could PM him. Probably he is too busy ATM enjoying the new amp

.
BTW I would love to hear this amp, so I will ask him soon

 

[StevieDvd]

Quote:

Originally Posted by gaijin Anyone had the chance to audition this amplifier and care to give some impressions ?

See here for my notes.

Steve

 

[Vic]

Quote:

Originally Posted by StevieDvd See here for my notes. Steve

That is funny: I just posted that one minute before your review appeared on the other thread

 

[ymngzhou]

It looks like really a "double" NX-01s~ if the NX-01 is as good as people say that, balanced it could only make it better~~
The man knows how to put "cheap" parts together and make it sounds great. Need impression~~

 

[StevieDvd]

Quote:

Originally Posted by ymngzhou It looks like really a "double" NX-01s~ if the NX-01 is as good as people say that, balanced it could only make it better~~ The man knows how to put "cheap" parts together and make it sounds great. Need impression~~

Not sure about the 'cheap' parts bit but if you did not open the case and just heard the sound then I think you'd be pleased. Rudi had no issue with me taking and posting pictures of the inside, but I'm not taking the pcb to check what's underneath so perhaps the secret ingredient is hidden

There is some sealant on the screws keeping the pcb secured.

Steve

 

[TheSloth]

Quote:

Originally Posted by BennyBoy Nope! I dont think the PS is worth a grand either, I just think its one of the best SS amps out. But I've yet to hear a SS amp sound better than a X-CanV3 with good tubes. And I have never listened to a balanced Head Amp, as I feel this is as wacky as using $100.~$500. power cords.

Yeah, the PS Audio is just the greatest. I mean, the 'gain cell' which is a pile of crappy potentiometers wired together into a complete distortion creating mess they call a great step forward, and then a class A/B output stage that looks striking similar to those rather old HeadRoom modules from the late '90's...

I won't bother to address your closing sentence.

 

[machead]

Quote:

Originally Posted by slwiser You may be right about that. If so then I would also expect that headphone manufacturer's would start building balanced phones with single ended adapters as standard. This really would be good for our hobby.

It seems to me that AKG has done just that with the K701. It has separate + and - wiring for each driver all the way to the 1/4" plug, which is essentially a "single ended adapter" in this case. Going fully balanced is simply a matter of removing the stock plug and replacing it with something that preserves the separate left and right circuits, as has already been done by at least one Head-Fi member.

 

[StevieDvd]

Quote:

Originally Posted by machead It seems to me that AKG has done just that with the K701. It has separate + and - wiring for each driver all the way to the 1/4" plug, which is essentially a "single ended adapter" in this case. Going fully balanced is simply a matter of removing the stock plug and replacing it with something that preserves the separate left and right circuits, as has already been done by at least one Head-Fi member.

Thanks,

Guess that answers my question about easy to convert to balanced headphones (other than HD650) then - may give them a bash balanced if I can pick them up cheap enough over here in the UK.

Ohh my wallet hurts!!!!

 

[Sovkiller]

Quote:

Originally Posted by machead It seems to me that AKG has done just that with the K701. It has separate + and - wiring for each driver all the way to the 1/4" plug, which is essentially a "single ended adapter" in this case. Going fully balanced is simply a matter of removing the stock plug and replacing it with something that preserves the separate left and right circuits, as has already been done by at least one Head-Fi member.

IIRC, Derek, basically all headphones with dual entrance cables, one per cup, has 4 conductors on it, Senns, R10, Grados, etc....But not sure to what extend you can mix those two grounds (from each channel) in a balanced configuration without messing the signal or the amp, is that safe in all cases???

 

[TheSloth]

Quote:

Originally Posted by Sovkiller IIRC, Derek, basically all headphones with dual entrance cables, one per cup, has 4 conductors on it, Senns, R10, Grados, etc....But not sure to what extend you can mix those two grounds (from each channel) in a balanced configuration without messing the signal or the amp, is that safe in all cases???

You aren't mixing grounds in a balanced configuration. The ground becomes the virtual middle point between the two signals, and both wires to the driver become drive wires. There is no physical ground wire.

 

[Sovkiller]

Quote:

Originally Posted by TheSloth You aren't mixing grounds in a balanced configuration. The ground becomes the virtual middle point between the two signals, and both wires to the driver become drive wires. There is no physical ground wire.

Not in the balanced, I was talking in the "single ended adapter" Derek mentioned, when you go from balanced to single ended, you have to connect the two grounds together, thati s what they do on the heapdhones that has separate cables to each cup, they connect both at the end, otherwise how could you get the single ended with two separate grounds??

 

[machead]

Quote:

Originally Posted by Sovkiller IIRC, Derek, basically all headphones with dual entrance cables, one per cup, has 4 conductors on it, Senns, R10, Grados, etc....But not sure to what extend you can mix those two grounds (from each channel) in a balanced configuration without messing the signal or the amp, is that safe in all cases???

Quote:

Originally Posted by TheSloth You aren't mixing grounds in a balanced configuration. The ground becomes the virtual middle point between the two signals, and both wires to the driver become drive wires. There is no physical ground wire.

Quote:

Originally Posted by Sovkiller Not in the balanced, I was talking in the "single ended adapter" Derek mentioned, when you go from balanced to single ended, you have to connect the two grounds together, thati s what they do on the heapdhones that has separate cables to each cup, they connect both at the end, otherwise how could you get the single ended with two separate grounds??

Alberto,
In most headphones that have dual entrance cables, the manufacturer economizes by connecting the two "-" leads together at the point where the dual cables become a single cable. Since the 1/4" plug has only three connections, they figure, why bother keeping separate returns for most of the length of the cable?

The answer, and one of the reasons why balanced headphone drive is theoretically better, is that all headphone cables have resistance. The currents flowing in the "-" leads cause small but significant voltage drops in their respective wires. If these two wires are combined into one common wire, the individual left and right currents still form components of the combined flow; but the voltage drops attributable to each of them are imposed on the net voltage seen by the other driver. This causes crosstalk between the channels, which does have an audible effect on the stereo image created by the headphones.

BTW, with unbalanced drive, it is conventional for the common "-" of the two headphone signals to be connected to the system ground. It could just as well be the "+" signals that are combined but that would invert the phase of the acoustic sound recreated by the headphones. With balanced drive, as Daniel pointed out, neither side of the headphone signal is connected to ground because there is no need for a "common" reference point.

The K701 compromise, together with most aftermarket upgrade cables, have the advantage that the left and right "-" signals are kept separate from the amplifier output jack all the way to the headphones. Well-designed amplifiers have very low resistance grounding schemes that minimize resistance (and, therefore, crosstalk) before the point where the signals reach the output jack.

 

[Sovkiller]

Quote:

Originally Posted by machead Alberto, In most headphones that have dual entrance cables, the manufacturer economizes by connecting the two "-" leads together at the point where the dual cables become a single cable. Since the 1/4" plug has only three connections, they figure, why bother keeping separate returns for most of the length of the cable? The answer, and the reason why balanced headphone drive is theoretically better, is that all headphone cables have resistance. The currents flowing in the "-" leads cause small but significant voltage drops in their respective wires. If these two wires are combined into one common wire, the individual left and right currents still form components of the combined flow; but the voltage drops attributable to each of them are imposed on the net voltage seen by the other driver. This causes crosstalk between the channels, which does have an audible effect on the stereo image created by the headphones. BTW, with unbalanced drive, it is conventional for the common "-" of the two headphone signals to be connected to the system ground. It could just as well be the "+" signals that are combined but that would invert the phase of the acoustic sound recreated by the headphones. With balanced drive, as Daniel pointed out, neither side of the headphone signal is connected to ground because there is no need for a "common" reference point. The K701 compromise, together with most aftermarket upgrade cables, have the advantage that the left and right "-" signals are kept separate from the amplifier output jack all the way to the headphones. Well-designed amplifiers have very low resistance grounding schemes that minimize resistance (and, therefore, crosstalk) before the point where the signals reach the output jack.

Well not in the ones I have seen, most of them what they do indeed is to follow the cable all along the conductor, that will be more economical as the cable is already done that way, cutting, and mixing cables, soldering them, and later on covering them is more expensive at the end, that just cover the two with a thicker jacket, and a nice splice point, and solder them at the end on the jack...

Now about the crosstalk, it is a common misconception about headphone listening, that you need a completelly and isolated two channel system, very extreme separation of channels in heapdhone listening is not a very good idea, you will get the unfamous blob in the head, that eveybody are trying to avoid, and the main reason why crosfeed exists. Ideally you need some flow of information from one channel to the other to create the right natural image in front of you, IMO it is waste of time to try to get the completelly independent two channel headphone amp, you need to mix the channels at some point in some way, similar to what the crosstalk does in some way, to create a natural feel and a natural soundstage, unless you are hearing all the time binaural recordings.

OTOH Balanced operation has other advantages as well, as offering a flow in the opposite way on the negative conductor that indeed creates a better control over the driver, but the elimination of crosstalk is IMO, not what we can call one of them...as simply we do not need that.

Also the unbalanced operation unless completelly dual mono, has the ground already mixed inside the amp, so running it along the cable that way, will not harm in any way the signal, it is already mixed, the crosstalk came already from the amp, and indeed it is measured most of the times on the amp, and not from the cables...
FYI we had an extensive discussion about that effect in the crossfeed thread, and some good DIYErs shime in with more technical explanations....


Derek your front panel will be shipped pretty soon....BTW....