[Radio_head]

Quote:

Edit: A dynalo with a better PSU...
 
do we have any inside pics of the GS-X-mk2? Any measurements on it?

Shots from Justin of the GS-X MK2 in various states of undress (from GS-X thread):
 

 

 

 

 

 

 

 

 
These are Justin's specs on his site, but I don't know if its still from MK1 or from the MK2:
 

[size=xx-small]Device Type[/size]	[size=xx-small]Solid State (JFET, Bi-Polar Transistors)[/size]
[size=xx-small]Class of Operation[/size]	[size=xx-small]Pure Class A[/size]
[size=xx-small]Frequency Response[/size]	[size=xx-small]5Hz-50KHz +/-0.1dB[/size]
[size=xx-small]Signal-to-Noise Ratio[/size]	[size=xx-small]>100dB[/size]
[size=xx-small]Total Harmonic Distortion[/size]	[size=xx-small]<0.006%[/size]
[size=xx-small]Stereo Crosstalk[/size]	[size=xx-small]>85dB @ 1KHz[/size]
[size=xx-small]Gain[/size]	[size=xx-small]1x / 0dB, 3x / 9dB and 8x / 18dB[/size]
[size=xx-small]Input Impedance[/size]	[size=xx-small]50K ohms[/size]
[size=xx-small]Output Impedance[/size]	[size=xx-small]less than 1 ohm[/size]
[size=xx-small]Output Voltage[/size]	[size=xx-small]15Vpp (single ended), 30Vpp (balanced)[/size]
[size=xx-small]Output Power[/size]	[size=xx-small]1 Watt (single ended), 2 Watts (balanced)[/size]
[size=xx-small]Inputs[/size]	[size=xx-small]1 XLR input, 1 RCA input[/size]
[size=xx-small]Outputs[/size]	[size=xx-small]2 1/4" headphone outputs, 1 balanced XLR headphone output, 1 XLR pre-out, 1 RCA pre-out, 1 XLR loop out, 1 RCA loop out[/size]
[size=xx-small]Operating Voltage[/size]	[size=xx-small]100-120VAC or 220-240VAC[/size]
[size=xx-small]Power Consumption[/size]	[size=xx-small]15 Watts[/size]
[size=xx-small]Chassis Dimensions[/size]	[size=xx-small]14.5 (L) x 9.0 (W) x 5.0 (H) inches[/size]
[size=xx-small]Weight[/size]	[size=xx-small]12lb / 5.4kg[/size]

 

[MacedonianHero]

^ Definitely the GS-X (pre-Dynalo+) specs. 

 

[sachu]

cool.. not a bad looking chassis.. but damn whoever started the two box build design trend. 
 
 

^ Definitely the GS-X (pre-Dynalo+) specs. 
 

So we don't have the GSX Mk2 specs yet?

 

[thegrobe]

cool.. not a bad looking chassis.. but damn whoever started the two box build design trend. 


So we don't have the GSX Mk2 specs yet?

Oh my bad...haha shows what I know

 

[Radio_head]

MH - that's what I figured.  Haven't kept up that well with the GS-X thread, do you happen to know (or has Justin posted) the updated specs?  Are all specs changed across the board even for MK1 units with upgraded modules?
 
The faceplate is really sharp in person.  The top unit is surprisingly light while the bottom is surprisingly beefy.  Personally I like two box builds though I've never done any real testing between the same amp with/without external power.  I especially like the two box builds when the forms factors line up aesthetically.  BA, GS-X, many B22 builds are all great examples of two-box affairs that really aren't bothersome (although some umbilicals can be super annoying.)

 

[Gary in MD]

Quote:

You won't like the GS mk1 series much either then.

I heard the GS-X mk II at a meet in the DC area a couple of months ago.  I didn't think it was special in any way.  On the other hand, the Stax SR-007 on the BHSE... that was pretty special.  I'm still trying to figure out how I get that sound for pennies on the dollar (yeah, I know I probably can't, at least legally).

 

[Solude]

Power is 48Vpp balanced, 6W pure class A into 50ohm on tiny little heatsinks.  I believe Kevin measured it at 8W into 50ohm but conservatively... 6W.  I wonder why the LAu isn't cranked on bias with those massive sinks.  105mA is kind of sad given the 240mA of the single ended GS-X mk2 and 320mA of a single ended B22.  Frankly at 105mA, you can probably run bare.

 

[preproman]

I thought a stock B22 was about 120 to 160mA.  I'm going to bump mines up to around 200mA..

 

[fishski13]

Quote:

I thought a stock B22 was about 120 to 160mA.  I'm going to bump mines up to around 200mA..

 
the quiescent current bias and the topology of the output devices determine the total Class A.  since the B22 is a push pull Class A design, it will do 2x the quiescent current bias - so 160mA quiescent current bias will equal 320mA Class A per L/R channel.  if an amplifier is a single ended design with only one output device and a quiescent current bias of 160mA, then it will only do 160mA Class A and will clip above this bias. 
 
a balanced B22 will still only do 320mA Class A per L/R channel if the quiescent current bias is 160mA since the (+) and (-) across the driver are in series with one another.

 

[Solude]

Thanks for the reminder about bridging.  Corrected the original numbers.

 

[dBel84]

Quote:

Power is 48Vpp balanced, 6W pure class A into 50ohm on tiny little heatsinks.  I believe Kevin measured it at 8W into 50ohm but conservatively... 6W.  I wonder why the LAu isn't cranked on bias with those massive sinks.  105mA is kind of sad given the 480mA of the balanced GS-X mk2 and 320mA of a single ended B22.  Frankly at 105mA, you can probably run bare.

 
I have been informed that the GSXii manual reports 23Vp-p unbalanced spec. I am not sure about the actual bias , perhaps Justin can clarify as those SMD devices would be cooking. I am assuming your 105mA references the LAu. You are way off even for a single output , this IS the reason the LAu needs those heatsinks, it is so OTT that it will never go into AB mode driving any headphone currently in circulation. I will ask Alex to post the specs in the LAu thread and put this nonsense speculation to rest. The LAu is currently the most powerful dedicated headphone amp commercially available. 
 
For some reason people feel this is a contest , it is not. Both amps, are power houses, both are well built and both deserve a chance to prove themselves. Lets stop this kindergarten behaviour and move along. 
 
..dB

 

[Solude]

Justin numbers  He's also stated the output is biased to 30mA per device.  And yes it runs hot by headamp/preamp norms ~50C.
 
- Pure Class A output for the first 550 mW (50R) of output (extremely clear low level detail)

 

[dBel84]

LAu runs +/-24V rails. Measured data indicates a practical 31V peak for each channel (iirc 33ohm load) or 62V peak to peak. At 50 ohms this is about 620mA into the load or almost 10W (31 * 31 / 100 = 9.6W) of continuous sine wave power. OR a peak impulse power of 18W
 
NOW can we move on. 
 
..dB
 
EDIT : http://www.head-fi.org/t/659303/cavalli-liquid-gold/240#post_9668794 Alex has posted in the Liquid Gold thread 

 

[Saraguie]

Does all these measurements mean my Fiio E10 is not as good as a LAu? And is LAu like something I eat at a Luau, like LAu LAu?
 
Seriously, am I the only one who subscribes to this thread that is 90% lost about the meaning of what you guys in the last~ say 10 posts are talking about?

 

[MacedonianHero]

Quote:

Does all these measurements mean my Fiio E10 is not as good as a LAu? And is LAu like something I eat at a Luau, like LAu LAu?
 
Seriously, am I the only one who subscribes to this thread that is 90% lost about the meaning of what you guys in the last~ say 10 posts are talking about?

L = Liquid
Au = Gold (Latin Aurum) on the periodic table of elements Au, 79