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Jul 18, 2015 at 7:08 AM Post #196 of 25,848
Component count isn't a central aspect when it comes to compare the (dis)advantages of SE vs. balanced – the latter is always more expensive. jcx's argument is that you may very well benefit from the advantages of a balanced system without the disadvantages mentioned by Rob Watts, as above scenario seems to show.
 
I'm by no means a proponent of balanced design, just interested to know what's up with it. In this context my question: Doesn't signal inversion have some degradation potential when implemented in a balanced configuration? (Like e.g. negative feedback.)
 
Jul 19, 2015 at 1:38 AM Post #197 of 25,848
Component count is very important for transparency. Doubling the number of parts in the direct signal path does degrade depth perception and detail resolution.
 
But there is another problem with balanced operation. Imagine a balanced differential in, differential out amplifier. The input stage is normally a differential pair (maybe cascoded) with a constant current source. Now the input stage is free to move up and down to accommodate the common mode voltage - but the input stage common mode impedance is non linear, and if the common mode voltage has a signal component (it always will have due to component tolerances) then this will create a signal dependent error current, thereby generating distortion. Unfortunately, the negative feedback loop of the amplifier can't correct for this distortion as it can't see the error on the summing nodes. So there will always be a limit to the performance. With SE operation, this problem does not occur, as the differential input stage is clamped to ground.
 
Now DAC designers are well aware of this - that's why all high performance DAC's use two single ended I to V converters from the current OP of the DAC's, then use a differential to SE converter to create the voltage OP. There are other reasons for doing this as well, as the DAC requires a very low impedance virtual ground for low distortion, and you can only get this using dual SE amps - another problem is RF and its much easier to decouple SE than differentially - this in turn creates a lot more noise floor modulation, making it sound less smooth.
 
But for me the most important is transparency. I had an amp that had two modes - differential or SE - listening in balanced mode flattened the sound stage depth dramatically,and it sounded harder, less smooth. That said, there are circumstances when balanced operation can be better than SE, for example when you are looking at connecting a pre-amp to a power amp, and what is best depends upon particular circumstances. In short, if SE operation is noisy, try balanced.
 
Rob 
 
Jul 27, 2015 at 5:28 AM Post #200 of 25,848
rob watts said:
  I will be talking about the amplifier stage soon.
 
Rob
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at that cost the amp section should sound better and higher quality than my 2000$ amp, i mean it seriously should....
 
else you guys (at this price) should have gone for a DAC only DAVE and made the it (price wise) more obtainable by us head-fiers who can afford most of the high end gear.
 
Jul 30, 2015 at 7:04 PM Post #203 of 25,848
Now we have 3 super TOL DAC that offer a very serious Headphone-out :  TotalDac D1,  NAGRA HD DAC and the DAVE.
 
- I tested the headphone OUT of the TotalDAC D-1 Dual, and it was EXCELLENT with a HD800 and also another headfier uses it with his ABYSS !! (on the XLR Balanced output instead of the SE JACK in order to get 6 volts)
 
 
 
- I also tested the headphone output of the NAGRA HD DAC with my LCD-X and is was also excellent. And  6Moon recommend it with the HD800. Same for Hifi+.
 
    ->  does someone know the specs of the NAGRA internal headphone AMP ? do you know if it makes usage of the vacum Tube inside the DAC ? 
 
 
 
- So, now the question becomes: how good and powerful is the headphone-out of DAVE ? Can it drive also an ABYSS to it's full potential  ?   Is it more powerfull than the TT headphone-out ?
 
  

 
Jul 31, 2015 at 7:21 AM Post #204 of 25,848
bmichels

Please try one thing,I suspect that Vega might have enough power to drive LCD X without any amp,its Orfeo output 1 ohm impedance and 4.5v in balanced output.It have two three pin male XLR output for balanced signal and your LCD X cable have one 4 pin male,I suggest get 4 short copper wires and connect them in non permanent way with glue or tape between Vega and LCD,3 + 3 is 6 not 4 like your audeze cable,one pin in each 3 pin xlr vega output is for electrical grounding so leave them alone,know whitch one they are becose if you accidently connect ground to lcd 3 you get no sound
 
Jul 31, 2015 at 9:28 AM Post #206 of 25,848
Its 5 bits at 104 MHz, 17th order. The noise shaper gives 350dB THD and noise digital domain performance - that's way better than usual (140 dB is typical).
 
The noise shaper will resolve an audio signal to 48 bit accuracy.
 
Rob
 
Jul 31, 2015 at 9:38 AM Post #207 of 25,848
Rob, 
 
How powerful is the headphone-out of DAVE ? Are there some specs published yet ?
 
Can it drive also ABYSS to it's full potential  ?   Is it much more powerful than the TT headphone-out ?  
 
And compared to the headphone out  of the  NAGRA HD DAC or of the TotalDAC D1-Dual headphone out (which is on the back, and VERY powerful) ?
 
Thansk
 
Jul 31, 2015 at 9:49 AM Post #208 of 25,848
Rob Watts,thats awesome,thats highest data output dac that I know.
 
One thing worries me,you create best dac in the world but its all limited by the output stage/preamp/headphone amp.I worry especialy about crosstalk,how much crosstalk will dave have between 20hz and 16000hz? I cant hear higher than 16khz 
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 Also how much noise will there be once it comes out of the preamp/headamp in the DAVE?
 
Jul 31, 2015 at 10:03 AM Post #209 of 25,848
goobicii said:
  Rob Watts,thats awesome,thats highest data output dac that I know.
 
One thing worries me,you create best dac in the world but its all limited by the output stage/preamp/headphone amp. I worry especialy about crosstalk,how much crosstalk will dave have between 20hz and 16000hz? I cant hear higher than 16khz 
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 Also how much noise will there be once it comes out of the preamp/headamp in the DAVE?
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What do you mean by that?
 
Jul 31, 2015 at 10:17 AM Post #210 of 25,848
jazz said:
   
What do you mean by that?
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modern high end DACs arent in my opinion limited by the dac chip inteslf but by the analog output stage/pre amp or headamp thats in the DAC
 
most manufacturers list fantastic specs and they are not lying but what the DAC spits out after output stage into dedicated amp or headphone is degraded by the amplification.The dac chips themself make very little power,it needs to amplified and that adds noise.Another thing is you can theoreticaly make xilinx FPGA + dac combo capable of 9999999999999999999999999999999999999999999999999999db dynamic range but thats all limited by how good the power supply is,last thing,many amps and dacs suffer from crosstalk.If something have -90db crosstalk that doesnt rise within audible range thats good performance.For me crosstalk is just another form of distortion,so dac that measures 130db signal to noise but have -70db crosstalk at 18khz is in my book a 70db dynamic range not 130db.Best option is monoblock,some dacs like VEGA have monoblock like crosstalk performance,but that is very rare.
 
Yggy have perfect theoretical chips but the cheap 2200 dollar execution left it with 90db crosstalk so in reality its 15bit dac,an example how output stage and powersupply can affect theoreticaly superb chips
 
 
DAVE in my opinion have theoretical potential to be best dac ever made,I repeat that,most accurate most advanced dac on this planet ever created,but that all can be destroyed by output stage and powersupply that isnt perfect.
 
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