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XONAR STX and Vanguard TCXO: disappointment - Page 3

post #31 of 39
12/19/11 at 1:01pm
Thread Starter 

Good point

 

My amp run very hot when fed with HF noise, so I used to think it was spending a lot of energy amplifing that noise, I didn't consider the interaction between switching frequency and noise frequency... 

 

Anyway, returning to the original topic, if someone could help me to make the vanguard working properly I'd be very happy

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post #32 of 39
12/19/11 at 9:24pm

It may be that you got a bad sample. It may also be the extra wiring needed to adapt the crystal to your board. Could also be the wiring itself adding some small amount of distortion due to the dielectric properties of the insulation. You also have extra inductance of the wiring itself where even with short lengths can cause issues in some situations if the wiring length is increaded over the original length.

 

When a freind of mine that used to be the lead sound engineer for A&M records (he maintained all of their sound equipment as well as designed & built some of it) built his own amp. All signal carrying wiring was insulation free, even that that had as much as 400 volts on it. The amp was impecably built & never had any problems as all lines that had high voltage on them were well seperated from any potential places that could arch.The only high voltage lines that were signal carrying lines that had any insulation on then was the lines coming from the output transformers & these had 830 volts on them! All this was done to reduce any signal smearing caused by the insulation & the wide spacing between these eliminated any potential arch places also reduced what is known as miller effect which can reduce the bandwidth of the amp by keeping the input wiring well away from the ouput wiring. Insulation can store & release energy at the wrong time. This can possably work against you  with your crystal. 

 

Not that this is your case as you are dealing with low voltages but when dealing with high voltage low current signals dielectric proerties become a major factor in the qualty of the amp. Losses pile up very quickly under these conditions.Air has very low storage capacity so reduces distortion due to the dielectric to the lowest practical limit. Only vaccume is lower in storage but that is not practical in most cases.

 

You can try to eliminate the insulation of your add on wiringbeing very carefull of the routing to keep away from any place it could arch to see if that helps. You may be having trouble with the extra lenth of wiring needed to adapt the crystal to your card as well , if this is the case then you may be out of luck.


Edited by germanium - 12/19/11 at 9:32pm
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post #33 of 39
12/20/11 at 12:20am
Thread Starter 

Germanium, this is a very good idea

 

While I'm aware of insulation induced distortion (all of my signal cable are made from enamelled or cat 5 wire), I don't know why I didn't take care of it in this case, and used a normal multistranded wire !!

 

And here we are talking about a 24 Mhz signal !!!

 

My big fault

 

I'll try to replace it with cat 5 or enamelled 0.5 mm coil wire

 

 

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post #34 of 39
12/20/11 at 2:55am
Thread Starter 

Ok, replaced the oscillator output cable with a naked cat 5 wire

 

Well, things seems improved, instruments definition and focus are ok, sound stage is good, but ... I don't know, the music is still uninteresting, uninvolving, voices have quite a metallic flavour, especially on sibilant, and the overall feeling is like listening to something syntesized instead of the real event

 

With the stock quartz you have more sense of warmth in the music, more presence, but anyway I can't go back anymore, one of the old quartz soldering pad came away during last desoldering ...

 

 

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post #35 of 39
12/20/11 at 6:03am
Thread Starter 

Just tried to solder the oscillator output pin directly to the PCB, no more wires, but same result, cold, edgy and unpleasant sound

 

I'm concerned about grounding anyway: the oscillator ground PIN is connected to a ground point near the old quartz, and VDD pin to the +5V of a dedicated low noise regulator, with regulator input and ground connected to the PC molex +12V

 

Don't know if would be better to connect oscillator GND to the regulator ground

 

 

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post #36 of 39
1/4/12 at 1:28pm

Sorry, but calling the Essence One a step up from the STX is not knowing your chips ;-)

The Essence One uses the inferior 1795 instead of the 1792A. And a 4 digit dac does not outshine the the stx. I know. My friends know, and many more people know. I came from a DAC12 Marantz combo and also used a Marantz SA7S1, which both are put to shame by the STX. I did mod my STX to balanced output directly from the I/V stage without coupling caps and straight into my Nelson Pass pre amp. I have heard systems of 100.000 euro onwards, but this little tweaked combo shines magnificently. I also use jplay in full hibernation mode.

regards.

 

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post #37 of 39
1/4/12 at 1:48pm
Quote:
Originally Posted by Phiton View Post

Sorry, but calling the Essence One a step up from the STX is not knowing your chips ;-)


It would be best to rely on measurements, not the names of chips which may or may not be utilized to their full potential.

 

Anyone know of third-party measurements of the One?

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post #38 of 39
1/9/12 at 12:06am
Thread Starter 
Quote:
Originally Posted by Phiton View Post

Sorry, but calling the Essence One a step up from the STX is not knowing your chips ;-)



I have to say that while listening to my STX now, after all mods, I can't imagine how a DAC could perform better

 

The sound is so amazingly detailed and alive, full of warm and punchy bass

 

I just tried to swap out the 3x 4562 for 3 x lm 49990 mounted on adapters; the result is quite impressive about detail and instrument microtexture, but bass lost some weight, and overall sound is too dry for my taste

 

Is not harsh or cold, just dry, no meat around instrument, no warmth, less musical than 3 x 4562

 

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post #39 of 39
5/29/12 at 2:04pm

gb

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