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UPGRADING THE CRYSTAL (X0) ON ESSENCE STX - Page 15

post #211 of 238

I took a look on my STX, there is two power regulators (one for 12V and one for 5V):

 

5V@1A is a AZ7805D (TO-252) marked as U20:

http://www.bcdsemi.com/ASP/productpic/2004981742391148.pdf

 

12V is a 7812 (TO-252) marked as U24.

 

X1: 24.576MHz @ 5V (so called crystal or TCXO).

 

I'm planning to change OPAs too.

 

1st option LME49720HA+OPA2111SM.

2nd option 2xOPA-Earth + 1xOPA-Sun

 

And of course the crystal.

 

Last mod would be the capacitors to Premium type (better than Fine Gold).

 

About the OPAs, what's better?  1st option or 2nd one?

post #212 of 238

Update: Brought Bursons and did wonders!

 

I used AZ7805D (U20) for +5V and GND as well.

post #213 of 238
Quote:
Originally Posted by catx View Post

I've just upgraded my ST with the 0.3ppm Vanguard you can find on ebay

 

 

 

 

Sound improvement is definitely huge!



Hi catx, please can you tell me in which way the sound is better? I'm thinking on getting one of this cards... so your impressions would be great :D 

post #214 of 238
Quote:
Originally Posted by thoppa View Post


BTW, have you measured the output DC offset on the output without the coupling caps ? I imagine it's quite high (2 volts dc or more ?) but I assume that you are feeding the signal into gear that has input coupling caps ?

My card is finished. I'd say the XO made the biggest difference, replacing the ceramic feedback caps and using a linear PSU were tied for second. Replacing the output coupling caps comes a close third. Replacing the decoupling power caps came last. After all the changes, I rolled my fave op amps for a week or two and I settled on LME49720HA in the I/V and AD8620BR in the buffer.



Actually all my amps are D.C. coupled & are capable of amplifying D.C.. I found that by direct coupling the line out of the Essense STX card you can actually reduce the D.C. offset of any direct coupled or D.C. coupled amp from the output of practically any such amp following it.

 

post #215 of 238
post #216 of 238


Yes! 

post #217 of 238

Has any other guy changed the crystal,so as to tell us what the quality upgrade is?I have a ST card,having changed the opamps only.

post #218 of 238
Quote:
Originally Posted by Theodore View Post

Has any other guy changed the crystal,so as to tell us what the quality upgrade is?I have a ST card,having changed the opamps only.



You already have better timing with the ST as it has a secondary chip that cleans the XO signals further.

 

This chip is only found on the ST.

post #219 of 238

 

I am ready to change the crystal on my essence ST but I have this question.

What is the difference between:

Vanguard Ultra precision Golden TCXO, 0.3ppm 24.576MHz and Vanguard Ultra precision TCXO 1ppm 24.576MHz.  (both found on ebay)

And which is better.

post #220 of 238

If im doing this upgrade on my ST, what is the effect ill be hearing on my music?

post #221 of 238

Better sound of course...

 

 

BTW, Thanks the guyz who posted before, nice explaination.

post #222 of 238
Quote:
Originally Posted by Theodore View Post

Has any other guy changed the crystal,so as to tell us what the quality upgrade is?I have a ST card,having changed the opamps only.



The best way to keep constant the frequency is to maintain the temperature at 25 degrees Celsius and filter feeding by intermodulation. After the above we can change and the local oscillator.Then, perhaps! you can hear the difference.

 

---The best way it's the only way--- !!! 

post #223 of 238

Nice thread! 

post #224 of 238

Hi everyone!

 

I am about to upgrade my STX situated in a GZ-M1 box from Gigabyte

The space left from the sidecover to the cards is 37 mm , and from card top to my video card is 28 mm

Is there any chance to build in a burson discrete set, or change to ST, place the card to an upper pci socket?

(The card above the stx is an XTREME MUSIC with PCI slot)

 

Thanks!

 

 

IM009006.JPGIM009016.JPGIM009009.JPG

 

 

post #225 of 238

First post... and reviving an old thread. I bought one of those vanguard clocks and I'm going to try this mod. 

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