[Magister Mundus]

About the LME49990 op-amp...
 
I have a Xonar STX card and would like to buy 3x in order to try the combination, but I'm not sure where to buy it.
 
Ebay?
 
Can someone please direct me to the cheapest one on eBay for "3x quantity" who ships to Brazil?
 
Thank you.

 

[mrlimbo]

Quote:

About the LME49990 op-amp...
 
I have a Xonar STX card and would like to buy 3x in order to try the combination, but I'm not sure where to buy it.
 
Ebay?
 
Can someone please direct me to the cheapest one on eBay for "3x quantity" who ships to Brazil?
 
Thank you.

frugalphile on Ebay comes highly recommended , many on here have bought from him 
 
http://www.ebay.co.uk/itm/190762476231?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[mrlimbo]

Quote:

 
Interesting. What was terrible about it?

The sound !!

 

[demontux]

how good the STX with the Q701 ? does it give them any added fullness or improve them ? how does the amp of the STX work with Q701 ? (not talking just on volume) does it add or get them to their full potential ? thanks

 

[foreign]

Double amping for me created low amounts of white noise which isn't the external amp but the card ?? Initially thought it was the tube amp but after a replacement and buying an external dac to test it everything was flawless. Just seems the stx doesn't like an additional source in my case anyway lol

 

[bcschmerker4]

Quote:

Double amping for me created low amounts of white noise which isn't the external amp but the card ?? Initially thought it was the tube amp but after a replacement and buying an external dac to test it everything was flawless. Just seems the stx doesn't like an additional source in my case anyway lol

For an external amplifier, e.g. my Pyle® PCA-2 40Wx2 RMS solid-state power amp, I prefer to tap from the dual-RCA analog output to get around any noise-floor issue that double-amping would cause.  The onboard Texas Instruments® TP6120A2 does generate a small amount of noise at its outputs, as is the case with most amplifiers - nature of analog electronics.

 

[foreign]

Ino

For an external amplifier, e.g. my Pyle® PCA-2 40Wx2 RMS solid-state power amp, I prefer to tap from the dual-RCA analog output to get around any noise-floor issue that double-amping would cause.  The onboard Texas Instruments® TP6120A2 does generate a small amount of noise at its outputs, as is the case with most amplifiers - nature of analog electronics.

I noticed this aswell that's why I bought an external little dot dac 1 to pair with my tube amp. For gaming I really do love the stx but for music the tube amp and little dot dac via toslink or USB does just have a little more warmth/bigger soundstage and airiness to it. For some reason the RCA out on the STX just used to produce a bit of distortion out of the tube amp. Maybe its just my pc but with USB or digital Toslink its completely gone and sounds flawless.

 

[xeizo]

It's not very strange the ST/STX distorts when using the RCA:s in some combinations, that's because ST/STX outputs a more powerful signal over RCA than what most consumer electronics are constructed to handle. It works fine with professional equipment, but not with all consumer gear.

The solution is very simple, just turn down the volume on the ST/STX to max 76% of full volume or -6dB and it will output a more standard signal = no more distortion!

 

[foreign]

It's not very strange the ST/STX distorts when using the RCA:s in some combinations, that's because ST/STX outputs a more powerful signal over RCA than what most consumer electronics are constructed to handle. It works fine with professional equipment, but not with all consumer gear.

The solution is very simple, just turn down the volume on the ST/STX to max 76% of full volume or -6dB and it will output a more standard signal = no more distortion!

No it's still there the distortion using RCA is at low level volume aswell as high. It's as if the stx isn't shielded properly as the tube amp is quite powerful it picks up everything. If I use any other source there isn't distortion no matter what volume is set at laptop, iPod , CD player , DVD player. So its safe to say its the stx and not my as you put it consumer grade tube amp .

 

[stv014]

Quote:

No it's still there the distortion using RCA is at low level volume aswell as high. It's as if the stx isn't shielded properly as the tube amp is quite powerful it picks up everything. If I use any other source there isn't distortion no matter what volume is set at laptop, iPod , CD player , DVD player. So its safe to say its the stx and not my as you put it consumer grade tube amp .

 
Shielding should not affect distortion, only noise. Do you really get distortion (like clipping), or noise/interference that is there even when nothing is playing ? If the latter, and it only appears with the tube amp, you may have a ground loop. If it is really distortion, even at relatively low volume, you may have a faulty card, because it should not distort, even at 100% volume.

 

[foreign]

The distortion only happens when there's no noise if I move the mouse for example I can actually hear it through the headphones. When I connect via:
1. stx - spidf (toslink) - ext dac -tube amp - hd650 there's no distortion.

2. stx - RCA out - tube amp - hd650 distortion present.

3. Stx - double amp (tube amp) - hd 650 distortion present.

4. (if i dont use Stx in the equation) USB - ext dac - tube amp - hd650 there's no distortion.
Mind you the amp is always plugged into the same power socket from the wall. Guess it could be as you said ground loop issue.

 

[stv014]

Quote:

The distortion only happens when there's no noise if I move the mouse for example I can actually hear it through the headphones. When I connect via:
1. stx - spidf (toslink) - ext dac -tube amp - hd650 there's no distortion.

2. stx - RCA out - tube amp - hd650 distortion present.

3. Stx - double amp (tube amp) - hd 650 distortion present.

4. (if i dont use Stx in the equation) USB - ext dac - tube amp - hd650 there's no distortion.
Mind you the amp is always plugged into the same power socket from the wall. Guess it could be as you said ground loop issue.

 
Did you also try STX (headphone output) -> HD650 ? If that is not noisy, then a ground loop is a likely explanation, and is also a common problem for other people who use a grounded external amplifier. Using the same power socket can help to eliminate AC hum from ground loops, but when the source of the ground noise is the computer, it might not fix the problem.

 

[germanium]

Quote:

The distortion only happens when there's no noise if I move the mouse for example I can actually hear it through the headphones. When I connect via:
1. stx - spidf (toslink) - ext dac -tube amp - hd650 there's no distortion.

2. stx - RCA out - tube amp - hd650 distortion present.

3. Stx - double amp (tube amp) - hd 650 distortion present.

4. (if i dont use Stx in the equation) USB - ext dac - tube amp - hd650 there's no distortion.
Mind you the amp is always plugged into the same power socket from the wall. Guess it could be as you said ground loop issue.

 
Sounds like a ground loop problem to me. I have had that exact problem before & it was a ground loop. I eliminated the ground loop & the noise disappeared. What you are hearing is not distortion but electrical noise generated by the computer when the power supply it worked. this noise would normally be eliminated by the ground circuit but if there is a ground loop it won't be eliminated but fed back. Often this is worse than not being grounded at all. With this last statement I want to say I do not recommend eliminating ground as the ground is a safety feature. Only that you need to find the source of the ground loop.

 

[foreign]

Sounds like a ground loop problem to me. I have had that exact problem before & it was a ground loop. I eliminated the ground loop & the noise disappeared. What you are hearing is not distortion but electrical noise generated by the computer when the power supply it worked. this noise would normally be eliminated by the ground circuit but if there is a ground loop it won't be eliminated but fed back. Often this is worse than not being grounded at all. With this last statement I want to say I do not recommend eliminating ground as the ground is a safety feature. Only that you need to find the source of the ground loop.

Straight out of the stx its fine no problems at all. It really sux because I really do enjoy the tube sound amp for music. What I'm doing is using just the Stx for gaming with senns pc360 and if I listen to music I use the external dac and amp via USB with the hd650. Best of both worlds. The Stx is great for gaming and I like using Dolby for directionality. The Stx is also good for music but I do prefer the tube sound. ill keep trying to isolate the grounding noise with either a filter or grounded Rcas in the future it might not help but its worth a try. I really did think it might be the case thank you for trying to help me with this dilemma I really appreciate the feedback.

 

[beepover]

I ordered two LM6172's. Should I have ordered 3 and replaced all the opamps on the STX? I have an HD650 and HD600 and hoping the LM6172's give me more focused sound stage (right on stage with musicians), warm sound and high extensions. At least that is the op amp I am looking for. Any recommendations anyone? Should I get a tube amp? Little Dot III or DarkVoice 336.
 
beepover@aol.com
 
Victor