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How to prevent amplifier from picking up interference from computer? - Page 2

post #16 of 49
11/3/12 at 12:45pm

Try a cheater plug then just to see what happens. They only cost a couple of bucks. If the cheater plug doesn't work, then you know you have to look harder for a solution.

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post #17 of 49
11/3/12 at 1:21pm
Thread Starter 

I don't live in America so I can't use 3-to-2 prong adapter/cheater plug. And even if there were one for European outlets I would avoid the dangerous risks of using one, as I mentioned before.

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post #18 of 49
11/3/12 at 2:20pm

Have you tried a GFCI strip/outlet?

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post #19 of 49
11/3/12 at 3:09pm
Thread Starter 
Quote:
Originally Posted by chewy4 View Post

Have you tried a GFCI strip/outlet?

I haven't. I'll look into it but I have a feeling it won't so much solve the problem I'm having.

 

I have been considering trying out the Ebtech HumX... But since I live in Europe I will have to get a 110V to 220V converter to use it. It should be the safe alternativ to cutting the ground pin or using a cheater plug, and without causing any loss in frequencies if using an isolator. Question is if any of these alternatives will work...

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post #20 of 49
11/3/12 at 4:45pm
Quote:
Originally Posted by boyyo View Post

I don't live in America so I can't use 3-to-2 prong adapter/cheater plug. And even if there were one for European outlets I would avoid the dangerous risks of using one, as I mentioned before.

 

My point was to try one just to see if that solved the problem, in case the issue is not related to the ground loop. If the cheater plug doesn't solve the issue, then you have noisey PC. 

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post #21 of 49
11/4/12 at 9:10am
Thread Starter 

Obviously I might avoid getting the CI-2RR isolator... Mayhaps I will look into the Lundahl trafos for ~200 euro for 2x. But at this point I'm seriously considering getting an external DAC, run it through S/PDIF on the Essence ST which will instead become the bridge.. but keep it for the purpose of connecting the 5.1 system via the H6 extension. I think that option would be a cheaper solution than getting through the trouble of getting a high-end isolator that will STILL degrade the frequencies to some degree, may it be by a margin.

 

Question is: would an external DAC via coaxial bypass the opamp section of the Essence? I'm guessing yes..

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post #22 of 49
11/4/12 at 9:31am

Yeah, it would bypass it. The only thing the ST would be doing at that point is adding dolby headphone to the sound if you have it enabled.

 

However, I worry that you might still have some issues with coaxial. Probably not, but I would go optical just to be safe.

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post #23 of 49
11/4/12 at 10:00am
Quote:
Originally Posted by chewy4 View Post

However, I worry that you might still have some issues with coaxial. Probably not, but I would go optical just to be safe.

 

And in that case, if the motherboard audio has optical out, it might be as cost effective to sell the ST on ebay and get a desktop DAC/headphone amp that also has RCA output for your amplifier. Something like the Matrix Cube.  

 

I don't have a bias against the ST. I have the STX. But if I had been dealing with this problem like you had, I'd look for a different solution, and one that is more elegant than running another DAC off the ST. I just ordered a Little Dot I+ last week, and if the STX and the Little Dot don't play nice, the STX is going out the door.  For instance, I just picked up the Fire Phoenix for $100 for use in another setup and compared it to my STX. I really couldn't tell any audible difference. I don't recommend that desktop DAC/amp given that there seem to be quality control issues, but I'm sure that there are alternatives that are within your budget range. 

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post #24 of 49
11/4/12 at 10:04am

Another long shot.

Replace your current 3 op-amps (operational amplifiers) with shielded LME49720HA op-amps (Metal TO-99).

Most Essence owners seem to like the sound quality of the LME49720 op-amps as an upgrade to the stock op-amps.

Hopefully the shielding (TO-99) will reduce or eliminate the noise problem.

If it was the (unshielded) op-amps in the first place that was the cause of the noise problem.

 

This seller seems to have good feedback from other Head-fi that have bought from him (Frugalphile).

http://www.ebay.com/itm/LME49720HA-LME49720-TO99-DIP8-/190747097228?pt=US_Amplifier_Parts_Components&hash=item2c6969b88c

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post #25 of 49
11/4/12 at 10:25am
Quote:
Originally Posted by cel4145 View Post

My point was to try one just to see if that solved the problem, in case the issue is not related to the ground loop. If the cheater plug doesn't solve the issue, then you have noisey PC. 

 

From the OP - which states that the problem is fixed by a cheap ground loop isolator transformer, and nothing else - it is already quite clear that the noise is indeed caused by a ground loop. Another simple test is to connect the headphones directly to the sound card (which could possibly drive the headphones fine in the first place).

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post #26 of 49
11/4/12 at 10:26am
Thread Starter 
Quote:
Originally Posted by PurpleAngel View Post

Another long shot.

Replace your current 3 op-amps (operational amplifiers) with shielded LME49720HA op-amps (Metal TO-99).

Most Essence owners seem to like the sound quality of the LME49720 op-amps as an upgrade to the stock op-amps.

Hopefully the shielding (TO-99) will reduce or eliminate the noise problem.

If it was the (unshielded) op-amps in the first place that was the cause of the noise problem.

 

This seller seems to have good feedback from other Head-fi that have bought from him (Frugalphile).

http://www.ebay.com/itm/LME49720HA-LME49720-TO99-DIP8-/190747097228?pt=US_Amplifier_Parts_Components&hash=item2c6969b88c

That would be a LONG shot biggrin.gif

 

Among the opamps I currently have, I also have LME49720NA, the ones without the shielding. But I'm very sceptical to it actually eliminating the noise since it seems clear it is a ground loop or interference from the GPU. I could always try ONE since it's like 12 bucks with shipping, I assume I only need one since the RCA only uses the buffer slot and not the I/V opamps?

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post #27 of 49
11/4/12 at 10:28am
Thread Starter 
Quote:
Originally Posted by stv014 View Post

 

From the OP - which states that the problem is fixed by a cheap ground loop isolator transformer, and nothing else - it is already quite clear that the noise is indeed caused by a ground loop. Another simple test is to connect the headphones directly to the sound card (which could possibly drive the headphones fine in the first place).

It's true, I have no ground loop noise when connecting the headphones directly to the soundcard. But I want to use my tube amp rather than the amp on the ST.

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post #28 of 49
11/4/12 at 10:34am
Quote:

Originally Posted by boyyo View Post

 

What would you say for the LL6810 then? I have less knowledge about transformers.

Here's the datasheet for the model: http://www.lundahl.se/pdf/6810.pdf

 

It does not have quite as detailed specifications as the Jensen, but it apparently has less high frequency roll-off, but significantly more distortion. It also has lower resistance (both input and output). In any case, if it costs 200 €, from that price you could get an external DAC with optical input, or a USB DAC + USB isolator.


Edited by stv014 - 11/4/12 at 10:40am
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post #29 of 49
11/4/12 at 10:37am
Quote:
Originally Posted by boyyo View Post

It's true, I have no ground loop noise when connecting the headphones directly to the sound card. But I want to use my tube amp rather than the amp on the ST.

Have you tried setting the Essence ST headphone amp. to it's lowest gain setting and plug the tube amp. into the Essence ST's headphone jack?

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post #30 of 49
11/4/12 at 10:41am
Quote:
Originally Posted by PurpleAngel View Post

Have you tried setting the Essence ST headphone amp. to it's lowest gain setting and plug the tube amp. into the Essence ST's headphone jack?

 

It would not help.

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