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Bottlehead Crack interference

post #1 of 24
Thread Starter 

I just picked up a bottlehead crack, and I am getting some interference through it. It was worse until I changed to a different plug, but the interference is still very audible when music isn't very loud. I am running rca to the Crack from my essence stx. The essence stx is setup with asio, bitperfect, playing media through jriver mc18. Just to test it out, I dug out some adapters and ran rca to the crack from the headphone out on the essence stx. The interference was completely eliminated that way, but unless I was hearing things, the sound wasn't as good from the headphone out to rca.

 

The rca cables are cheap, just what I had lying around until I can diy some better ones. I don't think it's a power cable issue because when i have no music running and crank the volume up, any kind of moving of windows or apps in win7 x64 causes more interference. I believe nothing else is being powered on the same cable run that connects to the essence stx, so I'm just trying to see if anyone has some input before I start redoing cable management. Any input would be great.

post #2 of 24
Thread Starter 
I've been playing with this for a couple of days now, and I can't figure it out. I got some double shielded rca cables, put some ferrite chokes on, and still get the interference. I'm running dual monitors, and have tried disconnecting both of them. I took my graphics card out of the system, and ran of the Intel hd3000. I redid the cables so that the essence stx was the only thing on that line from the power supply, and even tried a ferrite choke there. I moved the whole system to a different outlet on a different breaker. I know it's not the amp because I ran it straight from my phone and it was dead silent, no interference. The only thing I haven't tried yet is getting my old power supply, and having that run nothing but the essence stx, and my other power supply run everything else. I havrnt tried that because I'm not sure how safe that is.

Any thoughts or ideas would be greatly appreciated.
post #3 of 24

Did you try not grounding the amplifier or the PC ? Not that I would recommend doing that for regular usage (it is grounded for safety in case it fails), but if the noise disappears in a quick test, it confirms that you have a ground loop, which is a fairly common problem when using grounded external amplifiers with PC sound cards. I assume there is no noise at all if you simply drive the headphones with the Xonar STX, even from the line output with which you have the problem (it can drive headphones with an RCA->female TRS cable) ?

 

If the headphone output with an adapter works for whatever reason, it is recommended to use the medium ("300 Ω") gain, with 4-5 dB less than maximum volume to approximately match the level of the line output. You do lose about 10 dB of dynamic range, but the quality should still be good enough.


Edited by stv014 - 8/20/13 at 3:06am
post #4 of 24
Thread Starter 
Quote:
Originally Posted by stv014 View Post

Did you try not grounding the amplifier or the PC ? Not that I would recommend doing that for regular usage (it is grounded for safety in case it fails), but if the noise disappears in a quick test, it confirms that you have a ground loop, which is a fairly common problem when using grounded external amplifiers with PC sound cards. I assume there is no noise at all if you simply drive the headphones with the Xonar STX, even from the line output with which you have the problem (it can drive headphones with an RCA->female TRS cable) ?

If the headphone output with an adapter works for whatever reason, it is recommended to use the medium ("300 Ω") gain, with 4-5 dB less than maximum volume to approximately match the level of the line output. You do lose about 10 dB of dynamic range, but the quality should still be good enough.

I tried it again last night, and got interference from the headphone out. I haven't tried running it without grounding yet. What would be the quickest way to try that? One of those cheap extension cords with just the 2 prongs in the wall? I'd prefer trying it with just the amp, because a blown amp will put me back $300, and a blown pc will be closer to $2000. So if it is a ground, just get a ground loop isolator?
post #5 of 24

Do you mean you get interference when using the headphone output to drive your headphones, without the Bottlehead Crack ? If that is the case, then your problem is not a ground loop with the amplifier.

 

On the other hand, if you mean headphone (and also RCA) output to Crack is noisy, but not using the external amplifier is not, then a ground loop is a likely explanation. An isolator (basically an audio transformer) would fix it, but it may slightly degrade the sound quality if it is not a good one (which are not that cheap). Or you could use an external DAC with optical S/PDIF or isolated USB input. Or just use the Xonar STX alone.


Edited by stv014 - 8/20/13 at 11:58am
post #6 of 24
Thread Starter 
Sorry, should have clarified. Driving the headphones straight out of the stx is fine, anything run to the crack is noisy. My next step is going to be an external dac, but in the meantime I need to lose the noise. Driving me nuts.

How much degradation will come from an isolator, and what is the sweet spot in price vs performance for not too much degradation? Don't bother spending time on research if you're not sure, just looking for a ballpark. Is there any easy way to try running it unfounded? like one of those cheap extension cords that has 2 prongs in the wall, but accepts a 3 prong plug? Thanks for the relies btw.
post #7 of 24

It is not worth spending much on it if you are going to get an external DAC anyway (just make sure you do not buy one that will also be affected by the same problem). Here is a decent transformer that costs $178, but I do not think it is worth it, especially as a temporary solution.

post #8 of 24
Thread Starter 
Is there anyway to tell if a dac will suffer the same affliction? I have been looking into a few different options. Schiit bifrost or maybe a modi, hrt music streamer ii+, good used deal on an essence one, or something comparable in the up to $400 range used or new. I hear arguments for and against the usb vs optical, so I'll just have to read up on that one. The new essence stu seemed interesting, but just seems like an upgraded version of the stx.
post #9 of 24

I'm getting the same beeping hiss interference from my internal x-fi titanium hd using the RCA outputs to my Asgard 2. I'm pretty sure its from the sound card since i ran an ipod to LOD to rca to the amp and didn't get the same hiss and beeps with my computer off. I even have the asgard 2 on a power conditioner so it maybe a ground loop. I was about to order some shielded RCA cables from blue jeans cable but seeing your problem is similar it may not fix it. 

post #10 of 24
Thread Starter 
Quote:
Originally Posted by xero404 View Post

I'm getting the same beeping hiss interference from my internal x-fi titanium hd using the RCA outputs to my Asgard 2. I'm pretty sure its from the sound card since i ran an ipod to LOD to rca to the amp and didn't get the same hiss and beeps with my computer off. I even have the asgard 2 on a power conditioner so it maybe a ground loop. I was about to order some shielded RCA cables from blue jeans cable but seeing your problem is similar it may not fix it. 

Double shielded is definitely worth checking out, but blue jeans would be an expensive experiment. If you want to give it a try, you can pick up some 1m double shielded interconnects and a couple of ferrite checks from Radioshack for under $30. If it doesn't help, then just take them back. It could be a placebo effect hard at work, but I want to say that it did help a little. The cables more than the ferrite chokes. It's just pretty maddening that I'm getting better sound from my phone than from an essence stx. We're both in the same boat lookin for a paddle.

post #11 of 24
Quote:
Originally Posted by meeklo062704 View Post

Is there anyway to tell if a dac will suffer the same affliction? I have been looking into a few different options. Schiit bifrost or maybe a modi, hrt music streamer ii+, good used deal on an essence one, or something comparable in the up to $400 range used or new. I hear arguments for and against the usb vs optical, so I'll just have to read up on that one. The new essence stu seemed interesting, but just seems like an upgraded version of the stx.

 

I am not sure about the others, but I think the HRT has isolated USB input. Also, you can buy a USB isolator for other USB DACs for about $50 (maybe you can find one for less), if necessary. The Modi is within a budget of $150 even with a USB isolator. Optical S/PDIF should work, too.

post #12 of 24
Thread Starter 
Its very difficult to pick a dac when it's mostly based on other people's opinions. Like is a bifrost worth 2 or 3 times more than a modi? Computers are easy, everything has a discernable system to compare to a similar product, can be put through benchmarks, etc... But for a lot of dacs and amps, its just not that easy. Amplifiers, op amps, inputs, everything mixes with something else differently, and then quality of workmanship comes into play too. I wish there was an easier way to pick a dac. Like reading a list of components inside would tell you everything you needed to know. So my plan of action is to buy at the price point just this side of diminishing returns. Like a dac that costs 3x more than a bifrost probably won't perform 3x better to an untrained unprofessional ear. If you want 2x the performance then you need to spend 10x as much. So I'm trying to stay in that window of price where its the best performance vs price ratio.
post #13 of 24
Thread Starter 

Cheater plug knocked it right out. Dead silent now. How bad of an idea is it to run a cheater plug? I don't want to drop money on a decent ground loop isolator if I'm just going to get a dac in the next couple of months.

post #14 of 24

did you end up running the cheater plug on the PC? 

post #15 of 24
Thread Starter 
Quote:
Originally Posted by xero404 View Post

did you end up running the cheater plug on the PC? 

No, I ran the Crack through it. I'd much rather have the Crack blow up than the computer.

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