Lower my noise floor? Something between source and input

[drewhaynes]

Hi all,

I notice with my Crack + HD650, with the volume turned half way up, no music playing, there is a pretty audible noise floor - not very noticeable when playing music. When I pull the RCA's out, it goes dead silent. I assume this means something in my signal is raising the noise floor.

I am using a GrubDAC that I built years ago. The output on the GrubDAC is a hardwired male 3.5mm. This is going to a 3 foot RCA-to-female-3.5mm.

What tests would you pros step through to identify the issue - it sounds like something I should be able to eliminate, right?

Thanks!

 

[Paul Birkeland]

If you play music through your DAC and turn the Crack half way up, what kind of volume do you get out of your HD650's?

 

[drewhaynes]

With volume halfway up.. music is plenty loud, if that's what you mean. While listening, you don't notice any issue. At half volume, NO music playing, there is a hiss - and it is not totally steady noise/static... it has little fluctuations like some sort of interference. No biggie if that's totally normal, I just wondered if something was introducing noise to my inputs.

 

[Paul Birkeland]

Yeah, this isn't that unusual for a DAC powered from USB (or from using the 1/8" TRS jack on a computer, computers are generally very noisy).

 

[drewhaynes]

If you are familiar with them.. would building something like an AMB y1 or y2 be a good upgrade in your opinion?

 

[Paul Birkeland]

A quick look at the Y1 shows that it is externally powered, which is generally a very good indicator that it will be quieter than a USB powered device.

 

[drewhaynes]

A quick look at the Y1 shows that it is externally powered, which is generally a very good indicator that it will be quieter than a USB powered device.

Yes I believe you can power it with a wall plug, or some people build a dedicated PSU for it (like the omega-11 or omega-22 I believe). AMB Audio are the guys who design the DIY combo of the Beta-22 solid state amp and Omega-22 PSU, which from what I've heard is one of the best SS amps you can get, but the combo gets quite pricey!

 

[attmci]

Man, you need a much better DAC before invest in HD800.