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Bottlehead Kits => Crack => Topic started by: drewhaynes on September 27, 2017, 02:14:11 PM

Title: Lower my noise floor? Something between source and input
Post by: drewhaynes on September 27, 2017, 02:14:11 PM
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!
Title: Re: Lower my noise floor? Something between source and input
Post by: Paul Birkeland on September 27, 2017, 02:37:57 PM
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?
Title: Re: Lower my noise floor? Something between source and input
Post by: drewhaynes on September 27, 2017, 02:42:56 PM
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.
Title: Re: Lower my noise floor? Something between source and input
Post by: Paul Birkeland on September 27, 2017, 03:47:08 PM
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).
Title: Re: Lower my noise floor? Something between source and input
Post by: drewhaynes on September 27, 2017, 03:57:44 PM
If you are familiar with them.. would building something like an AMB y1 or y2 be a good upgrade in your opinion?
Title: Re: Lower my noise floor? Something between source and input
Post by: Paul Birkeland on September 27, 2017, 07:01:18 PM
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.
Title: Re: Lower my noise floor? Something between source and input
Post by: drewhaynes on September 28, 2017, 04:18:27 AM
Quote from: Caucasian Blackplate on September 27, 2017, 07:01:18 PM
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!
Title: Re: Lower my noise floor? Something between source and input
Post by: attmci on October 01, 2017, 04:29:01 PM
Man, you need a much better DAC before invest in HD800.