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December 04, 2020, 05:51:30 AM

Author Topic: Raspberry Pi?  (Read 829 times)

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Offline Natural Sound

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Re: Raspberry Pi?
« Reply #15 on: October 11, 2020, 04:00:45 PM »
Anyone with a SET amp that sounds a little bass anemic with a digital source may want to consider the Allo Boss route. There are several design explanations for this. Specifically there are three separate power rails. One for the audio section, clock and DAC chip. Accompanied by film caps in the audio section and a super cap for extra instantaneous current kick when needed. It really is a "bang for the buck" item at $65 U.S.

It's been another week with the Allo BOSS. I've listened to it every day with my Crack-Speedball/HD600 combo doing my work from home routine. This little DAC is amazing. It easily competes with other high end (high dollar) DAC's that I have in my collection.

Offline Natural Sound

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Re: Raspberry Pi?
« Reply #16 on: October 20, 2020, 05:10:27 PM »
OK Guys and Gals one more comment before I succumb to the silence as being a sign of me being boring as f*%k. Up to this point I have been powering the Pi and BOSS from a single supply with amazing results given this price point. I've powered this combo with a standard switching PS ($10), an iFi PS ($50) that does an adequate job of filtering out noise in the audible 20-20kHz range. The third supply I tried is another great value from the fine folks at Allo (Shanti Dual Linear @ $159).

I'm rather smitten with this setup lately as I've spent many hours listening and critiquing and I've been super happy so far. This evening I decided to try something a little different. The Sahanti LPS is a dual output isolated PS. The Allo BOSS has the capability of being decoupled from the computer supply via a jumper on the circuit board and powered separately. I decided to give this option a try and I'm really glad I did. The result wasn't subtle at all. It transformed an already fantastic low cost DAC to levels far exceeding my expectations.

This is how I'll be powering my BOSS from now on. Or at least until I get another harebrained idea in my head anyway. ;)

 

Offline Deke609

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Re: Raspberry Pi?
« Reply #17 on: October 21, 2020, 03:33:51 AM »
I use the Shanti as well. It powers my Allo USBridge Sig that sits between my Roon Core (Intel NUC) and my DAC.  Before getting the USBridge Sig, I was using the original USBridge (non-Sig) powered by a more expensive linear power supply made by Uptone Audio.  I needed a new power supply b/c the Sig required more current than the Uptone Audio could put out. Result: to my ears the the combo of Sig and Shanti was a little cleaner in the highs than the previous set up, and cost less.

I'm pretty impressed with the value proposition of Allo. 

cheers, Derek
Derek
______

Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline kgoss

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Re: Raspberry Pi?
« Reply #18 on: October 21, 2020, 06:12:14 AM »
I have not played with Raspberry Pi, but I know a lot of people who have and really love them.  I do use a computer as a source for digital music along with external DACs.  For me anyway, a DAC that had power from the computer as its only option would be a non-starter.  Inside a computer is a very harsh and noisy environment electrically.  Especially when things like fans, GPUs, hard drive motors, etc, come on.  Now, this has no effect in the digital domain or the computers would not work at all.  This is primarily because the concept of time has no bearing on a binary digital signal.  However, when a DAC converts that signal to analogue time and electrical noise affect it greatly.  So I am not at all surprised you heard such an obvious improvement when you switched your DAC to a power supply separate from the Pi.

Keep the experiments and observations coming!
Ken Goss

Offline grufti

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Re: Raspberry Pi?
« Reply #19 on: October 21, 2020, 12:09:29 PM »
Come again, what are you trying to say? You can't possibly be serious.

"This is primarily because the concept of time has no bearing on a binary digital signal."


Offline Natural Sound

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Re: Raspberry Pi?
« Reply #20 on: October 21, 2020, 03:53:02 PM »
I use the Shanti as well. It powers my Allo USBridge Sig that sits between my Roon Core (Intel NUC) and my DAC.  Before getting the USBridge Sig, I was using the original USBridge (non-Sig) powered by a more expensive linear power supply made by Uptone Audio.  I needed a new power supply b/c the Sig required more current than the Uptone Audio could put out. Result: to my ears the the combo of Sig and Shanti was a little cleaner in the highs than the previous set up, and cost less.

I'm pretty impressed with the value proposition of Allo. 

cheers, Derek

I'm going to pick up a DigiOne Signature and another Shanti as soon as the U.S. distributor gets his shipment. This will feed the Bottlehead DAC in my main system. The BOSS / Shanti combo is being used in my home office.

I agree, Allo is an exceptional value.

Offline kgoss

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Re: Raspberry Pi?
« Reply #21 on: October 22, 2020, 07:08:56 AM »
Quote
Come again, what are you trying to say? You can't possibly be serious.

OK, I will try to explain.  But I am not going to hijack this thread which is about the Raspberry Pi.

To keep things as simple as possible lets talk about a single bit moving from a hard drive to memory.  First of all, the digital domain is a binary world.  The bit is either on or off (1 or 0) absolutely, there is no state other than those two.  Let's say the bit is a 1 on the hard drive.  When it is read from the hard drive it begins a long journey through the CPU to be written into memory.  Along the way there is lots of error correction done to ensure the value stays a 1.  If an error is detected and cannot be corrected along the way, the value is thrown away and the read from hard drive is done again.  The end result is that the bit (value=1) is written into memory.  The only thing that matters is the value of that bit in memory is 1.  Time is not a factor in this outcome because time is irreverent in the digital domain.  The correct value is written to memory no matter if it takes 1 microsecond or 1000 milliseconds.  Slow computers drive us crazy, but in the end they always have the correct value.  If that was not true computers would be useless, and we all know even a slow computer is better than no computer.

On the analogue side of a DAC time is extremely critical.  The DAC chip relies on a constant stream of zeros and ones over a time period (sample rate) to construct as close an approximation of the smooth analogue signal as it can given the sample rate.  If there are breaks in that data stream for any reason data is lost and if enough data is lost you will hear it.  There is no data correction in analogue like there is in the digital computer.  Data lost is lost forever.  So power supply noise, RF interference, power supply fluctuations all affect this analogue world and will affect the quality of the music you hear.

In my opinion, that is the reason PB always asks headphone amp users with noise problems if they have a USB powered DAC.  Then the question is can the DAC be powered externally and could they switch to an optical connection.  The optical connection means no power to the DAC is coming from the noisy computer, and that solves the problem a lot of the time.  Very long story short, I believe powering a DAC separately from a computer is always the best solution,
Ken Goss

Offline grufti

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Re: Raspberry Pi?
« Reply #22 on: October 22, 2020, 10:15:35 AM »
Your "explanation" documents that you really don't understand timing in digital circuits. Please explain to yourself why a computer will crash eventually when overclocked. Don't do it here because it will indeed hijack the thread, but realize that I have designed high speed digital circuits in my life, timing is everything because you are still dealing with the same physics. Also, no, error correction in digital systems is not always 100% successful.
« Last Edit: October 22, 2020, 03:34:39 PM by grufti »