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New FIFO buffer for RPI/SBCs
New FIFO buffer for RPI/SBCs
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Old 11th January 2019, 10:53 AM   #2961
soundcheck is offline soundcheck  Germany
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Join Date: Mar 2005
Location: DUS
Quote:
Originally Posted by cdsgames View Post
Still we think Katana is the best DAC for RPI as this point and with proper supply its beats a lot of commercial DACs.
Nobody questions that Katana is the best HAT.
It's been Allo who announced the "blow-away-$1000-class" target though. And you didn't mean HATs only.

The latest Beekhuizen Katana 1.2 review states, that his Katana setup
"comes close" to his Chord Mojo setup - a $480 DAC.

That doesn't look good to me on the first glance, it'd be well below
the "blow-away-$1000-class" target.

Ok. I don't really trust his reviews. But that's a different story.
But maybe - he's right or at least has a point?
The problem. It's still pretty much the only review out there.
(As a matter of fact - Allo even refers to his reviews. )

Anyhow.

I do hope that Allo gets the quality issues under control soon.
And I do hope that the new PS puts the Katana at least slightly above that Mojo.

I also hope with all your promising products in pipe we can start over at square 1 in a couple of weeks.
We shouldn't forget though. Just with the new PS it's then gonna be a close to $500 DIY streaming solution (without isolator).
And this amount will make live not that much easier.





Enjoy.

PS: Advise: Allo -- remove that "blow-away-$1000-dacs" statement. This just "blows" right back into your faces.
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Old 11th January 2019, 11:09 AM   #2962
cdsgames is offline cdsgames  Canada
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Quote:
Originally Posted by soundcheck View Post
Finally we're getting there.

A 2-in-one solution. Nice.

Will it be SMPS or Linear?

However!

3+1 A ???

What's the "1" for?

Too low for a RPI 3B+ (according to spec) and too low for Katana !??!

It would then require two of these for a Katana stack.

Or you power the DAC/isolator and the controller/output stage each with one of these two outputs
and use another SMPS for the PI e.g. your $11 SMPS.

Is that the way you're thinking?


Looking forward to it.

We are talking worst cases scenario but we will test it with Katana. In fact power available and design was made for 3.9A and 1.6A but we under quote at this point.



This is an LPS. Problem on SMPS is that every time we lower differential noise , common mode noise increases . Same for leakage current (grounding increases diff noise). In any cases new PCB might solve those problems. We will start testing soon..
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Old 11th January 2019, 08:53 PM   #2963
fabio1068 is offline fabio1068  France
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Join Date: Dec 2016
Hello,

I am assembling the power supply for my Katana, but I am having an issue with the +-15V.

At first, I used only two supply: 5V for RPI + 5V for MC
Katana works as expected, I hear the music.

Then I tried to add the external +-15V with the following steps:
- turned off the Sw3 switch
- moved the jumpers J28 and J29 to close 1&2 pins
- connected power wires, +15V to pin1(close to sparkos label) GND to pin2 and -15V to pin3

When I try to play music, sometimes there is no sound at all, sometimes I get like a whistle, a medium/high frequency sound. I do not know exactly how to describe it, also because I turn the power off quickly in order to avoid damaging the boards.

Then, when I go back to the standard 2 power supply, everything works normally.

Did anyone have the same issue? Or am I doing something wrong?
Any advice/help?

PS the stack is composed of MC+THDopamp+Katana+Isolator+Raspberry Pi 3B. The OS is Volumio 2.513
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Old 12th January 2019, 02:14 AM   #2964
ktham is offline ktham  Canada
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@fabio1068


Are the external +/- 15V supplies two separate individual supplies or is it a single unit with a +/- 15 V rail(s) and a common ground?


If using separate 15V supplies then the 0V of the positive supply and the positive of the negative supply need to be tied together on the GND pin of J27 Pin2.


The power up sequence for this mode( using an external +/- 15V supply) is the external +/-15V goes first, the MicroController next and once the green lights stabilize the Rpi is powered on.


In the absence of pictures of your arrangement this is what comes to mind based on my experience with Katana. Good luck.
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Old 12th January 2019, 02:14 AM   #2965
LizardKing01 is offline LizardKing01  United States
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Join Date: Oct 2016
I am going finally use the Katana in my main system. I have approximately 143 hours of burn in time using the Katana connected to powered speakers. I have it shut down, that is fifth time i have down that to allow the caps to charge up and down.
I stil only have two power supplies connected at this time. I am hoping that next week, I can connect a +/-15 volt LPS to the SQ board.



I do not like the ideas of using the usb connections so hopefully I can connect a LPS to the RPI below that board and on the MC board, as well.
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Old 12th January 2019, 03:00 AM   #2966
Markw4 is offline Markw4  United States
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Location: California
Quote:
Originally Posted by fabio1068 View Post
When I try to play music, sometimes there is no sound at all, sometimes I get like a whistle, a medium/high frequency sound. I do not know exactly how to describe it, also because I turn the power off quickly in order to avoid damaging the boards.
What power supply are you using? Can you attach a picture?

Can you measure the +-15v power supply outputs right after you turn on power? You could try measuring DC volts first, then if you have time try measuring AC volts to see if any ripple or other AC there.

Do you have an oscilloscope to look at the power rails?
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Old 13th January 2019, 02:36 PM   #2967
fabio1068 is offline fabio1068  France
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Join Date: Dec 2016
@ktham and @Markw4

I think I found out what is happening, even though I do not know why.
I measured with a multimeter (sorry no oscilloscope :-)) DC and AC voltage relative to GND at J27 pins and at the wires of the big black capacitor on MC.
Measure with only the katana stack powered on, raspberry not powered.
RCA cables connected to speaker ampli, to hear any sound/whistle.

For the first 8 minutes from power on, I get:

J27: DC -15.00 V
DC +15.06 V
AC 40mV on both rails

Cap: DC -14.06 V
DC -0.8 V

The MC board is not powering the positive rail of OPAMP board. That is why I cannot hear anything.
Then, after more or less 8 minute (much less if the stack is already warm), I get a sudden whistle from the speakers that last about 10 seconds.

When the whistle stops, I measure:

J27: DC -14.98 V
DC +15.00 V
AC 40 mV

Cap: DC -14.06
DC +14.14
AC 40 mV

the OPAMP board is now powered correctly, and if I turn the raspberry on, I can play music normally.


The voltage regulators used for both the 5V on MC and +-15V are:
Module d'alimentation lineaire regulee OP TL072 MJE15034 28V - Audiophonics

All regulators are powered by a single transformer with multiple secondaries. For that reason the 5V and +-15V are powered at the same time.
Is just the power sequence creating this malfunctioning? It looks weird to me.
Maybe somebody else is able to replicate this issue? Or is my MC board that is faulty?

Here some pictures of my setup
Attached Images
File Type: jpg IMG_20190112_181152142.jpg (339.8 KB, 163 views)
File Type: jpg IMG_20190112_163259686.jpg (406.0 KB, 163 views)
File Type: jpg IMG_20190112_163240744.jpg (452.0 KB, 160 views)
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Old 13th January 2019, 05:11 PM   #2968
jonners is offline jonners  United Kingdom
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Location: Gloucestershire
@fabio1068

I am using a similar regulator board with my Katana, but I haven't enabled the separate 15V supplies yet.
You may already be aware of this, but these boards have a current limiting resistor. Mine (from eBay) had 2.2R fitted, which limited the current to about 300mA. That's fine for the 15V supplies, but for a 5V supply that requires more current a lower value resistor is needed. Are you certain that your 5V supplies are not dropping below 5V?
I got some help with this from this thread: low noise Pre-Amp / DAC power supply MJE15034 TL072 Regulator based on STUDER 900
Edit: From the Audiophonics pics, it looks as if those resistors might be 0.22R. If that's the case, they won't limit until 3A!

Last edited by jonners; 13th January 2019 at 05:34 PM.
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Old 13th January 2019, 05:38 PM   #2969
Markw4 is offline Markw4  United States
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Join Date: Jul 2016
Location: California
@fabio1068,
Sounds like your power supply might be overheating after some time of operation, then partially shutting down, cooling, and after some more time, restarting. That is to say, the time constant you describe sounds like it could be thermally related.
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Old 13th January 2019, 06:13 PM   #2970
fabio1068 is offline fabio1068  France
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@jonners
I read that thread. My board has no problem to power the katana with only one 5V supply, so it can deliver more than 1A easily.

@Markw4
It is not a problem of overheating,It is quite the contrary:
When the system is warm, I can play music for several hours without problem.

The issue is there only at startup expecially cold start
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