THIS IS COMPLETELY OFF TOPIC - BUT.... 🙄
As OlegSh reported, it's tough to get a clean signal from a computer based source. A lot of noise is contained in the amplification system prior to the standard mini-jack on the desktop back-plane or laptop port. I have had excellent results using the SPDIF out (now standard on almost all motherboards) and the new Subbu/JP V3 DAC. The PC software and firmware drivers can be by-passed for a pure signal, which requires a pot or preamp for volume control, but using the digital control of a program like JRiver MC or Foobar produces a signal far better than a computer audio out jack.
Currently, the DAC, which has caps immediately before the outputs, is connected directly to the FE build - which has C13 at the input. That has proven to be a safe and very clean combination allowing PC volume control. Mine even has full smartphone access.
The V3 is my new go to DAC, is relatively inexpensive and is quite easy to build. Just as I try to promote the FEs whenever I can, I encourage members wanting a high quality PC based music server to investigate adding their names to the second run (over 500 sold on first) group buy now open. The designers packed a remarkable high level of performance into a very compact and inexpensive package that really complements what Dairio has done with the Fremen Edition.
Worth a look - IMHO
First run & Info - Subbu DAC V3" GB Interest
Second Run GB Sign-up Sheet.
As OlegSh reported, it's tough to get a clean signal from a computer based source. A lot of noise is contained in the amplification system prior to the standard mini-jack on the desktop back-plane or laptop port. I have had excellent results using the SPDIF out (now standard on almost all motherboards) and the new Subbu/JP V3 DAC. The PC software and firmware drivers can be by-passed for a pure signal, which requires a pot or preamp for volume control, but using the digital control of a program like JRiver MC or Foobar produces a signal far better than a computer audio out jack.
Currently, the DAC, which has caps immediately before the outputs, is connected directly to the FE build - which has C13 at the input. That has proven to be a safe and very clean combination allowing PC volume control. Mine even has full smartphone access.
The V3 is my new go to DAC, is relatively inexpensive and is quite easy to build. Just as I try to promote the FEs whenever I can, I encourage members wanting a high quality PC based music server to investigate adding their names to the second run (over 500 sold on first) group buy now open. The designers packed a remarkable high level of performance into a very compact and inexpensive package that really complements what Dairio has done with the Fremen Edition.
Worth a look - IMHO
First run & Info - Subbu DAC V3" GB Interest
Second Run GB Sign-up Sheet.
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Hi Andrew, Right now it only accepts SPDIF via RCA or BNC, There have been many requests to add I2S and I suspect that is in development. JP and Subbu took over a year to develop this version and they got lots of nasty grams from impatient members - so no formal info/confirmation is available yet.
Stay tuned.....😉
Stay tuned.....😉
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What product types output SPDIF?
What comes out of:
Digital radio tuner?
Digital TV (Freeview)
CDP?
DVD?
DVD Hi Res?
Mobile phone?
Laptop PC?
Desktop PC?
Tablet PC?
What comes out of:
Digital radio tuner?
Digital TV (Freeview)
CDP?
DVD?
DVD Hi Res?
Mobile phone?
Laptop PC?
Desktop PC?
Tablet PC?
did the other than SPDIF not happen?Pick your Flavour : Versions
- SPDIF SE : 1 DAC PCB + 1 ES9023 + 1 PSU PCB + 1 WM8804 (if you want SPDIF)
- I2S SE : 1 DAC PCB + 1 ES9023 + 1 PSU PCB (informations to come)
- Balanced : 1 "Mother" SE version (SPDIF or I2S) + 1 "Piggy Back" PCB + 2 ES9023 + 1 PSU PCB
Inputs : What to eat ?
- SPDIF : BNC or RCA (75 Ohms - Wolfson WM8804 Receiver - Coaxial/RCA no Toslink embedded)
- I2S : U.FL connectors pads - External I2S source providing I2S clocking (No WM8804 installed)
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Just tried to disconnect the transformer screen from the chassis. No effect. The buzz is there if PGND is disconnected from the chassis. Each amp channel has only 6 wires connected to it if PGND is disconnected: 4 wires from the transformer and 2 goes to the speaker. What can be wrong 😕
To fight the noise I will try to provide 1k load to the source. In principle computer output should be able to drive ~100 Ohms load, e.g. headphones. This should effectively kill all the noise but leave the signal because the headphones play clean. I'll let you know if it works. I understand that this is mostly curing the symptoms rather than solving the problem but I am out of good ideas now.
PS: Signed up for Subbu DAC V3. I missed the previous GB.
To fight the noise I will try to provide 1k load to the source. In principle computer output should be able to drive ~100 Ohms load, e.g. headphones. This should effectively kill all the noise but leave the signal because the headphones play clean. I'll let you know if it works. I understand that this is mostly curing the symptoms rather than solving the problem but I am out of good ideas now.
PS: Signed up for Subbu DAC V3. I missed the previous GB.
I am about to set up raspberry pi as a headless music server running volumio. It is all for test and trial of my first pc based system. I hope it will work fine.
The buzz, when no Chassis, indicates a wiring error.
the speaker Return should NOT go back to the PSU.Just tried to disconnect the transformer screen from the chassis. No effect. The buzz is there if PGND is disconnected from the chassis. Each amp channel has only 6 wires connected to it if PGND is disconnected: 4 wires from the transformer and 2 goes to the speaker. What can be wrong 😕..................
That is a wiring error.
ONE wire connects the PSU Zero Volts to the Main Audio Ground.
All the other amplifier voltage references connect to the Main Audio Ground.
They DO NOT go back to the PSU.
I believe I connected the speakers correctly. The speaker return goes to the OUT_GND pin near the DC protection relay. Or am I missing something? Where else can it be connected? The only other place can be PGND which is at the PSU.
The speaker hot wire is connected to the OUT pin right after the R3. The MyRef FE board has limited number of possibilities to do thing wrong.
The speaker hot wire is connected to the OUT pin right after the R3. The MyRef FE board has limited number of possibilities to do thing wrong.
this rings alarm bells.4 wires from the transformer and 2 goes to the speaker
What is going back to the transformer?
OlegSH, is there a diagram attached to your transformer (like Antek has)? Four wires is correct, but problems will occur if they are not paired correctly. The power entry FE and standard MyRefs are not exactly the same.
EDIT: OOPs, we posted at the same time. Would still like to see the diagram if you have one.
EDIT: OOPs, we posted at the same time. Would still like to see the diagram if you have one.
Attachments
The transformer has the diagram. All pairs of same color are secondaries. They should be identical according to specifications. See pictures in post #1825 which show the wiring of my amp.
That's exactly what I saw that made me curious. Same color pairs is simply something not often seen - at least by me. Just wanted to confirm that arrangement. Thanks
Oleg, is your chassis connected to earth ground? Doing that along with grounding PGND to chassis helped cure my noise problem. I also used shielded cable and got pretty bad hum (as opposed to the more buzzing sound that occurred when the chassis wasn't grounded) when the shield wasn't grounded - I have no idea what exactly was going on there, but grounding the shield helped. Anyway, as far as I can see your chassis should definitely be connected to the amp's ground, I thought that was what HSGND was all about (and why does it say "do not connect to chassis/heatsink" next to it on the PCB?). I had terrible noise when that wasn't connected.
Also, grounding the chassis to earth ground might be worth a try - my hum/buzz problems disappeared when I connected everything to earth ground (the FE ground plane as well as the shields on my cables).
And this one may be obvious, but you did try the DC coupled input as well as the one with the input cap, right? Are there any audible differences?
Also, grounding the chassis to earth ground might be worth a try - my hum/buzz problems disappeared when I connected everything to earth ground (the FE ground plane as well as the shields on my cables).
And this one may be obvious, but you did try the DC coupled input as well as the one with the input cap, right? Are there any audible differences?
Hi butizzle,
My chassis is connected to earth ground permanently. The HSGND I did not try yet. The PGND to chassis did kill the buzz completely. The noise is now much less pronounced also (not really related to PGND connection). The fact that my amp has no volume pot makes it not so good match for sources with low signal to noise ratio (e.g. built-in computer/laptop sound cards). I'll give HSGND a try. May be it will further decrees the noise. I also tried the AC and DC coupling of the amp with no change in noise level. DC vs AC coupling sound quality I can't review due to the lack of a good source which is my next project. I'm waiting for Subbu DAC V3 but might consider Red Baron or DDDAC if I'll lose my patience at some moment🙂
Oleg
My chassis is connected to earth ground permanently. The HSGND I did not try yet. The PGND to chassis did kill the buzz completely. The noise is now much less pronounced also (not really related to PGND connection). The fact that my amp has no volume pot makes it not so good match for sources with low signal to noise ratio (e.g. built-in computer/laptop sound cards). I'll give HSGND a try. May be it will further decrees the noise. I also tried the AC and DC coupling of the amp with no change in noise level. DC vs AC coupling sound quality I can't review due to the lack of a good source which is my next project. I'm waiting for Subbu DAC V3 but might consider Red Baron or DDDAC if I'll lose my patience at some moment🙂
Oleg
Hi butizzle,
My chassis is connected to earth ground permanently. The HSGND I did not try yet. The PGND to chassis did kill the buzz completely. The noise is now much less pronounced also (not really related to PGND connection). The fact that my amp has no volume pot makes it not so good match for sources with low signal to noise ratio (e.g. built-in computer/laptop sound cards). I'll give HSGND a try. May be it will further decrees the noise. I also tried the AC and DC coupling of the amp with no change in noise level. DC vs AC coupling sound quality I can't review due to the lack of a good source which is my next project. I'm waiting for Subbu DAC V3 but might consider Red Baron or DDDAC if I'll lose my patience at some moment🙂
Oleg
I see.. PGND and HSGND are shorted so that should not make any difference. I'm afraid I'm pretty clueless as to what might be causing your buzz/hum - your amp shows the same behavior as mine with no/shorted inputs, but mine doesn't buzz when everything is properly grounded and inputs are connected, no matter the source...
Mine also does not buzz when connected to low output impedance sources. The problem with the buzz is there when for example my tablet disconnects the output internally when nothing is playing. This is really annoying. Therefor I connected the PGND to chassis which killed the buzz entirely. The noise I really attribute to sources rather than the amp.
Oleg
Oleg
The HSGND should be used to ground the heatsink when it's not part of the chassis (already grounded), for example with a wood chassis.
If the heatsink is already grounded, connecting HSGND will result in a ground loop.
If the heatsink is already grounded, connecting HSGND will result in a ground loop.
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