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Review and Measurements of the Topping D70 DAC

Jimster480

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However, I do have a minor issue with clicks coming out of the speakers when switching sources. But I also have a work-around solution. Sharing for the benefit of those with the same issue. Details below:

My LG TV is connected to the D70 via optical. Then I have an Acer thin client connected via USB. I encounter a very soft click when switching from USB to optical, then a louder click when switching from optical to USB. The click happens only when there is no audio playing on the source I switch to. So to avoid the click, I just have to remember to play something on a source before I switch to it.
I think this is a topping relay click.
It happens in my DX7 also.
PS Audio PerfectWave MKII with Bridge network card
Cambridge Audio Azur 851N network player
Ayre QB-9 DSD
Teac UD-503
Nice collection, I bet you are glad the D70 stacks up :)
 
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I just bought this dac for use in my office. Will be pairing it with the Drop 789 amp.

the OCD in me is going crazy with the (slightly) tilted LCD screen, similar to the review unit at the start of this thread.

has anyone gotten the new Bluetooth version yet, or some later production models, which have the LCD tilt rectified?
 
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I just bought this dac for use in my office. Will be pairing it with the Drop 789 amp.

the OCD in me is going crazy with the (slightly) tilted LCD screen, similar to the review unit at the start of this thread.

has anyone gotten the new Bluetooth version yet, or some later production models, which have the LCD tilt rectified?
Sorry to hear about your screen. I got mine on July 23, 2019 through Amazon and the screen is not tilted.
 

amirm

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the OCD in me is going crazy with the (slightly) tilted LCD screen, similar to the review unit at the start of this thread.
You should be able to open the unit and shift the front PCB and with it, the display.
 
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You should be able to open the unit and shift the front PCB and with it, the display.
haha u r right.. why didn't I think of that?!

just popped open the front panel. couldn't shift the pcb much. but managed to straighten out the text by shifting the LCD panel in its housing. looks perfect now.

Thanks for that, Amir.
 

Julf

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Topping D70 is connected to the nuforce ha-200 headphone amplifier
by RCA and a slight background noise is heard. If I change to Topping D10 this noise disappears completely. I tried to change the wires, turn off other devices, until I found a solution, the noise does not disappear.
 
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That's strange, as you read the D70 had an extremely (read: utterly inaudible) noise floor. Could this be a ground loop?
 
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Topping D70 is connected to the nuforce ha-200 headphone amplifier
by RCA and a slight background noise is heard. If I change to Topping D10 this noise disappears completely. I tried to change the wires, turn off other devices, until I found a solution, the noise does not disappear.
Yes, might be a ground loop. I had some very slight ground loop noise after I installed the D70 in my system.

The D70 has a ground pin. I lifted the ground by removing the ground pin on the power cord and success: no more ground loop noise. Lots of modern electronics have no ground pin (such as AV Receivers) to reduce ground loop issues. However, not sure how safe this is in the case of the D70. So far no problems.
 

Julf

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The D70 has a ground pin. I lifted the ground by removing the ground pin on the power cord and success: no more ground loop noise. Lots of modern electronics have no ground pin (such as AV Receivers) to reduce ground loop issues. However, not sure how safe this is in the case of the D70. So far no problems.
Usually the ground pin is there for a reason (safety approval).
 

SIY

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Usually the ground pin is there for a reason (safety approval).
Yes, might be a ground loop. I had some very slight ground loop noise after I installed the D70 in my system.

The D70 has a ground pin. I lifted the ground by removing the ground pin on the power cord and success: no more ground loop noise. Lots of modern electronics have no ground pin (such as AV Receivers) to reduce ground loop issues. However, not sure how safe this is in the case of the D70. So far no problems.
If you can do some basic soldering, there's a better way. Inside the cabinet, the safety ground pin will usually have a short wire directly to the case from the power entry module. Likewise, the signal and/or power supply boards will have some connection to the case. Trace where the latter is and either cut it (if it's a wire) or insulate it (if it's a screw to a standoff or similar). Now take two power diodes (say, 5-10 amps at 200V or higher), connect them in parallel but with one reversed (engineers colloquially refer to this as '69' mode), parallel that with a 600-1000V ceramic disk cap (value not critical, 1000pF or 1nF is typical), and wire the signal or power supply board ground to the case through the cap-bypassed diode pair. This retains the shielding properties of the case, but will break up the ground loop without compromising safety.

If the visualization is unclear, see Figure 6 of this article. The groundbreaker consists of D104, D105, and C108.
 
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If the visualization is unclear, see Figure 6 of this article. The groundbreaker consists of D104, D105, and C108.
Great. Thanks for this. A nice, cheap solution that should work for all kinds of electronic devices that cause ground loops. I was able to find the diodes and capacitors that you described on Amazon in large batches, for cheap. My only concern is the impact this will have on warranty and resale value.
 
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FYI for anybody thinking of installing a groundbreaker for their D70. I just finished taking mine apart. The power entry module ground pin wire goes directly into the circuit board and not to the case. As far as I can tell, there is no grounding to the case anywhere except a connection from the circuit board to the outer barrel of the RCA coax input on the rear panel. Doesn't look like installing a groundbreaker circuit is going to work here.
 

levimax

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FYI for anybody thinking of installing a groundbreaker for their D70. I just finished taking mine apart. The power entry module ground pin wire goes directly into the circuit board and not to the case. As far as I can tell, there is no grounding to the case anywhere except a connection from the circuit board to the outer barrel of the RCA coax input on the rear panel. Doesn't look like installing a groundbreaker circuit is going to work here.
Take a look at this article, it has some good background on causes and possible solutions to ground loops as well as safety issues with grounding. Section 9 shows a ground breaker very similar to what you are working on as well as some ideas on how to hook it up.
https://sound-au.com/earthing.htm
 

Julf

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Take a look at this article, it has some good background on causes and possible solutions to ground loops as well as safety issues with grounding. Section 9 shows a ground breaker very similar to what you are working on as well as some ideas on how to hook it up.
https://sound-au.com/earthing.htm
For anyone reading this and wondering if there's something wrong with the D70, I thought I would make it clear that regarding ground loops or any other type of noise, there is nothing wrong with the D70. My minor ground loop problem is due to the home theater bypass RCA cables from my receiver that are connected to my integrated amp. When these are not connected, even when using a properly grounded cable, the D70 produces no ground loop noise whatsoever.
 
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