My a30pro gives off a humming sound in my headphones , when i switch from lift to gnd the noise gets even worse. I also noticed when i use a different amp pugged in the mains it has the same hum as the a30pro . Only when i turn the a30pro off i no longer hear the buzzing. As if it interduces noise in my mains. I use topping dx3pro as a DAC connected to L30 ii which is connected to the A30pro. when i use Bluetooth on the Dx3 pro and unplug the USB from it the noise also stops. Anyone here have a solution?
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Help with Topping A30Pro Review (Balanced Headphone Amp) problems
- Thread starter Alalla
- Start date
What is connected with usb to your dx3pro?
- Thread Starter
- #3
my pc, though if i use the dx3pro+ as an amp i dont hear any of the humming or buzzing. I also tried connecting the L30ii to smsl SU1 and then to the A30pro and i hear the buzzing. it stops when i disconect the usb + from the pc or if i shut down the a30pro
It comes from the pc probably. Can you try with your phone or a laptop with battery power through usb?
- Thread Starter
- #6
I see. Another thing i tried is to run a jack to RCA from the topping dx3 pro to the A30 pro it did remove the buzzing. There was some noise though. I unplugged the topping DX3 and left the jack to RCA cable in the A30pro still hearing the noise. The noise stopped only after i removed the Jack to RCA cable from the A30pro.
- Thread Starter
- #7
I tried with my phone and these is less humming. i do still hear it especially at high gain.
- Thread Starter
- #8
Anyway for some reason when i have some cable plugged in the RCA input of the A30pro i get the buzzing. Dont tell me its picking up radiowaves or something. I dont hear anything close to it when i use the L30ii at high gain at max volume.
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Just one cable or any cable?
Try this: remove everything from the same outlet especially devices that use smps if possible and power them from a different outlet or power the a30 pro from a different room.
- Thread Starter
- #11
Any cable. and it turns out it indeed worked as an antenna the source of the humming was the topping dx3. For some reason the Dx3 emits the hum, so any cable near it picked it up. The noise is nonexistent if i use the SMSL su1, I do still hear some noise from the PC but that might be a grounding thing. I already bought the optical adapter so i will test it out when it arrives. My only issue now is that i hear a hum if i connect the A30 pro to L30 ii pre-amp. And the dx3pro + has become basically useless as a DAC. Does anyone know if my Dx3 pro+ could be faulty? its a float though so it might be just how it is.
When i unplug the power supply from the dx3pro the humming stops but there is still noise coming off of it even though its off. So i took a wire and connected it to my outlets ground and taped it to the outside case of the dx3pro . Only then it went quiet. I will look if i have another power supply that i could use it with.
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Do you have USB connected to the DX3? Is that device plugged into the same outlet as the DX3 and A30Pro
- Thread Starter
- #14
The dx3 outputs noise even without being connected to any device. i think its better if i post some pictures
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Sorry, I missed earlier that you mentioned you disconnected everything including any USB cables to upstream device.
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I can't see all of the cable between the DX3 and the A30Pro. And you have other electronics in close range.
What happens if you take the DX3 and the A30Pro to some other room far from any electronics (and on a different circuit breaker)? Connect them exactly as you show in the "NO USB DX3 --> A30pro = noise" photo, and test that with the DX3 and the A30Pro moved further away from each other. If you still have noise, send a photo of that setup.
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Route the audio cable so that it does not cross any power lines, and is as far away from the power sources as possible? Also, can you plug the devices directly into wall outlet and remove the extension cable? Trying to get your configuration to the smallest RF footprint as possible to eliminate as many variables as absolutely possible.
Also, at that point, add details on where on the volume the audio noise is hearable.
(As a side note, I have an A30Pro and even when I turn the volume all the way up, I do not hear any noise at the highest gain level on either the XLR or RCA inputs. And all of my electronics are inside an AV cabinet close to each other; though good care to keep power cords as isolated from audio cords as possible.)
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