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FM radio interference on DAC + headphone amp stack
- Thread starter bsdinis
- Start date
OK, it would be best returned to the seller.
theREALdotnet
Major Contributor
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You have a peculiar style of asking for help. Just saying.
So is the amp the problem or isn’t it? The interference goes away if both cables are unplugged but was there without the Topping?
Have you tried grounding the amp? You could use one of the unused RCA inputs for this - just connect ring to ground. You'll need to connect it to some equipment that has a mains ground, or if you are confident with electrical wiring of mains plugs, make a wire from the ground pin of an electrical plug (make sure you connect to ground and not live!!!)
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Sometimes it is difficult to get some orientation in similar threads. Are you saying that the input connector is open?? Then the test is invalid. You have to short center pin of the input RCA-CINCH to its sleeve (ground) and investigate if it still demodulates FM. Open input has high impedance and is catching everything from surrounding elmag. fields. It is difficult to participate in threads like this one.
Is your cable at Topping line out connector is TS or TRS.Also, just having any of the cables plugged into the amp's input makes the interference stronger, doesn't matter if I plug a cable into the right or into the left input.
I can still hear the radio station without the cables, but it's much stronger when I plug them in.
It's much much easier to hear it with my IEMs than with my over-the-ear headphones.
TS look like this:
Devinal Unbalanced XLR Male to 1/4" Inch TS Mono Male Plug Audio Connector, 6.35mm to XLR Cable for Amplifiers, Instruments etc.[6 Feet] : Amazon.sg: Musical Instruments
Devinal Unbalanced XLR Male to 1/4" Inch TS Mono Male Plug Audio Connector, 6.35mm to XLR Cable for Amplifiers, Instruments etc.[6 Feet] : Amazon.sg: Musical Instruments
www.amazon.sg
CableCreation 2M TRS 6.35mm (1/4 Inch) Male to XLR Male Cable, Gold Plated connecto, Professional Series 3 Pin XLR Plugs,6FT : Amazon.sg: Musical Instruments
CableCreation 2M TRS 6.35mm (1/4 Inch) Male to XLR Male Cable, Gold Plated connecto, Professional Series 3 Pin XLR Plugs,6FT : Amazon.sg: Musical Instruments
www.amazon.sg
TRS tip will save your lots of problems.
- Thread Starter
- #29
I tried editing that older post, the interference does not go away completely when unplugging the cables, it's just not as loud and I hadn't noticed it before.
- Thread Starter
- #30
- Thread Starter
- #31
I just found another problem with the Sabaj, my room is pretty noisy, both my motherboard and my display/screen emit nasty coil whine, especially the screen.
I moved just the amp and tried it in the kitchen and in the living room to make sure that my room was not the source of the radio interference;
There is a nasty high-pitched whining noise coming from the amp, and I was able to pinpoint the amp's own backlight as the culprit - this backlight whining noise wasn't as noticeable in my room due to my computer's fans and screen coil whine. I can confidently say the backlight is the culprit because the whining noise changes its pitch depending on the character(s) shown on screen, and it gets proportionally louder when I increase the backlight's brightness.
And about the radio interference, it's the same in my room, or in the kitchen or in the living room.
I moved just the amp and tried it in the kitchen and in the living room to make sure that my room was not the source of the radio interference;
There is a nasty high-pitched whining noise coming from the amp, and I was able to pinpoint the amp's own backlight as the culprit - this backlight whining noise wasn't as noticeable in my room due to my computer's fans and screen coil whine. I can confidently say the backlight is the culprit because the whining noise changes its pitch depending on the character(s) shown on screen, and it gets proportionally louder when I increase the backlight's brightness.
And about the radio interference, it's the same in my room, or in the kitchen or in the living room.
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- Thread Starter
- #32
Another problem... is this supposed to light up? lol
The thing emitting the red light should the the IR receiver, right? It is emitting visible red light, by the way, it is visible to the naked eye.
The thing emitting the red light should the the IR receiver, right? It is emitting visible red light, by the way, it is visible to the naked eye.
That's weird. I was going to suggest a power led next to the IR receiver - but it clearly isn't that. Or at least not one that is functioning correctly.Another problem... is this supposed to light up? lol
The thing emitting the red light should the the IR receiver, right? It is emitting visible red light, by the way, it is visible to the naked eye.
fpitas
Master Contributor
IR LEDs do emit a little in the visible spectrum. They don't have the narrow bandwidth of a laser.Another problem... is this supposed to light up? lol
The thing emitting the red light should the the IR receiver, right? It is emitting visible red light, by the way, it is visible to the naked eye.
IR recievers don't though.
fpitas
Master Contributor
True, not normally.
- Thread Starter
- #38
Amazon scheduled with Seur to pick up this amp on Monday. Should I pick up another A20h? A friend of mine bought the exact same amp (because of me) and he told me his unit does not pick up any interference, I haven't had a chance to listen to his amp, though.
Blumlein 88
Grand Contributor
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If it is reasonably easy to do, get your friend to bring over his unit and plug it into your gear. See if his picks up interference. Then you'll know if yours was a one off problem unit or that something is different about your setup. If his gets interference, I'd try another brand or design.
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