I have some old speakers in the house that I wanted to test. So instead of messing with the real stereo unit from the 80s, I bought a $30 stereo from Amazon, and new speaker wire.
The speakers sound okay, but there’s a hum coming from them all the time. Even with the stereo volume knob turned all the way down. Is this normal for stereo systems and I just haven’t noticed?
I once bought a pair of of powered speakers that were huming. Had them sent back to manufacturer and got new replacement, non-huming pair. They had unbalanced analog inputs.
Cheap amps work bad with mid/high-end speakers. Cable should be shielded. Amp should be grounded well. If speakers have balanced inputs (TRS - tip, ring sleeve), I suggest to use a balanced cable. If it just TS (tip/sleeve) or RCA, then it is not balanced and it doesn’t matter what cables you will use. Your amp is most likely the culprit.
Generally it means the amp is “noisy” and has a bad ground or other issue.
Thanks I’m probably going to return these.
To be honest, anything you get on Amazon is going to be shit compared to almost any stereo unit from pre 1990.
I dont understand why people need new. For audio gear, old is almost always better (if its not outright broken).
All my gear is 70s-90s and sounds and works great, and im not getting bezos closer to his trillion.
Sorry for the rant friend, good luck!
You can’t compare a $30 Amazon stereo to anything made before 1990. That would be equivalent to something costing $10-$15 back then, which wouldn’t have even existed.
There’s plenty of extremely high quality audio equipment that is made today, it just costs real money, just like it did back then.
Yes, for a lot of people, used gear would probably work fine, but it wouldn’t have the inputs they need (no HDMI, no Bluetooth, etc.) heck, a lot of folks would expect it to have WiFi to cast their Spotify music to it.
True. I dont care about any of that, just sound and analog inputs, so id never buy used unless it was actually a high quality or boutique build. Or better yet a kit!
Someone should make an Amazon for used gear, with the same fast shipping and return policy. BC you are right and the new stuff is often such low quality.
There is a goodwill near me with OK prices, but it is a crapshoot whether what you bought will work. From what I’ve seen, used gear shops where they repair and test are mostly for rare and expensive collectors items and not worth it.
I recently had to spend $160 to buy a used VCR capable of PAL/multisystem, on eBay.
Someone should make an Amazon for used gear, with the same fast shipping and return policy. BC you are right and the new stuff is often such low quality.
That’s eBay, isn’t it?
Part of the reason Amazon works well is because they sell high volumes of each product, allowing them to distribute products ahead of time across warehouses to match expected demand. You can’t do that if you only have exactly one of each item.
There’s zero profit in this. The overhead of storage and broken equipment would be insanely high and impossible to manage. Not to mention old gear is a lot heavier, more expensive to ship.
No to mention people interested in cool old gear are as rare as unicorns these days. Young people couldn’t care less for the most part. Most of them wouldn’t know what soldering even is, theyre not gonna try to repair old gear when their phone can do everything.
Nope those days are gone. Now you either suck it up and pay thousands for quality or hope you get lucky at a garage sale! Or there are still cool antique stores here and there that are carrying good old gear that they test out and sell relatively cheap.
Speakers don’t hum, stereos (and other sources) do. Cheap stereos use cheap components. Cheap components are electronically noisy and poorly shielded and hum.
I bought these shungite pyramids to insulate my 48k gold cables. Never once heard a hum.
I hope people realize you are being sarcastic.
I’m no stereo expert, but from what I understand the hum comes from interference or ground problems. I’ve been told that adding ferrite chokes (like the ones on old VGA cables) to your cables can help, but you probably have to try a couple of things to fix it.
Also: typically, only analog cables have issues with electronic interference. Digital either works or it doesn’t. In other words, gold plated triple shielded digital cables are a waste of money.
If the ferrite is filtering a hum you can hear, it’s also filtering parts of your music that you can hear because a ferrite just dampens a frequency range and can’t tell what is and isn’t supposed to be there.
Thank you! TIL
So my great gold plated toslink cables are snake oil? :O /s
Not all! So about this bridge…
A low hum is almost certainly going to be 60Hz (or 50Hz in some parts of the world) line noise.
As many have said, it’s often a ground loop - but since you have a single device plugging in to unpowered (presumably!) speakers, that’s not the problem. In your case, the stereo itself is producing the hum.
So if you’re in North America, there’s one thing to check before returning. I’m guessing that a cheap Amazon amp has either a wall-wart or two-prong plug. If possible, try rotating the plug 180 degrees and see if that helps.
However, there’s a good chance that the plug is polarized (i.e. one prong is larger than the other) in which case you won’t be able to flip it.
If I bonk my PC speakers, the hum goes away for a while. Wiggling the wires can make it come and go. Probably a short in a wire or connecter, right? They’re 20yo.
NOT a polarized plug. The hum seems the same both ways. The hum is also unaffected by twiddling the volume knob
Actually, it is 100/120Hz because of weak capacitors/bad filters in the power supply.
You can try a “ground loop isolator” to get rid of the hum
I learned a little bit about ground loop and it seems like this mainly happens when you are plugged into power using two different sources? How is there a ground loop when the speaker is connected to the stereo and the stereo is the only thing plugged into power.
Disconnect all copper input cables from your amp. If the hum stops, it was a ground loop.
There are already no input wires (it is using Bluetooth) so I guess it is not a ground loop.
Thank you for the education! I’m assuming that the inputs, if they are grounded, can lead to the ground loop?
Google “60 hz hum”. It can sometimes be helped by plugging the various components (amp and preamp) into the same power strip.
There are also devices to fix the “ground hum”, but I’d say to read a couple of the articles on some audiophile sites. Also: see if it happens with nothing plugged in. If that’s the case and the outlet/plug is properly grounded, it might just poor manufacturing/design.
Right now, the stereo is connected to power and the speakers are connected to the stereo and that’s the only thing that’s connected. So, either the 60 hertz hum is being picked up by the speaker wire which is unshielded as far as I can tell. Or are you saying the stereo itself could be poorly designed? Because that is probably the most likely thing with an Amazon stereo.
For some reason, this stereo only comes with a two-prong power plug, not a grounded one, so that’s probably a bad sign.
So i could write an entire book here about this topic as ive spent most of my life around audio.
But the simple part is, even if its a 2 prong, you may still have a chassis ground on the metal casing you need to hook to an outlet plate screw or other ground.
The other issue could just be your house wiring. Some houses are not wired correctly and may not have proper grounding so you are picking up noise there.
The other issue is, cheapo pots (like volume controls) sometimes make noise when they are all the way off due to imperfect contacts being used in their build.
Speaker wire is always unshielded.
If you have a bunch of wires running parallel to 120v you’ll get noise. If you have lot of cables coiled up you’ll create an antenna and possibly pick up a radio station.
What make and model are these speakers? Its very possible they have a crossover in them with bad capacitors.
They are AR something from the 70s or 80s (?). They might have been built from a kit. I’ll update when I get home.
I’ll look for a ground conntector on the chassis.
I have other speakers in the house, which connect to a whole home stereo system with wiring in the walls, which have a very very slight hum at 0 volume, compared to these. That may be the whole house being slightly ungrounded? But it is different from my test setup, which has a noticeable hum.
This “test” setup is on top of the dining room table with the stereo plugged into a wall outlet via an extension cord. About 10ft each of 16 gauge twisted wire speaker cable connects the stereo to both the L and R speaker.
The stereo is this one: Daakro AK45 Stereo Audio Amplifier,300W Home 2 Channel Wireless Bluetooth 5.0 Power Amplifier System, Home Amplifiers FM Radio, USB, SD Card, with Remote Control Home Theater Audio Stereo System : Electronics
https://www.amazon.com/gp/aw/d/B0BX8TGZZF
Thank you for sharing your expertise!
I see! OK looking at that unit, it doesn’t appear to have a separate ground. Although it does seem to be a low build quality which could be causing your issue. If you wanted you could try running it on DC power since that would be filtered, it could fix your issue.
Are the in wall speakers on a different amplifier?
I am leaning toward it being your house wiring or the amplifier. The speakers and their wiring are likely fine.
Yes the house speakers (almost imperceptible hum, with the wires in the wall) are amplified by an Onkyo Tx-8011, which goes through a Niles audio HDS-6 high definition speaker selection system, with the protection toggle always engaged.
For protection, it says:
Disengaged:
1-2 8 ohm
1 4 ohmEngaged:
3-6 8 ohm
2-6 4 ohmBut honestly I don’t have the users manual and I don’t know what it means.
Back to the test setup (with the louder hum; speaker wire NOT in the walls, just draped over the dining room table), the speakers are AR18s, U028144. The 2 pronged plug is NOT polarized. I’ll look for a DC power supply and see how that goes.
Looks more like bad design unless there’s a ton of other cables or if some of your cords/cables are in loops. I just checked my amp/preamp, and surprisingly they’re not using grounded plugs either, and it’s fairly high-end gear.
Only other thoughts:
- plugging directly into the wall if you’re plugged into a surge protector, or plugging into a Surge protector if you are plugged into the wall.
- I would also try moving the volume up and down a little bit because I’ve seen gear where that caused hum issues (god knows why).
- try plugging in a source in case they’re somehow using the connectivity to other gear to provide the grounding (grasping at straws here).
Unfortunately, it’s been long enough since I’ve dealt with ground hum issues that the I’ve forgotten all the tricks. :( You might need to find an audiophile group. Because even cheap-ass gear shouldn’t do that.
I’ll try the tricks! I’m betting the volume knob / potentiometer is a cause.
Update: twiddling the knob does nothing.
