I'm tired of hum - how about car amps at home?

S

svtcontour

Enthusiast
Hi guys, this is my first post and it might seem a little rediculous...

Ever seince I've moved into my new home, I've had a little more hum from my stereo than usual. The hum comes from the transformer and can be heard a little via the speakers and does so even with no RCA cables attached (just being powered with no signal connected). The hum is constant in volume so at moderate volumes its totally inaudible but at very low volumes I can hear it.

The hum is present in my Threshold amp, SAE amp and Soundcraftsmen amp. Also the intensity of hum varies from time of day and sometimes its pretty bad and even has a slight buzz you can hear in the speakers.

Had an electrician come by and he said he couldnt find anything wrong with the house wiring and said that maybe its the power coming from the city to the house which might be a bit dirty in this area. Called the power company and pretty much they told me to go jump in a lake.

Ok so at this point I'm contemplating getting a large Astron 50A 13.8VDC linear power supply and putting it it in adjacent room and running a pair of 4AWG cables into the music room and powering two Orion HCCA car amps I have. I'm thinking this way maybe there will be no more 60Hz hum or buzz and as far as I remember, those Orions sounded pretty neutral and quiet and had excellent control over the speakers (at least when they were in the car).

Is this a very insane idea or can it work?

PS. I tried one of those bullsh*t monster power cleaners for $600 and it did nothing...so took it back to the store.
 
WmAx

WmAx

Audioholic Samurai
Hi guys, this is my first post and it might seem a little rediculous...

Ever seince I've moved into my new home, I've had a little more hum from my stereo than usual. The hum comes from the transformer and can be heard a little via the speakers and does so even with no RCA cables attached (just being powered with no signal connected). The hum is constant in volume so at moderate volumes its totally inaudible but at very low volumes I can hear it.

The hum is present in my Threshold amp, SAE amp and Soundcraftsmen amp. Also the intensity of hum varies from time of day and sometimes its pretty bad and even has a slight buzz you can hear in the speakers.

Had an electrician come by and he said he couldnt find anything wrong with the house wiring and said that maybe its the power coming from the city to the house which might be a bit dirty in this area. Called the power company and pretty much they told me to go jump in a lake.

Ok so at this point I'm contemplating getting a large Astron 50A 13.8VDC linear power supply and putting it it in adjacent room and running a pair of 4AWG cables into the music room and powering two Orion HCCA car amps I have. I'm thinking this way maybe there will be no more 60Hz hum or buzz and as far as I remember, those Orions sounded pretty neutral and quiet and had excellent control over the speakers (at least when they were in the car).

Is this a very insane idea or can it work?

PS. I tried one of those bullsh*t monster power cleaners for $600 and it did nothing...so took it back to the store.
It does sound like you have serious power quality issues. IF that is the case. there are two semi-practical solutions: (1) use a power re-generator device to produce clean power - very expensive; generally in the $2k+ range [and] (2) use source, pre-amp and amplifiers with switch mode power supplies; these should filter the power enough to remove any line quality issues.

Your car amp solution may work, but only if your sources don't have the power line noise issue also. If you go the car amp route, I recommend going with a power supply that uses a switch mode power system with heavy output filtering, as this is more likely to filter the line better and be immune from 60Hz hum. One popular example for audio purposes(audio display boards, car and boat shows, etc.) is the Cascade Audio Engineering ASP-55. It is such a unit, and it provides up to 55 amps continuous. It is also smaller, weighs less and is more energy efficient as compared to the type you listed. They are not cheap, usually selling for about $300. On eBay, the cheapest a new one will go for is $280 plus shipping.

-Chris
 
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S

svtcontour

Enthusiast
Thanks WmAx! I did some reading on the PSU brand you suggested and it does indeed seem like it would be a better choice. I think in the meantime I'll try and get a hold of a small 15A linear supply my friend has on his test bench and run the amps at low volume and see how it sounds. If all is good, then I think I'll go for one of the larger cascade units.

As far as my source goes, its got no noise issue nor does the preamp. Seems anything with a large transformer is the one at risk. What a shame. My Threshold is a ClassA as well. I mean the hum from that one is not much so maybe I can even keep that but I have built a pair of sub cabinets with 10" drivers and have an outboard crossover and wanted to use one of my other amps to drive the subs...so maybe one of the car amps can do that duty and give me no hum or buzz :)
 
F

fmw

Audioholic Ninja
I'm sure it would work. However, if what you have is 60 cycle hum, then I would go through all the things you need to do to eliminate it. Grounding, loops - all sort of stuff - first. If it is a buzz instead of a hum and it comes from a power supply transformer then you can either replace the transformer or the entire unit and the replacement should be fine in the same room with everything else.
 
WmAx

WmAx

Audioholic Samurai
I'm sure it would work. However, if what you have is 60 cycle hum, then I would go through all the things you need to do to eliminate it. Grounding, loops - all sort of stuff - first. If it is a buzz instead of a hum and it comes from a power supply transformer then you can either replace the transformer or the entire unit and the replacement should be fine in the same room with everything else.
Unfortunately, he says the hum/buzz come through even with nothing connected to the amplifiers. Note the plural: the problem occurs on at least separate power amplifiers. I have only experienced this kind of problem as he describes when powering an amp with a very dirty power supply -- like using a device that causes massive noise injection on the house line voltage or using a UPS in battery power mode as examples.

-Chris
 
Rickster71

Rickster71

Audioholic Spartan
Power companies are reluctant to take action with things of this nature.
If it was safety related, they'd be right on it.

You'll have to get someone with a scope, to prove to the utility co that the sine wave is dirty.
I remember TLS Guy having a similar power problems. A search of his posts, or a pm to him may shed some light.
 
Haoleb

Haoleb

Audioholic Field Marshall
One thing you may want to try is a device that will filter out any dc voltage riding on your mains ac voltage. It can cause problems similar to what you are describing. You can DIY one yourself or you can buy commercially available units. PS audio makes one called the humbuster, and CI Audio makes one called the XDC-2. I built my own to try on my preamp and it didnt fix the problem I was having but it may work for you.

http://www.psaudio.com/products/humbusterac.asp

http://www.ciaudio.com/
 
S

svtcontour

Enthusiast
Thanks for the responses guys. I might look into that hum buster if I end up having DC on the line. I'll talk to the power company one more time. If that doesnt work I'll see if i can get an electrician again to see if there is anything noisy or dirty with my line and either get a screenshot of the scope or some kind of printout then contact the electrical company again. If all else fails, then I will go the car amp route. Man what a pain this is :(
 
Haoleb

Haoleb

Audioholic Field Marshall
If you want someone to analyze your power in that much detail your going to need someone more skilled than an average electrician. You may want to try and get in contact with a local ham radio club or electronics repair tech that would likely have the required skill and tools.
 
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