Probably a silly question - Does an aluminum speaker cabinet attract more noise?

[amirm]

This is interesting indeed considering all these items are on different circuits with the audio system itself on multiple dedicated circuits (with ground). So this makes me wonder despite these circuits being separate if there is a leak finding its way into my audio circuit perhaps causing the noise I am hearing?

All the wires join back up at your panel so there is no isolation to speak of. Not sure why there is an impression that a "dedicate circuit" provides such a feature. It does not. It's main role is to provide maximum current since there are no other loads on it. Otherwise, the wires all terminate at the breaker panel and noise travels back and forth as it would with any other circuit.

I don't think you will find a solution to your problem. These amps are sensitive to power line activity and are just going to do what they are doing. Switching amplifiers are especially sensitive to supply line issues. Lots of feedback is used to mitigate some of this but issues can remain.

Are these DIY amps or name brand? What is their power supply?

 

[Folsom]

They're Merrill audio Veritas, based on Ncores. It's possible to build a compatible, non-problem, forms of conditioning for them. I'd still check the voltage at the wall given the condition of the rest of the house. But if it's a capacitance issue the only good way is to dampen the resonation which requires modifications to the SMPS unit, if they're indeed susceptible. You can PM me about it, but obviously we're talking warranty voiding. That said, Merrill may not have a clue about any of this...

 

[amirm]

Thanks. I looked at their site and the boxes don't show any regulatory certifications (FCC, CSA, UL). Are there any markings on the actual units?

 

[Folsom]

I don't know but that's utterly pointless to look up since they're hypex units. It's only likely some minor changes were done to the amp boards.

 

[cjf]

They're Merrill audio Veritas, based on Ncores. It's possible to build a compatible, non-problem, forms of conditioning for them. I'd still check the voltage at the wall given the condition of the rest of the house. But if it's a capacitance issue the only good way is to dampen the resonation which requires modifications to the SMPS unit, if they're indeed susceptible. You can PM me about it, but obviously we're talking warranty voiding. That said, Merrill may not have a clue about any of this...

Yes, these are the Merrills but I do have a few dual mono Hypex NC400 amps on hand that also have the same behavior when connected to these specific speakers. With that said, I would be open to experimenting with the NC400 amps and their associated NC600 SMPS supplies to try and find a solution.

I'm going to go out on a limb here and say that I may be one of very few if any other people on the planet running this pairing of speaker/amp so it's probably very likely such behavior wasnt something that was tested for during the build of the SMPS at Hypex. I'm going to shoot Hypex an email about this and see if they also have any ideas on what could be tried as well, if anything.

 

[cjf]

All the wires join back up at your panel so there is no isolation to speak of. Not sure why there is an impression that a "dedicate circuit" provides such a feature. It does not. It's main role is to provide maximum current since there are no other loads on it. Otherwise, the wires all terminate at the breaker panel and noise travels back and forth as it would with any other circuit.

I don't think you will find a solution to your problem. These amps are sensitive to power line activity and are just going to do what they are doing. Switching amplifiers are especially sensitive to supply line issues. Lots of feedback is used to mitigate some of this but issues can remain.

Are these DIY amps or name brand? What is their power supply?

Yes it seems I had a brain fart when saying there would be some isolation provided by using a dedicated line. I think I'm going to purchase a couple of those fancy Shunyata Defenders and plug them into the duplexes where the amps reside to see if they offer any benefit to this. These items would be the cheapest test I can think of trying without dropping a lot of money on something else that may or may not cure the noise.

 

[DonH50]

Actually, the cheapest initial trick I would try would be to add ferrite cores on the power and speaker lines. Places like Allied, Digikey, Mouser, Newark, etc. have selections of them, and probably places like Parts Express etc. They come in cylinders, clamp-ons, big rings you would wrap a few turns of wire through, etc.

A quick search at Mouser (first Google hit): http://www.mouser.com/Passive-Compo...rs-Ferrites/Ferrite-Clamp-On-Cores/_/N-bw7t7/

 

[Folsom]

In this case I'd get ferrite "freq 31" devices because the interference is likely in the lower range of RF.

Looking at the NC400 & SMPS with them first is a great idea. But #1 is to check the voltage at the wall where you plug them in.

 

[amirm]

I don't know but that's utterly pointless to look up since they're hypex units. It's only likely some minor changes were done to the amp boards.

It is the responsibility of whoever puts them in a box to provide such filtering and certification. It doesn't matter that they used pre-built modules.

 

[Folsom]

It is the responsibility of whoever puts them in a box to provide such filtering and certification. It doesn't matter that they used pre-built modules.

The filtration is built into the Hypex units. UL is only required in a few counties in the USA (for sales). Otherwise as a manufacturer you acquire it because many distributors won't pick you up if you don't have it. There's a lot of amazing equipment in the audiophile world without it. And it's nearly all much safer than cheap Chinese consumer grade crap. There are however some basic rules with any appliance that could get someone in trouble if they were done wrong.

 

[cjf]

Actually, the cheapest initial trick I would try would be to add ferrite cores on the power and speaker lines. Places like Allied, Digikey, Mouser, Newark, etc. have selections of them, and probably places like Parts Express etc. They come in cylinders, clamp-ons, big rings you would wrap a few turns of wire through, etc.

A quick search at Mouser (first Google hit): http://www.mouser.com/Passive-Compo...rs-Ferrites/Ferrite-Clamp-On-Cores/_/N-bw7t7/

OK, heres probably a dumb question but would there be any benefit of placing one or more of these Ferriite claps along the length of Romex coming from the breaker box before the AC Receptacle? Maybe one nearby the breaker box and another a few feet before the Receptacle? Or, would they only be useful on the cabling after the AC Receptacle?

Thanks for the link..looks like I'm going mineral shopping

 

[cjf]

In this case I'd get ferrite "freq 31" devices because the interference is likely in the lower range of RF.

Looking at the NC400 & SMPS with them first is a great idea. But #1 is to check the voltage at the wall where you plug them in.

Thanks..I'll take a look for that specific ferrite and a few others in the same range. I have not tested the plug yet. I'll do some shopping for a gadget to test it.

Out of curiosity, what would be a few reasons for the plug to not be serving up appropriate voltage? FWIW, each of the dedicated lines are run with 10ga Romex and are no longer than 20ft from the box.

Thanks

 

[amirm]

The filtration is built into the Hypex units.

What filtration? Does the module come with a power supply? If not, then that unit needs to have safety and emissions certification and necessary filtration.

UL is only required in a few counties in the USA (for sales).

That's not true. There is no law in US mandating getting UL certification. There can be jurisdictional issues that require it but it is not a general law. UL is there to give you tools to deal with lawsuits, indicating that you had done due diligence in the design. CSA certification however is a condition of import into EU.

Otherwise as a manufacturer you acquire it because many distributors won't pick you up if you don't have it. There's a lot of amazing equipment in the audiophile world without it. And it's nearly all much safer than cheap Chinese consumer grade crap. There are however some basic rules with any appliance that could get someone in trouble if they were done wrong.

My interest here is not safety or salability. It is that when a device has gone through a lab for such testing, basic problems like leakage and filtering are in place.

 

[Folsom]

Thanks..I'll take a look for that specific ferrite and a few others in the same range. I have not tested the plug yet. I'll do some shopping for a gadget to test it.

Out of curiosity, what would be a few reasons for the plug to not be serving up appropriate voltage? FWIW, each of the dedicated lines are run with 10ga Romex and are no longer than 20ft from the box.

Thanks

I don't know why you'd have abnormal voltages. I'm not saying you do, but the description you give makes me think it's a simple check to rule it out. Knowing as much as you can before you start spending $ every which direction is a good idea.

 

[Folsom]

Amirm I think you read "counties" as "countries". Some of them do not allow sales of non-UL equipment within them. However they may not specify ordering equipment from within the county.

You should really look up Hypex Amirm. They're a "turn-key" solution. Their plate amps are CE marked, btw. All of their SMPS's are turn-key as in you just plug the AC into them from an IEC socket. All of them feature at least filtration, if not also PFC (I'd have to confirm by having one in my hands). Their market is OEM, and they're the biggest thing in classD world-wide. The development of them is documented fairly well and known among many circle to be very good engineering. What you're suggesting is like asking if B&W measures their speaker's outputs.

 

[amirm]

Amirm I think you read "counties" as "countries". Some of them do not allow sales of non-UL equipment within them. However they may not specify ordering equipment from within the county.

I did, sorry .

You should really look up Hypex Amirm. They're a "turn-key" solution. Their plate amps are CE marked, btw. All of their SMPS's are turn-key as in you just plug the AC into them from an IEC socket. All of them feature at least filtration, if not also PFC (I'd have to confirm by having one in my hands). Their market is OEM, and they're the biggest thing in classD world-wide. The development of them is documented fairly well and known among many circle to be very good engineering. What you're suggesting is like asking if B&W measures their speaker's outputs.

I know they provide the components but once you put them in a box, wire them as you like and lay them out as you like, then it changes things. I looked up the specs for the SMPS and it has no measurements at all other than output power: http://www.hypex.nl/docs/SMPS1200_datasheet.pdf

 

[Folsom]

I can't recall the best place to find information on their SMPS's, but they are considered among the best.

 

[CharlesL]

cjf: "...One thing to mention is that when I put the Amp into standby mode (still powered on from an AC receptacle standpoint but the Output is "Muted") the noise goes away completely. .."

Sounds to me that the noise came from the amp.

 

[Sauerball]

Different situation with similar components, I've got Mola Mola Kalugas driving my pair of Q5. I hear zero noise unless I'm playing something. Wouldn't expect this noise is an issue with the modules but maybe implementation or power supply issues.

 

[cjf]

Different situation with similar components, I've got Mola Mola Kalugas driving my pair of Q5. I hear zero noise unless I'm playing something. Wouldn't expect this noise is an issue with the modules but maybe implementation or power supply issues.

A'hh someone else does exist running such a combo

So my next move is I'm going hunting for noise in the grid within the house. I started this excursion yesterday by flipping breakers in the panel one by one and then running upstairs to place ear on tweeter again. I believe I may have stumbled onto one possible noise source (of many I'm sure) creating a low level "Scan" type sound every once while my ear is resting on the tweeter. This noise appears separate from the constant high pitched whistle I also hear.

The "scanning" noise I hear may be coming from a brain box in the basement responsible for controlling my Sump Pump. Its one of those boxes that senses a power failure and changes the sump pump to switch to the backup battery. This brain box is on the same circuit as some of the wall outlets not used for audio on the first floor living room where my listening room is located. I've got some more hunting to do to confirm this 100% but that one particular noise seemed to go away when that breaker was off. I may try and put a few of those clip on Ferrite cores on the power cables responsible for the Sump and see what happens.

If I only had a totally separate power source I could switch to within the house to quickly confirm or deny that all these noises are from something on the grid and not from the audio equipment itself

Again, I consider myself fortunate that once the system is powered up and at a steady state that the remaining noise does not effect my listening enjoyment of the equipment and no one would be the wiser unless I told them to put their ear on the tweeters. I may just end up living with the strange startup noise I hear as long as it doesn't turn into something that could eventually damage the equipment. Right now I just leave the system powered on at all times and luckily the Hypex modules only draw a few watts at idle so my wallet shouldn't suffer much by doing this.

Thanks