[syn959]

Is it normal to hear a low hum from the HPA4 basically whenever the unit is plugged, on or off? I don't hear it through headphones, but through the unit itself just sitting there on my desk.

No hum with mine either. Probably best to give Benchmark a call or an email if you haven't already so they can troubleshoot.

 

[phthora]

Good to know. Thanks. I've contacted the Benchmark service dept via email, so hopefully we can get to the bottom of this. It's slightly annoying, but more importantly, I want to make sure my unit is performing properly.

 

[llamaluv]

Good to know. Thanks. I've contacted the Benchmark service dept via email, so hopefully we can get to the bottom of this. It's slightly annoying, but more importantly, I want to make sure my unit is performing properly.

"DC offset" is something that immediately comes to mind (DC voltage floating on the AC mains), which can cause mechanical noise in an amp's transformer.

 

[syn959]

Good to know. Thanks. I've contacted the Benchmark service dept via email, so hopefully we can get to the bottom of this. It's slightly annoying, but more importantly, I want to make sure my unit is performing properly.

Hopefully Benchmark will help you figure out the issue. Any hum or high pitch noise from electronics bothers the heck out of me as well so I feel your pain. Especially from such a clean and transparent amp!

 

[phthora]

"DC offset" is something that immediately comes to mind (DC voltage floating on the AC mains), which can cause mechanical noise in an amp's transformer.

I am running my gear through a power conditioner, I would hope that would prevent that sort of thing. I'll be checking a few things like that later, per the advice of the service department. I'll post an update once things get interesting.

Hopefully Benchmark will help you figure out the issue. Any hum or high pitch noise from electronics bothers the heck out of me as well so I feel your pain. Especially from such a clean and transparent amp!

Thanks! It's not much of a concern soundwise, but it seems like something that shouldn't be happening so I want to make sure it doesn't develop into a major issue. The worst part, honestly, is the sinking suspicion that I am going to have to send the amp back and listen to the b-team exclusively for a few weeks. Not to be overly dramatic or anything, but that is going to be a hard transition.

 

[twoloszyn]

I am running my gear through a power conditioner, I would hope that would prevent that sort of thing. I'll be checking a few things like that later, per the advice of the service department. I'll post an update once things get interesting.



Thanks! It's not much of a concern soundwise, but it seems like something that shouldn't be happening so I want to make sure it doesn't develop into a major issue. The worst part, honestly, is the sinking suspicion that I am going to have to send the amp back and listen to the b-team exclusively for a few weeks. Not to be overly dramatic or anything, but that is going to be a hard transition.

Thankfully you have a B-Team to back you up! If mine goes I got nothing but the line out on my PC or phone so that’s something to be grateful for

 

[twoloszyn]

I thought this video fit some of the inquiries in this thread by me and others fairly well:

 

[phthora]

Thankfully you have a B-Team to back you up! If mine goes I got nothing but the line out on my PC or phone so that’s something to be grateful for

You live dangerously, my friend, and I respect that.

 

[MacedonianHero]

There's no hum with mine.

None here either...ever. Ground loop somewhere in the home maybe? I'd try seeing if it is still there in other power outlets.

 

[phthora]

None here either...ever. Ground loop somewhere in the home maybe? I'd try seeing if it is still there in other power outlets.

So, it turned out to be the DAC3-B that was the culprit, while the HPA4 displayed no hum at all. It also shows up when connected to a power conditioner. I'm not at all familiar with ground loop issues, does that still sound like a possibility here?

 

[JP281]

So, it turned out to be the DAC3-B that was the culprit, while the HPA4 displayed no hum at all. It also shows up when connected to a power conditioner. I'm not at all familiar with ground loop issues, does that still sound like a possibility here?

My DAC3b also has this humming. Almost positive it's a normal thing because it never turns completely off

 

[MacedonianHero]

So, it turned out to be the DAC3-B that was the culprit, while the HPA4 displayed no hum at all. It also shows up when connected to a power conditioner. I'm not at all familiar with ground loop issues, does that still sound like a possibility here?

I'd still try the DAC3-B on another outlet to see if there is a hum with it and not a ground loop.

 

[FourT6and2]

I'm running DAC3-B and HPA4. No hum with either.

 

[phthora]

I'd still try the DAC3-B on another outlet to see if there is a hum with it and not a ground loop.

Different power cord, different outlet, different circuit, same faint hum.

And, as much as I appreciate the help, this is all academic at this point since Benchmark is in the middle of resolving the issue. I don't want anyone wasting their time on a problem that is now moot. You know, unless you find it interesting like I do, then by all means!

 

[nordkapp]

My DAC3-B makes a micro hum when off. Turn it on and it's gone...FWIW....It's completely unnoticeable unless I place my ear within approximately 10 inches of it.