[Trielobite]

Hi, I just received my IDA 16, and there is a hiss hearable from 4 feet away in the khz-range on both speakers. They are inefficient Dynaudios (86db), and I dread upgrading since I imagine the sound will be worse with more efficient speakers. There is also an audible speaker "pop" when changing inputs.

The sound is identical regardless of other devices plugged into the same wall socket, and the sound is also the same on other sockets, and the problem remains regardless of whether or not I connect the amp to inputs. My old amp (also class D) had none of these issues.

I don't think it's gain noise since the hiss remains level regardless of volume, and what I'm left with is poor shielding/IM radiation. I've ordered one of these: https://www.isoteksystems.com/product/discovery/evo3-isoplug/ to help alleviate noise from the circuit.

Is there any point in RMA'ing this for a new unit?

[avta]

I would definitely contact support. The unit should be silent. There may be a pop when you turn the unit on I think but that shouldn't be a problem.

[oskar]

There is certainly a problem there. My IDA-16 is dead quiet with 94db speakers.
No pop on start up and changing inputs.

[Trielobite]

Tried three sockets, but due to placement all of them are connected to the same circuit. No difference in hiss.
Strange.

[avahifi]

Is the amplifier getting hot?  If so the hiss may be symptom of an ultrasonic oscillation caused by a fault in the unit.  Be careful using it until the manufacturer can resolve the issue.

Frank

[Trielobite]

About 103-107 degrees if it has been running for a few hours. Warm, but not hot.

[avahifi]

Then it is probably not oscillating.  If hiss persists with no inputs connected and volume all the way down it is time to contact manufacturer.  They claim this is a very quiet amplifier.

Anything strange or different about your speaker cables?  Non-standard braided cable configurations can cause some amplifiers to oscillate.

Frank

[Trielobite]

The speaker cables are braided: https://www.futureshop.co.uk/wireworld-luna-8-speaker-cable-price-per-metre

[Trielobite]

Unfortunately I do not have other speaker cables on hand. Would it be diagnostically helpful to use another amp, or does the threshold for oscillation vary between power supplies?

[srb]

Unfortunately I do not have other speaker cables on hand

Regular old 18ga lamp/zip cord would be sufficient to test and see if the noise persists.

[Trielobite]

Tested just now with some generic speaker cable, same noise same level.

[John Casler]

Tested just now with some generic speaker cable, same noise same level.

Time to go to the NuPRIME website and submit a "Help Desk ticket"

[Trielobite]

Done.

I'm still curious as to what this could be, I've seen others mention an audible hiss, while many claim that the amp is dead silent. My other class D amp is a 2x80w/8ohm construction. Could the larger power supply equal more interference, or am I way off?

[seikosha]

Done.

I'm still curious as to what this could be, I've seen others mention an audible hiss, while many claim that the amp is dead silent. My other class D amp is a 2x80w/8ohm construction. Could the larger power supply equal more interference, or am I way off?

Sometimes people just can't hear that stuff.  I was at a guys house once and his speakers were hissing and I asked if it bothered him.  He had no idea at all that they were hissing, but I could hear it at the listening chair.  Conversely, just last week, my girlfriends cable box started making a weird staticy kind of buzz.  She asked me if I could hear it and I said no.   When I walked up close to it within a couple of feet I could finally pick it up, but she could hear it across the room.

[seagreen]

I had a similar sounding high-pitched hiss with an ST-10. Thinking it was some issue on my end, I spent a ton of time trying to track it down before ultimately sending it in. Turns out this is an issue with some NuPrime amplifier modules. Once mine we replaced the unit is dead silent. That may or may not be your issue, but what you're hearing is not normal and likely not the fault of some other comments in your system.

Good news is that once I got mine fixed it sounds incredible and I still glad I got it!

[Trielobite]

I had a similar sounding high-pitched hiss with an ST-10. Thinking it was some issue on my end, I spent a ton of time trying to track it down before ultimately sending it in. Turns out this is an issue with some NuPrime amplifier modules. Once mine we replaced the unit is dead silent. That may or may not be your issue, but what you're hearing is not normal and likely not the fault of some other comments in your system.

Good news is that once I got mine fixed it sounds incredible and I still glad I got it!

Thanks for the encouragement. For what it's worth my IDA 16 sounds downright incredible, and provides bass response I never knew my speakers were capable of.