Recommend a NS10 Amp?

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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Hi again Hugh and James

Yes it was a great shame, as my pockets would have thanked me had the IMG STA 400-D worked out, (thanks for correcting my typo James:-) It wasn’t to be unfortunately, but I am still glad that I got the chance to put it to the test as otherwise. I would have been left wondering!!!

I have a further question for you both or anyone else that can shed some light…do amps generally require burn in like say monitors do??

Many thanks in advance
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Re: Recommend a NS10 Amp?

Post by Martin Walker »

Angelface78 wrote: Wed Oct 20, 2021 3:28 pm However, the fan noise was noticeable but not as much of an issue as the strange rattling noise and hum that it also produced.

This could have been a mains transformer inside the unit buzzing acoustically, whose level is tied in to the purity of the mains waveform you receive, and as such might be inaudible, or even change in level throughout the day.

So it's certainly possible that the rattling noise wouldn't be audible to the amp's designers and many of its users.

Then of course it could be due to dodgy design ;)

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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Thanks Martin for your helpful explanation as to what may have been the cause, as I did wonder! The noise did seem to be louder at points and less so at other times during testing. Therefore, what you have mentioned does seem possible. However, it was slightly irritating and I tend to think if things start out as a small annoyance a lot of the time they then become bigger annoyances:-) or sometimes you simply get used to it!! Although, I didn’t feel it was something I could live with hence me returning it pretty swiftly.
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Re: Recommend a NS10 Amp?

Post by James Perrett »

Martin Walker wrote: Wed Oct 20, 2021 11:24 pm
Angelface78 wrote: Wed Oct 20, 2021 3:28 pm However, the fan noise was noticeable but not as much of an issue as the strange rattling noise and hum that it also produced.

This could have been a mains transformer inside the unit buzzing acoustically, whose level is tied in to the purity of the mains waveform you receive, and as such might be inaudible, or even change in level throughout the day.

This uses a switch mode power supply so no mains transformer to rattle or hum. The important parts of this amp (power supply and amp modules) look identical to my main monitor amp which produces very good results. I'd guess that one of the fans was faulty as, from looking at internal pics, that's about the only thing in there that could produce a rattle.

The cost of the amp is actually cheaper than the cost of buying the individual modules for the private constructor so I'd be tempted to buy it and then rip out all of IMG's modifications (the fans and the input board) and just feed the balanced inputs of the Hypex modules directly. The fans are unlikely to be needed in the typical studio environment - certainly mine are still cool after a days work.
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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Thanks James for your response. You are clearly very knowledgeable and know these amps well-far more then me that’s for sure:-)! The very fact you mentioned possibly purchasing the unit to rip it apart indicates to me that you have a good working knowledge of them, as the thought of doing anything like that would fill me with absolute dread😄. Let’s say I know my limits!! But please report back should you decide to do so. I would be interested to hear your experience.
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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Hugh Robjohns wrote: Mon Sep 20, 2021 10:53 am Just for clarity... ART have two similarly-named, but completely different products.

The CleanBOX II is a dual-channel passive box containing a pair of audio transformers connected with TRS sockets in and out. The transformers provide galvanic isolation between the line level inputs and outputs (to break ground loops) and also convert between balanced and unbalanced connections on either side.

Image

It operates at nominally unity gain (ie, the output level is the same as the input level) and is ideal for converting between unbalanced outputs and balanced inputs, or vice versa, and for breaking ground loops.

It has a slightly more expensive (but far more versatile) sibling called the DTI which is essentially the same thing in a differently shaped box with a plethora of different parallel-wired connectors on each side (XLR, TRS and RCA-Phono). This makes it far more convenient for connecting different devices as well as for splitting and duplicating signals. (I have five of them at the last count as they are so extremely useful).

Image

Then there's the CLEANboxPro which is a dual-channel 'level converter'.

Image

It looks similar to the DTI, but it has volume knobs on the front and no TRS connectors!

Internally, this is a very different device, though. It is an active product that requires external power, and it is intended to connect unbalanced domestic equipment like video recorders etc to balanced professional equipment. To that end, it receives unbalanced (RCA-phono) inputs at a nominal -10dBV and provides +12dB boosted balanced outputs at +4dBu. It also receives balanced +4dBu inputs and attenuates them by 12dB to provide unbalanced outputs at -10dBV. (The actual gain is adjustable.)

The nature of the active circuitry means there is no galvanic isolation between inputs and outputs. It's a useful box for converting between consumer and professional equipment connections, especially if you need to also adjust the signal levels, and can also be used to interface between pro gear and fx pedals. But it will not help with ground-loop problems.

Hi Hugh or anyone else who can answer this question:-)

I reintroduced my IK ilouds micro monitors back into my system as a second set of reference monitors. However, there is a buzz and hum coming from them constantly, which I am trying to eliminate. It is less noticeable when music is playing of course, but when the music stops it’s quite noticeable. Do you think any of the Art devices such as the DTI or Cleanbox. Pro might help with this? I would prefer a passive design over powered if possible. I am currently using Pseudo Balanced RCA Phono to TRS Jack Van Damme leads connection from speakers to Audient Nero Monitor controller, so I don’t think the issue is with the leads-as they were quite expensive and I did purchase them to try to mitigate potential unbalanced to balanced issues. So I wonder if an Art device would be helpful in this instance?

Many thanks in advance
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Re: Recommend a NS10 Amp?

Post by Hugh Robjohns »

I suspect the problem here is that the speakers lack a solid ground connection (since they appear to be powered from a double-insulated external PSU).

That being the case, your 'pseudo-balanced cables' probably aren't helping, and isolation transformers could make it even worse.

I'd suggest trying simple mono jack (TS) to RCA-phono cables. That way the shield of the RCA cable will carry the ground back to the Nero... which will hopefully be carrying a solid ground from other devices connected to it.

If the Nero itself lacks a solid ground (as it too is powered from a double-insulated PSU) then you could try grounding the speakers with a wire between something you know to be grounded and something earthy on the speaker.
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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Thanks so much Hugh for your very helpful and also insightful response.

It’s disappointing that the pseudo leads aren’t helping here, but it’s good to know. I will certainly do as you have kindly suggested re. Leads but think that will require me purchasing some new ones! I did also try attaching Ferrite noise suppressor cable clips to the power supply lead, but this did nothing at all, so I removed them.

I always wonder why these manufacturer’s use these power supplies especially for audio when they are aware of the noise that they can potentially introduce. I know cost is the probably the main reason, but I’d much rather spend a bit more to be free from hum:-)!!

Also I am slightly unclear re. how to ground speakers using wire as you kindly mentioned! So I am hoping the new leads might do the trick instead , as I wasn’t sure if the speakers or power supply were faulty.

Thanks again Hugh
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Re: Recommend a NS10 Amp?

Post by Angelface78 »

Update Hugh….great news hum/buzz has left the building!! I failed to mention that yesterday I decided to connect the Ebtech Line Level Shifter between Nero and ilouds.

It was this that was causing the issues! I just decided to disconnect it when you mentioned that the Art devices that are similar, use transformers and that would likely worsen the issue, which was indeed the case! How is this even possible? Given that it it states it “Eliminates hum and buzz”?!

Even better I was able to continue using the Pseudo cables, so I didn’t have to purchase any further ones, which is also a bonus:-).

Thanks so much for your help once again, as had you not mentioned about transformers I would never have thought this would have in anyway been the culprit and I am so relieved that it was not a dodgy power supply or defective speakers and that with your help I was able to resolve it :thumbup:
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Re: Recommend a NS10 Amp?

Post by Hugh Robjohns »

Angelface78 wrote: Thu Oct 21, 2021 6:09 pm Update Hugh….great news hum/buzz has left the building!!

Hurrah!

I failed to mention that yesterday I decided to connect the Ebtech Line Level Shifter between Nero and ilouds. It was this that was causing the issues! .... How is this even possible? Given that it it states it “Eliminates hum and buzz”?

They eliminate hum and buzz caused by ground loops... when there are multiple grounds in the system. But your problem wasn't a ground loop it was no ground at all !

So it was exactly as I said. The speakers lacked the solid ground which they expected via the input connections because the Ebtech's transformers isolate its input and output connections, hence no ground at the speaker.

Your 'pseudo balanced cables' you have are obviously wired in such a way as to convey an earth via the screen.
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Re: Recommend a NS10 Amp?

Post by Angelface78 »

You were absolutely spot on! Thank you for explaining everything, which now I understand I feel a little daft!!😄 Just glad there are helpful individuals on here -like yourself, to give very helpful advice.

Thanks so much once again.
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Re: Recommend a NS10 Amp?

Post by Hugh Robjohns »

:thumbup::ugeek::D
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