Recommend a NS10 Amp?

[James Perrett]

But I am still a little confused concerning Class D amps as my research consensus was mostly to steer clear of them as they often introduce noise and require some sort of int built noise filter etc. I am clueless in this area so maybe you could explain this?!

Yes, Class D amps need some kind of filter on the output but that filter is built into the amplifier so isn't something that you need worry about (with a properly designed amp). Hypex based amplifiers are used by many mastering engineers and, while some mastering engineers have moved on to using the newer nCore modules, the older UcD modules (which are what the STA-400D uses) were highly regarded when they came out and still perform extremely well.

As far as noise is concerned, I use them with very efficient monitors in a very quiet room (any gear with a fan is placed outside the studio) and I have to put my ear right up to the speaker to hear any noise (which is just a very slight hiss).

If you want to see the full technical paper on the UcD amplifiers then it is explained in

https://www.hypex.nl/img/upload/doc/an_ ... lifier.pdf

The Hypex application note library is at

https://www.hypex.nl/p/application-notes-white-papers/

[Arpangel]

If you like the sound of your current amp, just add an ART Clean Box, instant balanced inputs, and a cheap solution.
I did this with my Quad amp, works perfectly, gets rid of all the noise and hum.

Thank you Arpangel for your input, which I am very grateful for. Now this sounds interesting!! Now in answer to your question as to whether I already like the sound of my amp. I cannot say I dislike it, but since researching the topic it got me wondering whether I am getting the best sound from my NS10’s due to the current amp choice. If the choice of amp is not going to hugely change the sound of NS10’s then I would rather not have that huge outlay and instead would purchase a subwoofer!! You have given me food for thought-which I am appreciate. I have had a quick look at the Art clean box pro. I wasn’t aware that such a box existed, but I am intrigued!!

Currently the line 1 inputs of amp (rca) are connected to my monitor controller output for NS10’s -using rca -trs leads. Therefore, how would I incorporate this into my setup? Sorry if this is obvious, but I just a little unsure.

Many thanks in advance

I use my Clean Box Pro to go from my mixers balanced main outputs into my power amp, because I was having hum issues, I’m assuming from what you say you have a balanced source on your monitor controller.
You’re using balanced to unbalanced leads at the moment if I’m correct? If you use the Clean Box, you’d be using TRS to XLR.
With your current leads, as long as they are working correctly, and there are no noises, hums etc they should be fine, going to balanced leads and a Clean Box won’t make anything sound any better.

[Hugh Robjohns]

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.



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).



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



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.

[Angelface78]

But I am still a little confused concerning Class D amps as my research consensus was mostly to steer clear of them as they often introduce noise and require some sort of int built noise filter etc. I am clueless in this area so maybe you could explain this?!

Yes, Class D amps need some kind of filter on the output but that filter is built into the amplifier so isn't something that you need worry about (with a properly designed amp). Hypex based amplifiers are used by many mastering engineers and, while some mastering engineers have moved on to using the newer nCore modules, the older UcD modules (which are what the STA-400D uses) were highly regarded when they came out and still perform extremely well.

As far as noise is concerned, I use them with very efficient monitors in a very quiet room (any gear with a fan is placed outside the studio) and I have to put my ear right up to the speaker to hear any noise (which is just a very slight hiss).

If you want to see the full technical paper on the UcD amplifiers then it is explained in

https://www.hypex.nl/img/upload/doc/an_ ... lifier.pdf

The Hypex application note library is at

https://www.hypex.nl/p/application-notes-white-papers/

Thank you James Perrett for your helpful explanation of class d amps and for the link you kindly provided. I will continue to read up on the amp in question, but already I am seeing the brand name on some retailers websites, which is encouraging! Thank you for the recommendation. Do you think this would be a noticeable upgrade from my current Yamaha As301 amp?

[Angelface78]

use my Clean Box Pro to go from my mixers balanced main outputs into my power amp, because I was having hum issues, I’m assuming from what you say you have a balanced source on your monitor controller.
You’re using balanced to unbalanced leads at the moment if I’m correct? If you use the Clean Box, you’d be using TRS to XLR.
With your current leads, as long as they are working correctly, and there are no noises, hums etc they should be fine, going to balanced leads and a Clean Box won’t make anything sound any better.

Thanks Arpangel for your response once again. Just to be clear I am connecting an unbalanced source to my Nero monitor controller. As follows;- amp rca (end-TRS monitor controller end). So I am not sure whether the clean box pro-like you have kindly suggested or the DTI version, like Hugh Robjohns also mentioned would be better?! As I do have some hum coming from speakers which has improved since upgrading monitor controller from passive to active, but it is still present when volume is cranked up. So am hoping either box will resolve this perhaps?!

[Angelface78]

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.



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).



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



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.

That’s Hugh, for explaining the differences, as I must admit when I initially came across them and did wonder whether I had typed in the correct name as I noticed the variations that you have listed here on different music retailer websites!

Okay, as I am also experiencing hum well do you think the DTI would be better suited perhaps to my situation? whereby I am using unbalanced inputs of amp to balanced inputs if monitor controller? The DTI appeals as it is passive and also has trs inputs in addition to rca and Xlr so a bit more flexibility there. However, arpAngel also mentioned that he clean box pro helped with his noise issue (hum) and it has input volume knobs, which could be handy-but not imperative, so I am still undecided?! Although, I am still trying to decide whether to simply just update amp with something with balanced inputs and hopefully get rid of hum as result as well!! Kill two birds with one stone….so to speak!

It was interesting to read your comments about NS10’s not being fussy about the amp that drives them, as there is so much conflicting information out there, but I am inclined to trust you more as I have been reading your articles for some time. Therefore, I think it’s fair to say I trust your judgement:-) Decisions, decisions!!! Many thanks for your help thus far and if you can think of anything further that might swing my decision I would welcome the additional feedback

[James Perrett]

Do you think this would be a noticeable upgrade from my current Yamaha As301 amp?

I don't know the AS301 but, if it is competently designed, the difference in sound will be small - especially as the NS10's aren't the most revealing of speakers in my experience.

[Angelface78]

Well I appreciate your input and honest opinion James. I just need to decide on my next move!! Glad to have learnt about other possibilities, which is great and having now been introduced to a new amplifier brand! Thank you

[Arpangel]

IMO amplifiers will make a large contribution to your overall sound, not as obvious as changing monitors, bit it’s there, oh yes it is.
I have three amplifiers here for my passive speakers, and all sound different, I choose which one to use according to what speaker I'm using at the time.

[Angelface78]

Thanks ArpAngel for your response, which I do appreciate. It does appear to be the opinion of some others too. But for me never really hearing them on higher end amps (apart from being in studio sessions-where at the time it was not necessary for me to be checking out how the NS10’s sounded and what drove them:-). It’s left me now wondering what am I missing out on in my home studio?!

[Hugh Robjohns]

There are a host of adjectives describing the quality of a power amplifier, and a similar number of different interpretations and perceptions on what those adjectives mean.

A more powerful amp, in general, will control the speaker more effectively than a low-powered amp -- meaning, for example, that it can make the bass driver start and stop moving more precisely. This is a good thing... but the potential downside is that it can also 'overpower' the speaker causing damage to drive units.

With the best will in the world, NS10s aren't the most accurate of speakers, or the most difficult to drive. Historically they were often driven with Quad amps -- 303s (50W/channel) or 405s (100W/channel) -- but to be honest pretty much anything with around 100W/ch would do the job perfectly well.

I don't believe there is a 'holy grail' of most desirable amp to partner the NS10, and I suspect whatever weakness you're trying to address with a different amp is more likely to be an inherent limitation of what the NS10 can actually do!

[Angelface78]

With the best will in the world, NS10s aren't the most accurate of speakers, or the most difficult to drive. Historically they were often driven with Quad amps -- 303s (50W/channel) or 405s (100W/channel) -- but to be honest pretty much anything with around 100W/ch would do the job perfectly well.

I don't believe there is a 'holy grail' of most desirable amp to partner the NS10, and I suspect whatever weakness you're trying to address with a different amp is more likely to be an inherent limitation of what the NS10 can actually do!

Thanks again Hugh, I appreciate that. You explained that wonderfully!

The main reasons for the upgrade is so that I can have balanced inputs and also the additional power. Hoping the upgrade will eliminate the hum I am getting, which I suspect is as a result of unbalanced connections. Certainly no expecting miracles so to speak but an overall improvement would be great:-)

[Angelface78]

The Nord One MP NC252 250W, was also suggested as a worthy contender and it is one of the choices I am considering. Any thoughts? Opinions welcomed

https://www.nordacoustics.co.uk/product ... -power-amp

Thanks in advance

[Hugh Robjohns]

Yes, it uses Hypex NCore class-D module amps which are very good.

[Angelface78]

Yes, it uses Hypex NCore class-D module amps which are very good.

Thank you Hugh for your response, which is encouraging and also very helpful.

[James Perrett]

Yes, that Nord Amp is supposed to be slightly better than the UcD based amps that I mentioned before but it is around double the price. I'm not sure that you'd notice the difference with NS10's.

[Angelface78]

Yes, that Nord Amp is supposed to be slightly better than the UcD based amps that I mentioned before but it is around double the price. I'm not sure that you'd notice the difference with NS10's.

Thanks James for your response. I haven’t ruled out the option you kindly provided. Although, I have been on the hunt for user reviews and they are extremely thin on the ground! The main thing I need to ascertain is how “silent” is the unit?! especially with it using fans and not convection cooling. I just need to ensure that it doesn’t generate any audible noise, as I will be sitting very close to it! Also I would be absolutely thrilled if I can spend less then the Nord, but it does cause me to wonder how are they able to produce this unit at such a low cost?!

[James Perrett]

I'd be surprised if the fans even came on at typical monitoring levels because the modules run fairly cool in my experience. However, I can't say for sure as I've not used those particular amps so I don't know what temperature thresholds they've set for the fans.

[Angelface78]

I'd be surprised if the fans even came on at typical monitoring levels because the modules run fairly cool in my experience. However, I can't say for sure as I've not used those particular amps so I don't know what temperature thresholds they've set for the fans.

Appreciate your response James and for your honesty. I’m awaiting a response from them to hopefully answer my questions. So will be sure to update if I do go ahead with the purchase.

[Angelface78]

Hello again,

I just wanted to provide an update on the amp situation:-). James: you might be interested to know that I did in fact purchase the amp, which you so kindly recommended ING STA-400D. However, unfortunately I did have to return the unit! Namely due to the noise it was producing, which was too loud when sitting in close proximity. However, the fan noise was noticeable but not as much of an issue as the strange rattling noise and hum that it also produced. I appreciate the recommendation and I am glad that I did get to audition the unit and could see that it would have been less of an issue if i was not so averse to noise and also if I was situated further away from the unit.

I then proceeded to order the Avantone CLA 100 based on your advice regarding wattage Hugh: I decided to go for the 100 watt p/c model as opposed to its bigger brother CLA 200. I figured the CLA 100 would be perfect for my needs as I don’t listen to my NS10’s at glass shattering levels!! but rather quite modest levels. Early impressions so far is that I am really happy with it. It’s still early days but i certainly hear an improvement in the NS10’s, which is great. I had comments from someone who came into my home studio and commented on “what’s changed” as they thought I had new monitors and said “sounds great and completely different”, so they were unaware that I had in fact changed the amp, so that is also encouraging. I will continue to test and update if anything changes.

Thanks for all your help and advice.

[Hugh Robjohns]

Great news. Thanks for the update -- it's always helpful to hear how the recommendations worked out.

Disappointing about the unwanted mechanical noises from the ING amp.

[James Perrett]

Thanks for the update. It is disappointing to hear that, what should be a very fine amp, was messed up by something that IMG added.

[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

[Martin Walker]

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

Martin

[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.