Recommend a NS10 Amp?

[Arpangel]

I’d say you want to steer clear of lean sounding bright amps, the 405 is fine, it’s got some grunt and isn’t too bright. Audiolab 8000A is another one to consider, very nice amp, quite neautral.

[DC-Choppah]

Go on ebay or your local pawn shop and look for high quality old stereo equipment.

There is some great stuff out there.

For example: https://www.ebay.com/itm/Rotel-RA-02-St ... SwqfVfMDK1

[Hugh Robjohns]

Maybe I was unlucky but the Teac amp that we had in the studio really brought out the worst in them.

Intriguing... define 'worst in them' please! I think I've only knowingly heard one Teac amp, and I wasn't enamoured. As I recall, I thought it sounded 'fizzy' and lacking control.

However, having just done a little searching, it appears that they are based on a very early version of the 405 and suffer from all the disadvantages such as high noise levels and a mistake in the Zobel network routing.

That seems a disappointing cockup. Which clones are these? I think there are a number of different ones about aren't there?

[James Perrett]

It was a Teac AX75 amp Hugh - originally sold by Thatched Cottage Audio to partner the NS10's. Plenty of power but with an exaggerated high end.

I just did a quick Ebay and Google search where it seems that the Chinese 405 modules are often proudly sold as Mk1 modules with NOS 301 op amps. Other forum comments turned up the issues with the early modules and mentioned the fact that the design was taken from a published article which presumably gets around any legal issues. I see there are also a few that are marked 405-2 which, if they are accurate copies, will have overcome these issues although they possibly could do with a few mods to optimise their sensitivity for studio use.

[Sam Spoons]

Unlike some here, I actually found the Quad 405 (hifi) or 520 (pro) amps worked very nicely with NS10s. Yes, they are discontinued, but they are easy to source second hand, built like tanks top last a lifetime, easy to maintain, and Quad will still service them to as-new condition for astonishingly little outlay, if necessary.hugh

A bit late as I've been travelling down to the coast but Quad were not remotely interested in fixing my 522, or advising the engineer who was attempting to fix it (he failed). Thankfully Folderol has sorted it out for me (I have yet to plumb it into the studio and my period correct Kef 104ABs, sorry Foldy ). There were a couple on ebay in much better condition than mine, the cheaper went for about £250 IIRC but I wanted my 522 fixing partly for sentimental reasons, I've owned it for around 30 years, and partly to avoid another bit of kit ending up in landfill.

OTOH, I did buy a mint condition StudioSpares Titan 600 off ebay for £65 delivered a few weeks ago so bargains do exist.

[Angelface78]

Hello, I am a newbie here:-) However, I have read SOS magazine for over a decade, so I thought what better place to come to get advice regarding my next home studio purchase?!!

I am in the market for a new amp to drive my NS10’s. I have previously used Hifi Amps with them, but I have been looking for something with balanced inputs (which my current Yamaha AS301 amp does not have). I don’t personally have any experience with using the NS10’s on more expensive or vintage amps, but I have visited a few studios that have and based on my research I am learning more and more about them and it appears the amp does make all the difference to how these speakers sound……Or does it?!

So it’s interesting to now see here that the NS10’s are not really fussed by the amp they use! I have been following Hugh Robjohns articles for many years and so know he is very well versed in this area and he knows his stuff! So, I cannot simply overlook what he says. I am therefore now wondering whether the investment I was considering is really going to make a huge difference like I have read it would?! I was considering the Avantone CLA-200, but I would be really interested in hearing from anyone that uses it or has used it in the past. Or from anyone that could recommend a suitable alternative. I am in the market for a brand new unit and don’t require it to have DSP, but balanced inputs are a must!

Many thanks in advance

[James Perrett]

If I was in the market for a new amp now I'd see if I could find one of the Monacor or IMG Stageline STA-400D amps. I'm not sure if they are still current but the electronic design looks almost identical to the monitor amps that I built from Hypex modules.

https://monacor.co.uk/sta-400d.html

They're amazing value for money (assuming that they haven't messed anything up in the additions that they've made).

[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.

[Angelface78]

If I was in the market for a new amp now I'd see if I could find one of the Monacor or IMG Stageline STA-400D amps. I'm not sure if they are still current but the electronic design looks almost identical to the monitor amps that I built from Hypex modules.

https://monacor.co.uk/sta-400d.html

They're amazing value for money (assuming that they haven't messed anything up in the additions that they've made).

Thank you so much for your response James Perrett, I really appreciate it. Although, I am not very familiar with the brand of amps you have recommended I did have a look and they are significantly cheaper then the Avantone CLA 200 that I was considering, which is great. 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?! Once again thank you for your help thus far and I welcome any further help and/or advice you might be able to provide.

[Angelface78]

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

[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?!