Aussie Amplifiers nxV101

[agisthos]

You dont see much discussion of Anthony Holten's 'Aussie Amplifiers' here. He has been at it since the 90's and all his designs are constantly evolving and apparently the latest R2 modules sound very good.

I have not built any of his stuff but now plan to - the latest product called the nxV101 is what I am looking for, a pre-made DIY amplifier module that has the pwer supply built in. I may even go all audiophile and run each module with a seperate torroid for each side of the rail ie 4 torroids for a 2 channel amplifier.

http://www.aussieamp...com/modules.htm

Edited January 1, 2013 by agisthos

[Addicted to music]

I have been eye Anthony's products for @ least a decade, most of his stuff is high quality and visually appealing. Recently I am thinking of the nxv500 r2 for ages or possible the next version up. The only thing that is stopping me is the full use of SMD and that includes the resistor that is used on the o/puts mosfets for current sharing. The one he uses are SMD, maybe you should question that especially when he is quoting 2 ohm stable! The reason is that I will be using them to drive a resistive load of 1.8ohms and as far as I'm concern they must be at least rated at 5W min. But for a 8ohm load it's less of an issue.

The other issue I have is the use of spade connection, screw types are more secure and positive, I avoid all spades from experience, in some of his modules it is almost impossible to replace as there are no room.

So as you can see, I would love to purchase from him, but these are the concerns I have but I'm sure all his modules are great sounding. They are just different compared to what I have.

[agisthos]

Yes I agree with you about the spade connectors, I would prefer to remove them and solder my wiring directly to the board, no doubt causing headaches to accomplish this.

My new speakers are very efficient so Im not concerned about the use of SMD components. In fact his use of them is what allows him to manufacture these modules in larger runs and at such a great price ($280 each !!)

[Addicted to music]

Yep, not bad at all, fully built and all you do is add the PSU and the cabinetry, Since its all SMD, you might want to also think about how you are going to replace an SMD if things go very wrong. I hate soldering and desoldering SMDs even if I have a desoldering station, Handing SMD is my fear of getting these modules. Dont get me wrong, SMD in low wattage and low voltage are great as they reduce the paracitic capacitance and inductance in a component and are generally more accurate. But there are cheap ones out there as well and you can never identify who or how there made and specified tolerances. To me using SMD in a power application doesnt fit well.

An example is in SMPSU or high torque brushless motors. Depending on the wattage of the application SMDs are rarely used, and if they are used they have a high failure rate where SMD resistors go open! I have seen SMD completely vapourised, due to excessive loads.

If Anthony only employ them in the front end, where low current is applied!

[henry218]

hi agisthos,

 

have you build the aussie amps yet? i wonder why not much discussion here, but few people from norway were raving about it.

 

cheers

henry

[brenden]

These are the best sounding resistors for current sharing in power amps, Fukushima metal plate .Bit hard to source ,but I think THL audio sell them .

This is a photo of one of my Stax DA100m monos .NAD used to use similar resistors in their old amps ,and probably quite a few other brands .

I replaced them with Mills wirewounds once and, it dulled the gorgeous top end of the Staxes .

The construction of these resistors is like a large version of a Vishay metal foil . The beauty is that they are reasonably cheap ,and not all that known among most DIY audiophiles.

[davewantsmoore]

i wonder why not much discussion here, but few people from norway were raving about it.

 

Anthony lives just up the road from me.... I should really give them a try one day  (like others, I've been 'eyeing them off' for years)

[henry218]

dave,

 

you owe it to stereo net

in all seriousness, some people claiming its at the same class as passlabs, krells and the likes. The modules in similar form as the class d, which is convenient for newbie diyer like myself.

 

i just ask for more info today, it does seems possible of using connexelectronic smps800RE, but dont know if the sound signature will change or not.

 

cheers

henry

[hochopeper]

I've got an amp with 2 of the now older nxv203 powered with coldamp sps80. Goes hard, goes well. Going to compare it to 2x lme49830 lateral fet The Wire amps and 2xThe Wire LPUHP amps. IMO all high power class ab amps should have regulated smpa psu. All my amps are filled with smd bits and have excellent performance on paper and sound good too.

I've had nothing but good experiences from my dealings with Anthony.

[henry218]

hi hochopeper,

 

so much different in power, wouldnt that be unfair comparison?

 

so you think its better to use smps than a linear supply for class ab amp/modules? interesting..

 

cheers

henry

[Addicted to music]

These are the best sounding resistors for current sharing in power amps, Fukushima metal plate .Bit hard to source ,but I think THL audio sell them .

This is a photo of one of my Stax DA100m monos .NAD used to use similar resistors in their old amps ,and probably quite a few other brands .

I replaced them with Mills wirewounds once and, it dulled the gorgeous top end of the Staxes .

The construction of these resistors is like a large version of a Vishay metal foil . The beauty is that they are reasonably cheap ,and not all that known among most DIY audiophiles.

 

Brenden,

 

fully agree on the resistors,

 

I have them in current sharing in my 240W@ 8 ohm, to me these metal plates are proven reliability and even though I havent sighted the specs and compared them to the Vishay metal foil resistors they look so much more robust compared to the SMD metal foil that some manufacturers are using. 

FWIW I have used this power amp that is mosfet base driving 1.8ohm ribbons for the 20+yrs.  They werent cheap 20yrs ago at around $2.00 each, but cheaper than the exotic glorified ones that are being deployed now!

[MellowFellow]

I run an nx-V300 and it's a great amp. More power than I've ever considered exploring and when put next to amps 5x and 10x it's price, it compared very well - beating the 5x (rotel) and being close enough to the 10x (mark lev) that I wasn't jealous. I'm slowly putting together plans for an active setup and expect to use 6-8 channels worth of Aussie Amp's because they're not just great value, they're great amps.

 

If you're able to DIY, try to listen to an aussie amp before buying another brand. If you can't DIY, get Anthony to build it for you because even with his premium it's a good amp.

[Addicted to music]

I run an nx-V300 and it's a great amp. More power than I've ever considered exploring and when put next to amps 5x and 10x it's price, it compared very well - beating the 5x (rotel) and being close enough to the 10x (mark lev) that I wasn't jealous. I'm slowly putting together plans for an active setup and expect to use 6-8 channels worth of Aussie Amp's because they're not just great value, they're great amps.

 

If you're able to DIY, try to listen to an aussie amp before buying another brand. If you can't DIY, get Anthony to build it for you because even with his premium it's a good amp.

 

Hi MF,

 

I have been eyeing anthony's amps for at least a decade and have been tracking his site,  its good to hear you like his product, I want to build the 500v2 but at this stage struggling to find a cabinet that looks nice to house it thats cost effective. 

 

In your apinion do you think the detail resolution and transparency on micro details is up there against the better known commercial ones?

[MellowFellow]

In your apinion do you think the detail resolution and transparency on micro details is up there against the better known commercial ones?

Resolution and micro detail possibly aren't the aussie amp's strongest points - I really notice the control over bass, speed of transients and a magical quality that draws you into the music on this amp. I'm not convinced my speakers are resolving enough to claim 'micro detail' either though because they're built to suit my taste in music, which is primarily rock. Depending on your taste in music and speaker efficiency, you may get better detail from a nice tube amp (Weston, for example) at the expense of the things the aussie amp does well.

 

I'm yet to hear anything that beats the aussie amp which can be bought new for aussie amp money. With enough auditions, careful selection and some bargaining you may be able to find an older big-name amp that suits your style better but then you're comparing 2nd-hand (probably 30yo) amps to brand new. 2nd-hand aussie amps are incredible bargains due to how much DIY depreciates.

 

...all this is based on the nxV300, which has half the output transistors of the 500V2, so I'd guess the 500V2 is in another league.

[hochopeper]

hi hochopeper,

 

so much different in power, wouldnt that be unfair comparison?

 

so you think its better to use smps than a linear supply for class ab amp/modules? interesting..

 

cheers

henry

 

 

The subjective comparison is mostly for a laugh because I'll have them all sitting around for a little while until I finish some DSP electronics for my active speakers where all of these amps will be used permanently and each is matched to the application for gain, power and performance ...

 

 

 

SMPS ... the great enemy of audiophiles. It's a bit odd to discuss it in a thread on an amp with a linear supply on board but here goes ... 

 

For amps that are producing more than ~100W into 8ohm the voltage and current requirements mean for some pretty substantial linear power supplies. With modern SMPS the noise/emi performance can be such that it is negligible to the performance of the amplifier and can allow high power output without such a large linear supply. SMPS also allows you to find regulated power supply, a linear regulated power supply capable of high power output (50-60V rails and enough current output to support the signal swinging that far) gets to be a design needing almost as much heatsinking as the amplifier itself.

 

 

 

Here is some measurements from The Wire Class AB LME49830 amp presented in this thread on diyAudio - http://www.diyaudio.com/forums/showthread.php?t=196932

 

FFT - input tied to ground:

 

FFT - input connected to measurement source:

 

THD+N vs measured level:

 

Distortion Product ratios with high bias:

 

Voltage rail behaviour with a full power pulse:

 

All the above measurements are by opc from that diyaudio thread linked above, it is an amp that is capable of 190W into 8ohm powered by an SMPS  (Audiopower DPS600). The SMPS is fully regulated and has separate regulated power rails for the front end to the output stage. Downside with this SMPS is that the regulation feedback loop means SMPS is only able to supply one amplifier, so a stereo amp needs two PSUs, you must build monoblocks. It's compact and it's measured performance is about as good as what anyone could want. I'm using these mono blocks to power midrange in an active MTM, they're only going to be used for roughly 70Hz - 2kHz. (I know it is overkill in the extreme)

 

This amp uses the same output lateral mosfets as Anthony uses in the latest generation Aussie Amps but with a different front end. I challenge anyone to find a floor in those measurements other than religious un-belief in mosfets.

 

 

 

The nxv203 that I use has a coldamp SPS80 SMPS that is also regulated but uses different regulation method and is able to supply the 2 x nxv203 modules that I have in the one amp. I've not got any measured data captures for it but Anthony said that he looked at the rail behaviour under load and said the rails are much more stable than any linear supply he's ever seen under full load pulse. This means that you're able to run lower voltage rails than you'd need with a linear supply because you'd normally be allowing for voltage sag under load, so the amp runs cooler.

 

 

Cheers,

Chris

[henry218]

hi chris,

thanks for that. i got some smps800re, ive been meaning to try the nxv amps, just wondering if its as good as high performance amps out there as the modules are not cheap.

cheers

henry

[murrmax]

 

 

Resolution and micro detail possibly aren't the aussie amp's strongest points - I really notice the control over bass, speed of transients and a magical quality that draws you into the music on this amp.

 

I'd agree that all in all they're very good amp modules my experience is with the Nxv200's, great for rock and the bass is the strong point. Overall great and hard to beat for the money; but treble lacks a little finesse with the best in comparison if i was to be critical. Careful matching with the tweeter would be my only reservation.

[murrmax]

The other thing I forgot to mention that in an active setup using minidsp

There's no pop, thump etc when I turn off the amps this is a major bonus !