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New NAKSA now arrived!

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The input and VAS stages of the NAKSA are single ended, Class A of course. Input is singleton, so you can assume that it uses current feedback.

The drive to the mosfet permits more output power to clip; it enables kicking the gates a bit higher/lower. There is a constant power buffer between the VAS and the output driver stage. I decided to go with complementary mosfets again so I could more precisely control the H2 and H3 harmonics. Finally, there is a reduction in global NFB, which of course increases the H2/H3/H4, but reduces the trail of higher artefacts.

The VAS / IPS sounds similar to my TGM6 or maybe not... Well it looks very nice, lovely harmonic profile from Singleton input (did you know Henry Singleton founded the company I work for ? - no relation to the amplifier of course !). And nested feedback to reduce global NFB factor for all the benefits that it brings. I see you use a Vbe multiplier so I assume you are using Vertical MOSFETs. Wow, I can imaging a couple more pairs of output devices and you have a monster amp on your hands ! :cool:

Anybody got some sound impressions to post - we'd love to hear more about how this new amp sounds - please tell us !

Edit: Jens - just saw your post - have you got it powered up ? and since you don't want that NAKSA 70 anymore I'll offer to recycle it for you :D (just kidding)
 
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The VAS / IPS sounds similar to my TGM6 or maybe not... Well it looks very nice, lovely harmonic profile from Singleton input (did you know Henry Singleton founded the company I work for ? - no relation to the amplifier of course !). And nested feedback to reduce global NFB factor for all the benefits that it brings. I see you use a Vbe multiplier so I assume you are using Vertical MOSFETs. Wow, I can imaging a couple more pairs of output devices and you have a monster amp on your hands ! :cool:

Anybody got some sound impressions to post - we'd love to hear more about how this new amp sounds - please tell us !

Edit: Jens - just saw your post - have you got it powered up ? and since you don't want that NAKSA 70 anymore I'll offer to recycle it for you :D (just kidding)

I suppose I could just wait for Hugh to post, but I'll jump in with a couple things. Yes you are correct in that the output devices are vertical mosfets, a single pair. Hugh tends to favor single pairs. I'll leave the rest of the explanation to him. And the singleton input stage is one of Hugh's signature designs.
Soundwise, well, you can read what I have posted earlier. I've been listening to my N80's for nearly a year now. I think it wonderful. A higher power version of this amp might improve bass output some, but the bass from this amp is really quite good, far exceeding expectations for something with less than 3 digit output power.
 
Hi Bigun,

Steve is on the money! I did a proaudio amp last year which used a pair of complementary FQA Fairchild, both rated to 40A and 290 watts, and it does 180 watts from 65V rails. They are tetchy to drive, but the amp sounds very good. Two pairs of these would easily put out 350 watts//8R.

Oddly, the size of an amp is not also rated to the output. Small amps, such as the Hiraga Monstre, are huge out of all proportion to the output (8W). And very large tube amps can sound rather twee - surprisingly!

Hi Jens,

How are you going? Have you coaxed your N80 to squawk?

Cheers,

Hugh
 
I would like to add one more thing here, and it is about sound quality.
Some time ago I read on Arthur Salvatore's website that a good judge of an audio system is how low you can have the volume and still hear everything. This is in direct contrast to the usual habit of wanting to turn it up, up and up. Often times this is because one just can't quite hear the fine details in the music and the thought is to turn it up, so as to enable one to hear more. But it's not there! It doesn't work.
Or, Arthur wrote something to the effect that when you feel you have to turn it up to hear more, something is wrong with the audio system. Arthur left it at that, but I think this particular issue goes straight to the heart of amplification, and that it's all about the amplification.
The Naksa 80 amplifies everything and has great punch and dynamics. And more importantly, you can hear all of this at a very low volume level. I noticed this pretty early on in having the amp. And I think it may be one of the most standout qualities of this amp.
Sure, there are times when you just want to turn it up. But you can still hear everything perfectly when it's way down low.
 
Hi Jens,

How are you going? Have you coaxed your N80 to squawk?

Cheers,

Hugh[/QUOTE]

Hi Hugh,

Unfortunately, only managed to get one amp done yesterday. Did test it briefly on a separate speaker - all seemed well ;)

I am off for a business trip tomorrow, so I don't know how much I can get done before that, but rest assured I will report as soon as I get some real music going on the N80s :D

Cheers,

Jens
 
Very interesting, I can imagine that a single output pair offers the advantage of a cleaner transfer function. I've read about the valve guys finding that paralleled output tubes don't sound as good as a single tube. I've never tried using MOSFETs, you both have me tempted - my own feeble attempt at DIY amps usually take their inspiration from Hugh so I always look carefully to see what I can learn and try.
 
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Hi Audiostar,

Thank you for your email.

The Grover Notting, sold by Classic Audio P/L in Melbourne, is related to the NAKSA, no doubt about it. It has a balanced input, full discrete, a >115Hz crossover, also discrete, and a DC protection sense feature with a relay; these are essential for proaudio, but not required for hifi.

The initial production was set up Xmas last year, and is now fully manufactured in Melbourne. It was a big project, and very difficult due to my illness. But every audio engineer who has heard it is very impressive, modesty cannot permit their names!

The amp is sold with premium Scanspeak drivers and highly developed closed box speakers for studio use. The Universal, which is 105W rms, is sold for $31K including speakers. Frank has sold a Mastering series to a well known US company with a R&D facility in Sydney in Australia.

Cheers,

Hugh
 
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Now back from my business trip and have just gotten everything up and running a few minutes ago :)

I will not offer any listening impressions just yet, except that the NAKSA 80s are very silent indeed. I thought the NAKSA 70s very silent, but the 80s take this a notch further. Very good indeed!

I will keep everything playing throughout the day for bedding in (using my tuner as source), before I go on to serious listening - so more later :D
 
Hi Hugh and everyone,

I have now had my NAKSA 80s up and running for a few days and have managed to do a little serious listening.

The first day the amps changed a lot - bedding in. I think that Hugh said somewhere that these amps bed in around 90% within half a day or something. How long the remaining 10% will take, well - I don't know.

However, what I do know is that on the evening of the first day I was duly impressed! Here's what I wrote to Hugh (who had asked if I liked the amps) after that first listen-in:

I managed to listen to one record, which I bought recently:
Adele's live concert at Royal Albert Hall. This is by no means an audiophile recording, but it is a live recording, and electronic 'fiddling' with the recording is therefore limited ;-)

I felt that I was much closer to the actual concert than before - the sense of 'thereness' was much heightened in comparison to the N70s. Also, small details that I did not hear before stood out clearly (a small clap out of turn, a hoot all the way back in the hall). Adele's voice had a new clarity and much less grain to it, and distance between performers like Adele and e.g. backing vocals seemed much more 'right'. Drums came across as much more sharply shown. And yes, soundstage in general was improved.

But those are all technicalities - what really hit the nail was that the performance was so much more involving, and I found myself with eyes getting wet listening to some of the tracks ...

Mind you - these are all just initial impressions!

Like it? Are you crazy? These babies can do the real thing: Music!


I have now listened to a few more CDs/tracks, and the impressions from the first listen stand. To those impressions I would like to add that the N80s do something that very few amps I have heard can do: It can be extremely soft (as in without any grain at all) and at the same time extremely detailed, giving room to all those tiny details that lends to credibility and naturalness - and it has a lot of slam in the lower midrange (I do not use it for the bass, so no impressions for that).

And again - the soundstage, which was already really good on the N70s (at least in my system), is improved even further (in all dimensions) with the N80s.

Finally, this amp is truly involving - I kept finding myself listening to the music instead of trying to dissect what this amp does. I know of no better praise I can give to a piece of audio equipment than saying that this amp gives you music! And the NAKSA 80 does this - in spades! :D

Cheers,

Jens
 
more feedbacks from the naska 80 owners?
I'm in search for an easy end game power amp section and this one seems loke a valuable one.
I'm just wondering how it could compete against ClassDAudio amp kits or even hypex modules (USD HG with HxR or Ncore)
Any hint is welcome.
Best regards
 
I'm just wondering how it could compete against ClassDAudio amp kits or even hypex modules (USD HG with HxR or Ncore)
Any hint is welcome.
Best regards

My hint is this d182:
* if you want cheap, with an impressibly large "watt count" and your ears can't tell you what Class D doesn't deliver ... buy Class D. :p

* if you want an amp which actually sounds excellent ... buy a NAKSA 80. ;)


Regards,

Andy
 
Congratulations on the new design Hugh. I have no doubt that it sounds fantastic and I am most interested to see your transition to SMT and automated construction. Such a big step and admirable given the other distractions in your life. Looking forward to hearing more reviews and perhaps a live audition one of these days!

Best wishes,
Greg.
 
Hugh,

Would love to have a chat as it has been a long time.

Unfortunately due to a new job I am home late on weeknights so I must have missed your call. However, I will call you on the weekend.

Sorry for hijacking the thread with a personal note - not sure if you're getting your emails these days at your old address.

Cheers,

Greg.
 
more feedbacks from the naska 80 owners?
I'm in search for an easy end game power amp section and this one seems loke a valuable one.
I'm just wondering how it could compete against ClassDAudio amp kits or even hypex modules (USD HG with HxR or Ncore)
Any hint is welcome.
Best regards

Dookie,
At this time there are very few N80 owners to help you out. Give it a year for these to populate a bit if you are awaiting comparisons.
If you can't wait, well, this is a safe purchase and about the same amount for complete amp as what you pay for a complete Ncore.
 
Dookie,
At this time there are very few N80 owners to help you out. Give it a year for these to populate a bit if you are awaiting comparisons.
If you can't wait, well, this is a safe purchase and about the same amount for complete amp as what you pay for a complete Ncore.

Steve is just so right - this is a safe purchase!

I had a guy over yesterday to listen to my system. He had just this week listened to a lot of stuff, including some of the new ClassD amps. In his view, there was no comparison - the NAKSA 80 is just so much more pure music :)

This amp is nothing less than awesome.

I have been doing some more listening and hope soon to find the time to write a little more about it ...

Cheers,

Jens
 
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