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Old 30th July 2013, 08:07 AM   #91
AKSA is offline AKSA  Australia
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Yes, Sean,

The Tortech would be just fine, fits nicely and good stability.

The heatsinks for the N80 are indeed 300mm long, 75mm height and 50mm in the fins.

Some as the existing heatsink except for the ledge.

You would have to fit 4 1/8" (3.2mm) holes for the output devices, two for each channel.

Cheers,

Hugh
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Old 30th July 2013, 10:15 PM   #92
seano is offline seano  Australia
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Cool. Turns out that I have another pair of ledged heatsinks for the AKSA in the shed so the old AKSA will have a potential home to go to if I do pull the trigger. Now to the finance department...I hope to be back with goodly news

In the meantime...may the shed be with you.
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Old 7th August 2013, 05:57 PM   #93
polaron is offline polaron  France
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Default One or two?

Hello everybody!

I am happy and proud for beeing a member of this forum.
I've been talking to Hugh by email (thanks Hugh for replying so promptly to my silly questions), about the Naksa 80, and finally I decided to express my thoughts here, and learn something more with you.

Hugh, as you know, I have two very nice r-core transformers for the Naksa 80, each one with 300VA and 30v x 2. I haven't read a single comment talking about using two transformers with the 80. May be because in this case it is not a good idea.

Nevertheless, I don't mind to expose my ignorance and ask you IF two transformers with those specifications would improve the sound... I'm asking this because I have the two.
Just for information, monday I was seeing these transformers in the website and yesterday a friend of mine gave me two of them, exactly the same I intended to order here in France. This is a sign... The universe is telling me : "Go ahead, you're in the good way, that's the right amp!" (Joking...)

And by the way, I'd like to say that I find that the 80 is a bargain. I am 50 years old and heard (and had) LOTS (lots!) of amplifiers. I know when an hi fi product is good, there are to many signs and words from different persons about it, so I am sure that I will not be disappointed with this one.

Just one more question. If I "build" the 80 with only one transfo, may be I will buy the suggested case, and it is a good thing that it acts like a heat dissipator. What is the maximum high for the transformer with this case? These R-cores are big.

That's all. Thank you for reading and for the comments! Please post more pictures! (Hi-erotic-fi)...
And thanks Hugh for everything you make for us, special thanks for the Naksa 80. Congratulations!
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Old 8th August 2013, 06:42 AM   #94
AKSA is offline AKSA  Australia
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HI Polaron,

Thank you for your post. Good questions!

Strictly you do not need two transformers for the NAKSA 80. The reason is that only two secondary windings are required to supply two rails of positive voltage and two rails of negative voltage for the two channels. One secondary supplies the positive rails for both channel, and the other secondary supplies the negative rails for both channels. All the wiring is built into the pcb, and you need only connect the two secondary wires to the pcb to set this up. This means the connections to the trafo are failsafe - very significant when audiophiles are building power supplies.

I did it this one because I wanted to integrate the full power supply for both channels. To keep crosstalk from two supplies from two rails, I separated each rail for each channel, so that:

#1 No center tap is used on the transformer; only two secondaries, four wires total.
#2 Decoupling four banks of filter caps with 0.15R resistors quarantine the rectifier high currents, the speaker earth returns, and the channel supplies, so that crosstalk is minimised. It is very slightly better with two complete transformers, and I use this is the more powerful NAKSA 100, but the qualitative difference sonically is very, very close. This approach is extremely quiet, which is important with amps which use single ended topologies like the NAKSA.
#3 A single 300VA transformer offers superior regulation to two 160VA transformers, typically 6.5% v. 9% (at both full output). A single trafo is much cheaper too!
#4 Two transformers can be used, with the two 30Vac secondaries paralleled for more current delivery. But take care to parallel two secondaries of one transformer so that the starts of the secondary windings are connected, and the finishes are connected. Reverse this, and you will blow the transformer! The custom enclosure will fit a single 300VA toroid, up to 120mm OD by 60mm Height. The custom enclosure has an inset securing bolt fitted. Furthermore, you could fit both of your R cores within the enclosure too, there is sufficient spaces.

The sound quality of the NAKSA 80 is very, very good. One 64 year old audiophile, who has, like you, heard 'everything', feels it is the best amp he has noticed. Numerous anecdotes from various audiophiles have been very positive, and I'm pleased about this because an improving quality indicates R&D is working as it should. I've been working 19 years designing amps, starting in 1994 with the Glass Harmony, a SET mosfet/bipolar/tube hybrid of 28W per channel, and I would be very disappointed with my hard work if my amps were getting worse over time!

Thank you for your kind comment about the cost. A few weeks ago, an audiophile bitterly complained about the high cost. If you consider my costs with Chinese prices of conventional, mass produced modules he is absolutely right; the NAKSA is expensive. However, in the last five months the AUD has been dropping like a stone, so its cost is improving, but more importantly, the design is completely original, brand new IP, and consequently its performance is markedly different to anything else in the market place. Compared to expensive, store built amps from very reputable manufacturers the NAKSA is very reasonable, up there with the best sound quality, and of course you have easy access to the designer via forum or email. That is a strong advantage, particularly as I'm committed to sonic quality and little else, and you can discuss the design detail (within some limitations) on the forum.

Thank you for your interest!

Ciao,

Hugh
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Old 8th August 2013, 10:20 AM   #95
polaron is offline polaron  France
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Thanks Hugh,

...for the clear reply. Well, if the differences are not significant in terms of sound, I will use only one transformer. I will keep the other to another project, wich is a very simple power supply to my Gaincard, from 47 Laboratory.

I love the gaincard, specially with the Jordan (full range drivers) in a kind of VTL transmission line simple design. Hope that the Naksa 80 matches well with the Jordan. Why shouldn't it? Essence speakers from 47Labs, (Konus Audio), are easy to drive, they only sound good with very good amps and excellent sources, otherwise they will sound like a can.
I will add to the Naksa a nice D/A converter. I think that I will be able to have a circuit board from a Minerva dac or an MSB dac. I will have to buy a case and make a power supply, wich is the easiest part. But first comes tha Naksa. Meanwhile I will match it to a Bushmaster dac from Beresford, wich is incredibly good for the money.

Et voilą!
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Old 8th August 2013, 10:28 AM   #96
polaron is offline polaron  France
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Default Small case for me...

I think that I will have to make a wood case myself for the Naksa 80, as my transformer is 65mm high... Arrrghhh!! Hope I will not have dissipation issues.
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Old 8th August 2013, 03:07 PM   #97
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polaron, where are you from?
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Old 8th August 2013, 03:22 PM   #98
polaron is offline polaron  France
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Hi meanman1964
I am Portuguese, living in France, Fontainebleau.
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Old 8th August 2013, 09:23 PM   #99
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polaron,take a look at Audiophonics - Cābles, Amplificateurs et Accessoires DIY for cases
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Old 10th August 2013, 06:54 PM   #100
polaron is offline polaron  France
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Yes meanman, thank you.
I know this website very well, I boughgt a few items from them; but for my amp I'd like another kind of box, so I will make a beautiful box in wood, that will match with my hifi furniture that I am making. I will post some photos when everything will be ready.
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