Yes, the pcbs, topology and entire power supply is quite different. Actually, there is an on board power supply on the module for EACH rail, so it's a full on design for ultra quality. Problem I have at present is that I can't get the first batch out of the factory, it's taking too long.
Hugh
Hugh
Member
Joined 2009
Paid Member
Thank you Gareth, have you figured out the NAKSA topology? I know you are constantly chasing the amp topologies, and you are one of the most builders and testers on this forum..... strength to you, Sir.
I'm waiting on my first patch of N125s. Like the N80 it's a completely different topology. Singleton input, mosfet outputs with trick drive system, unusual VAS arrangement, it sounds very, very different to the old AKSA, which was an old, standard Bailey design tweaked for best possible performance, ported and polished. The NAKSA, trying to exploit the good AKSA name, takes all my lessons over 20 years into a different, svelte beast. I do wonder how long the AB technology will persist; Class D is runner up at present but will likely overtake very soon.
I am quite sure that harmonic profiling is attracting attention. I'm convinced this is the only we can resurrect the analog ways. I have been working on a high quality headphone amp, and this technique has completely demonstrated it can reduce development time by perhaps 80%. With good software a good virtual analysis can predict sound quality within minutes.
Hiraga was right. The French pointed the way in this area as far back as the sixties; google Eric Juaneda and you will see more proof of this. His circuits are almost eccentric, but when you examine them in LTSpice the results are astonishing.
Cheers,
Hugh
I'm waiting on my first patch of N125s. Like the N80 it's a completely different topology. Singleton input, mosfet outputs with trick drive system, unusual VAS arrangement, it sounds very, very different to the old AKSA, which was an old, standard Bailey design tweaked for best possible performance, ported and polished. The NAKSA, trying to exploit the good AKSA name, takes all my lessons over 20 years into a different, svelte beast. I do wonder how long the AB technology will persist; Class D is runner up at present but will likely overtake very soon.
I am quite sure that harmonic profiling is attracting attention. I'm convinced this is the only we can resurrect the analog ways. I have been working on a high quality headphone amp, and this technique has completely demonstrated it can reduce development time by perhaps 80%. With good software a good virtual analysis can predict sound quality within minutes.
Hiraga was right. The French pointed the way in this area as far back as the sixties; google Eric Juaneda and you will see more proof of this. His circuits are almost eccentric, but when you examine them in LTSpice the results are astonishing.
Cheers,
Hugh
Member
Joined 2009
Paid Member
Hi PP,
Ah, the power supplies are built onto the N125 module, one for each rail, so the question is not quite correct; all you need for the N125 module is a transformer with two separate secondary windings!
I designed integrated power supplies onto the module so I could control the power supply, particularly earthing which is a perennial problem with audio amplifiers. Furthermore, the heat output of a 124W amp at full power is considerable, and I was obliged to separate the output devices to equally heat across a 300mm heatsink, so the module was necessarily long and therefore installing the power supplies was easily accommodated.
Much of the cost of an audio amplifier is invested into the power supply filter caps. This approach means that while the module is expensive to buy, you now only need a transformer and an enclosure. I had designed a very clever case, and I can sell this with the modules too - with heatsinks fitted, drilled, tapped - at a very competitive cost.
Since I sell from one of the most expensive countries in the world at the most remote area of the planet I can only compete with exceptional performance and design, as the reference cost of a commodity product across the world now is peanuts from China.
Kapitz?
Cheers,
Hugh
Ah, the power supplies are built onto the N125 module, one for each rail, so the question is not quite correct; all you need for the N125 module is a transformer with two separate secondary windings!
I designed integrated power supplies onto the module so I could control the power supply, particularly earthing which is a perennial problem with audio amplifiers. Furthermore, the heat output of a 124W amp at full power is considerable, and I was obliged to separate the output devices to equally heat across a 300mm heatsink, so the module was necessarily long and therefore installing the power supplies was easily accommodated.
Much of the cost of an audio amplifier is invested into the power supply filter caps. This approach means that while the module is expensive to buy, you now only need a transformer and an enclosure. I had designed a very clever case, and I can sell this with the modules too - with heatsinks fitted, drilled, tapped - at a very competitive cost.
Since I sell from one of the most expensive countries in the world at the most remote area of the planet I can only compete with exceptional performance and design, as the reference cost of a commodity product across the world now is peanuts from China.
Kapitz?
Cheers,
Hugh
Hi PP,
Transformers needed are 2 x 300VA toroids each with two 35Vac secondaries - see website. Standard toroids are fine earlier used with the AKSA 100 is just fine.
Altronics, Harbuch and Tortech all make them in Oz, easily sourced. They cost around $75 each.
The case is $165 plus GST, with complete holes, cuts, folds, and semi-gloss powder case. Makes building the amp a snap. See attachment!
Cheers,
Hugh
Transformers needed are 2 x 300VA toroids each with two 35Vac secondaries - see website. Standard toroids are fine earlier used with the AKSA 100 is just fine.
Altronics, Harbuch and Tortech all make them in Oz, easily sourced. They cost around $75 each.
The case is $165 plus GST, with complete holes, cuts, folds, and semi-gloss powder case. Makes building the amp a snap. See attachment!
Cheers,
Hugh
Attachments
Hi AS,
Not sure, maybe yes, maybe no! Design of a power supply for any audio product is tricky because there are many competing issues in the functionality. For example, most think that when you use very large capacitor banks the sound is better; I refute this from my tests. To me, the subjective assessment is that while bass is tighter, the sound becomes 'leaden', slower. I suspect this is because the surge charges become very large from the rectifiers, and these charges overcome the very small earth return currents from the speaker voice coils. The effect is intermodulation, which slows and coarsens the sound presentation.
There are a few regulated power supplies for audio amps. Again, my feeling is that there is no headroom in the supply; that is, a very short, high amplitude signal has a few extra volts from a filter reservoir with an unreg ps; a regulated approach means that the undistorted output is set at a lower limit, attracting clip.
Finally, the PSRR of the amp is critical. If you can proof the amp from peturbations from the supplies, then it will be quieter and generally deliver cleaner sound.
Perhaps not what you wanted, but my thoughts on this....... I have spent a long time on the power. One of my tricks is to be used a full wave rectifier on EACH rail, not one for both. That improves the sound quality too.
Cheers,
Hugh
Not sure, maybe yes, maybe no! Design of a power supply for any audio product is tricky because there are many competing issues in the functionality. For example, most think that when you use very large capacitor banks the sound is better; I refute this from my tests. To me, the subjective assessment is that while bass is tighter, the sound becomes 'leaden', slower. I suspect this is because the surge charges become very large from the rectifiers, and these charges overcome the very small earth return currents from the speaker voice coils. The effect is intermodulation, which slows and coarsens the sound presentation.
There are a few regulated power supplies for audio amps. Again, my feeling is that there is no headroom in the supply; that is, a very short, high amplitude signal has a few extra volts from a filter reservoir with an unreg ps; a regulated approach means that the undistorted output is set at a lower limit, attracting clip.
Finally, the PSRR of the amp is critical. If you can proof the amp from peturbations from the supplies, then it will be quieter and generally deliver cleaner sound.
Perhaps not what you wanted, but my thoughts on this....... I have spent a long time on the power. One of my tricks is to be used a full wave rectifier on EACH rail, not one for both. That improves the sound quality too.
Cheers,
Hugh
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