Hi Folks,
Today I fired up my brand new SAKSA, the next generation of the Aspen range! This amp has:
1. Heritage from the original AKSA 55, particularly the midrange and top end.
2. VAS stage enhanced from the original NAKSA 80.
3. Improved output drive system from the Maya.
4. Footprint from the NAKSA 80, identical to the pinout and heatsink.
5. Lender VAS drive with shunt compensation and phase lead - no lag comp.
6. Nested feedback like all my recent amps deliverying low global feedback - 29dB.
7. Strengthened output stage over the NAKSA 80, all complementary mosfets rated at 280W and 38A.
8. Snubbers on all gates to guard against self-oscillation, the bane of mosfets.
9. Clip indicator (RED!!!)
10. Same price as the NAKSA 80, $AUD930 including 300x75mm 0.37C/W heatsink.
Technical:
The amp has a THD of 0.06% at 12.5W, 1KHz into 8R, 97% being H2 and H4
All fuses are 10A. Slew rate is 15V/us, 1dB down at 12Hz and 150KHz (LP filter in place).
Subjectives:
Very strong bass and midrange. Top end utterly clean. Lots of speed, PRAT, and engagement. You close your eyes, and tap your foot. Very spatial, you can 'see' the instruments in place front to back on a large orchestra. HUGE soundstage and very low intermodulation on choir and orchestra.
This will last as long as the original AKSA. This is a superior amp with a huge of careful engineering and psychoacoustic detective in it. It is knocking on the door of the Maya, and that is a watershed of my amp designs.
I have my first batch and ready to roll for despatch. Wait for a bit on an old, slow guy when I respond, but I'm still the same old Hugh of yore and I will get through all of it over time........!
A very happy day for me, this year both new ground breaking designs have come to life!
Ciao,
Hugh
Today I fired up my brand new SAKSA, the next generation of the Aspen range! This amp has:
1. Heritage from the original AKSA 55, particularly the midrange and top end.
2. VAS stage enhanced from the original NAKSA 80.
3. Improved output drive system from the Maya.
4. Footprint from the NAKSA 80, identical to the pinout and heatsink.
5. Lender VAS drive with shunt compensation and phase lead - no lag comp.
6. Nested feedback like all my recent amps deliverying low global feedback - 29dB.
7. Strengthened output stage over the NAKSA 80, all complementary mosfets rated at 280W and 38A.
8. Snubbers on all gates to guard against self-oscillation, the bane of mosfets.
9. Clip indicator (RED!!!)
10. Same price as the NAKSA 80, $AUD930 including 300x75mm 0.37C/W heatsink.
Technical:
The amp has a THD of 0.06% at 12.5W, 1KHz into 8R, 97% being H2 and H4
All fuses are 10A. Slew rate is 15V/us, 1dB down at 12Hz and 150KHz (LP filter in place).
Subjectives:
Very strong bass and midrange. Top end utterly clean. Lots of speed, PRAT, and engagement. You close your eyes, and tap your foot. Very spatial, you can 'see' the instruments in place front to back on a large orchestra. HUGE soundstage and very low intermodulation on choir and orchestra.
This will last as long as the original AKSA. This is a superior amp with a huge of careful engineering and psychoacoustic detective in it. It is knocking on the door of the Maya, and that is a watershed of my amp designs.
I have my first batch and ready to roll for despatch. Wait for a bit on an old, slow guy when I respond, but I'm still the same old Hugh of yore and I will get through all of it over time........!
A very happy day for me, this year both new ground breaking designs have come to life!
Ciao,
Hugh
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Oh man, you make some beautiful amps !
Can you tell us why u use, different height/voltage type of PSU elco's ?
Is speaker DC-protection necessary to ad, or is it ok to use without external module ?
Congrats
Can you tell us why u use, different height/voltage type of PSU elco's ?
Is speaker DC-protection necessary to ad, or is it ok to use without external module ?
Congrats
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Joined 2009
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Hi Zia, Thiago, Ben, Patrick and Gareth -
Thank you sincerely for good wishes! I'm very pleased with it and I'm very happy that people think it looks good. After all, if its to sell it has to look good!
1. Protection: None on the output node, but fuses sufficient. The output devices are so large (38A/40A; 250V/150V and both 280W) and so tied down with snubbers I do not expect anyone to blow it up; with heavy current it will take out the fuses, and fuse the power supply 0.15R 2W resistors between 1st and 2nd caps. That will remove the power completely. With only 42V rails I consider no other protection needed, but you can use on externally if you wish. There have been no failures in a couple of years for the NAKSA 80; I would expect this product, with much bigger output devices and stronger stability this would be as good if not better than the predecessor.
2. The smaller caps take power directly from the rectifiers, one bridge for positive, the other bridge for negative. A 0.15R resistor lies between small and large caps; the small caps smooth the mains pulses (4,400uF total) and the large caps are both speaker current bypasses and further smoothing caps. This separates some of the rectifier pulses from the caps which deal with the speaker current, avoiding intermodulation with the power supply. The large 4,700uF takes care of the speaker earth current, one for each rail. Effectively this is a bifurcated power supply, allowing me to use one 300VA toroid.
3. 15V/uS is fine and dandy for 85W. It would not be adequate for 20KHz from a 250W amp. This is imposed by the input LP filter. You need only about 5V/uS for a 80W amp.
Cheers,
Hugh
Thank you sincerely for good wishes! I'm very pleased with it and I'm very happy that people think it looks good. After all, if its to sell it has to look good!
1. Protection: None on the output node, but fuses sufficient. The output devices are so large (38A/40A; 250V/150V and both 280W) and so tied down with snubbers I do not expect anyone to blow it up; with heavy current it will take out the fuses, and fuse the power supply 0.15R 2W resistors between 1st and 2nd caps. That will remove the power completely. With only 42V rails I consider no other protection needed, but you can use on externally if you wish. There have been no failures in a couple of years for the NAKSA 80; I would expect this product, with much bigger output devices and stronger stability this would be as good if not better than the predecessor.
2. The smaller caps take power directly from the rectifiers, one bridge for positive, the other bridge for negative. A 0.15R resistor lies between small and large caps; the small caps smooth the mains pulses (4,400uF total) and the large caps are both speaker current bypasses and further smoothing caps. This separates some of the rectifier pulses from the caps which deal with the speaker current, avoiding intermodulation with the power supply. The large 4,700uF takes care of the speaker earth current, one for each rail. Effectively this is a bifurcated power supply, allowing me to use one 300VA toroid.
3. 15V/uS is fine and dandy for 85W. It would not be adequate for 20KHz from a 250W amp. This is imposed by the input LP filter. You need only about 5V/uS for a 80W amp.
Cheers,
Hugh
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Congratulations!
Hi Hugh
Its great to read that you have released yet another fine product. I'll have to explore the possibility of slotting one into my system, to replace my 6 yer old NAKSA 70.
Regards, Peter Roberts 😀
Hi Hugh
Its great to read that you have released yet another fine product. I'll have to explore the possibility of slotting one into my system, to replace my 6 yer old NAKSA 70.
Regards, Peter Roberts 😀
Hi Patrick,
Good question!
More bass, slightly warmer midrange, very good at lower output, and more engagement.
Words are never enough.......
It certainly is a different amp to the NAKSA, which features resolution and depth of image. I think the SAKSA brings it back to the original AKSA, but with more of everything. It's also much stronger, and a bigger scale, particularly capable with difficult speakers.
Ciao,
Hugh
Good question!
More bass, slightly warmer midrange, very good at lower output, and more engagement.
Words are never enough.......
It certainly is a different amp to the NAKSA, which features resolution and depth of image. I think the SAKSA brings it back to the original AKSA, but with more of everything. It's also much stronger, and a bigger scale, particularly capable with difficult speakers.
Ciao,
Hugh
Hi Hugh,
Congratulations on creating yet another amp!
Now, the NAKSA 80 is not half bad, but I'm sure the SAKSA is even better 🙂
I can see that you mention stronger bass as a main feature, which is absolutely great for loudspeakers with "difficult" phase angles - and interesting PSU scheme, by the way 😉
I shall be looking forward to listening to your new amps during my visit next year!
Cheers,
Jens
Congratulations on creating yet another amp!
Now, the NAKSA 80 is not half bad, but I'm sure the SAKSA is even better 🙂
I can see that you mention stronger bass as a main feature, which is absolutely great for loudspeakers with "difficult" phase angles - and interesting PSU scheme, by the way 😉
I shall be looking forward to listening to your new amps during my visit next year!
Cheers,
Jens
Can't tell you - I have not yet measured it!
However, I caution you against assessing amps on slew rate; beyond a minimal figure, there is no effect on sound quality.
Cheers,
Hugh
However, I caution you against assessing amps on slew rate; beyond a minimal figure, there is no effect on sound quality.
Cheers,
Hugh
Hi Hugh,
What is the input impedance for the SAKSA?
And is it the same as for the new MAYA?
Cheers,
Jens
What is the input impedance for the SAKSA?
And is it the same as for the new MAYA?
Cheers,
Jens
Hi Jens,
Thanks for the post!
SAKSA 85 Zin is same as the Maya, 28k, and indeed the same as the NAKSA 80.
I'm actually listening to it now, it's wonderful, I'm very pleased, extremely refined and quiet.
I have to do the documentation now, I will throw up a nice photograph in an enclosure tomorrow.....
Ciao,
Hugh
Thanks for the post!
SAKSA 85 Zin is same as the Maya, 28k, and indeed the same as the NAKSA 80.
I'm actually listening to it now, it's wonderful, I'm very pleased, extremely refined and quiet.
I have to do the documentation now, I will throw up a nice photograph in an enclosure tomorrow.....
Ciao,
Hugh
Thanks Hugh - points at similar input modules, I guess 😉
Will be looking forward to piccies of the baby 🙂
Jens, you will thoroughly enjoy it. I went around to Hugh's place yesterday for a first listen and the SAKSA 85 is quite special. I still have and love my Soraya/GK2 combo but its amazing how clear (and seemingly powerful) this new little amp is. Hugh just keeps chipping away with incremental improvements and refinements and what amazes me, he does so with seemingly less complex circuits and layouts. It is also amazingly quiet as he says, quieter even than my Soraya though part of that is toroids that buzz slightly after 8 or so years. Can't wait to have a proper listen to a Maya when Hugh has his current personal build finalised. 😀