I just wonder that it needs to be modified for 11 or 16ohms speaker like a specific schematic only for 4ohm speaker.The standard AN is 40w into 8 ohms. Therefore, it will be only 20w into 16 ohms.
If your LS3/5A spkrs really are 16 ohms ... I suggest you may not have enough power to drive them to their best.
My speaker is 11ohms actually.
LS3/5A's don't have a wide dynamic range. My hunch is the AN39 will drive them comfortably beyond their SPL sweet spot. Absolutely no problem getting my LS50's on the end stop. Remember that 20W is NOT half as loud as 40W, it's just -3dB spl. That is nothing like half the perceived loudness, that is usually -10dB spl.
Simon is right. Moreover, LS3/5A's are played in small rooms, most don't play them in ballrooms, and most likely the speaker will croak at 95dB SPL. It's a very low sensitivity speaker (82-83dB/1 watt). You can even see on the Rogers website, that it is rated for 25 watts "Speech/music". It also has essentially no bass output (F3 starts at 80 Hz with a small woofer). So basically, midbass.
The AN is a great amplifier, and has a great damping factor for a SE design (about 160 from what I recall), so it will control the LS3/5A woofer cone very well.
I think the 15 ohm rating is really in the lower midrange to upper midrange. See older stereophile measurements here.
@namghiwook
Did you get your M2X working? Have you played it on the LS3/5A? How does it sound with the M2X? That will tell us a little more about your listening habits and needs.
Best,
Anand.
The AN is a great amplifier, and has a great damping factor for a SE design (about 160 from what I recall), so it will control the LS3/5A woofer cone very well.
I think the 15 ohm rating is really in the lower midrange to upper midrange. See older stereophile measurements here.
@namghiwook
Did you get your M2X working? Have you played it on the LS3/5A? How does it sound with the M2X? That will tell us a little more about your listening habits and needs.
Best,
Anand.
I suggest that depends on what sort of spkrs you have!
I built 2x 4ohm ANs, to drive the 3 ohm mid panels & 2 ohm ribbons of my 3-way active Maggies. These are 40w into 4 ohms - and are stable into 2 ohms. Every now and again I could see the red, clip-LED flashing on the channels driving the mid panels.
Then I replaced the Maggies with some DIY "zero baffle" spkrs, using drivers which are supposedly 90+dB efficient. These were built using 4 ohm SB Acoustics 'Satori' drivers - and, again, I see the red clipping LEDS occasionally come on, in the channels driving the woofers.
BTW, I don't listen at head-banger levels and my room is not large (5.8m x 3.6m x 2.7m).
Hi BAS!
I have built both. The Alpha Nirvana is definitely better in all parameters (neutrality, staging, imaging precision, and particularly microdetails). The Alpha 20 was an improvement over the Nelson Pass Aleph J and closer to Zen Mod’s Aleph J Zen. I would put the Alpha 20 and Aleph J Zen on practically the same plane as far as sonic impressions go. But the Alpha Nirvana is another level above those 3 designs as the current source design is different - it isn’t an Aleph based current source. It also puts out more power, which is impressive as all 4 designs are Single Ended Class A. In my system, since I use very sensitive speakers, the increase in power was of only academic importance. In the all important, 1st watt as they say, I liked the Alpha Nirvana the most of all 4.
What you need is an audition. I am not far…you can pm me.
My impressions…
Best,
Anand.
I have built both. The Alpha Nirvana is definitely better in all parameters (neutrality, staging, imaging precision, and particularly microdetails). The Alpha 20 was an improvement over the Nelson Pass Aleph J and closer to Zen Mod’s Aleph J Zen. I would put the Alpha 20 and Aleph J Zen on practically the same plane as far as sonic impressions go. But the Alpha Nirvana is another level above those 3 designs as the current source design is different - it isn’t an Aleph based current source. It also puts out more power, which is impressive as all 4 designs are Single Ended Class A. In my system, since I use very sensitive speakers, the increase in power was of only academic importance. In the all important, 1st watt as they say, I liked the Alpha Nirvana the most of all 4.
What you need is an audition. I am not far…you can pm me.
My impressions…
Best,
Anand.
Hi Scott,
Here are some video clips of the Alpha Nirvana. Anand has a very good description of the sonic qualities. It’s a Class A amp that has the bass authority of a Class AB amp while sounding like a SE Class A amp overall.
I put the CRC PSU directly on the amp here to free up room on the chassis floor which has dual trafos and a soft start and speaker protection SSRs.
Here are some video clips of the Alpha Nirvana. Anand has a very good description of the sonic qualities. It’s a Class A amp that has the bass authority of a Class AB amp while sounding like a SE Class A amp overall.
I put the CRC PSU directly on the amp here to free up room on the chassis floor which has dual trafos and a soft start and speaker protection SSRs.
Question for Hugh @AKSA I really like my A39, thank you for sharing this with the community. But...like any audio addict I need my next fix, I need to tinker I know I could throw some cash at it with some naked foil resistors and pricey German capacitors, but I can't help wondering if there are gains to be had with something like CCS's for the VAS transistor or input LTP? My EE skills are lousy but I'm willing to have a go. What do you think?
I know I could throw some cash at it with some naked foil resistors and pricey German capacitors, but I can't help wondering if there are gains to be had with something like CCS's for the VAS transistor or input LTP? My EE skills are lousy but I'm willing to have a go. What do you think?
Hi Simon,
What you propose will change the nature and sound quality of the amplifier and essentially make it a different amplifier. This is DIY and you are free to play with the circuit as you wish. I would suggest getting in the LTSpice simulation and testing your schemes for adding another transistor for a CCS that can maintain circa 2.6mA on the top of the Long Neck Pair. A CCS on the VAS stage is more difficult. In all cases, extensive sets of simulations will be needed to make sure it works in all ranges.
I know that Hugh’s designs are tailored to have a dominant second harmonic, lower third harmonic component and monotonically descending higher orders. Also, the FFT profile should be similar at low and mid and high power. There are also a lot of special tricks in the feedback network to allow a high damping factor at low frequencies for the slamming bass. It’s fun to play on LTSpice doodling but takes a lot of insight and trial and error. You could start another thread. If you can improve on this FFT then maybe you have something. Here is current amp simulation at 28vpp into 8ohms (about 12w power and quite a loud volume for most speakers):
Usually, adding more parts and CCS will lower THD so that the smaller peaks will be lower relative to the main peak. That sound might be to your liking and there are other amps that do this and also maintain a similar profile.
What you propose will change the nature and sound quality of the amplifier and essentially make it a different amplifier. This is DIY and you are free to play with the circuit as you wish. I would suggest getting in the LTSpice simulation and testing your schemes for adding another transistor for a CCS that can maintain circa 2.6mA on the top of the Long Neck Pair. A CCS on the VAS stage is more difficult. In all cases, extensive sets of simulations will be needed to make sure it works in all ranges.
I know that Hugh’s designs are tailored to have a dominant second harmonic, lower third harmonic component and monotonically descending higher orders. Also, the FFT profile should be similar at low and mid and high power. There are also a lot of special tricks in the feedback network to allow a high damping factor at low frequencies for the slamming bass. It’s fun to play on LTSpice doodling but takes a lot of insight and trial and error. You could start another thread. If you can improve on this FFT then maybe you have something. Here is current amp simulation at 28vpp into 8ohms (about 12w power and quite a loud volume for most speakers):
Usually, adding more parts and CCS will lower THD so that the smaller peaks will be lower relative to the main peak. That sound might be to your liking and there are other amps that do this and also maintain a similar profile.
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Simon
X has precisely stated my thoughts accurately and I can stress that replacing resistors with CCS will change the harmonic profile
Accordingly if you change the bootstraps you will alter the sound quality, however I can cannot say it might worsen the SQ; you might prefer it!
Cheers
Hugh
X has precisely stated my thoughts accurately and I can stress that replacing resistors with CCS will change the harmonic profile
Accordingly if you change the bootstraps you will alter the sound quality, however I can cannot say it might worsen the SQ; you might prefer it!
Cheers
Hugh