Anand,
What I meant unobtanium was not the pcbs but the components
(Mosfets and the switcher ic).
Only Mouser ships me the parts here to Srilanka and I receive within a week.
So if Mouser does not have a part I am out of luck.
My other concern with the clc power supply is that it does not contain the
Capacitance multiplier section. Only 20,000 uF final caps per rail.
I will go ahead with the build and comment on the results.
Since 'X' is silent on my question I assume that the N & P mosfets emit
equal amount of heat. I will mount them separately on two heatsinks and
expect them to share the heat without one side over heating. I will also
comnent on the result.
By the way 'X' when will be the 'RTR SSR Speaker Protection Gen2' avilable again?
Thank you all
What I meant unobtanium was not the pcbs but the components
(Mosfets and the switcher ic).
Only Mouser ships me the parts here to Srilanka and I receive within a week.
So if Mouser does not have a part I am out of luck.
My other concern with the clc power supply is that it does not contain the
Capacitance multiplier section. Only 20,000 uF final caps per rail.
I will go ahead with the build and comment on the results.
Since 'X' is silent on my question I assume that the N & P mosfets emit
equal amount of heat. I will mount them separately on two heatsinks and
expect them to share the heat without one side over heating. I will also
comnent on the result.
By the way 'X' when will be the 'RTR SSR Speaker Protection Gen2' avilable again?
Thank you all
My opinion the reason this amp has so much authority is the SLB power supply, even though I run my power supply remotely I used 16ga silicone covered rc cable X recommended and I never see power supply sag. Lyle Lovetts Joshua Judges Ruth is recorded at a low level allowing a large dynamic range, there is bass on that recoding that some systems you never even hear. The Alpha Nirvana coupled with the sub system I have reproduces bass you feel and hear. Jazz recordings with stand up bass are quite lively.
Bill
Bill
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wirewiggler,
I need bass at low volums in the system for night listening.
Thats the main idea to go for a classA amplifier.
Do you have a powered subwoofer or just drive passive bass woofers with the AN amp
in your system?
Do you prefer this amp to other amps tried out in your same system?
John.
The idea behind my previous post was to collect some feed back
from you successfull diyers.
In the olden days when a new project came, the members who
built these projects would comment on the results.Some even had
comparrisons to known brands.
These were indipendant, unbiased reviews which inspired others
to build the project.
Even Mr Pass in his B1 project, highly praised its advantages, which
drove me to build it. Even today I enjoy it as a result.
I have red the AN class A project many times and know it like the back
of my hand. Hardly found reviews which would louver a newbe
to build ths project.
In this time where class D is making a high impact on the
power amplier field, what are the advantages one would have with this
class A amplifier?
Even Mr.X has come up with a new class D design!
Please permit me to make this request from you builders to comnent
On your experience.
I consider that as the final part of your project.
John.
from you successfull diyers.
In the olden days when a new project came, the members who
built these projects would comment on the results.Some even had
comparrisons to known brands.
These were indipendant, unbiased reviews which inspired others
to build the project.
Even Mr Pass in his B1 project, highly praised its advantages, which
drove me to build it. Even today I enjoy it as a result.
I have red the AN class A project many times and know it like the back
of my hand. Hardly found reviews which would louver a newbe
to build ths project.
In this time where class D is making a high impact on the
power amplier field, what are the advantages one would have with this
class A amplifier?
Even Mr.X has come up with a new class D design!
Please permit me to make this request from you builders to comnent
On your experience.
I consider that as the final part of your project.
John.
Hi Srian,
I think the last extensive listening impressions / review came from Wirewiggler on this post.
Alpha Nirvana 39w 8ohm Class A Amp
If you want my opinion, and I’ll try not to be biased. Of all the Class A amps that I have made (the DIYA VFET “Kit” amp not included), the Alpha Nirvana is the only one that is currently boxed up and in a chassis and on my permanent amp collection. It’s that good! Things it excels at: capturing the immediacy of the moment in the recording, smooth clear vocals that touch one’s emotional heart strings, wonderfully vivid top end, and thundering bass authority. How good is it compared to my latest Class D amp? The Class D beats it in absolute baseline noise level: the RTR TPA3255 with a MicroAudio SMPS and a BTSB panel mount balanced buffer is absolutely silent when no music is playing. You cannot tell it is turned on. I have measured the noise floor and it’s flat at about 1uV rms (-120dB). Most linear supplies and analog discrete amps, even with cap multipliers etc will never be as silent. The bass on the Class D is probably about the same, but the mid range smoothness and harmonic distortion profile that defines SE Class A amps, and the clarity of the Alpha Nirvana being pure Class A - cannot be beat by a Class D amp, not at this point anyhow. What the TPA3255 also has on the Alpha Nirvana is 100w on tap and stable into 4ohm loads.
However, I am currently working on a 100w pure Class A amp that has BTL outputs (much like a TPA3255) and it’s sounding like the best of both worlds. The headroom afforded by a 100w amp just gives so much more ease and ability to slam hard on kick drums and midbass.
I think the last extensive listening impressions / review came from Wirewiggler on this post.
Alpha Nirvana 39w 8ohm Class A Amp
If you want my opinion, and I’ll try not to be biased. Of all the Class A amps that I have made (the DIYA VFET “Kit” amp not included), the Alpha Nirvana is the only one that is currently boxed up and in a chassis and on my permanent amp collection. It’s that good! Things it excels at: capturing the immediacy of the moment in the recording, smooth clear vocals that touch one’s emotional heart strings, wonderfully vivid top end, and thundering bass authority. How good is it compared to my latest Class D amp? The Class D beats it in absolute baseline noise level: the RTR TPA3255 with a MicroAudio SMPS and a BTSB panel mount balanced buffer is absolutely silent when no music is playing. You cannot tell it is turned on. I have measured the noise floor and it’s flat at about 1uV rms (-120dB). Most linear supplies and analog discrete amps, even with cap multipliers etc will never be as silent. The bass on the Class D is probably about the same, but the mid range smoothness and harmonic distortion profile that defines SE Class A amps, and the clarity of the Alpha Nirvana being pure Class A - cannot be beat by a Class D amp, not at this point anyhow. What the TPA3255 also has on the Alpha Nirvana is 100w on tap and stable into 4ohm loads.
However, I am currently working on a 100w pure Class A amp that has BTL outputs (much like a TPA3255) and it’s sounding like the best of both worlds. The headroom afforded by a 100w amp just gives so much more ease and ability to slam hard on kick drums and midbass.
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Thanks, X, for your assessment and impressions. Very encouraging! Yes, now I have to speed up my building and hopefully will have my AN done by yearend.
Thanks also to sriam for the nudge to report our listening impressions. I’m sure Hugh appreciate them too. I certainly will tell you all what I hear when I hear it.
Thanks also to sriam for the nudge to report our listening impressions. I’m sure Hugh appreciate them too. I certainly will tell you all what I hear when I hear it.
Syrian
I do run a subwoofer crossed at 80hz, it does catch low notes. What I like about the Nirvana is the speed and control of bass down to 80 hz. For low level listening with bass or if your listening room is large you need a larger bass driver, or more bass drivers. I really like the classyD amp X has and may have to build one for summer use. I am currently building a sit amp that I would like to bi-amp with the Alpa Nirvana. I will have to build new speakers for that.
Bill
I do run a subwoofer crossed at 80hz, it does catch low notes. What I like about the Nirvana is the speed and control of bass down to 80 hz. For low level listening with bass or if your listening room is large you need a larger bass driver, or more bass drivers. I really like the classyD amp X has and may have to build one for summer use. I am currently building a sit amp that I would like to bi-amp with the Alpa Nirvana. I will have to build new speakers for that.
Bill
Class A and the ethos of such amplifiers
I remember as an undergrad in hearing the first 1969 JLH, which had been built by a fourth year EE at Adelaide University. Vinyl, of course, but the amp was built in a shoebox, point to point, very badly (engineers are concerned with the function, not the form!!). Even the soldering was dreadful.
I was only 18 then and the sound was as close to natural as I'd ever heard. I grew up with a very nice Williamson PP tube amp, and it sounded pretty good. In 1971 I built a 12W Class with Fairchild/Schlumberger transistors and it was not good. I recall the 1969 session was 'Summertime', from Paul Desmond. It was glorious. I promised myself that one day I would produce an amp like the JLH 10W with real power, and higher efficiency. I recall being appalled with the efficiency of the JLH and wondered why an AB could not sound like so good as a Class A, and thinking that if you could do that, you could sell a lot of amplifiers.
Fast forward to a couple of years ago when I designed the AN. I'd had a lifetime of studying amps, and tinkering with all sorts of designs, and had been entranced with Nelson Pass' designs and built his first Zen in the late 80s. Here was a superb designer who had distilled the essence of good sound, and worked with amazingly simple Class A topologies. The Zen was 10W too, but there was so much heat I had to use a fan. At that time fans were noisesome, awkward machines, not like the modern sophisticated fan like Noctua. So, I appraised the art twenty years later but still no efficiency.
Then I saw the Aleph J. With a swinging current source, you could double the efficiency to a theoretical 50%. I'd seen that mosfets, my preferred output devices, have poor linearity until about half an amp, and this Aleph gave great promise. With the topology in my mind, one morning I was enjoying a shower after a refreshing sleep, and realised that replacing the lower output device with a pmos rather than a nmos you could define the voltage output at a far greater linearity than the original Aleph J. I recognised Nelson designed his Aleph for musical colour, but it had quite distortion, and the output voltage accuracy was set by the negative feedback loop. With a pmos in place of the lower nmos, you could reduce thd by maybe 10 times and simplify the swinging CCS so it could adjust to any load. These are eureka moments in our lives.......... of course, these are not original ideas; they are just clues in our memory, other circuit blocks we might have seen years before. There are very few new ideas, after all.
X built one in a couple of days. He was impressed. I don't build much these days; I'm old, slow and unmotivated. But he thought it was so good it needed a bigger version, so I designed a higher power amp. He built that one too and said it sounded like an earthquake on low bass.
Fortunately AndyR, a good friend here in Melbourne, decided to build a 4R version for his new speakers, a line array of very expensive SB Satori drivers. I modded the design for 4R loads, but it took a year - Andy is meticulous and builds on a grand scale - and when I heard them a couple of months ago I declared that they were arguably the best amps I had ever heard. I wrote a long review on this amp in this thread, in fact. Here it is, #1598 Alpha Nirvana 39w 8ohm Class A Amp It was actually better than the original JLH I'd held in my mind from 1969; it had more power, and it did about the heat of the JLH, 39W rms with 90W in fact, an efficiency of 43.3%, about as good as you could get it. And in the interim, most actives have become faster and more linear. There have been many arguments that the Alpha Nirvana is not a true Class A; but the outputs never turn off, and the drive to the output is to ONE mosfet, not two, so it is a SE PP design, after Professor Murray's design with tubes in the mid-sixties. You can do better than that topology for 'natural' sound quality, but X's single ended amp with an inductor - a microwave OT in fact - is a genuine Class A but I do not believe the sound is any better than the AN.
When you design for commercial products, there is a lot of careful documentation and analysis, necessary to enter the marketplace and sell at a profit. There is design, prototyping, measurement, testing, refinement of layout, careful selection of parts, accurate BOM, stuffing legend, and then marketing copy, including reviews. The reviewing necessarily involves giving amplifiers to some of the reviewers, and/or buying expensive print advertising. Nothing is done for nothing in any industry, so that takes time and effort.
When you design for hobby interest, like the AN, some of this steps can be eliminated, particularly as they are hard work. I'm doing all the hard work for my middle power new amplifier, a Class AB of 125W called the Titan. It's taken me months to get through all the hurdles. This stuff is difficult, and that's why not many people do it. So to take that final step of reviewing and publishing the information on DIY amp is hard to achieve, but there is quite a bit comment on this thread. X did a lot of measurements, too, so that area is covered. Nelson does this stuff because he has a staff, and a successful commercial enterprise selling into a very large market. He has been very generous over the years, but when pressed on the sonics, he usually demurs, saying it is audio, and it's just entertainment.
And that's my excuse too. Many amps, particularly those with higher THD because the design has eschewed global feedback, confer coloration; called by many as an effects box. And amps are a bit like food, clothes, cars, and culture; people have diverse preferences and there is plenty to spread around.
If you like the Class A sound, you will love the Alpha Nirvana.
Hugh Dean
I remember as an undergrad in hearing the first 1969 JLH, which had been built by a fourth year EE at Adelaide University. Vinyl, of course, but the amp was built in a shoebox, point to point, very badly (engineers are concerned with the function, not the form!!). Even the soldering was dreadful.
I was only 18 then and the sound was as close to natural as I'd ever heard. I grew up with a very nice Williamson PP tube amp, and it sounded pretty good. In 1971 I built a 12W Class with Fairchild/Schlumberger transistors and it was not good. I recall the 1969 session was 'Summertime', from Paul Desmond. It was glorious. I promised myself that one day I would produce an amp like the JLH 10W with real power, and higher efficiency. I recall being appalled with the efficiency of the JLH and wondered why an AB could not sound like so good as a Class A, and thinking that if you could do that, you could sell a lot of amplifiers.
Fast forward to a couple of years ago when I designed the AN. I'd had a lifetime of studying amps, and tinkering with all sorts of designs, and had been entranced with Nelson Pass' designs and built his first Zen in the late 80s. Here was a superb designer who had distilled the essence of good sound, and worked with amazingly simple Class A topologies. The Zen was 10W too, but there was so much heat I had to use a fan. At that time fans were noisesome, awkward machines, not like the modern sophisticated fan like Noctua. So, I appraised the art twenty years later but still no efficiency.
Then I saw the Aleph J. With a swinging current source, you could double the efficiency to a theoretical 50%. I'd seen that mosfets, my preferred output devices, have poor linearity until about half an amp, and this Aleph gave great promise. With the topology in my mind, one morning I was enjoying a shower after a refreshing sleep, and realised that replacing the lower output device with a pmos rather than a nmos you could define the voltage output at a far greater linearity than the original Aleph J. I recognised Nelson designed his Aleph for musical colour, but it had quite distortion, and the output voltage accuracy was set by the negative feedback loop. With a pmos in place of the lower nmos, you could reduce thd by maybe 10 times and simplify the swinging CCS so it could adjust to any load. These are eureka moments in our lives.......... of course, these are not original ideas; they are just clues in our memory, other circuit blocks we might have seen years before. There are very few new ideas, after all.
X built one in a couple of days. He was impressed. I don't build much these days; I'm old, slow and unmotivated. But he thought it was so good it needed a bigger version, so I designed a higher power amp. He built that one too and said it sounded like an earthquake on low bass.
Fortunately AndyR, a good friend here in Melbourne, decided to build a 4R version for his new speakers, a line array of very expensive SB Satori drivers. I modded the design for 4R loads, but it took a year - Andy is meticulous and builds on a grand scale - and when I heard them a couple of months ago I declared that they were arguably the best amps I had ever heard. I wrote a long review on this amp in this thread, in fact. Here it is, #1598 Alpha Nirvana 39w 8ohm Class A Amp It was actually better than the original JLH I'd held in my mind from 1969; it had more power, and it did about the heat of the JLH, 39W rms with 90W in fact, an efficiency of 43.3%, about as good as you could get it. And in the interim, most actives have become faster and more linear. There have been many arguments that the Alpha Nirvana is not a true Class A; but the outputs never turn off, and the drive to the output is to ONE mosfet, not two, so it is a SE PP design, after Professor Murray's design with tubes in the mid-sixties. You can do better than that topology for 'natural' sound quality, but X's single ended amp with an inductor - a microwave OT in fact - is a genuine Class A but I do not believe the sound is any better than the AN.
When you design for commercial products, there is a lot of careful documentation and analysis, necessary to enter the marketplace and sell at a profit. There is design, prototyping, measurement, testing, refinement of layout, careful selection of parts, accurate BOM, stuffing legend, and then marketing copy, including reviews. The reviewing necessarily involves giving amplifiers to some of the reviewers, and/or buying expensive print advertising. Nothing is done for nothing in any industry, so that takes time and effort.
When you design for hobby interest, like the AN, some of this steps can be eliminated, particularly as they are hard work. I'm doing all the hard work for my middle power new amplifier, a Class AB of 125W called the Titan. It's taken me months to get through all the hurdles. This stuff is difficult, and that's why not many people do it. So to take that final step of reviewing and publishing the information on DIY amp is hard to achieve, but there is quite a bit comment on this thread. X did a lot of measurements, too, so that area is covered. Nelson does this stuff because he has a staff, and a successful commercial enterprise selling into a very large market. He has been very generous over the years, but when pressed on the sonics, he usually demurs, saying it is audio, and it's just entertainment.
And that's my excuse too. Many amps, particularly those with higher THD because the design has eschewed global feedback, confer coloration; called by many as an effects box. And amps are a bit like food, clothes, cars, and culture; people have diverse preferences and there is plenty to spread around.
If you like the Class A sound, you will love the Alpha Nirvana.
Hugh Dean
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Sorry - have only just seen this.
If you look at the s/sheet I sent you, you will see that, yes, R136 on the AN 8R schematic does not appear on Hugh's AN 4R schematic. That's why there's a '-' in Col B.
On Hugh's advice, I included this resistor ... as there is space for it on the PCB.
Andy
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But surely, X - if the very clever red 'clip LEDs' on the AN never flicker on - even on transients, when listening louder than normal - 100w will be of no benefit with my current spkrs?
Andy