In the Alpha Nirvana thread Hugh recently posted this:
“ I continue developing the AN in fact. Maybe I will do one for commercial; but a Class A is always very challenging because of the high dissipation and low power; a combination which makes it expensive to build, as you know well. “
So my purpose in starting this thread is to encourage Hugh to implement his development ideas and release some new commercial Class A modules. I for one would buy a pair if he did.
Post your encouragement if you think Hugh should complement his range of Class AB modules with a full Class A design 😉
“ I continue developing the AN in fact. Maybe I will do one for commercial; but a Class A is always very challenging because of the high dissipation and low power; a combination which makes it expensive to build, as you know well. “
So my purpose in starting this thread is to encourage Hugh to implement his development ideas and release some new commercial Class A modules. I for one would buy a pair if he did.
Post your encouragement if you think Hugh should complement his range of Class AB modules with a full Class A design 😉
Hmmm......... gotta think about this..........
In 1994 I developed and built ten hybrid tube/mosfet Class A amplifiers dubbed the Glass Harmony.
It used a 6SL7 with a B+ of 340V and current of 2 x 1.6mA, it was t-barred. The output stage was SE mosfet, using a CCS load.
It did 28W rms into 8R, and run at 2.8A from Vcc of 50V. That's 140W, spread across two MF30-150 Conrad heatsinks.
Boy, did it get hot. But it sounded glorious. Sold six of them! One channel failed after about 15 years, not bad for IRFs running at 38W each.
The AN was open source, but a future Class A (and I have one in the wings but still thinking about the effort and money to field it) might not be in the future.
I have just finished a 125W Class AB called the Titan, just released in monoblock. I think it's more dynamic than most Class A, and certainly very musical and engaging. I'm not sure a real Class A is worth it, certainly not in hot climates. And all of the world it appears temperatures are on the move, and energy becoming more and more expensive. Ahem.........
Recently I heard the Starkrimson, which uses very fast gallium nitride outputs running at 500KHz. A very good amplifier, wonderful sound, but not many musicians, if you get my drift.
Thanks for the vote of confidence!!
I'm about to post a pair of Titans to Adelaide, we shall see what George thinks of the sound!
Cheers,
Hugh
In 1994 I developed and built ten hybrid tube/mosfet Class A amplifiers dubbed the Glass Harmony.
It used a 6SL7 with a B+ of 340V and current of 2 x 1.6mA, it was t-barred. The output stage was SE mosfet, using a CCS load.
It did 28W rms into 8R, and run at 2.8A from Vcc of 50V. That's 140W, spread across two MF30-150 Conrad heatsinks.
Boy, did it get hot. But it sounded glorious. Sold six of them! One channel failed after about 15 years, not bad for IRFs running at 38W each.
The AN was open source, but a future Class A (and I have one in the wings but still thinking about the effort and money to field it) might not be in the future.
I have just finished a 125W Class AB called the Titan, just released in monoblock. I think it's more dynamic than most Class A, and certainly very musical and engaging. I'm not sure a real Class A is worth it, certainly not in hot climates. And all of the world it appears temperatures are on the move, and energy becoming more and more expensive. Ahem.........
Recently I heard the Starkrimson, which uses very fast gallium nitride outputs running at 500KHz. A very good amplifier, wonderful sound, but not many musicians, if you get my drift.
Thanks for the vote of confidence!!
I'm about to post a pair of Titans to Adelaide, we shall see what George thinks of the sound!
Cheers,
Hugh
Hugh, you live in a hot climate and that perhaps influences your thinking, but large parts of the world are much more Class A friendly! If you want confirmation of the level of interest in Class A amps then just spend 15 mins surfing the threads on DIYA. It would be my guess that at least 75% of the amps being discussed and made are Class A. You say you have one ready in the wings, well it would be a great shame if it wasn’t allowed out onto centre stage . . .
I suspect that Class-A power amplifiers represent an unusually large amount of traffic on the Forum, including an unusually large percentage of completed DIY projects displayed here, for a quite pedestrian reason: Newbie Appeal.
Newbies as a group, post a disproportional amount of messages here. Help me find this, please what's the difference between 4R7 and 47R, why is one of my two channels buzzing, I need another part X but it's out of stock what do I do now, I haven't read all 900 messages in this thread someone read them for me and answer my question Q, I'm no good at math please confirm I calculated Ohm's Law correctly, and so forth. You've seen these and many others I'm sure. Simple inquiries become twelve messages of back and forth. Whereas no-longer-newbie members, as a group, tend to post more sparsely.
So we've got a huge amount of newbie generated traffic. What projects do newbies usually discuss?
The projects with greatest newbie appeal are, of course, (A) full and complete kits, and/or (B) the ones created by world famous & legendary designers, whose commercial offerings sell to wealthy physicians and investment bankers for tens of thousands of dollars. Look around on this site and its companion Store, at least 85% of the full and complete kits happen to be Class-A power amps. And 95% of those were created by legendary designer Nelson Pass. If they buy a kit, newbies don't have to source components, don't have to locate and purchase a chassis, don't have to drill anything, do get comprehensive step-by-step Build Guides with 50 color photographs, and when they've completed the project they have bragging rights to say "I own a Nelson Pass designed amplifier AND it cost less than six hundred dollars." It's an extremely attractive proposition.
Obviously, their enormous appeal to newbies doesn't prove that Class-A amps are superior. It's merely that on these Forums, the available Class-A amps are perceived to be easy projects with large amounts of technical support available, and high likelihood of success. So newbies buy them and post about them. A lot.
Among the no-longer-newbie members, there are some who genuinely prefer Class-A, some who genuinely prefer Class-D (especially if designed by Bruno Putzys), and some who genuinely prefer Class-AB. But these folks are outnumbered, at least here on the Forums.
Newbies as a group, post a disproportional amount of messages here. Help me find this, please what's the difference between 4R7 and 47R, why is one of my two channels buzzing, I need another part X but it's out of stock what do I do now, I haven't read all 900 messages in this thread someone read them for me and answer my question Q, I'm no good at math please confirm I calculated Ohm's Law correctly, and so forth. You've seen these and many others I'm sure. Simple inquiries become twelve messages of back and forth. Whereas no-longer-newbie members, as a group, tend to post more sparsely.
So we've got a huge amount of newbie generated traffic. What projects do newbies usually discuss?
The projects with greatest newbie appeal are, of course, (A) full and complete kits, and/or (B) the ones created by world famous & legendary designers, whose commercial offerings sell to wealthy physicians and investment bankers for tens of thousands of dollars. Look around on this site and its companion Store, at least 85% of the full and complete kits happen to be Class-A power amps. And 95% of those were created by legendary designer Nelson Pass. If they buy a kit, newbies don't have to source components, don't have to locate and purchase a chassis, don't have to drill anything, do get comprehensive step-by-step Build Guides with 50 color photographs, and when they've completed the project they have bragging rights to say "I own a Nelson Pass designed amplifier AND it cost less than six hundred dollars." It's an extremely attractive proposition.
Obviously, their enormous appeal to newbies doesn't prove that Class-A amps are superior. It's merely that on these Forums, the available Class-A amps are perceived to be easy projects with large amounts of technical support available, and high likelihood of success. So newbies buy them and post about them. A lot.
Among the no-longer-newbie members, there are some who genuinely prefer Class-A, some who genuinely prefer Class-D (especially if designed by Bruno Putzys), and some who genuinely prefer Class-AB. But these folks are outnumbered, at least here on the Forums.
I've used various of Hugh's Class AB amps over the past 20 years ... but I have to say I love my 4R version of the AN Class A amp the most.
But, yes, the heat that 4x Class A amp channels put into the room is a bit of a problem in our summer.
(So I keep my Class AB NAKSA 80s as 'summer amps' - they never get more than slightly warm!)Andy