iconic amps, I can name 10-20-30 models.
Let's say your question lacks precision.
if you want to start with a nice diagram, simple and that works really well, there are more than 10 possible answers alone but I can recommend the JLH69 whose PCBs and even kits are available on the net for a few bukcs.
With that, you can't go wrong.
and it's even better on the tube generation (balad, festival, award series, citation)
I am sorry that I did not manage to explain my purpose with my post.
The lack of presession was deliberate, it was to learn about what "milestones" what did stick out from the rest trough time.
This is my problem, if I want to get a schematic can I get 1 billion in 2 seconds but 30% of them is less than ideal, 30% is run-of-the-mill DIY 20% is maybe interesting, 4% is worth an extra look, but maybe only 1% is of the category where we are talking about designs that did something special, and only again 1% of those made a lasting impression, walked into history as iconic, a historical treasure. I am trying to find those, learn what made them special, and maybe build a couple of them. 🙂
Have not read rest of the thread, so it could have been mentioned.
JLH classA amps were very popular for sound. I got about half a dozen versions, but high power penultimate seems best.
All available on web, schematics with modern transistors, pcb, adjustment, all available.
After being a certified professional audio/video service tech for over 4 decades, working in the shop has taught me plenty of "what is good, or great, and what is just alright, but...."
Seeing literally thousands of products on my service bench, how they are designed, built, allows me to determine my own preferences, something the general public could never do.
Of course, online, you'll get tons of recommendations, bias's, arguments, beliefs, and snake oil sales pitches.
But before that, your own portfolio has to be intact and solid.
I mean, just having a cheap radio shack soldering iron and a hand-me-down from gramps meter isn't enough to make anyone a qualified tech, or have the needed understanding to determine what is good or bad.
Enjoy.
Thank you for your suggestion, may I ask you what you in particular think make them worth a special place?
Commercial amplifiers almost always have a low-impedance voltage output, while loudspeakers of the usual electrodynamic type distort less with high-impedance current drive. Maybe you could improve on most of the commercial designs by experimenting with current drive and with ways to equalize out the resulting frequency response peaks.Very well put.
Not just on this forum, either. Almost every area of technology (not just electronics) has advanced far beyond the point where untrained dabblers (i.e., amateur enthusiasts like us) can approach anywhere near the cutting edge. Usually, what we can do is decades - or centuries - behind the state of the art.
Gnobuddy,
Your post 18 and 20 caught my eye. Once in a blue moon the 'state of the art' appears, like here.
Marcel's mention of current drive in the post above was spot on. You can improve on commercial amp/speaker systems simply by going to current drive. In DIY we can do that. In the commercial world they can't go there because they are 'stuck in a rut' with convention (voltage drive of speakers).
Your post 18 and 20 caught my eye. Once in a blue moon the 'state of the art' appears, like here.
Marcel's mention of current drive in the post above was spot on. You can improve on commercial amp/speaker systems simply by going to current drive. In DIY we can do that. In the commercial world they can't go there because they are 'stuck in a rut' with convention (voltage drive of speakers).
heh,heh....I have known professional audio engineers, technicians and such with long careers in the pro and commercial audio field but most of them still had tin ears and relied almost entirely on instruments to tell them anything about the systems they were concerned with.
The question is likely about what makes an exceptionally fine sounding amp which in turn, infers that the audio system itself is really a part of the music making....i.e. it does not follow the paradigm of what an amplifier should be according to said experts and adds something subtle and uniquely pleasing to the listener's experience. Otherwise, any amplifier with great specs and reliable build quality would indeed sound as good as any other. They'd all be cheap and competitively priced too, which might actually be a good thing
The question is likely about what makes an exceptionally fine sounding amp which in turn, infers that the audio system itself is really a part of the music making....i.e. it does not follow the paradigm of what an amplifier should be according to said experts and adds something subtle and uniquely pleasing to the listener's experience. Otherwise, any amplifier with great specs and reliable build quality would indeed sound as good as any other. They'd all be cheap and competitively priced too, which might actually be a good thing
Boothroyd Stuart Meridian 100 series amps/pre amps easily fit the op's bill. Sota for late 70's British Naim killer. Timeless compact design and lightning fast performance. 7db headroom. Spanks the Quad's wooly bass/mid heavy performance. My 105 monos never lit up the clip LED's on my Kef 105 86db sens. speakers unless I deliberately cranked the volume just to make sure they work. Easily drove them to their max output capability of 108db with plenty to spare. Fastest most accurate transient performance I've heard to date. Very pleasing and coherent. Mimics the real event well.
I also have known those "professionals" and I agree with you that it's common to rely on testing bt instruments.
Those types mildly annoy me.
They act like extensions of their equipment - almost robotic-like.
In my world, feet on the ground, and being comfortably reasonable, there are many "nuances" involved in having a satisfying audio result.
And adhering just to testing equipment is only a part of the cake ingredients.
Indeed, everyone's hearing abilities are different, and you have to take that into account.
Just like the "voicing" of components themselves are unique.
The "icing on the cake" is a hard, yet not impossible thing to acomplish.
The First Boothroyd Stuart Meridian stuff was really cute, but not that well built.
Other amps of the day like Ampzilla, Dreadnaught Clarke, Marantz 500, certainly NAIM (250 was the best amp we found to drive Dayton-Wrights, what a combo), were standouts of the day, but during my days of retail hifithe NAD3020/7020 made the biggest impact.
dave
Other amps of the day like Ampzilla, Dreadnaught Clarke, Marantz 500, certainly NAIM (250 was the best amp we found to drive Dayton-Wrights, what a combo), were standouts of the day, but during my days of retail hifithe NAD3020/7020 made the biggest impact.
dave
I have 2 pairs of 105 monos from 1978 still functioning as they should with no repairs. I have to disagree with your asessment of their build quality. I traded the NAD 7020(oops, just checked HiFi Engine and realize it was a 7080 I bought...1978) a month after I bought it for the Meridians. The NAD had zero headroom and blew up a brand new pair of B&W DM7s. Nothing special about it. I can't speak for the 7020. I like the original Son of Ampzilla (over it's big brother and subsequent GAS500) and the Naim because they did have some speed and although the Meridians were a bit obscure, they did sound remarkably better to my ear and were very well received by those who sold and experienced them. The others just didn't come close to that convincingly realistic presentation. Leach's LSR&D amps were also very natural sounding which I have several of also. About as flat a FR as you'll ever hear but still not fast like the Meridians. The only other amp I would compare their performance to is the original Krell KSA100, very similar actually except for the serious bottom end of course. But the Meridians still come out on top otherwise. The HK Citation XX, Harman Kardon's masterpiece is a great all round performer, very similar sounding to the GAS500. Then there was Bedini, imo overrated. The best of the lot imo is the 25/25. I was going to say the 100/100 but the smaller one is a bit faster while the bigger one has a great sound stage but lacks the transient performance I like.
After this rant I must confess I prefer my Acoustats driven by their direct drive servo OTLs. 😉
After this rant I must confess I prefer my Acoustats driven by their direct drive servo OTLs. 😉
3020 and 7020 were the same but for the tuner.
They were poorly built but introduced decent sound at a price point unheard of before. We probably sold in excess of a 1000. Later a power amp could be added (the PS Audio power amp was popular). Only a couple of the meridians came thru. It was the switches we had issues with.
dave
They were poorly built but introduced decent sound at a price point unheard of before. We probably sold in excess of a 1000. Later a power amp could be added (the PS Audio power amp was popular). Only a couple of the meridians came thru. It was the switches we had issues with.
dave
Mark Tillotson.
"Before any comparison, you need to declare your weighting function - what aspects are most important to you..."
That's a good point, possibly the most important though potentially, also most subjective one. I sense that for you, class A is history because of it's energy usage (though I may be wrong). Is the primary purpose of the amplifier for most, not to be a part in a chain to produce the desired sound "quality" and volume level, be it as a form of entertainment or as, like a picture, a "memory jogger"? Class A' does this for me more than any other method other than live performance. In the west we like to navel gaze about such things. After all mostly we have the luxury to do so. How fair would it be to have a personal energy tariff, a mental "guide" at least (if that is what has maybe driven your statement) for everybody. So if one chooses not to drive vehicles for pleasure, maybe repair and/or keep products longer, not take flights for holidays (or when teleconferencing would do). If one eats less meat to save energy, or lives in an energy efficient home generating part of your own needs or in a lifestyle conducive to a healthy environment. Then one could "offset" to a degree at least one against the other.
It is always very easy to point the finger at one simple thing that we may disagree with, and having worked in various places from sheds in fields to the luxurious environs of Cambridge and other science parks, I have myself wondered if the lakes, regularly manicured gardens and spacious offices were really truly necessary. All these things have a cost.
None of this should stop us trying to do better, but what is life for if not to be enjoyed to the detriment of no others.
Just my 2d's worth
"Before any comparison, you need to declare your weighting function - what aspects are most important to you..."
That's a good point, possibly the most important though potentially, also most subjective one. I sense that for you, class A is history because of it's energy usage (though I may be wrong). Is the primary purpose of the amplifier for most, not to be a part in a chain to produce the desired sound "quality" and volume level, be it as a form of entertainment or as, like a picture, a "memory jogger"? Class A' does this for me more than any other method other than live performance. In the west we like to navel gaze about such things. After all mostly we have the luxury to do so. How fair would it be to have a personal energy tariff, a mental "guide" at least (if that is what has maybe driven your statement) for everybody. So if one chooses not to drive vehicles for pleasure, maybe repair and/or keep products longer, not take flights for holidays (or when teleconferencing would do). If one eats less meat to save energy, or lives in an energy efficient home generating part of your own needs or in a lifestyle conducive to a healthy environment. Then one could "offset" to a degree at least one against the other.
It is always very easy to point the finger at one simple thing that we may disagree with, and having worked in various places from sheds in fields to the luxurious environs of Cambridge and other science parks, I have myself wondered if the lakes, regularly manicured gardens and spacious offices were really truly necessary. All these things have a cost.
None of this should stop us trying to do better, but what is life for if not to be enjoyed to the detriment of no others.
Just my 2d's worth