No doubt, if you buy Krell you are not buying an empty box, but they have "progressed" so far out of my range it is not worth even dreaming about them. Pass has done the same. I wish they would produce a bread-n-butter amp. Use their knowledge to do another "only" good 100W amp us semi-normal people could dream about again.
Remembering back 8000 or so posts, measurements? I have been improving my test set up and just happen to have had the mic feeding an RTA sitting next to my old disgraced Paradigms. The DAC feeding some old Joni Mitchel I know brick walls at 22K. My modified Hafler is quite clean. Yet POW, the amount of spikes above 23K were astounding. I put a LP second order filter across the speaker to no effect. It is amazing how much these tweeters miss-behave all by themselves. THAT would seem to be the problem my wife has with her sensitive hearing. Neither of my recent speaker builds with Seas tweeters do this( she approves of them) and the HDS I am planning on using next does not. So, what kind of measurement that could be typed up as a number for marketing could reflect this problem?
In 1995-2002, their 250 WRMS amp used a whopping 118 transistors for the VAS only, plus current amps, plus fully electronic regulation for all of it on several levels.
Just testing all those devices had to cost a bundle. It's things like this that we tend to forget in our own projects, our time is for free because we're having fun.
Consequently, as you say, the prices have escalated into astronomy. Everyone seems hell bent on outdoing and outcosting everyone else.
In the beginning, in the early 80ies, Krell did have KSA 50, 100, etc, from smaller to bigger, a bit of something for everyone.
If you're interested, I do have Krell clone set of schematics around somewhere, I can look and send them to you to any adress you designate.
Cheers,
DVV
Whats a semi-normal Budget .....?
I think that in the end, most of us will have the basic answer: something that costs a percentage of what we make which won't hurt us.
The simple fact that we live all over the world changes the price point view all by itself.
That is most likely distortion and break up; some tweeters can produce a lot of ultrasonic harmonics and have ultrasonic break up modes that can be hit by them. Have you got some hard dome (alu, mylar) in there?
Whats a semi-normal Budget .....?
Realizing that "normal" people need a decent $100 table top radio, I accept that I am not in the normal class. I am also old enough not to be in the ego class. Basic marketing says if they are the top prestige class, their entry level should be just over the top of the next class down. Was that not the basis for the old KSA100? So, by today's market, that would be in the 2500 to 3K range. I could actually think about that. Plus, stores could actually have one. They can't have too many 10K amps sitting around. Those days are sadly gone. Boulder Sound Gallery and Listen Up are but fond memories of when I lived in a more civil place in a more civil time. Yea, I have at least thought seriously about an A21. Tease me with one step up. Although I do have my doubts that any speaker made, or any source material available, can really make use of an amp that good. I can AFFORD a table radio. I am willing to PAY for HI-FI, I don't bother even looking at bragging rights class.
With a 2K budget tou have a lot of choices for "high-end " sound , used of course, 500-1K the choices are small.
The only hi- end sound under 1k i have heard personally is from Aragon, PS -audio and some threshold, the occasional Krell Ksa80 show up around 1k . imo Krells sound best below 8 ohm , The 4004 aragon also has good sonics , favorite being the PS-audio 200cx for under 1K....
The only hi- end sound under 1k i have heard personally is from Aragon, PS -audio and some threshold, the occasional Krell Ksa80 show up around 1k . imo Krells sound best below 8 ohm , The 4004 aragon also has good sonics , favorite being the PS-audio 200cx for under 1K....
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Yup, itr ia an aluminum dome. Fortunatlly the Seas 27TD series, either soft or metal, is far better behaved. My last two projects use one of each. Everything has it's breakup modes, just the Studio 20's seem to be far below the line. Still, when they came out they were a steal at $600 a pair, besting many at twice the price. All that really says is how bad so many speakers were. We spent a long time blaming the amplifiers.
When it comes to Sound Quality Vs. Money, I just came across this and thought it interesting:
http://www.gearslutz.com/board/high-end/296081-1-86-vs-1-925-microphone-sound-clips.html
Excuse me while I make a parts order...
http://www.gearslutz.com/board/high-end/296081-1-86-vs-1-925-microphone-sound-clips.html
Excuse me while I make a parts order...
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Yea, you list a lot of good old amps. I almost bought an Aaragon 2002 when new, but went for the B&K instead. I have been out-bid a couple of times on e-bay as well as on more than one Acrus, Forte, and Nak PA-5. I thought I scored a Threshold once, but got sniped in the last second. When they go past half of their new price, that says a lot for their enduring quality, but I back off knowing restoring any of these is not cheap.
The baby PS that looked like a Quad painted black was nice. Then there were some sleepers in consumer clothing, a Kenwood or two, occasional Marantz or Onk. You would really need to know which was which. All of them are old. All of them need at least a re-cap by now, and if anything actually fails, the parts are no longer made. John convinced me to get an HCA1200, and I would up with two. What I notice most now is how bad so many of my CD's are. With the Rotel's they sort of masked some of the issues. Well done recordings though, are quite a bit better. Even the remastered version of Sgt. Pepper is shocking in the difference, and those masters were nothing to brag about to start with. Maybe we need a knob on out preamps for source quality. Garbage to Nirvana.
Anyway, I understand that tiny bit about amps now so I can concentrate on building better speakers. I did convert one of my RB951's to Miller compensation, and yup, it opened it up some and the profile of noise and distortion matched other amps but that uncovered other tradeoffs. So I put it back to be the beguine amp it was made as. That proved it is the topology that matters and not something obscure in the interface.
The baby PS that looked like a Quad painted black was nice. Then there were some sleepers in consumer clothing, a Kenwood or two, occasional Marantz or Onk. You would really need to know which was which. All of them are old. All of them need at least a re-cap by now, and if anything actually fails, the parts are no longer made. John convinced me to get an HCA1200, and I would up with two. What I notice most now is how bad so many of my CD's are. With the Rotel's they sort of masked some of the issues. Well done recordings though, are quite a bit better. Even the remastered version of Sgt. Pepper is shocking in the difference, and those masters were nothing to brag about to start with. Maybe we need a knob on out preamps for source quality. Garbage to Nirvana.
Anyway, I understand that tiny bit about amps now so I can concentrate on building better speakers. I did convert one of my RB951's to Miller compensation, and yup, it opened it up some and the profile of noise and distortion matched other amps but that uncovered other tradeoffs. So I put it back to be the beguine amp it was made as. That proved it is the topology that matters and not something obscure in the interface.
Here's what prompted me to google around for that model mic capsule and find that page - they're being obsoleted:
http://www.diyaudio.com/forums/parts/230336-panasonic-wm-61a-mic-capsule-discontinued.html
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Two notes here.
You are absolutely right when you say we blamed the amps for what had nothing to do with them. Also, speaker designer didn't give a hoot what the amp saw of their impedance modulus, they simply passed the blame on to the amp designers.
Secondly, some years ago, just before they were shut down, Son Audax published a catalog of their own speaker drivers. Some 15-20 years ago, they produced a soft domw tweeter which could be found in at least 50% of British speakers at the time. Their own waterfall diagram showed that the driver was intermodulating like crazy, yet people swore by it. Their titanium dome, on the other hand, had an exemplary clean waterfall diagram up to +1.5 dB above nominal power, yet people shunned it because it was made of metal, claiming it sounded sharp and shrill.
I own two pairs of speakers from the same stable, and whichever amp I plug in, the titanium dome is much more clear and defined than the "legendary" soft dome. To someone accustomed to the sound of the soft dome, this may appear to be shrill, but give it a few days and I doubt you'd want to go back to the soft dome.
Nige, all of my amps, except the Karan, are economy class, more or less. I have no idea how much the Karan costs today, but I'd guess no less than $7,000 in the USA, and the last UK price I heard some years ago was 4,500 UKP.
My favorite, which never ceases to amaze me, the HK 6550, cost DM 1,100 in December 1993 when I bought it. The HK 680, their top of the line model in 1999, cost me about the same, but I got it just after it was discontinued in favor of a new series.
The Marantz set, preamp and amp, cost about $950 in their day, which was 1978-1980.
The Luxman C-03 preamp cost around $850 in 1995, when it was finally discontinued, as Luxman's longest lived model ever.
Yamaha stopped being interesting to me soundwise by around 1985, but then I didn't exacty follow up on their production. I did have an AX-592 integrated amp in 1995 (nominally 2x100 WRMS/8 Ohms), which was all right, but no more than that.
For clarity and definition, the HK 6550 will give the Karan a run for its money in relative terms (i.e vis a vis price/performance ratio), but then it's no big news that the High End is above the diminishing returns point in absolute terms.
I have considered making an electrostatic mike . An old Grundig one impressed me greatly . It looked a good DIY project .
A question about amps which I don't think was ever asked ? Has anyone measured the effects on speaker distortion due to feedback and damping ? I know CCS verses CVS arguments rage ( mostly we use CVS amplifiers ) . It strikes me that there will be a sweet spot where it is optimum . My conjecture is that if damping is high the speaker is forced to move more correctly ? If the grip is loosened the error signal will sum with the output and will be corrected . Common senses says it will resemble a square law and will favour traditional CVS amplifier type . My few tests with negative output impedance suggest a special speaker required , perhaps ideal for open baffle and only at LF ?
The problems of tweeters suggests it should be the same story . A notch filter active design perhaps ? It seems to me hyper stupid to use a class B/D amp to drive a tweeter ( I am stupid/lazy by my own definition I add ) . The old JLH 10 W amp would seem ideal ?
An analogy with engines again . When BMW brought out the K series motorcycles they were scrutinized for using a simple chain drive to the valve camshaft . Honda would use a Hy-vo plate chain . That is a chain of all plates and no rollers . BMW stated that at a critical 8000 rpm the weight of the chain was significant and favoured the simple chain . At 10 000 rpm the story changed . BMW developed the engine to be optimum at 8000 rpm rather than ask it to slew harder one could say ( jerks in drive train ) . I love optimum design . How very brave of BMW not to follow the advertising objectives . I must admit when I saw that chain I was horrified , I was wrong !
A question about amps which I don't think was ever asked ? Has anyone measured the effects on speaker distortion due to feedback and damping ? I know CCS verses CVS arguments rage ( mostly we use CVS amplifiers ) . It strikes me that there will be a sweet spot where it is optimum . My conjecture is that if damping is high the speaker is forced to move more correctly ? If the grip is loosened the error signal will sum with the output and will be corrected . Common senses says it will resemble a square law and will favour traditional CVS amplifier type . My few tests with negative output impedance suggest a special speaker required , perhaps ideal for open baffle and only at LF ?
The problems of tweeters suggests it should be the same story . A notch filter active design perhaps ? It seems to me hyper stupid to use a class B/D amp to drive a tweeter ( I am stupid/lazy by my own definition I add ) . The old JLH 10 W amp would seem ideal ?
An analogy with engines again . When BMW brought out the K series motorcycles they were scrutinized for using a simple chain drive to the valve camshaft . Honda would use a Hy-vo plate chain . That is a chain of all plates and no rollers . BMW stated that at a critical 8000 rpm the weight of the chain was significant and favoured the simple chain . At 10 000 rpm the story changed . BMW developed the engine to be optimum at 8000 rpm rather than ask it to slew harder one could say ( jerks in drive train ) . I love optimum design . How very brave of BMW not to follow the advertising objectives . I must admit when I saw that chain I was horrified , I was wrong !
Let me add a very personal note to the discussion.
If we for a moment disregard output power, I believe there have been and there are quite well designed units out there, from various sources. I have and still believe that absolute sound quality is not directly related to power output in any way, even if more power may well be beneficial.
This is because I have heard quite a number of times and under very different circumstances several amps which were low powered, yet managed to sound just as good, often better and - lo and behold! - BIGGER than many of their commercial counterparts. Not to enlarge too much, this is my personal sound quality list dating back to the 1975-1983 period, ALL of which still hold their ground today:
1. Otala-Lohstroh 25W/8 Ohm amp as per the 1973 IEEE publication;
2. Jean Hiraga 25W/8 Ohm amp, as published in France's SON magaizine, and
3. Naim Integrated amp from 1983, 2x30W/8 Ohm.
My HK 6550 (2x50/70W into 8/4 Ohms) is still an enigma I am struggling with, six months down the road. I hear it, but still have problems believing that a simple volume pot change can cause any amp to hop at least two classes, and probably three, classes up sound quality wise. It's a phenomenon I have never encountered before. Most devices do show an improvement, to be sure, but nowhere near this little guy, usually simply modest. This kind of improvement I have never witnessed before. A shock to the system.
Because of all this, I believe that given my objectively small room and my relatively effcient speakers (92 dB/2.83V/1m), a 100W/8 Ohm amp should be more than sufficient for my purposes. I realize that those with just 3 dB less effcient speakers would need double that power, and if they have larger rooms, even more.
I do not deny the virtues of available power, I simply question the universal approach many people have, whereby more power automatically means better sound. As a matter of fact, I believe the relative opposite is true - the more power you have, the harder it becomes to get it just right at both high and low power levels, most vommercial products do best at around half the nominal power, but lack finesse at both low and high ends of their operating range.
This is backed up by my experience of hearing nominally higher power amps almost collapse when pushed hard ito a real world speaker, or when played at the usual low level room volumes. This applies to strictly commercial units, although I have been severly let down by some nominally High End products as well, from respected names.
As opposed to many others, I do not blame the designers' prowess, but the economy of the business. If those engineers were given more design liberty, I feel relatively certain we'd have a lot more good amps to choose from, and at prices not much higher than they already are. TVRGEEK and I would be much happier, I believe.
In some ways, the audio industry is the victim of its own advertising clout. Some things were adcertised to death and to the point where it was implicitly suggested that if you don't use ultra fast output devices, that's really no sound, just noise. Yet, some very highly respected manufacturers (e.g. Boothroyd-Stuart Meridian) still use what Nige called "medium speed" devices (notably the Motorola/ON Semi MJxxxxx series of 250W, TO-3, series), which on paper do not compare too well with more modern, faster devices, but in real life still manage to sound superb even if they do get to only 4, 5 or 6 MHz.
In many cases, sounding actually better than the ultra fast Sanken RET devices. Imparting that priceless feeling of unlimited power I have yet to hear from a Sanken based amp (I'm sure there are some around, I just haven't heard them). Krell uses MJ4281/4302 devices, which, as far as I can see, are TO-3 packaged MJL 3281/1302, with another added 50 Watts of power capability per device. 2x5 pairs per channel for nominally 250W/8 Ohms in balanced mode. And boy oh boy, do they sound good, or what!
But that's the true High End. In commercial products, plastic packs are THE norm, nice and cheap, easily available off-the-shelf if need be. Look over the transistor tables and you'll see that the sheer available choice of them in the 60-100W class is nothing less than stunning. Everybody and their dog have them, with a choice, too.
Now try to find TO-92 platic packaged NPN FETs, and better yet, PNP FETs. Almost zilch, nada, the prime manufacturer Toshiba has all but eliminated them, starting with dual FETs. Only very few remain, and they are a bitch to get hold of.
All of which, in my mind, boils down to show - make it LOOK like it can do a lot, but in reality, the sound quality has not progressed much over the last 20 years or so. In fact, I believe it has even regressed somewhat.
If we for a moment disregard output power, I believe there have been and there are quite well designed units out there, from various sources. I have and still believe that absolute sound quality is not directly related to power output in any way, even if more power may well be beneficial.
This is because I have heard quite a number of times and under very different circumstances several amps which were low powered, yet managed to sound just as good, often better and - lo and behold! - BIGGER than many of their commercial counterparts. Not to enlarge too much, this is my personal sound quality list dating back to the 1975-1983 period, ALL of which still hold their ground today:
1. Otala-Lohstroh 25W/8 Ohm amp as per the 1973 IEEE publication;
2. Jean Hiraga 25W/8 Ohm amp, as published in France's SON magaizine, and
3. Naim Integrated amp from 1983, 2x30W/8 Ohm.
My HK 6550 (2x50/70W into 8/4 Ohms) is still an enigma I am struggling with, six months down the road. I hear it, but still have problems believing that a simple volume pot change can cause any amp to hop at least two classes, and probably three, classes up sound quality wise. It's a phenomenon I have never encountered before. Most devices do show an improvement, to be sure, but nowhere near this little guy, usually simply modest. This kind of improvement I have never witnessed before. A shock to the system.
Because of all this, I believe that given my objectively small room and my relatively effcient speakers (92 dB/2.83V/1m), a 100W/8 Ohm amp should be more than sufficient for my purposes. I realize that those with just 3 dB less effcient speakers would need double that power, and if they have larger rooms, even more.
I do not deny the virtues of available power, I simply question the universal approach many people have, whereby more power automatically means better sound. As a matter of fact, I believe the relative opposite is true - the more power you have, the harder it becomes to get it just right at both high and low power levels, most vommercial products do best at around half the nominal power, but lack finesse at both low and high ends of their operating range.
This is backed up by my experience of hearing nominally higher power amps almost collapse when pushed hard ito a real world speaker, or when played at the usual low level room volumes. This applies to strictly commercial units, although I have been severly let down by some nominally High End products as well, from respected names.
As opposed to many others, I do not blame the designers' prowess, but the economy of the business. If those engineers were given more design liberty, I feel relatively certain we'd have a lot more good amps to choose from, and at prices not much higher than they already are. TVRGEEK and I would be much happier, I believe.
In some ways, the audio industry is the victim of its own advertising clout. Some things were adcertised to death and to the point where it was implicitly suggested that if you don't use ultra fast output devices, that's really no sound, just noise. Yet, some very highly respected manufacturers (e.g. Boothroyd-Stuart Meridian) still use what Nige called "medium speed" devices (notably the Motorola/ON Semi MJxxxxx series of 250W, TO-3, series), which on paper do not compare too well with more modern, faster devices, but in real life still manage to sound superb even if they do get to only 4, 5 or 6 MHz.
In many cases, sounding actually better than the ultra fast Sanken RET devices. Imparting that priceless feeling of unlimited power I have yet to hear from a Sanken based amp (I'm sure there are some around, I just haven't heard them). Krell uses MJ4281/4302 devices, which, as far as I can see, are TO-3 packaged MJL 3281/1302, with another added 50 Watts of power capability per device. 2x5 pairs per channel for nominally 250W/8 Ohms in balanced mode. And boy oh boy, do they sound good, or what!
But that's the true High End. In commercial products, plastic packs are THE norm, nice and cheap, easily available off-the-shelf if need be. Look over the transistor tables and you'll see that the sheer available choice of them in the 60-100W class is nothing less than stunning. Everybody and their dog have them, with a choice, too.
Now try to find TO-92 platic packaged NPN FETs, and better yet, PNP FETs. Almost zilch, nada, the prime manufacturer Toshiba has all but eliminated them, starting with dual FETs. Only very few remain, and they are a bitch to get hold of.
All of which, in my mind, boils down to show - make it LOOK like it can do a lot, but in reality, the sound quality has not progressed much over the last 20 years or so. In fact, I believe it has even regressed somewhat.
Just to echo dvv's comments: well sorted out 20W amp into 90dB sensitivity gives one all the sound volume, and quality, that one could want in a conventional living area.
And, yes, shortfalls in engineering application are the reason why this, and nominally much more powerful setups typically don't do the job ...
Frank
And, yes, shortfalls in engineering application are the reason why this, and nominally much more powerful setups typically don't do the job ...
Frank
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