A different tack,
This thread has obviously drawn the interest of people well worth talking to, and while the OP seems to have found what he wants to go after, there's something left wanting. In short, frankly, I think he's settled for the wrong prize. . . or one more limited than necessary so early in the game anyway.
There's nobody here who doesn't admit that in the end, the final judge is the listener, and thus it follows (to me at any rate) that the only way to judge the relative merits of different competently designed topologies is to hear them.
So , wouldn't a more openly profitable approach to the task of discovering what is best be to ask something like "Is it possible (for a guy on a budget) to design and build a sort of universal phono stage power supply of very high quality that will enable him easily (in a plug and play sort of way) to try a number of different circuit types for evaluation, with an important consideration for the design being that no circuit's failure to measure up sonically should be attributable to the power supply itself ?
Too tall an order?
This thread has obviously drawn the interest of people well worth talking to, and while the OP seems to have found what he wants to go after, there's something left wanting. In short, frankly, I think he's settled for the wrong prize. . . or one more limited than necessary so early in the game anyway.
There's nobody here who doesn't admit that in the end, the final judge is the listener, and thus it follows (to me at any rate) that the only way to judge the relative merits of different competently designed topologies is to hear them.
So , wouldn't a more openly profitable approach to the task of discovering what is best be to ask something like "Is it possible (for a guy on a budget) to design and build a sort of universal phono stage power supply of very high quality that will enable him easily (in a plug and play sort of way) to try a number of different circuit types for evaluation, with an important consideration for the design being that no circuit's failure to measure up sonically should be attributable to the power supply itself ?
Too tall an order?
hum/noise in a phono stage i think is still the biggest challenge for any builder...
i like your suggestion about power supply, makes perfect sense to me, i am in the process of building one....
and the two module approach is what i am looking at..
IMO, yes. An engineered design is a system, and if you change one thing, it's doubtful that everything else will be optimal. For example, if signal circuit A runs best at 250V, has a PSR of 60dB, and draws 50mA, the optimum supply is unlikely to work well for signal circuit B which runs best at 400V, has a PSR of near-zero, and draws 5 mA.
@Tony- it is not a test structure that I would emulate.
You are free to continue considerations for choosing 1st tube for a phono stage.
You are free to ask and/or share your knowledge.
Is it a technical observation, or a personal one?
If it is technical, on what is it based?
It may be a game to you, it isn't a game to me.
Indeed, though one can rely, to a degree, on the listening impressions of others, which seem to have similar taste and preferences concerning the sound of a reproduction system.
When one considers building an amp and asks for opinions, or suggestions – and there are different conflicting opinions and suggestions – one need to choose between those conflicting opinions and suggestions.
One may make ones' choice based on ones' own experience with similar gear, in addition to leaning towards the opinions and suggestions of those who seem to have similar approach to audio gear.
Is it a question concerning what you are interested in, or are you trying to coerce me asking a question which I don't want to ask at this point?
Or maybe you try to suggest, in a roundabout way, that my decisions making process is flawed?
Should you ask me directly why I didn't take such a course, I'd reply you.
Right now I only see criticism from your part, while I'm not sure what this criticism is about.
Firstly .... gee, what a 'rapidly posted' thread; don't you guys work anymore - are you all retired affluent??
So Joshua, apology for going back somewhat. Also the several questions I have have me at a disadvantage, not only because of all the dignatories posting here, but they will all be somewhat off-topic. Still, also having modestly being round the block a few times (though not nearly always first at the winning line) ....
You have used the above statement several times - and I must grant that for you; you did say it was personal, so I can have no quibble with that at all ...
but I am under the impression that there is enough research out there to have given one a fair model of human hearing, thus using the right measurements, I can carefully say that I can come close to what things should sound like eventually.
Problem for designers like me: For whose taste do I design? I cannot listen to a phono stage alone; how do I eliminate all the subsequent effects? I do seem to 'get it right' by looking at measurements alone (again all of the right measurements). So far all of my designs have been accepted - unless I am so singularly gifted that I just happened to get it right every time before listening (in which case I think Oslo, Norway, must have slipped up somewhere with my Nobel Prize ....)
Well, you know your business, SY, and I feel out of my league going to bat against you, but a poster's gotta do what a poster's gotta do.
Wouldn't it be reasonable for the duration of the search period to permit some inefficiency?
What about an engineered design that can come under the heading of bench supply but specifically suited to powering phono stages - maybe with a higher power shunt regulator on the output . Let's take your given voltage and current maximums of 400VDC and 50mA. That's 20 watts acoss the reg with no load. Relatively easy once that is built to lower voltage or current, add branches etc. as needed, no?
I am not sure I have followed here (again apology for only coming here now). The other harmonics do not increase because one has been reduced .... again that is also not what you say, but at such a low level I don't follow how remaining harmonics can have more of an influence on what one hears just because one is lowered. Do we have to do here with the misguided notion (Hiraga I think) that it is OK as long as the harmonic ratio is a certain one? I have always taken it that high order harmonics are bad news (full stop) regardless of the percentage of 'benign' ones (talking of low level all the time ....).
Then your fear of NFB viz-a-viz a cathode follower. Not quoting now, but one cannot take the (ill) effect of NFB as proportional to its percentage. Trying to be brief: I know about the 'multiplication' of harmonic distortion as a result of too much NFB, but that is not as simple as just a cathode follower with a loop gain of say 26 dB - unless there is something stressfully wrong with its operating point. I have simulated poor designs that exhibited this effect with only 20dB of global NFFB, but then I have checked a 'clean (open loop)' amplifier with NFB where the 11th harmonic only started 'looping back' at >34dB of NFB, and the lower ones much later. So it depends very much on the rest of the design, and I will be most surprised if this phenomenon shows with any half-decent cathode follower.
Finally: You are a remarkable man; strong convictions, now and then a wee bit off, yet eager to learn and most patient (to be blunt). My respects for that, and this thread which you are supporting! I wish you every success with your undertaking!
I said it was personal in order to skip long, arduous debates.
What is the basis for that impression of yours?
Do you have an example of set of measurements that is in full correlation with listening impressions? Are those listening impressions relate to a single person, or to many people?
You are the only one who can possibly answer that question.
No one can.
What subsequent effects?
I'm glad you attained it. I'm not as lucky as you are. Perhaps after you'll share the set of measurements you use, I'll share your luck.
What are all those right measurements?
I'm glad for you.
BTW, by whom your designs were accepted?
Again, I'm glad for you.
Possibly it is so.
Now, let me ask you few questions.
I assume that in order to measure an amp, you have first to build it. Am I correct here?
I assume that before you start building an ump, you decide about its' architecture. Am I correct here?
If the answer to the above is "yes", upon what do you decide about the basic architecture? Or do you have but one design?
Is it a question, a statement, or what?
If it is question, try to phrase it in a more coherent way.
What is your point? Are you in favor of cathode followers?
If yes, go ahead and build ones. I promise not to criticize you for doing so.
It looks like you take the technical discussions here personally.
Possibly it may be more useful to you to stick to a more scientific, objective approach.
I wish you whatever you wish me.
Again no desire to perpetuate off-topic, but to answer some questions at least:
As said, results of and reports on a multitude of listening tests as performed over decades by many research centres. Much of this research can be found on internet; I do not have ready quotes for you now - sorry - but recently I looked up some again for an article, and quickly came to >100 references.
Again, as said. In total all the tests must have used hundreds of listeners, some trained, some musicians, some laymen, done at dozens of research institutions the world over over decades. These can be found under 'Hearing Psychology' et al, a number of publicised reports in the AES Journal etc. It is a vast field; one has to select those which apply to what one wants. Research was about hearing per se which I studied, not the small field of hi-fi reproduction alone. At best one finds an average listener; experiments also indicated the great variation in personal perceptions, placebo effects and such.
The rest of the equipment, room effects..... Even if these were the same (sic), there is (poor) hearing memory. It is well documented how difficult it is to repeat results particularly where the differences are small. You mentioned yourself that a friend was satisfied one day, not so the next.
Much of what was quoted here. (Certainly not only frequency response and t.h.d.!) Spectrum analyses, phase effects (regions of rapid changes in..), noise and its spectrum, worst-case parameters .... When all of that is right, I am not sure what else can compromise an acceptable result. We are talking of a phono stage/pre-amp, not a 500W multi-stage power amplifier.
Thanks! And accepted by the client - but you have read my real yardsticks above.
By this time on experience. No, I do not have only one design, but then also not that many - in how many different ways can one make a phono stage? And why would one start from square 1 every time? As said one simulates on the way there and finally measures - and yes, one listens, of course! But I never had to alter anything after and as result of a listening test (where would I start?). Once or twice when I demonstrated an amplifier, that was the first time I also heard it. It is also known that many erstwhile designers e.g. Williamson, Leak, Peter Walker (Quad), etc. only heard their products after having finalised the design - and in those days testing equipment was not nearly as sophisticted as these days.
But not to 'thread-jack' further. I do emphasize that if for whatever reason anybody prefers something, that is his right as it is his money, regardless of whether snake oil plays a role.
Thanks for your attention! (Back to topic.)
As said, results of and reports on a multitude of listening tests as performed over decades by many research centres. Much of this research can be found on internet; I do not have ready quotes for you now - sorry - but recently I looked up some again for an article, and quickly came to >100 references.
Again, as said. In total all the tests must have used hundreds of listeners, some trained, some musicians, some laymen, done at dozens of research institutions the world over over decades. These can be found under 'Hearing Psychology' et al, a number of publicised reports in the AES Journal etc. It is a vast field; one has to select those which apply to what one wants. Research was about hearing per se which I studied, not the small field of hi-fi reproduction alone. At best one finds an average listener; experiments also indicated the great variation in personal perceptions, placebo effects and such.
The rest of the equipment, room effects..... Even if these were the same (sic), there is (poor) hearing memory. It is well documented how difficult it is to repeat results particularly where the differences are small. You mentioned yourself that a friend was satisfied one day, not so the next.
Much of what was quoted here. (Certainly not only frequency response and t.h.d.!) Spectrum analyses, phase effects (regions of rapid changes in..), noise and its spectrum, worst-case parameters .... When all of that is right, I am not sure what else can compromise an acceptable result. We are talking of a phono stage/pre-amp, not a 500W multi-stage power amplifier.
Thanks! And accepted by the client - but you have read my real yardsticks above.
By this time on experience. No, I do not have only one design, but then also not that many - in how many different ways can one make a phono stage? And why would one start from square 1 every time? As said one simulates on the way there and finally measures - and yes, one listens, of course! But I never had to alter anything after and as result of a listening test (where would I start?). Once or twice when I demonstrated an amplifier, that was the first time I also heard it. It is also known that many erstwhile designers e.g. Williamson, Leak, Peter Walker (Quad), etc. only heard their products after having finalised the design - and in those days testing equipment was not nearly as sophisticted as these days.
But not to 'thread-jack' further. I do emphasize that if for whatever reason anybody prefers something, that is his right as it is his money, regardless of whether snake oil plays a role.
Thanks for your attention! (Back to topic.)
Hi Joshua,
I use a curve tracer from Hagerman to test and to match my tubes, but that does not come cheaply.
A simple tube Tester like the TV-7 can be used to check the tubes for basic health. Then use the actual circuit for testing mu and matching the tubes. That is the cheapest and simplest way.
Or build a little test rig for the tubes you want to test, a simple gain stage with cathode and plate load resistor. Then apply a signal to the input from the signal generator and measure the output with a scope. This way you will get the exact amplification figure.
Best regards
Thomas
I use a curve tracer from Hagerman to test and to match my tubes, but that does not come cheaply.
A simple tube Tester like the TV-7 can be used to check the tubes for basic health. Then use the actual circuit for testing mu and matching the tubes. That is the cheapest and simplest way.
Or build a little test rig for the tubes you want to test, a simple gain stage with cathode and plate load resistor. Then apply a signal to the input from the signal generator and measure the output with a scope. This way you will get the exact amplification figure.
Best regards
Thomas
Hi!
This is one way to approach it. Joshua chose such a way by looking at choices for the 1st tube.
But there are other ways too. You can first decide upon a circuit architecture and then look for parts (tubes) which full fill the requirements set by that architecture.
Best regards
Thomas
This is one way to approach it. Joshua chose such a way by looking at choices for the 1st tube.
But there are other ways too. You can first decide upon a circuit architecture and then look for parts (tubes) which full fill the requirements set by that architecture.
Best regards
Thomas
I was on the ETF several times, nice festival but also a myfi festival.
I never heard a really good demonstration there, because of the lack of good speakers (and, partly, good listening rooms).
I never heard a really good demonstration there, because of the lack of good speakers (and, partly, good listening rooms).
The rebuilt Quads from Arendt-Jan I heard there 3 or 4 years ago were stunning. The fancy horn systems... meh.
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