Propriety :conformity to conventionally accepted standards of behaviour or morals.
Guess that does seem like the right word for the context.
Duly Corrected....
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Dan.
Usually I am the one who is the grammar Nazi....thank you for drawing that to my attention
.Dan.
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My point is to to get the system out of the way and allow the performance good or bad to shine through...same old, same old....
Dan.
There are indirect effects as well.... amplifier power and distortion increased and heating and excessive speaker excursion. Unless the amp input is rolled off in the bass to remove all the artifacts of timing, wow, flutter... it creates distortion in the amplifying stages and speaker which can be high/audible. A High-Pass filter which does not add audible group-delay at the low end is another added issue. Geeez, I am glad I dont have a masochistic LP system any more.
THx-RNMarsh
Scott, that is an interesting theme you raise. Is speaker distortion different from electronic distortion? And does it matter?
Were I stand on this is that what comes out of the audio chain is the only thing that is relevant, in the end. It stands to reason that the ear is the final arbiter, and that therefore a microphone is the appropriate instrument to measure performance.
With acoustic measurements, it is impossible to tell what the origin is of a particular distortion, and therefore loudspeaker distortion and electronic distortion must be of equal importance.
Over the years, I noticed that the VAS bias current typically amounts to 2-3 times the input stage bias current. Now, sompe people like keeping their cool and running their IP stage at low bias currents, others like to run 'em hot and are not squeamish about IP stage bias.
I am one of those. I like the sound og higher bias IP stages, it usually sounds more open and detailed to me than a low bias version of the same, and the same goes for the VAS. I've seen them bwung un with ahything from 5-35 mA, depending on type of connection and other factors, but the one thing that seems to be same all of the time that it's the higher bias VAS which manages somthing very dear to me, that wonderful feeling of efortlessness when driving a power amp, as if it really deesn't care for all this petty nonsense I am feeding it with. In short, I like running my amps "hot". And I do not complain about th additional heat sinks I will need, to me, that's the cost of doing it. But over the years, I seem to have stabilized a about 20-25 mA for the VAS, and since by default I'll use 2SC3503/2SA1381, worst case dissipation will never reach 2W, something the Data Sheet say it should be able to do, maxing out at around 5W, if memory serves.
A far bigger problem is finding at which bias current per device losing crossover products? Again, it depends in what type of output stage I'm using, and can be anything from 50 to 150 mA per device.
How does this agree - or not - with your experience?
I am one of those. I like the sound og higher bias IP stages, it usually sounds more open and detailed to me than a low bias version of the same, and the same goes for the VAS. I've seen them bwung un with ahything from 5-35 mA, depending on type of connection and other factors, but the one thing that seems to be same all of the time that it's the higher bias VAS which manages somthing very dear to me, that wonderful feeling of efortlessness when driving a power amp, as if it really deesn't care for all this petty nonsense I am feeding it with. In short, I like running my amps "hot". And I do not complain about th additional heat sinks I will need, to me, that's the cost of doing it. But over the years, I seem to have stabilized a about 20-25 mA for the VAS, and since by default I'll use 2SC3503/2SA1381, worst case dissipation will never reach 2W, something the Data Sheet say it should be able to do, maxing out at around 5W, if memory serves.
A far bigger problem is finding at which bias current per device losing crossover products? Again, it depends in what type of output stage I'm using, and can be anything from 50 to 150 mA per device.
How does this agree - or not - with your experience?
Rischard, in your experience, where would you put the -3 dB rolloff pointat the amp input?
DVV, I generally agree with you on this: I run both the input stage and the VAS stage at the highest current allowable. I want an 'effortless' drive stage. Higher operating current gives lower open loop distortion, higher F(t), and the ability to deal with nonlinear capacitance that is always present with solid state devices. etc.
I thought the very low sidebands was Jocko's complaint. This is what I was talking about, 10 sec of 1kHz test tone which is 100Hz per division. The rotational harmonics are easily visible within the sidebands which are substantial.
Attachments
I can do better - how's this for jitter
Measured on a actual turntable that's regarded as 'a great one'.
Jan
Mine is off of a local crowd-funded product U-Turn Audio the one Fremmer gave a very positive review to. +.19% off speed out of the box better than my old (deceased now) VPI, this thing sounds way better than it deserves to. The VPI got dropped on its head and the disassembled tonearm has been a thorn in my side, one of those nagging projects. My dog mercifully relieved me of it by knocking the little plate of tiny set screws and miniature bearings into the carpet.
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People can quibble about turntable speed accuracy, BUT what do you expect from a $179 turntable? Gee, I did not know they came so cheap!
I use a Linn LP12 with a few upgrades. I have used this same model turntable since 1974. It is a pretty good turntable, even today, BUT it is not perfect.
Recently, within the last 2 weeks, I did some serious listening at an audiphile's house where he had a $100,000 turntable. It WAS better than my LP12, sonically, but is it worth $100,000 to me? No, not really.
Many turntables are designed with flaws, both fixable and non-fixable. Autos have the same problem. The latest challenge that I have heard of, is German-Swiss turntables, that were wonderful in the past, being disappointing for a number of reasons today. One of my techs is on such a quest for a decent turntable, BUT he is more critical of turntable problems than even I am, and he had to settle for something costing like $1500, and he has to wait for delivery. People appear to use the 'formula' for making a great mechanical device, when demand drops to almost nothing for years, and it doesn't necessarily come back right away. Customer and measured feedback is mandatory to get improvements.
I use a Linn LP12 with a few upgrades. I have used this same model turntable since 1974. It is a pretty good turntable, even today, BUT it is not perfect.
Recently, within the last 2 weeks, I did some serious listening at an audiphile's house where he had a $100,000 turntable. It WAS better than my LP12, sonically, but is it worth $100,000 to me? No, not really.
Many turntables are designed with flaws, both fixable and non-fixable. Autos have the same problem. The latest challenge that I have heard of, is German-Swiss turntables, that were wonderful in the past, being disappointing for a number of reasons today. One of my techs is on such a quest for a decent turntable, BUT he is more critical of turntable problems than even I am, and he had to settle for something costing like $1500, and he has to wait for delivery. People appear to use the 'formula' for making a great mechanical device, when demand drops to almost nothing for years, and it doesn't necessarily come back right away. Customer and measured feedback is mandatory to get improvements.
I hear you! About a year ago, I noticed something was going in very, VERY low, and it wasn't good. I looked up and saw my bass driver trying to break out, a really powerful subsonic, I'd say around 15 Hz or so. It came from the radio station, switchig to any other station made id disappear. Ever since then, I switched on the Subsonic filter on the Luxman C-03, - 3dB at 15 Hz, 6 dB/oct. And lo and dehold, that mean subsonic was gone.
I looked over some sites and noticed that quite a few tuners are actually specified 10-15,000 Hz, a few as low as 5 Hz.
Point is, you can "import" problems from outside your system without even realizing it.
Exactly! I don't push it to dangerous levels, but hey, what's the problem of running a JFET with a voltage drop of 3.5V across it at 5 mA? As much as his predecessor, although its predecessor does have two cascode BJTs sitting on top of it.
The attainable Ft is a relative gain. For example, if I push a 2SC3503 trannie at say 15 mA, moving that on up to 20, then 25 mA will bring little gain in Ft, as shown in its Data Sheet, its THD will not drop significantly, but it will sound better in the end, even if I can't measure it, or it comes back to me as a very small benefit.
At some point, you start fighting for the little bits here and there, thinking that every little bit counts in the big picture.
Another such small thing is adding local PSU capacitators, in my case rated at 2200uF, right next, almost on top of, each power device. Sure, that's costlier, but it's supremely flexible when planning out the general outlay, they are compact enough not to need too much space and with good planning, they need very little real estate. AND they add their fair share of overall energy storage, but they sit about half en inch for their respective drivers.
John, much as you, as an engineer and probabky a perfectionist, might balk from this, but EVERYTHING works on basis of the law of diminishig returns. A say 1% improvement over your Linn might cost say $100, but the next 1% will cost more than $100. It rockets upwards at lightning speed. And becomes unreasonable very soon (the price, I mean).
WE mention this here more often as a necessary compromise, while in fact, 99% of the time it's really a cost compromise. I'm sure you could outdo yourself right now, just like that, and you'd be left with an oustanding product with an even more outstanding price, in a shrinking market, where the majority only cares about the price. Far too few care about the quality, and many of them simply don't have the moola for a stratospherically priced TT.
I last had that dilemma in 1977. I purchased my Dual 604 because it played music say 5% worse than the next model, 704, which cost TWICE the money. I will blaspheme now and say that I just wasn't up to giving twice the not insignificant money for what I always saw as an inherently flawed medium. I was lucky when my cartridge DIDN'T produce 1% of IM.
My graphs are from a $ 3990 Kuzma turntable/arm combo.
But that's not the point. The point is that, like many others, I really enjoy playing my (again slowly growing) record collection. And, after so many decades in audio, I can easily hear the wow and flutter if I concentrate on it. But I only seldom do that, most times just enjoying the music.
So what does that tell me about the listening experience? Again, it points to a remarkable capability of my perception apparatus that it can just ignore what it is not interested in.
That wow and flutter is there of course, and it gets transmitted through the ear, via the auditory nerves into the brain. But it does not reach my consciousness, does not become part of that fraction of all sensory input that makes it to the forefront at any one time.
Not that this is anything new of course, but it's always nice to realize it once in a while lest you become to complacent about that fascinating organ you carry between your ears!
Jan
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