I, for one, eagerly anticipate your report!
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DIY Purifi Amp builds
- Thread starter JimB
- Start date
If you mean stored energy in the thermal mass of the room, then no.
- foam insulation has an extremely low thermal mass - that's the point, it's a good insulator not a good energy store; the insulation is behind a thin sheet of plasterboard; the whole construction provides insignificant heat storage
- even if there were a high thermal mass, then with a lossy room the temperature will still drop, it will not be sustained
No. Its the balance between the heat input and the heat losses through the house structure and via air leaks.
I didn't want this conversation. You have chosen to extend it.
Your argument about the power of the boiler is irrelevant. On that basis an amplifier that puts out 200W cannot possibly control in the mW range; and single-ended class D amps can't possibly work because they work by switching hard against the supply rail.
Please, stop ranting, stop insulting, stop assuming your intellectual superiority above mine and try listening and thinking. You have exploded and extended this topic by predetermining that it cannot possibly happen rather than listening and understanding that it does happen and how it can happen. Each time you have come up with an argument about it cannot possibly be, ignoring energy balances, the control systems involved, and the reality of highly thermally efficient buildings.
To repeat, the combination of high levels of insulation with an effective control loop will sustain temperature by only outputting a few watts on average.
It does not matter if the boiler is putting out kW (I hope it is - the target temperature for the heating water is 75C - and this is what gives the system its transient response and ability to respond to a step change). The heating system is not consuming kW. The boiler is not the heating system, it is the power supply.
What matters is how the control system makes use of and releases that energy. The heating/control system does not control to Watts, it controls to temperature; each radiator controls to its own temperature. Each radiator controls to a 0.5C (that's not its accuracy, that's its control resolution.) When the room cools down it tops up the temperature by 0.5C. (The radiator valves are actually each an independent linear control system, so they never control by hard-on/hard-off; their internal control system is operating to a finer resolution, and they don't overshoot) It consumes only as much energy as it needs at that time to make this temperature rise at the radiator, and turns off again until more energy is needed.
The whole heating system is analogous to a class D amp. The boiler may switch hard between on and off (it doesn't by the way, modern boilers adjust their output crudely in proportion to the demand), but once the time constants in the system and the negative feedback of the control system has its effect, the overall control system is very fine.
Doing a finger-in-the air calculation with my lounge radiators, the maximum power output of the radiator is 750W - it is unlikely to be outputting this power level but let's use it for calculations. It comes on for, say 15mins then winds itself back down again. depending on the eternal temperature and the energy losses from the room it stays off for an hour. Overall consumption is therefore 1/5 x 750W = 150W. In reality the output is less.
Again. All heat sources heat your room; every watt has an effect, and it is the cumulative effect of all small energy sources that add together - how much of an effect that has and how significant it is, is dependent on the specifics of your room. In the calculation above 15W is significant, so too is the cumulative effect of all the LED bulbs. Especially significant is the 100W I generate.
Your calculations are about creating a step change and are not relevant to maintaining an energy balance.
Conservation of energy and energy balances always apply whatever the step response or mass or lag of the system.
The Passivhaus standard is 10W/m2 of floor area, based on the day with the highest heat output required - ie middle of winter.
So in the middle of winter, your 20m2 room above requires only 200W. In the UK, middle of winter would probably be considered to be -3/-5C.
At other times it requires less power.
As I've said, my living room isn't to passivhaus standards but is very highly insulated. There is no wind outside - that can have a dramatic effect on the rate of heat loss. It's currently 6C outside. At dusk 4-1/2 hours ago it was 11C. It has been 21C in the lounge until an hour ago and dropped to 20.5 where it has stayed. The radiators have not produced any heat this evening - the setpoint is 19.5 and so the heating will not have been asked for any heat.
It is the balance between the heat losses and the heat being put into the room - those cumulative few 10s of watts - which is sustaining the temperature.
Chris please leave this alone. You are simply wrong. As I showed above the heat increase from 15 watts in a room is so low and so slow (an important point you are missing - a watt is 1 joule per second) your central heating control system wouldn't even register it, let alone have the granularity and accuracy of control to adjust for it. It will under and overshoot by significant (in this context) amounts.
I would take apart the rest of your post above, there are so many errors in it, but doing so followed by your inevitable protestations, would only continue to disturb the thread. I will simply let you huddle around your 5 watt light bulb room heater mid winter freezing your nuts off
I would take apart the rest of your post above, there are so many errors in it, but doing so followed by your inevitable protestations, would only continue to disturb the thread. I will simply let you huddle around your 5 watt light bulb room heater mid winter freezing your nuts off
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The problem is, that it won't be worth anything if it's not level match at least, and double blind preferably. Without controls all you will have is the result of a level change or cognitive biases.
A 0.1dB level change will not be heard as a change in level, but it will be heard as a change in "detail" and "transparency" etc. Take away the level difference and the differences disappear. What really WOULD be interesting is to do the test well controlled and see what differences there are in the sound.
Now let's leave testing methodology to another thread.
The so called level match will be done this way, and for the following reasons. First the CD will have approx one hour of recorded music on it, of which we will actually listen to around 30 minuets with any request of another song on the CD which will then be included in the list. The different songs are not level matched and to do so would negate the whole exercise as it changes the songs that are recorded. The first song will be at a level that is at comfortable and normal listening levels. Without changing the volume level I will use a Radio shack meter to establish the relative level by a recorded 1khz signal and pink noise. As the different configurations have different gains the above procedure will at least establish a relative base line with the first song. All of the songs are very familiar to both my self and my wife, and the following songs will be adjusted to a normal listening level. I understand that this is not ideal, but I also feel it is as close to the way we normally listen to music. After the first CD, a second CD which has four songs level matched as above and will not change for the four songs as they are fairly close in relative level. The four songs will be used to finalize our preferences with comments as to each system, and why. I pretty much know the preferences as for myself as I spend a lot of time playing around and listening, so in one sense this to get my wife's opinion on the different configurations. No this is not perfect, and our preferences may or may not be valid for any one else, but then it is our toys and primarily for our benefit. My wife has very good hearing and i trust her judgment. We both are familiar with live, and recorded music. So please take the results for what they are our opinion.
JimM
JimM
The different songs dont need to be level matched, just when you change from one amp to the other. Dont change the volume for different songs as you will negate the level match.
Sorry can't do that, that is not the way we would normally listen to the music.
JimM
JimM
Then the results are meaningless, for all of the reasons explained before.
OP
- Thread Starter
- #729
Yes, UNLESS, they can use the same volume setting (precisely, such as digitally stepped) for each track. This depends on what volume controls @JimM has, but I don't think this is reasonably achievable with his gear (I also have some of those items). I'll suggest finding a volume setting that will work for the entire session (the range of selections). Then measure the test tone level, at the speaker terminals. This is what will be used, there after to setup a session. Once a session starts, no changing the volume. Right?
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True, if you can tweak the pre amp up and down by known steps.
noise
Member
For builders in the USA, where are you buying the Purify EVAL1 and Hypex PSU?
Yes it is. Even if the residual heat from an idling amp contributes to heating your house it is still very ineffecient heat. If you were to heat your home exclusively from the residual heat from amplifiers – you would probably need hundreds of them – then your electricity bill would be astronomical.
The Mark Levison does have stepped volume control with read out, the Benchmark does not. As I have stated I am not asking any of you to agree or disagree with our findings as it will be our opinion only. After spending 30 minuets with six sets of different system components the only thing you can establish is a general feel for your preference for each set anyway. As I stated the second CD which only has 4 songs will be level matched and the level will not change during the set, and this will be to finalize any preference one way or the other. Sorry this is the best we can do. Due to the coronavirus shut in it will only be just the two of us. Although I don't know any one else that would be willing to spend up to 3 to 3.5 hours playing around with this stuff anyway. Plus there is the seating, as there is only one sweet spot that will be delegated to the wife. As I stated this is more of a exercise to get wife's comments. I have pretty much made up my mind having spent hours with the PuriFi and ML components. Also the biggest problem component is the room, which is optimized for the 1.7, although most dynamic speakers work well with the room also. The speaker placement is as optimum as is practical as the room is also used for TV and movie watching, and will not be changed for the test. They are approx. 3 feet from back wall with sufficient side wall distance and placed on either side of the equipment and wall mounted TV, set up with tape measure to within 1/4 in. The 1.7 can and does have better spatial imaging further from the back wall but that is not the way we normally have them set up.
Thank you for your input.
JimM
Thank you for your input.
JimM
Shorter JimM: "Don't bother me with science and controls and stuff, we're playing Make Believe!"
OP
- Thread Starter
- #735
Well, once you have some impressions/conclusions, weigh them against the uncertainties of the test as performed. I'll be interested to hear your results after that (with your qualifiers). As you say, all the other factors are more significant than just the amps, hence the efforts to keep them constant in a direct comparison (room, seating position, etc.). Did you blow your nose? I'll just state that the single largest comparison variable for me is inner ear pressure - whether it is equalized or not. Huge. Really.
I don't even know what you mean by that remark, Technical expert of what? Why don't you or any one else who has a problem with this invest your own time and equipment for a test you feel is adequate for meaningful results. I have several times explained my goals and test procedure within the limits of my current equipment and capabilities and the reason why. I have not asked you or any one else to value my preference of any results from this exercise. One thing I do no, it is easy to criticize when you set back and do nothing. What my wife or I determine is our preference, as I commented it is our toys so we will determine which one of any we prefer. If that is playing make believe so be it. I am currently at the point to abandon commenting on any results we have or the whole project. I already have a opinion as to the different systems, but would like my wife's opinion to see how it correlates with mine. And I can do this with a lot less effort than currently planned. In fact this whole forum which started out as very helpful has informative has degenerated into a negative argumentative discussion about trivial stuff and ones opinion or preference over some else.
JimM
JimM
Why make other people's life so difficult...
Subjective impression is allowed in this forum, as long as it is not pretend to be objective and accurate.
Amir does subjective review in his speaker test and it doesn't always align with the (incomplete) objective measurement.
Subjective impression is allowed in this forum, as long as it is not pretend to be objective and accurate.
Amir does subjective review in his speaker test and it doesn't always align with the (incomplete) objective measurement.
If there's no basic controls, and you've been clear that you don't want to implement them, then the "preference" will likely have nothing to do with the sound. Yet the belief that it does will persist. That's why you're playing Make-Believe.
If you're going to bother doing an experiment, do proper controls. Level matching between amplifiers, double blind comparison. Else, it's a waste of keystrokes.
HALLELUJAH! I have sometimes dared say that the objective measurements are by definition of science incomplete, and I have been blasted. A lost of people claimed - literally - "Amir's measurement are for products X and Y both excellent, THEREFORE A and Y sound indistinguishable". This is weak science (as I have pointed out, and therefore I was claimed to be ignorant – which I am, but it also proved that those pointing t my ignorance were ignorant as well...).
Jim, the scientific evidence is very clear on this. Without controls you wont be concluding your sound quality preference. Your conclusions will be inaccurate and faulty. So your experiment has little value to anyone else, but more importantly to you.
This forum is about science. The points raised about your proposed experiment aren't trivial, they are fundamental to its success and accuracy. With respect, your reaction there just comes across as you just don't like, or want to accept the scientific message you are hearing.
That's not the fault of the forum.
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