I'm sure it gives perfectly accurate reproduction of this.
Mozart - Horn Concerto No. 4 in Eb major - Rondo, Allegro - YouTube
Mozart - Horn Concerto No. 4 in Eb major - Rondo, Allegro - YouTube
I know that piece I just referred to by heart, just about -- it's on my one of my primary test CD's -- and "explains" why I go to the efforts I do. On YouTube, via PC monitors, it sounds pretty bloody awful - a quaint, historical document of a type of music that was played once, scratchy, poor tone, just experiencing an acoustic "cartoon" ...
Well, I want a bit more than that, and get it too: on a good system it turns into a full blown, full blooded musical soundscape; all the instruments sound like they're being played by real people, the voices sound like they're coming from flesh and blood, there's a real sense of space, and all that old-fashionedness, curiousity shoppe "cuteness" subjectively disappears ...
Frank
Well, I want a bit more than that, and get it too: on a good system it turns into a full blown, full blooded musical soundscape; all the instruments sound like they're being played by real people, the voices sound like they're coming from flesh and blood, there's a real sense of space, and all that old-fashionedness, curiousity shoppe "cuteness" subjectively disappears ...
Frank
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Exactly what I also asked Nige a month or so ago. After a point, reworking anything becomes tedious, expensive and low yield work which is simply not worth it.
If you want more, then it's better and more efficient that you start from scratch and do it the way you think it should be done.
Hello Mr Wave , nice to have you back .
DF 96 . Agreed about messing about with 0 V reference points on amplifiers . I was thinking strictly the connection between the PSU capacitors . I can not remember an amplifier where at least to the eye it didn't look a no brainer to beef up the connection if a PCB . Reading Douglas Self on this I thought it had all been simplified . Tried what he suggested and got nowhere . It should be said I wasn't getting bad results anyway . It just didn't go anywhere applying strict rules . I concluded that the amount of copper matters most . I also found that returning the output Zobel to the star point often was worse ! Doubtless a bit of extra effort would have solved that ? Intriguing that for no obvious reason instability crept in ( the return wire was in free air and I did bend the wire to reduce inductance etc ) . Previously it was returned via amplifier ground by a less substantial wire ( tried it all ways if wondering ) . It was bad enough to kill a tweeter at one point !
I wonder sometimes when people say they heard a big difference going from lets say 2 x 10 000 uF to 2 x 68 000 uF would it be they reduced ripple in the 0 V reference ? That ripple not obvious if lets say 30 mA standing current ? My brother always said he could hear hum modulation with the Quad Valve amps . His point being Quad used common mode rejection of a valve op-amp arrangement to reject noise . He though it audibly obvious when approaching clipping . Drums lost tightness . He went on to say valve amps are low power and have acceptable distortion right up to clipping . Thus one gets perhaps 6 dB more usable power . That is fine if the bass is tight . Other than that he thought it an inspired design , not least it rejected the cheap all electrolytic PSU . A Siemens cinema amp was like that . Highly regulated supply to the drivers ( EF 41 x 2 ? ) . Very raw DC to the EL34's at 820 V ( 240 V ) !! I loved that amp especially with over driven National EL34's , its owner uses Siemens which are fine . 100 W @ 10% distortion , 9 dB feedback , 500 mV input sensitivity . 10 W 1.3% 1W 0.2 % . Thus up to 8W it was DIN 45500 . It would have no real distortion for speech . For explosions I can only imagine it was excellent when getting near clipping . The only defect was obviously low damping factor and that paper veil to the sound ( Pentode sound I feel ) . The transformer had a section which would drive 8 R . Probably to do exactly what I did , a bench test .
Dvv . Absolutely . I build most stuff Dead Bug style . Usually that works fine . The tricky bit is transferring it to PCB . A bit of Dead Bug plus PCB works . In the UK we have Silver DIP for cleaning cutlery . I have a hunch it would clean wires . I would wash them in detergent and then water afterwards . My Son has just qualified in forensic chemistry ( no job yet , it would help if he looked ? It adds to the diploma in Computer Science . I told him he can stay at college until 40 , his mother thought I was joking . It makes me feel better saying it , The course in electronics he almost past was cancelled because the tutor couldn't live on the salary ! We never once talked electronics I am relieved to say , he didn't need to . He plays classical guitar so why not music next ? Some degree in music would not go unnoticed by his dad ) . Not a vast leap to tackle this question Chris . He is obsessed with silver for medical uses .
DF 96 . Agreed about messing about with 0 V reference points on amplifiers . I was thinking strictly the connection between the PSU capacitors . I can not remember an amplifier where at least to the eye it didn't look a no brainer to beef up the connection if a PCB . Reading Douglas Self on this I thought it had all been simplified . Tried what he suggested and got nowhere . It should be said I wasn't getting bad results anyway . It just didn't go anywhere applying strict rules . I concluded that the amount of copper matters most . I also found that returning the output Zobel to the star point often was worse ! Doubtless a bit of extra effort would have solved that ? Intriguing that for no obvious reason instability crept in ( the return wire was in free air and I did bend the wire to reduce inductance etc ) . Previously it was returned via amplifier ground by a less substantial wire ( tried it all ways if wondering ) . It was bad enough to kill a tweeter at one point !
I wonder sometimes when people say they heard a big difference going from lets say 2 x 10 000 uF to 2 x 68 000 uF would it be they reduced ripple in the 0 V reference ? That ripple not obvious if lets say 30 mA standing current ? My brother always said he could hear hum modulation with the Quad Valve amps . His point being Quad used common mode rejection of a valve op-amp arrangement to reject noise . He though it audibly obvious when approaching clipping . Drums lost tightness . He went on to say valve amps are low power and have acceptable distortion right up to clipping . Thus one gets perhaps 6 dB more usable power . That is fine if the bass is tight . Other than that he thought it an inspired design , not least it rejected the cheap all electrolytic PSU . A Siemens cinema amp was like that . Highly regulated supply to the drivers ( EF 41 x 2 ? ) . Very raw DC to the EL34's at 820 V ( 240 V ) !! I loved that amp especially with over driven National EL34's , its owner uses Siemens which are fine . 100 W @ 10% distortion , 9 dB feedback , 500 mV input sensitivity . 10 W 1.3% 1W 0.2 % . Thus up to 8W it was DIN 45500 . It would have no real distortion for speech . For explosions I can only imagine it was excellent when getting near clipping . The only defect was obviously low damping factor and that paper veil to the sound ( Pentode sound I feel ) . The transformer had a section which would drive 8 R . Probably to do exactly what I did , a bench test .
Dvv . Absolutely . I build most stuff Dead Bug style . Usually that works fine . The tricky bit is transferring it to PCB . A bit of Dead Bug plus PCB works . In the UK we have Silver DIP for cleaning cutlery . I have a hunch it would clean wires . I would wash them in detergent and then water afterwards . My Son has just qualified in forensic chemistry ( no job yet , it would help if he looked ? It adds to the diploma in Computer Science . I told him he can stay at college until 40 , his mother thought I was joking . It makes me feel better saying it , The course in electronics he almost past was cancelled because the tutor couldn't live on the salary ! We never once talked electronics I am relieved to say , he didn't need to . He plays classical guitar so why not music next ? Some degree in music would not go unnoticed by his dad ) . Not a vast leap to tackle this question Chris . He is obsessed with silver for medical uses .
You have just illustrated the point for me. Tinkering is as likely to make something worse as to improve it, unless the tinkerer is smarter than the original designer and has taken the time to fully understand the original design.nigel pearson said:
You need to think about what the purpose of the output Zobel is. Is it to tame the source impedance of the amplifier, or to tame the speaker/cable load impedance? If the latter (as I believe) then it should be across the speaker connection. Understand the design before trying to change it!
I'll drink to that.
Sometimes, it takes me weeks to even understand the original design schematic. Fiddling around without understanding it is more likely to cause trouble than to improve anything.
That's is sort of where I got to DF 96 . I have seen it dogmatically stated otherwise . I repeated the experiment many times since and felt it to be an exception to the rule I found . As I terminate the speakers at the star point if my own design your answer works well with observation . I didn't accept the evidence of one thing to be the law for the other occasions . Intuitively if the star point doesn't work it should . It must be slightly more ideal or at least neutral . This was an amp with horrible hum problems amp I was looking at ( if sensitive speakers it would be obvious ) . I laid out the PSU differently as it was a dog's breakfast . It stayed the same . The preamp and amp had cascaded LM317's . Obviously an attempt at something . The transformer had two brass alignment capacitive nuts in the epoxy . I discovered that rotating the transformer affected a cure . Obviously the designer had spotted all of this . The best null was turning the transformer on end . Alas space didn't permit that . I drilled new fixing holes . I was then left with a choice . Minimum hum or nicest sound ? Nicest sound came when the hum was a little higher but less scope harmonics ( pointy bits ) . Neither was bad either way and perhaps 20 dB better than before ? It is very hard to say if my new PSU layout was better , it certainly looked neat . The amplifier sounded much better . Again the muddle that noise created was gone . I suspect the design had been set years before and new technicians just didn't check these things , not least where the transformers were made ? I got rid of 1 x LM317 and 1 x LM337 also . I replaced that with a cheap RCL filter . The R acting also as a fuse . The L was iron cored as that is all I had handy . As the LM317/337 had done most of the work I see no reason for the iron core to matter ? Certainly sounded great ( noticeably so with the choke , 22 000 uH as it insisted on saying ) . Iron cores used without the LM317 seem to ring on the scope . I did have slightly better RF hiss with the choke so kept it .
As for tinkering . I had to as it was that or the dustbin . I looked in my files for the graphs . Unfortunately this one time I didn't keep any , they were good reading .
As for tinkering . I had to as it was that or the dustbin . I looked in my files for the graphs . Unfortunately this one time I didn't keep any , they were good reading .
Sorry for the non sequitur. While not fully applicable, the following has some interesting sections on sound quality measurements.
http://cdn.rohde-schwarz.com/dl_downloads/dl_application/application_notes/1ma202/1MA202_1e.pdf
http://cdn.rohde-schwarz.com/dl_downloads/dl_application/application_notes/1ma202/1MA202_1e.pdf
Unless I am being very dense gootee they don't exactly sell the product . I wish they would give an example of experimental use and data . Maybe they did and I lost the will to live whilst trawling through it ?
I feel I need Richard Feynman to make it accessible. I just watched how badly NASA treated him over the Challenger disaster . Like something they picked up on their shoes and worse , a Rookie . If the film is to be believed he was led up a blind ally and was grilled just as anyone here is . Here we can take it with a pinch of salt , their it was trust and truth .
Tinkering . For 23 years it was my life and I did it even when I didn't want to . It was required . I guess I only tinkered with something unrequested about 10 times in my life . Much of what is made is work in progress . Whilst repairing something the extra effort to make it work properly is nearly nothing . A famous make of amplifier had one design which maybe went to market unfinished ? A track carrying the feedback was too long and convoluted . Disconnecting the track and using a piece of 2.5 sq mm cable cured that . The customer had very accurately described the fault just before failure . It was not obvious and required certain things to happen to set it off . I seam to remember it had a marked effect on measurements . I didn't have a spectrum analyzer then , a Ferrograph test set . The tinkering was requested . Having done work like that for 23 years I can tell you design errors are the norm . I gave up that work in 1997 , I still do a bit for friends . I would bet 90% of products sold in shops can be dramatically improved by the careful use of a little commonsense engineering . As I said today I can not see how reinforcing the 0 V between PSU caps can do any harm . I can not see any circumstances where even if marginal it wouldn't be an improvement . The word impossible comes to mind . OK mistakes can be made . Some are born geniuses , others learn . If I don't know something is wrong my oscilloscope always does .
I feel I need Richard Feynman to make it accessible. I just watched how badly NASA treated him over the Challenger disaster . Like something they picked up on their shoes and worse , a Rookie . If the film is to be believed he was led up a blind ally and was grilled just as anyone here is . Here we can take it with a pinch of salt , their it was trust and truth .
Tinkering . For 23 years it was my life and I did it even when I didn't want to . It was required . I guess I only tinkered with something unrequested about 10 times in my life . Much of what is made is work in progress . Whilst repairing something the extra effort to make it work properly is nearly nothing . A famous make of amplifier had one design which maybe went to market unfinished ? A track carrying the feedback was too long and convoluted . Disconnecting the track and using a piece of 2.5 sq mm cable cured that . The customer had very accurately described the fault just before failure . It was not obvious and required certain things to happen to set it off . I seam to remember it had a marked effect on measurements . I didn't have a spectrum analyzer then , a Ferrograph test set . The tinkering was requested . Having done work like that for 23 years I can tell you design errors are the norm . I gave up that work in 1997 , I still do a bit for friends . I would bet 90% of products sold in shops can be dramatically improved by the careful use of a little commonsense engineering . As I said today I can not see how reinforcing the 0 V between PSU caps can do any harm . I can not see any circumstances where even if marginal it wouldn't be an improvement . The word impossible comes to mind . OK mistakes can be made . Some are born geniuses , others learn . If I don't know something is wrong my oscilloscope always does .
Most of my life was sorting out amplifiers and tape decks . Life was like a Vet , seldom just one thing ( Doctors only do humans ) . Usually phone the company , fax a circuit , ask where to start . Example Rotel . Nige pull out the outputs , usually the drivers have survived . Give it a test . Replace what's wrong . Reset Bias . 30 minutes and job done . Other designs were less happy . A vague idea and how a certain area was always in doubt . My feeling is rushed to market and usually Japanese . From memory all designs I modified did work better . I felt it important to get them reliable . Trio Kenwood and Rotel were the best . Naim Audio the very best . Armstrong seemed to have a good 3 years then pop . That is not the usual pattern . Pop seems to be any time if a weak design . Armstrong was perhaps just capacitors . I say perhaps as I still don't really know . They just seemed to let go . My brother designed a new set of transistors to replace the obsolete types . These seem better . Not really apparent why as the originals were superbly specked and even have cog heat-sinks . When I say a new set he really went to town checking how they would perform .
My brother tinkered with TV's . He made every 1950 , 60 , 70's TV's he saw often enough reliable . The old people locally knew this . He wrote in TV magazine sometimes . His favourite TV's were ITT . Mostly the reliability was down to very small things . He was ambivalent about Sony , it was neither good nor bad . He was very good at audio engineering although not his passion . He saw it all in TV's .
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If it was April 1st I would have doubts . My fist thoughts were the laser doesn't cover the whole surface so how come we get the real deal Graphene ? But what would I know ? I dare say we might get something useful ?
Graphite oxide + water + laser = breakthrough. - YouTube
Graphite oxide + water + laser = breakthrough. - YouTube
I heard something about this when sitting in on a basic electronics class (I'll be teaching one in a few weeks). The teacher was trying to explain capacitors, and the student was asking about this, trying to tell the news story about how a graphene capacitor could replace a battery. It makes sense (especially after the video) now (I think).
On the other hand, a large bank of such capacitors could make for a near-perfect (and in very efficient) load-leveling storage device - charge it up during daylight and/or high wind with solar cells and wind generators, and discharge it into the grid at night when people are cooking dinner, watching TV, doing laundry and fast-charging their electric cars (or pulling 100+ amps from their 200 amp service to charge their car in an hour or two).
I can see it now, and I recall mentioning this before in a previous discussion on (theoretical) fast-charge electric cars. Every electric filling station will need to be an electric substation because of the huge amount of power needed for fast charging. A residential KWH meter would fly apart from spinning so fast.
On the other hand, a large bank of such capacitors could make for a near-perfect (and in very efficient) load-leveling storage device - charge it up during daylight and/or high wind with solar cells and wind generators, and discharge it into the grid at night when people are cooking dinner, watching TV, doing laundry and fast-charging their electric cars (or pulling 100+ amps from their 200 amp service to charge their car in an hour or two).
Feynman has a wonderful discussion of what really happens when we charge a capacitor, I think in his epic Lectures on Physics (with Leighton and Sands). It is not as simple as it is often suggested.
Not to throw a wrench into the machine, but as I have been led to believe, charging batteries involves a compromise. Charging them slowly takes more time but prolongs their service life, and charging them fast takes less time but also shortens their useful service life.
Other than that, I see many very useful benefits of going all electric. One could use a single motor, two motors and four motors, having a smaller motor drive each wheel separately. A natural four wheel drive, so to speak, with much less power loss than today, due to much more complex mechanics involved.
In some ways, an electric motor is the ultimate motor. No exhaust, no dangerous fuel involved, and it develepos maximum torque from rev No.1, i.e. its torque cruve is in fact a straight line.
The only thing I know I will miss is the sound of a healthy engine at 8,000 rpm and the growl of a decent V8. Heavenly!
Other than that, I see many very useful benefits of going all electric. One could use a single motor, two motors and four motors, having a smaller motor drive each wheel separately. A natural four wheel drive, so to speak, with much less power loss than today, due to much more complex mechanics involved.
In some ways, an electric motor is the ultimate motor. No exhaust, no dangerous fuel involved, and it develepos maximum torque from rev No.1, i.e. its torque cruve is in fact a straight line.
The only thing I know I will miss is the sound of a healthy engine at 8,000 rpm and the growl of a decent V8. Heavenly!
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