The problem with "know-how". - Page 8 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 27th June 2013, 12:42 AM   #71
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Fourier representations of music, and superposition? (so sinusoidal analysis is applicable?)

Last edited by gootee; 27th June 2013 at 12:45 AM.
  Reply With Quote
Old 27th June 2013, 10:25 AM   #72
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
I might respond to post 70 if I could understand it.

I don't recall saying anything about "rectangular signals" from a generator, or distortion figures with lots of 0's after the decimal point. Perhaps the OP has the same trouble understanding me as I have understanding him?

If we have yet another Fourier denier then it is not worth responding. I get bored talking to YAFDs on here.
  Reply With Quote
Old 27th June 2013, 10:45 AM   #73
diyAudio Member
 
Join Date: Mar 2007
Location: Oxfordshire
I don't much care if people swear as long as it isn't bullets aimed at me . Sometimes even that is OK . I do like courtesy and kindness . How can someone be all of those things and meet my criteria ? Well you can . The searing is the exception and is when ridiculously provoked . An understandable surprise in an impeccable human .

My mother would judge that person badly and would suggest if a friendship continued he or she change their ways .

This is how hi fi is . I have a 5 watts rule . Up to 5 watts proper hi fi ( DIN at worse ) . After that my amplifier can swear if it wants to . By then I feel like that also .

One of my amplifiers even at 150 watts has never said a bad word . It sounds about the same as the one that swears . Problem is the one that swears a bit also makes me cry with joy at times . Not because it is distorted , because it reminds me of when I was at a concert .

Sergey I get your extra dimension thing . Just don't know how to do the maths . To me it is how music causes it's own pre distortion which should matter . In a strange way SE tube amps are symmetrical . It is so difficult one either succeeds or fails . It is almost binary . My " priestly " amplifier is transistor and has twin VAS . It's symmetry is not a given quality . However it is symmetrical in the same way as the BMW motorcycle engine . The clock seldom stops running . The BMW has it's own problems and so does twin VAS ( secondary effects ) .

My main speakers are rather wonderful . They are big panels with very low distortion . If someone turns the bass up they stop being wonderful .The bass is almost better than real life becasue the microphone goes where I can't . Great for films and much better than the cinema . I doubt I could ever use them with a valve amplifier . Ones that would work are not as good as a transistor amp to my ears . That's where the priest comes in .

I will build the A2 211 amp . I have about a 20 % expectation it can work . The other took 500 hours , the A2 perhaps 2000 ? What I wont do is throw money at it . I will try by whatever means I don't know cathode feedback via the output in the style of PYE Mozart ( perhaps a winding is required like Quad ) . Perhaps the worst idea I ever had and if I had a grain of intelligence I wouldn't even say it . The idea is to drive my panels . I suspect a damping factor of 16 will do . I will have distortion in mind I can live with . It isn't euphonic . If it is , so is music . Zero distortion amps are euphonic if so . Any other distortion is horrible or fatiguing . The most common defect is a metallic quality ( 5 th + 7th ? ) . Guitar which you know to be acoustic might be a sampler as an example . The amplifier makes it difficult to say . Remember the sampler tries hard to be a guitar so we are not talking big effects . A CD player tries to be music in the same way .

My old Quad 303 is an excellent amplifier . I suspect it slightly converts music to MP3 as it's only defect ( notes fade into noise , they stop slightly before they get there , almost sounds better like that , very gentle ). Against the " best " amps in the world I expect it to win most of the time . Most people who owned one never had the speakers to know how good it is in battle . A gentleman and a solider !!! It won't put a Meyer to shame . Sonically it will shame plenty . If you look carefully on the analyzer it is a near zero distortion amp . You have to get it working to book spec before you do that . Then look again . The distortion that remains is Hiraga type . So - 80 dB ( 5 watt ) and fading . The criticisms made in the PDF I support . 99% of the time I don't listen that loud . Buy two and internally bridge them ? I think it should work . Bridge for current rather than voltage . Maybe use a fast transistor in the PSU . I can still get BDY 56 . Keep the output cap , it is a great protection device . On speakers that have real bass the cap is not a problem . I run a smaller cap to the tweeters . 99% of speakers do not have real bass , they double .

Quad Spot: Measuring distortion with software
  Reply With Quote
Old 27th June 2013, 11:20 AM   #74
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Quote:
Originally Posted by nigel pearson
In a strange way SE tube amps are symmetrical
A very strange way indeed: using the word 'symmetrical' in a sense which doesn't involve symmetry.
  Reply With Quote
Old 27th June 2013, 11:29 AM   #75
diyAudio Member
 
Join Date: Mar 2007
Location: Oxfordshire
Quote:
Originally Posted by DF96 View Post
A very strange way indeed: using the word 'symmetrical' in a sense which doesn't involve symmetry.
I agree and I know what I mean . There is a very small place where the signal seems reasonably symmetrical . A triangle wave is good to see it . Maybe it is what Sergey is saying ? As I said I do not have the maths for it . Bad hi fi is 2 D . Especially so on Quad ESL 63's . You see , what you hear from them has to happen in the chain . They are not the ones doing it . They can be so poor if wrongly feed .

It is binary. The trick is to get the amp to do it with typical valves . I got it in the end to do it with KT 88 and EL 34 to the point where it was almost identical . The big surprise was retesting the valves . The KT 88's were very different make to make . It might not be exactly symmetry . It is the sweet spot where the magic happens . It almost impossible to find . First thing is stop reading . It causes the correct answer to be lost . As Feynman says " First you have to define the problem " . If you use too many standard ideas what you will do is reinvent the wheel .

BTW the BH curve of the transformer comes into it . Far too long to discuss and I would need PHD help . Take it as the defect is in fact a nice thing . Like DC bias . Hate what it does to the bass . I said it before you had to . If there is a PHD in listening my daughter has it . She is Aspergers and was tested as an experiment in Oxford ( hearing of people like her ) . She has drastically better hearing than most . I supplied some of the test gear years ago . They use Hamsters rather than Mice because Hamsters are most like us in hearing . I source verified KEF T27's to do the work . The tests have to go above 40 kHz to be thought valid .

Last edited by nigel pearson; 27th June 2013 at 11:46 AM.
  Reply With Quote
Old 27th June 2013, 01:45 PM   #76
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Quote:
It is the sweet spot where the magic happens . It almost impossible to find . First thing is stop reading . It causes the correct answer to be lost .
Not too hot, not too cold, but just the right amount of 2nd for audio warmth. As this depends on the valve details and bias it is not surprising that it is different for each sample. I now understand what you mean by 'symmetrical': you mean just the right amount (for your ears) of asymmetry. Opposite meaning from that used by the rest of English speakers, but hey!

Stopping reading is more likely to cause the correct question to be lost.
  Reply With Quote
Old 27th June 2013, 06:26 PM   #77
diyAudio Member
 
Join Date: Mar 2007
Location: Oxfordshire
I was rather sad that my friend John intends to build a Mullard circuit with the bits I gave him . He beamed and said he always wanted to . John has test gear probably above Audio Precision in ability to measure ? It won't be as easy to uses for audio work as that's not it's prime function . My guess is he can look at the sub - 140 dB range . He builds installments for measuring minute magnetic field variation .

Hey Ho . His face said it all . That's what he wants to do .

I will suggest injecting some 100 kHz to see if we can make the linearity improve . It is a push pull . Then take it out as in class D . It might work .

Reading too many books = Mullard . The statement " a poor thing but mine own " that I hold to be important .
  Reply With Quote
Old 27th June 2013, 07:34 PM   #78
diyAudio Member
 
Join Date: Mar 2007
Location: Oxfordshire
DF 96 . Asymmetry almost symmetrical . Is all done by cheating I know . I did find the tripple cheat a bit special . That is both pre-distortion and loop feedabck + UL . With my transfomer 9.5 dB loop seemed splendid . 16.5 db was about the limit .

The point that seems most important is to get the valve centered with respect to bias . Then if two valves there are so many variations , more than that I dread to think . I did use transistor current sources and sinks until the end just to know how good it can be . I probably lost >6db of distortion reduction by not using them . My friend probably would have not listened to them if I had included them .

One thing I did find is running one valve about 80% above normal voltage was splendid . I read in it's notes the limiting voltage and used it . Reading carefully it was not clear it would be OK so I went to a more standard 320 V . Shame because it worked well . At home I would use it as it never gave trouble .
  Reply With Quote
Old 28th June 2013, 04:42 AM   #79
diyAudio Member
 
Join Date: Jan 2012
Location: Moskow
All this is very good and it is close for me. But truth search always leads to revising of customary concepts. With a support on the already known.

Last edited by Sergey A; 28th June 2013 at 05:00 AM. Reason: Summ
  Reply With Quote
Old 28th June 2013, 10:17 AM   #80
diyAudio Member
 
Join Date: Mar 2007
Location: Oxfordshire
The crazy example of this was Galileo . I think the Church of Rome held Aristotle to be part of the Bible ? That saves about 10 hours of typing . The C of R believed that the heavens were perfect and Earth was corrupt because Aristotle said it . The Moon was less perfect because the " bad " Earth was corroding the Moon . Seems reasonably correct to me so far . When Galileo showed that the Moon had mountains like Earth he was in trouble . It made all the C of R was saying a lie to many . So sad for he who they represented to cause that . Take he as a philosopher if you prefer .

Galileo took the invention of two children which he improved . Venice had the best glass makers in the world . That gave him an advantage . His big crime was he was arrogant and disliked . I never met him so I am only saying what is remembered by others , the children in Holland ( ? ) also .

The point is a very simple idea can change everything . Also bringing in the respected scientists or philosophers sometimes takes us away from the truth . I love philosophy , I seldom regard it as the truth . I think Descartes said " I think , therefore I am " , to which I say " if I don't think , therefore I would not be " .

The truth usually is simple . When complexity arrives usually it is wrong . Chaos maths is useful as it defines things we can not easily know and why it happened . We can always design so as not to have the problem . When in an aircraft I am sure of that . Our Prime Minister announced an upgrading of the power of our Weather prediction computer . Give me strength . How many billion pounds for one extra day ? I can tell him for 1 000 000 what he ( we ) need to know for eternity . Compared with Northern Spain it will be rubbish . That area is said to have an ideal climate . It might continue to have it regardless if I am right . Buy your house 100 metres above sea level and have room to grow things . Have big dogs that are " usually " friendly and be happy .
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
The ubiquitous 1/2"...um....3/4"...er 1" ?? polycarbonate "dome" tweeter River757 Multi-Way 16 8th July 2013 01:45 AM
3-way with big (10") woofer and monitor (6.5"+1") on top like "Tarkus" proxii Multi-Way 16 30th October 2012 01:43 PM
What makes an amplifier "bright", "warm", or "neutral"? JohnS Solid State 51 13th December 2009 07:42 PM
"lift off " or "Houston we have a problem" tenderland Tubes / Valves 16 1st May 2005 06:08 PM
Need help with IC Based Amplifier "pop" problem (Integrated Component) Monolith Solid State 7 13th March 2003 04:01 PM


New To Site? Need Help?

All times are GMT. The time now is 03:20 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2