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The Opamp thread - Page 287

post #4291 of 4812
Quote:

Please give us said pointers.

 

the Sound Science forum was  created as a ghetto to keep discussion of double blind testing, the Science of controlled listening out of "regular" threads on the grounds that it turns into flame wars

 

so that is now where such discussion lives - you can search for comments on op amp rolling - or create a dedicated thread there for discussion around the topic - but with DBT, ABX, psychoacoustic Science allowed

post #4292 of 4812
Quote:
Originally Posted by zilch0md View Post

 

Hi Soun,

 

You are very smart to have asked before trying those op-amps!

 

I'm not nearly as experienced at rolling op-amps as several others on this thread, but I've never heard of any of those, so unless you receive encouragement from someone else, I would say do not plug any of those into your iBasso D12.  

 

Wait for someone to make a recommendation of what they have tried successfully...

 

Mike

 

Cheers zilch0md, the aim was definitely not to fry a new present that I wanted for years.  So yes, definitely asking before doing anything drastic.

 

Quote:
Originally Posted by Mad Max View Post

 

MC1458

LMC6482

RC4558

LM833

All are dual-channel opamps indeed.  After inserting one in the right position and orientation, turn on the amp without your headphones plugged in and check and see if the chip gets very hot.  If so, then turn the amp back off and remove it.  Don't bother with those overheating chips, although all of these should work okay since they're all slow opamps.

 

LM833's datasheet says that it is for preamplification, among other things, so perhaps you should avoid putting that chip in the buffer position just to be safe.

 

Make sure that you don't put them in backwards or you will damage the opamp and possibly the D12.  Each chip has a notch that indicates which side of the chip that pins 1 and 8 are on.  Or there will be a printed or embossed dot next to pin 1.  Judging by this photo, when you insert an opamp into the D12, pins 1 and 8 should face your left if you are looking at the front of the amp with the headphone output and volume knob.

Edit: the linked photo shows single-channel opamps in the amp, make sure that you do not insert those dual opamps in the same manner!  I think that the duals go in the middle somehow.  Another D12 user should be able to confirm.

 

Thanks Mad Max, I did come across the same photo, so all good in terms of the chip orientation for when replacing.  Just no sure about if they are suitable at all.  I did read about buffer as well as actual opamp, so the bit about being able to load opamp into buffer is new to me as well, so more reading there I guess.  And lastly was definitely keen to learn more about voltage fitting etc.  So anymore insight on these are welcome.

 

The D12 came with a rolling kit as is, i.e. a dual opamp, so it has room for fitting it in the middle.  It was a little easier to figure this one out as it's of the same time, i.e. SOIC on DIP 8 converter (did more reading! :))

 

Cheers - Soun

post #4293 of 4812

Hi jcx,

 

Quote:
Originally Posted by jcx View Post

I think a very important idea for anyone new to this thread is that the thread contents may in fact not be "valuable information" - but are rather mostly "noise" - are based on dubious "socailly constructed" ideas

 

several conceptual errors collide here - naive "just listen" "subjective evaluation" and ignorance of op amp qualification by application circuit differences, not recognizing different performance demands in preamps, DAC I/V, filters, buffers, headphone driving

 

naive "just listen" "subjective evaluation" - is the mode throughout the audiophile world - overwhelmingly represented in the press, marketing - but ignores real human limitations, known perceptual psychology - try learning some of the science

 

and there are hundreds of op amps made for the very reason that they have different mixes of noise, frequency response, gain, slew rate, output current... each op amp's mix of specs may suit different circuit applications - since nothing practical can be built with "the best" specs for every application

 

but the overwhelming majority of "recommendations" here ignore/don't mention the circuit application, or even the power supply Voltages - and even within a category of a specific audio circuit type the engineer can make differing decisions on circuit details that affect op amp choice

 

obviously the idea of op amp rolling is compelling, people like playing - but most of the posts here are technically, psychoacoustically without value - a few could be harmful to your equipment

 

note to moderators - and committed kool aid drinkers (or "committed subjectivists") - I only point this out at very infrequent intervals - thousands of posts go by between "critical" posts - and I am addressing newbies - such as have recently posted - they deserve pointers to alternative opinions, information on the scientific, engineering basis of their hobby - to decide for themselves where to spend their time, money

 

First, let me establish that I have no problem with what you said in this post, above - your mission is obviously noble.

 

Quote:
Originally Posted by zilch0md View Post

Please give us said pointers.

 

Here, I was requesting that you provide the very "pointers" for the material to which you believe a "newbie" should have access.  

Quote:
Originally Posted by jcx View Post

 

the Sound Science forum was  created as a ghetto to keep discussion of double blind testing, the Science of controlled listening out of "regular" threads on the grounds that it turns into flame wars

 

so that is now where such discussion lives - you can search for comments on op amp rolling - or create a dedicated thread there for discussion around the topic - but with DBT, ABX, psychoacoustic Science allowed

 

But here, in your most recent post, "newbies" are left wanting.  

 

I've looked for this "Sound Science" forum, but cannot find it, and frankly, going only on your description of the forum, it seems to be some kind of leper colony for outcasts whose posts incite rage among those who regularly post to threads like "The Opamp Thread."  redface.gif

 

But, I'm still curious that this "Sound Science forum" might actually provide technically and psychoacoustically valuable information for newbies, that you believe could actually be consumed by a newbie to good affect. 

 

So again, please give us said pointers.

 

Something tells me that when a newbie gets to the this place of wisdom, it will be found indigestible.  That's the problem:  Those with a deep understanding of electrical engineering are unable to accept the fact that others have no choice but to experiment, in ignorance.

 

Where should a newbie with a brain go, to escape the ignorance you've suggested is so prevalent in this thread?

 

Thanks!

 

Mike

post #4294 of 4812

http://www.head-fi.org/f/133/sound-science

 

w

 

It's simply not true that 'others have no choice but to experiment, in ignorance'. For anybody with a computer and internet access, ignorance is a choice.

post #4295 of 4812
Quote:
Originally Posted by Soun View Post

 

Cheers zilch0md, the aim was definitely not to fry a new present that I wanted for years.  So yes, definitely asking before doing anything drastic.

 

 

Thanks Mad Max, I did come across the same photo, so all good in terms of the chip orientation for when replacing.  Just no sure about if they are suitable at all.  I did read about buffer as well as actual opamp, so the bit about being able to load opamp into buffer is new to me as well, so more reading there I guess.  And lastly was definitely keen to learn more about voltage fitting etc.  So anymore insight on these are welcome.

 

The D12 came with a rolling kit as is, i.e. a dual opamp, so it has room for fitting it in the middle.  It was a little easier to figure this one out as it's of the same time, i.e. SOIC on DIP 8 converter (did more reading! :))

 

Cheers - Soun

 

Yes, they're all compatible with the D12's 10V (+/-5V) supply.  That's what part of what I meant when I said that they should work, I should have been more specific.

post #4296 of 4812

http://www.head-fi.org/f/133/sound-science

 

like any forum there a major limitations to technical content, discussions wander, newbies, wannabes drop in without reading any of the thread to add further diversions...

 

but some pointers to the literature, some on the web can be dug out of some of the threads, occasional posts by recording engineers,
EE circuit designers, science trained pros interested in audio, knowledgeable in experimental design, statistics, psychology

 

for audio amplifier circuit design I'm afraid this head-fi sub forum is rather weak, the Headwise forum died, but archived content can be searched

 

http://www.diyaudio.com/index.php is one of the best I know of - but the headphone amp diy sub forum is still a small part

post #4297 of 4812

Thank you, gentlemen!

post #4298 of 4812

jcx, 

 

So where in the Sound Science forum, are the articles that explain to newbies how to determine if an op-amp is compatible with a given device, such as Soun's D12?

 

Seriously, I could pour through that forum for days and still not learn what I need to know. Not without asking questions.  And ultimately, I would have to trust the people who answer those questions, just as I have done when reading this thread - a thread which you've implied has little value. 

 

It's very easy for people who have the knowledge to scorn those who experiment in ignorance, especially when your solution is so vague:  "Go read the sound science forum, because there's little of value to be found in this thread"  (paraphrasing).

 

What kills me is that at no point in these recent posts has anyone (including me) suggested that Soun download and start reading datasheets for the op-amps he is considering.   And no one (including me) has suggested what questions he might ask of the D12 designers, that could be of use in determining whether an op-amp is compatible.  

 

Putting myself in Soun's shoes, we've given him nothing with which he can educate himself so that he can make his own decisions.  Nothing.

 

Mad Max, on the other hand, has come to the rescue with just the kind of recommendations I had suggested Soun wait to receive.  To me, trusting the experience of others makes a lot more sense than trying to educate yourself in the absence of any resource that covers the subject matter from A to Z.   Where is this material?   If it's in the Sound Science forum, where is it precisely?

 

Until then, I think newbies would do well to ignore your concerns for the value of this thread.  

 

Update:  I want to add that I can tell your heart in is in the right place, jcx - that you're not simply being elitist - but, I'm asking you to show more empathy still for those of us who don't have the first clue how to equip ourselves with the information that allows people like you to easily discern whether an op-amp is compatible - whether it can be "plugged in" without damaging either the amp or the headphone. 

 

Thanks,

 

Mike


Edited by zilch0md - 12/23/12 at 12:02pm
post #4299 of 4812

Has anyone here read Ethan Winer's The Audio Expert: Everything You Need to Know About Audio ?  It sells for only $46.71.

 

If so, would Soun be able to discern which op-amps are compatible with his D12 having read this book?

 

 

Maybe this would be more appropriate, but it sells for $157.88:  Ray Gayakwad's Op-amps And Linear Integrated Circuits.

 

Or perhaps Frank R. Dungan's Opamps & Linear Integrated Circuits & Technicians for $240.95.

 

Here's a book with "op-amp" in the title, that's only $70.95:  Joseph Carr's Electronic Circuit Guidebook, Vol 3 OP Amps - but it's not rated as highly as the others.

 

The best reviews seem to be for Sergio Franco's Design with Operational Amplifiers and Analog Integrated Circuits - for $193.72.

 

Has anyone here read any of these?

 

Thanks,

 

Mike

post #4300 of 4812
Strangely enough Mike, I've been considering getting a decent book to expand my understanding for quite some time. A couple of those titles are on Amazon here in the UK. I'll be watching for responses to your post......

I agree 100% with your previous posts also. Hopefully something positive for those of us who want to learn will come of this.
Edited by SpudHarris - 12/23/12 at 2:11pm
post #4301 of 4812

The thing is, zilch, that just reading one of these books isn't going to hack it. In fact you probably haven't even got the precursors to understand these books (other than the Winer one).

 

Trying to take your anger out on people who have made the effort to understand the subject doesn't improve the situation, however.

 

The first clue as to how to improve the situation is to learn to use google.

 

First try reading everything Wikipedia has to say on the subject of opamps, you can find that using google. Anything you don't understand, look it up using google.

 

Next you might like to read Walt Jung on opamps:- http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch6_final_I.pdf. It's one of the best things written on the subject, and it's free.

 

Unfortunately, it takes literally years of effort to gain anything approaching a professional appreciation of the subject.

 

None of this will happen unless you make the effort, and it certainly won't happen as long as you keep trying to pass the responsibility for your lack of education onto those who happen to have one.

 

w

post #4302 of 4812

zilch0md, please don't imply that I'm reliable as my experience and knowledge on circuits is approximately zilch.

lol

post #4303 of 4812
Quote:
Originally Posted by wakibaki View Post

The thing is, zilch, that just reading one of these books isn't going to hack it. In fact you probably haven't even got the precursors to understand these books (other than the Winer one).

 

Trying to take your anger out on people who have made the effort to understand the subject doesn't improve the situation, however.

 

The first clue as to how to improve the situation is to learn to use google.

 

First try reading everything Wikipedia has to say on the subject of opamps, you can find that using google. Anything you don't understand, look it up using google.

 

Next you might like to read Walt Jung on opamps:- http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch6_final_I.pdf. It's one of the best things written on the subject, and it's free.

 

Unfortunately, it takes literally years of effort to gain anything approaching a professional appreciation of the subject.

 

None of this will happen unless you make the effort, and it certainly won't happen as long as you keep trying to pass the responsibility for your lack of education onto those who happen to have one.

 

w

 

Excellent points you've made - especially the line I've highlighted, above, as it supports my argument beautifully.  

 

Your point - that anyone can learn anything, if they put enough time and effort into it, is absolutely valid.  

 

I think it's safe for all of us to assume that when Soun asked for help, he did so with the hope of rolling op-amps sometime soon - not "after literally years of effort" to gain  "a professional appreciation of the subject."

 

So, as much as I agree with the point you're making, it does not support jcx' contention that this thread is of little value or that the Sound Science forum is of greater value.  Your point only supports his contention that one should educate oneself before rolling op-amps, rather than relying on others' recommendations - but at least you are acknowledging that this can only happen at tremendous cost - literally years of effort!  Thank you for making that clear to everyone.  

 

Given that we can't all be experts on every subject, please look the other way if you have to, while I continue to rely on the expertise, opinions, hunches, truths and falsehoods of others.  My fields of interest are far too numerous to exert "literally years of effort" to become self-sufficient with each of them.  

 

I'm OK with seeking and trusting others.  If anyone advises me incorrectly, hopefully, a lurking guru will jump in and set me straight - in this forum and every other forum I frequent.  Meanwhile, I'll continue to use Google to research those topics that can be mastered in a few days, rather than literally years.  I'll hire a neurosurgeon, if I need one.

 

Thanks,

 

Mike

 

.  

post #4304 of 4812
Quote:
Originally Posted by Mad Max View Post

zilch0md, please don't imply that I'm reliable as my experience and knowledge on circuits is approximately zilch.

lol

 

Hey, I resemble that!  biggrin.gif

post #4305 of 4812
I learn something new every day, I make mistakes regularly when I push into areas I dont know, but I always try to be prepared by doing the reading. I learned through osmosis, one day things just start to click, the Walt Jung papers are an excellent recommendation, as are the writings of the sadly recently demised Jim Williams of linear technologies, who wrote the app notes for and designed many well liked opamps and regulators. ( here is some background on the man and there is a link to his archived writings at the bottom of the page, he had a great way of injecting humor and deep insight into the technology).

I learned practically everything I know through the internet and my own application, I have no related degree, just battle-scars =) the writings of Erno Borbely are a great start into discrete design for audio and for an understanding of Jfets, Mosfets etc. my knowledge is dwarfed by those I learn from and for that I can wholeheartedly recommend DIYAUDIO as well. diyaudio has everything from basic application, some nonsense wink.gif, right through to insider industry knowledge that cannot be found in any datasheet; straight from the 'horses mouth' like in the discrete opamp open design thread currently. I still have much to learn, but these days I know where to look/start.

in short, ibasso supplies the rolling kit with the dac/amp, good chance they are all compatible with the operating conditions of the unit. the D12 probably only has a dual opamp socket which you can use singles on a dual adapter and 2 buffer sockets if its like the D10

correction it has
1 x dual opamp socket
2 x single opamp sockets
(these do the voltage amplification, they are the VAS)
1 x dual opamp socket for buffers

but you can only use dual opamps as buffers, due to only a dual socket) you could use a dual adapter here to use 2 singles, or with some effort modify one fopr using 2 x BUF634 current buffers.
Edited by qusp - 12/24/12 at 5:54am
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