My "audiophile" LM3886 approach - Page 412 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 December 2012, 01:20 PM   #4111
diyAudio Member
 
Join Date: Sep 2007
Send a message via Yahoo to linuxguru
Quote:
Originally Posted by bcmbob View Post
Siva, did you ever find a LM3886 spice model that you can trust?
Bob - nope, the official model released by TI earlier this year turned out to be badly broken. They then released an updated TINA model, but it's encrypted, so there's no easy way to convert it to SPICE, and in any event, it's not clear that the TINA model fixes problems that were found in the earlier SPICE model.
  Reply With Quote
Old 27th December 2012, 01:22 PM   #4112
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Sorry to hear that. Puts a real crimp on trying to model an entire amp. Would it be possible to insert some values for a virtual device into a program like PADS, Eagle or something similar.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."

Last edited by bcmbob; 27th December 2012 at 01:28 PM.
  Reply With Quote
Old 27th December 2012, 06:26 PM   #4113
Reality first!
diyAudio Member
 
ClaveFremen's Avatar
 
Join Date: May 2005
Location: Milan, Italy
Quote:
Originally Posted by AndrewT View Post
Where is the science to support this preposterous conclusion?
In reality... maybe

If you would have considered that, as Siva noted (thanks, Siva ), the LM318 is a suface mounted part it would have been perfectly clear that there's no much difference.

For your convenience I've added a 1206 C7 to compare lenght, it's less than 1mm...

That is a 0.183735nH more (calculated using this calculator).

Let's assume the total lenght of the left trace is 5.5mm (1.242368nH), the difference is less than 15%.

Click the image to open in full size.

Quote:
Originally Posted by soongsc View Post
I see your Eagle PCB layouts have nice smooth transformation from thin traces to large pads. Did you use brute force or does Eagle PCB have the feature?
Hi George,

Eagle can't do it automatically but you can draw those smooth transofrmation pretty easily with Eagle.

Quote:
Originally Posted by linuxguru View Post
Edit: The only change that I would suggest is extending the small-signal lifted-ground plane below the LM318 on the other side of the PCB, at least to shield the signal traces.
I've considered it but the plane to be used would have been the 0V (signal ground).

I've had the doubt that some coupling would have been possible so I've dropped it, just to be safer.

Click the image to open in full size.

Quote:
Originally Posted by grigore View Post
I did not followed this thread since then. Plese tel me what developments have appeared in the mean time, if there is any important upgrade over the original.
Mauro didn't made further public upgrades (there's the My_EVO -Evolution, not public).

I did a My_Ref variation which includes a completely redesigned PCB, new PS, different grounding and compensation.

You can read about it:

My_Ref Fremen Edition - need help on PCB evaluation

My_Ref Fremen Edition - Beta build/Fine tuning

My_Ref Fremen Edition RC - Build thread

IMHO it's a clear improvement
Attached Images
File Type: jpg fe2.jpg (336.7 KB, 834 views)
File Type: jpg FE.jpg (400.3 KB, 813 views)
__________________
Dario
ClaveFremen "Bailando Salsa en el Sietch"

Last edited by ClaveFremen; 27th December 2012 at 06:28 PM.
  Reply With Quote
Old 27th December 2012, 10:48 PM   #4114
diyAudio Member
 
Robert Kesh's Avatar
 
Join Date: Oct 2012
Quote:
Originally Posted by AndrewT View Post
The differences being heard by some members tells me the signal is being changed in their implementations.
Not me. You can perceive difference where there is none, as dozens of psychology experiments will demonstrate.
  Reply With Quote
Old 27th December 2012, 10:59 PM   #4115
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Quote:
Originally Posted by Robert Kesh View Post
Not me. You can perceive difference where there is none, as dozens of psychology experiments will demonstrate.
PLEASE! PLEASE - DON'T BRING THAT ARGUMENT HERE!!!!

While your viewpoint is respected, we have not been burdened by that endless and pointless circular CF and would like to keep it that way. If we are ignorant of the volumes of pertinent scientific studies - please let us wallow in that shortcoming. Too many threads have been destroyed once that controversy is introduced.

Respectfully - PLEASE!
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 27th December 2012, 11:47 PM   #4116
diyAudio Member
 
Robert Kesh's Avatar
 
Join Date: Oct 2012
Quote:
Originally Posted by bcmbob View Post
PLEASE! PLEASE - DON'T BRING THAT ARGUMENT HERE!!!!

While your viewpoint is respected, we have not been burdened by that endless and pointless circular CF and would like to keep it that way. If we are ignorant of the volumes of pertinent scientific studies - please let us wallow in that shortcoming. Too many threads have been destroyed once that controversy is introduced.

Respectfully - PLEASE!
I don't mind much if people remain ignorant. And no one has to respond. But I don't think any viewpoint, my own included, should be suppressed for the sake of not disturbing the peace.

And my claim isn't controversial, it is very easy to demonstrate.

Wait! Was your post satire?
  Reply With Quote
Old 28th December 2012, 12:13 AM   #4117
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
No Sir, My comment was serious. Please note that I used the word respect twice in my message. I am simply stating the fact I have participated in at least three threads in the last two years where the identical positions - both pro and con - dealing with whether one can give credibility to what is heard/perceived are expressed. They all have decayed into personal snipes and dogma, again pro and con, and nobody's position ever seems to budge.

It is a very interesting area to investigate (just watched another series on how the mind can trick us last night - Discovery CH.) but consumes enormous amounts of time that I believe could be put to better use. Please believe that my comments are not a personal swipe at you and/or your body of knowledge specifically. I respect and enjoy science, but attempt to keep it within a usable perspective in matters artistic. In the end the technology is there solely to support a valuable and loved form of art - Music.

My hope is simply to avoid the clutter.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."

Last edited by bcmbob; 28th December 2012 at 12:19 AM.
  Reply With Quote
Old 28th December 2012, 12:28 AM   #4118
soongsc is offline soongsc  Taiwan
diyAudio Member
 
soongsc's Avatar
 
Join Date: Mar 2005
Location: Taiwan
I agree we should just discuss the technical aspects. What people can hear and how it is described contain too many variables to talk about. We should just respect the personal capabilities of individuals.
__________________
Hear the real thing!
  Reply With Quote
Old 28th December 2012, 02:50 AM   #4119
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Quote:
Originally Posted by ClaveFremen View Post
In reality... maybe

If you would have considered that, as Siva noted (thanks, Siva ), the LM318 is a suface mounted part it would have been perfectly clear that there's no much difference.

For your convenience I've added a 1206 C7 to compare lenght, it's less than 1mm...

That is a 0.183735nH more (calculated using this calculator).

Let's assume the total lenght of the left trace is 5.5mm (1.242368nH), the difference is less than 15%.
Dario,

What numbers were you using for the trace width and trace thickness, for the inductance calculator? The inductance figures seem quite low.

Also: Is this Mauro's original PCB layout? I think you mentioned whose it was, actually. I seem to remember Mauro allowing someone to produce and sell copies of his first layout. So maybe this is that one. Please forgive me, but I am unfamiliar with what versions and "spin-off" versions of the MyRef are in existence. If this one is "frozen" for no more development, or is out-dated, then I might not want to keep bothering you and Siva about it. It might be like stumbling in through the back door of a famous ancient cathedral and excitedly engaging the nearest priest in a discussion of changes to the architecture that I thought were needed.

Can you or someone please post links to the relevant threads for each of the major MyRef versions and spin-off versions or closely-related circuits? I think that I am finally ready for another project to build.

Thanks.

Tom
  Reply With Quote
Old 28th December 2012, 02:59 AM   #4120
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Quote:
Originally Posted by soongsc View Post
I agree we should just discuss the technical aspects. What people can hear and how it is described contain too many variables to talk about.
Roger that! And I concur.

Quote:
We should just respect the personal capabilities of individuals.
Or at least we should respect the fact that they are widely variable, and agree that we don't want to try to reconcile them (or even think about them), here.
  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



New To Site? Need Help?

All times are GMT. The time now is 04:13 PM.


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