Abomination! or Painting a Mustache on the Mona Lisa meets the Island of Dr. Moreau - Page 22 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 14th April 2009, 02:20 AM   #211
Account disabled at member's request
 
Join Date: May 2006
Just found my handdrawn schematic of the inputstage, I wrote down the model, its the L550, I ll try find full schematics on the net.
  Reply With Quote
Old 14th April 2009, 03:30 AM   #212
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
Quote:
Originally posted by homemodder
its the L550,

Thanks homemodder,
I found it but it the whole amp schematic. Some ideas for me here.

I cut this part out:
Attached Images
File Type: png 117.png (61.8 KB, 495 views)
  Reply With Quote
Old 14th April 2009, 08:28 AM   #213
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
If only you had the schematics of the 550-II series.
Attached Images
File Type: jpg l550-ii.jpg (54.0 KB, 470 views)
__________________
The buck stops Here
  Reply With Quote
Old 14th April 2009, 09:02 AM   #214
Account disabled at member's request
 
Join Date: May 2006
Jacco, that amp looks good, what is it about the 550 II series, what changes were made ?? I like these Luxman amps, they are very well designed, never listened to one but there are many people critisizing them and I find this unbelieveable. I have just finished prototyping and modifying a design based on a elite series Pioneer from 1988, another hell of a good amp, with just 24 transistors I easily get full power THD20 figures of quite a bit less than 0.001 200w and here we are 20 years later coming up with incredible complex designs to achieve the same. To me it sounds excellent, every bit as good as electrocompaniet. I dont understand the reason these japanese amps are said to sound bad, only if its a parts thing and then we are not talking of the transistors used. Ive come to highly respect some of these japanese designs.

MJL21193, yep thats the one. Ill make a clone of it on ltspice and see what it can do.
  Reply With Quote
Old 17th April 2009, 11:28 PM   #215
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
I continue to play...
Attached Images
File Type: png 117.png (41.3 KB, 371 views)
  Reply With Quote
Old 18th April 2009, 12:46 AM   #216
Banned
 
Join Date: Apr 2005
Location: Stockholm
John,
R2 and R32 could be shifted to active sources.
  Reply With Quote
Old 18th April 2009, 01:52 AM   #217
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
Hi Lumba,
Not sure what you mean - R2 limits current from VAS bases to D2, D3. R32 is a output emitter resistor - you must have meant R39 which likewise limits current.

New schematic (again). Looking better?
Attached Images
File Type: png 117.png (56.8 KB, 326 views)
  Reply With Quote
Old 18th April 2009, 03:09 AM   #218
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
And again. Change in the compensation scheme:
Attached Images
File Type: png 117.png (45.3 KB, 311 views)
  Reply With Quote
Old 18th April 2009, 03:12 AM   #219
Banned
 
Join Date: Apr 2005
Location: Stockholm
John,
maybe we can clear this up. Firstly, R2 is a current source (should have high impedance, positioned on the collector side), providing current for D1 and D6, which form a voltage reference (should have low impedance, positioned on the emitter side). An active current source has much higher dynamic impedance than a resistor.
D2 and D3 are not needed.
  Reply With Quote
Old 18th April 2009, 03:40 AM   #220
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
Thanks Lumba,
I can be thick-headed

Like this? Also, I ditched the other compensation scheme.
Attached Images
File Type: png 117.png (46.1 KB, 331 views)
  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
Old meets new but can this be solved? barchetta Pass Labs 4 11th March 2007 08:29 PM
Old Meets New philipbarrett Tubes / Valves 3 22nd August 2005 01:03 AM


New To Site? Need Help?

All times are GMT. The time now is 04:01 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