Roender's FC-100 prototype and builder's thread - Page 73 - 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 8th April 2013, 05:55 PM   #721
roender is offline roender  Romania
diyAudio Member
 
roender's Avatar
 
Join Date: Sep 2006
MJE15035 looks good but MJE15034 seems to be very different from my transistors, direct samples from ON Semi. Maybe you have a fake transistor?!
  Reply With Quote
Old 8th April 2013, 06:08 PM   #722
diyAudio Member
 
Join Date: Jul 2008
Location: Lviv
Quote:
Originally Posted by roender View Post
MJE15035 looks good but MJE15034 seems to be very different from my transistors, direct samples from ON Semi. Maybe you have a fake transistor?!
I did direct samples from Onsemi, however such hfe spread of mje devices seems depends on from country of origin. Chinese devices used to have such wide hfe spread, thus low quality production.
__________________
If for pristine and pure adoration - it's diyAudio dedication!

Last edited by AndriyOL; 8th April 2013 at 06:11 PM.
  Reply With Quote
Old 8th April 2013, 06:11 PM   #723
atupi is offline atupi  Romania
diyAudio Member
 
Join Date: Oct 2010
Location: Bucharest
Hi Mihai,
i have all my MJE transistors from Onsemi directly.
__________________
Rega RP-1/Simplistic RIAA by Salas/ DCB1 clone/ MyRef Fremen Edition/FC-100/ XTZ 99.26 MkII speakers
  Reply With Quote
Old 8th April 2013, 09:35 PM   #724
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Peter,
I think you may be measuring the change in hFE as Tj changes.
__________________
regards Andrew T.
  Reply With Quote
Old 9th April 2013, 12:07 PM   #725
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by PeterLeest View Post
........The Hfe would increase a bit in each test (is it affected by heat ?). ...........
hFE is affected by Tj.
As Tj increases hFE increases.
But, I would expect similar increase for both NPN and PNP.
Your results don't show that NPN to PNP correlation.
__________________
regards Andrew T.
  Reply With Quote
Old 9th April 2013, 03:45 PM   #726
diyAudio Member
 
Join Date: Jun 2004
Location: Singapore
Quote:
Originally Posted by AndrewT View Post
hFE is affected by Tj.
As Tj increases hFE increases.
But, I would expect similar increase for both NPN and PNP.
Your results don't show that NPN to PNP correlation.
I did another test. Yes, the hFE increase is indeed similiar. BTW, I find Locky curve tracer is a very convenience and useful DIY tool.
Attached Images
File Type: jpg MJE15034 MJE15035 curve.jpg (213.0 KB, 293 views)
  Reply With Quote
Old 14th April 2013, 11:37 AM   #727
diyAudio Member
 
Join Date: Jun 2004
Location: Singapore
I finally fire up the board and the current readings are fairly close to Roender rating

Q17 collector 1.1 mA
Q13/11 collector 9.2 mA
MJE15035/34 R15 80 mA

Shunt read 39V & main is 36V. For basis, it started at 29C for 185 190 190 mA, and settled at 175 185 185 mA after heat sink heat up and stabilized at 45C, power TRs are 47C.

For the Shunt, MJE15034/35 run very hot at 53C, is there a problem?

For dummy resistive 8R load test; the square wave looks very good without ringing (1 KHz to 100 KHz). Then, I parallel a 1 uF capacitor to the load, I have oscillation, tune up power and fuse brown.

Whats next ?
Attached Images
File Type: jpg IMG_0420.JPG (188.0 KB, 251 views)
File Type: jpg IMG_0427.JPG (165.3 KB, 252 views)
  Reply With Quote
Old 14th April 2013, 01:49 PM   #728
roender is offline roender  Romania
diyAudio Member
 
roender's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by PeterLeest View Post
I finally fire up the board and the current readings are fairly close to Roender rating

Q17 collector 1.1 mA
Q13/11 collector 9.2 mA
MJE15035/34 R15 80 mA

Shunt read 39V & main is 36V. For basis, it started at 29C for 185 190 190 mA, and settled at 175 185 185 mA after heat sink heat up and stabilized at 45C, power TRs are 47C.

For the Shunt, MJE15034/35 run very hot at 53C, is there a problem?

For dummy resistive 8R load test; the square wave looks very good without ringing (1 KHz to 100 KHz). Then, I parallel a 1 uF capacitor to the load, I have oscillation, tune up power and fuse brown.

Whats next ?
You should insert in series with the output an 1...2uH air coil paralleled with some low ohm 2W resistor for supreme stability in any capacitive load.
For any real load this isn't necessarily unless you are using some very capacitive speakers.
  Reply With Quote
Old 14th April 2013, 03:02 PM   #729
diyAudio Member
 
Rudi_Ratlos's Avatar
 
Join Date: Jun 2009
Location: Hamburg / Germany
Lee, the power dissipation of the shunt's MJE - transistors results from the output voltage of the shunt's transformer.
I myself am using a transformer with 34VAC secondaries, and my MJEs are not getting as hot as yours.

You have asked: what is next?
What about listening to the beautiful music that the FC-100 is producing?

Best regards - Rudi_Ratlos
  Reply With Quote
Old 16th April 2013, 12:56 AM   #730
diyAudio Member
 
Join Date: Jun 2004
Location: Singapore
Hello, I did some testing for 8R resistor load at 20KHz. One channel is fine, another is overshoot, slower slew rate and non-linear. anyway to fine tune ? thanks for help. I haven't put in the output coil.
Attached Images
File Type: jpg IMG_0416.JPG (167.3 KB, 204 views)
File Type: jpg IMG_0415.JPG (163.0 KB, 192 views)
File Type: jpg IMG_0422.JPG (166.2 KB, 56 views)
File Type: jpg IMG_0423.JPG (160.9 KB, 53 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



New To Site? Need Help?

All times are GMT. The time now is 02:10 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