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 2nd May 2013, 05:27 PM   #1
diyAudio Member
 
Join Date: Oct 2011
Location: Close to Copenhagen
Default The Mitronic PA100 2SJ50/2SK135 ready for test.

With some delay because of repair of several Luxman amplifiers a.m., the Mitronic PA100 is ready for the complete measuring test.

The first data from the Mitronic PA100 at only +-30Vdc and 50mA pr. output device:

https://picasaweb.google.com/vbkolse...96040978440882

MITRONIC PA100 and the first measurement data:

The plus / minus 30 Vdc and 50 mA for each output transistor revealed the following data:

At 100kHz / 1 Watt output power was the PA100 amplifier - 0.1 dB down.
At 250kHz / 1 Watt output power was the PA100 amplifier - 1.0 dB down.
There could not be measured higher in frequency as the built-in RC circuits 10R / 47N in the amplifier limited the measurement.

By only + - 30Vdc and an output power of 1 Watt, and from 20 Hz to 20 kHz on the HP distortion analyzer, the overall distortion was below 0.02%.
Quite good of the design from 1982.

At full voltage of about +-60Vdc will the amplifier undoubtedly provide other measurement data.

https://picasaweb.google.com/vbkolse...97038376433890


MITRONIC PA100.
All transistors measured after Hfe, amplification:

Right channel: 2SA970 BL Hfe: 296, 296, 295
BF760 Hfe: 116
BF757 Hfe: 120/120
Hitachi 2SJ50: 1,151V, 1,141V.
Hitachi 2SK135: 0.943V , 0,939V.
Right channel DC offset: <0.507 mV DC

The incredibly low DC offset is a result of the measured transistors.
https://picasaweb.google.com/vbkolse...97619801908146

MITRONIC PA100.
All transistors measured after Hfe, amplification:

Left channel: 2SA970 BL Hfe: 301, 302, 299
BF760 Hfe: 117
BF757 Hfe: 121/116
Hitachi 2SJ50: 1,341 V, 1,340 V
Hitachi 2SK135: 1,044 V, 1,040 V
Left channel DC offset: <4,502 mV DC

The incredibly low DC offset is a result of the measured transistors. The left channel DC offset however, is approx. 4mV higher than the Right channel, but still very low.

Overall view of the Mitronic PA100:

https://picasaweb.google.com/vbkolsen/MitronicPA100#

This MITRONIC PA100 amplifier circuit seems to work nicely. It is difficult to spot any shortcomings in the first measurement tests , I would say ......but more to come.....

http://www.tubeamp.hobbysider.dk
  Reply With Quote
Old 2nd May 2013, 06:01 PM   #2
Gudmund is offline Gudmund  Iceland
diyAudio Member
 
Join Date: Feb 2010
Default PCB files

Quote:
Originally Posted by Leakstereo20 View Post
With some delay because of repair of several Luxman amplifiers a.m., the Mitronic PA100 is ready for the complete measuring test.
I have looked for that circuit erlier. After the final test, I would like to have the gerber files.

Regards Gudmund
  Reply With Quote
Old 3rd May 2013, 07:50 AM   #3
diyAudio Member
 
Join Date: Oct 2011
Location: Close to Copenhagen
Quote:
Originally Posted by Gudmund View Post
I have looked for that circuit erlier. After the final test, I would like to have the gerber files.

Regards Gudmund
The MITRONIC PA100 must be assembled in a cabinet with power supply before it is possible to get the final data .
I do not have a + - 60Volt supply available which have limitation of amperes built in . Construction may take some time

Regards Kim
  Reply With Quote
Old 3rd May 2013, 07:18 PM   #4
Gudmund is offline Gudmund  Iceland
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by Leakstereo20 View Post
The MITRONIC PA100 must be assembled in a cabinet with power supply before it is possible to get the final data .
I do not have a + - 60Volt supply available which have limitation of amperes built in . Construction may take some time

Regards Kim
No problem...the good stuff comes to the one who are waiting.

Gudmund
  Reply With Quote
Old 4th May 2013, 10:04 AM   #5
diyAudio Member
 
Join Date: Oct 2011
Location: Close to Copenhagen
Quote:
Originally Posted by Gudmund View Post
No problem...the good stuff comes to the one who are waiting.

Gudmund

Gudmund,.... before you take action to make a layout of the circuit there is a single component that can be better. C3 and C4 on the schematic are two polarized capacitors from Nippon Chemicon .... instead of these two polarized capacitors use a single bipolar Nichicon "Muse" 100uF / 50V ( the green ones).
Nichicon "Muse" capacitors should have better audio signal characteristics.

rgds. Kim
  Reply With Quote
Old 5th May 2013, 06:46 PM   #6
diyAudio Member
 
Join Date: Oct 2011
Location: Close to Copenhagen
Quote:
Originally Posted by Gudmund View Post
No problem...the good stuff comes to the one who are waiting.

Gudmund
Now when the amplifier PA100 is in place in terms of voltages and bias current, we will try to use better resistors even though the selected 1% types and Philips PR resistors are not of poor quality.
SHINKOH tantalum to 2.80 for 0.5 Watt and 5.50 for 1Watt is not cheap, but if there are other resistor types such as TAKMAN carbon film non-inductive, non-magnetic, 2% to 0.55 for 0.5 watt and 1Watt for 1.00 .... so there is an obvious opportunity to experiment

PR9372 metal films, Amtrans carbon film,Audio Note,Shinkoh,Charcroft,Takman,Arcol,Mills,Takman,H olco,Allen Bradley,duelund resistor,Kiwame carbon film,M-resist supreme resistors
  Reply With Quote
Old 5th May 2013, 06:52 PM   #7
Gudmund is offline Gudmund  Iceland
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by Leakstereo20 View Post
Now when the amplifier PA100 is in place in terms of voltages and bias current, we will try to use better resistors even though the selected 1% types and Philips PR resistors are not of poor quality.
SHINKOH tantalum to 2.80 for 0.5 Watt and 5.50 for 1Watt is not cheap, but if there are other resistor types such as TAKMAN carbon film non-inductive, non-magnetic, 2% to 0.55 for 0.5 watt and 1Watt for 1.00 .... so there is an obvious opportunity to experiment
Kim, I must admit that experiments with resistors will only be actual for me when both mosfet outputs channels plays here

Regards
Gudmund
  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
2sk135 2sj50 akersa Parts 46 2nd May 2013 05:23 PM
Need 2sk135 and 2sj50 MOSfets ElectricMan Solid State 5 16th December 2010 07:00 PM
sub for 2sj50/2sk135 sasha Solid State 20 27th March 2008 03:28 PM
2sj50/2sk135 jean-paul Swap Meet 0 26th February 2006 09:16 PM
I need 2sk135 and 2sj50 DJG Swap Meet 32 7th February 2006 09:03 PM


New To Site? Need Help?

All times are GMT. The time now is 09:25 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