Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Hiraga "Le Monstre"
Hiraga "Le Monstre"
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 28th September 2018, 04:24 PM   #1621
sottomano is offline sottomano
diyAudio Member
 
Join Date: Mar 2011
Quote:
Originally Posted by vishalk View Post
[...]can i use my scope or DMM to check if it's oscillating?[...]
I don't know your scope, but you'll need one with a certain bandwith (I suggest at least 20 MHz). DMM is not of much help.
Then you need a signal generator, or you can use your soundcard with REW.
Drive your amp at different levels, with sine and square wave signals, with resistive and real loudspeaker loads. If the output shows other waveforms than the input (overshoots, high frequency content, ...), that is not good and shows that the amp is not stable enough. Do a Google search on "Amplifier Oscillation" and look at the pictures in the search results....

Quote:
Originally Posted by vishalk View Post
[...]The thing is i don't just want "ok" transistors, i want proven and tested transistors that perform well with this circuit that others have recognised.
Sanken and OnSemi are pretty much state of the art. You may also try 2SC5200 and it's PNP counterpart from Toshiba, an excellent transistor.

You need constant (high) hfe at higher currents, a fast transistor, cob as low as avialable.

There is no such thing as a "wonder-transistor", and the difference between those suggested is overrated in my opinion.
  Reply With Quote
Old 28th September 2018, 06:27 PM   #1622
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
Quote:
Originally Posted by gaborbela View Post
How much the DC offset?
Of course, you set up the DC offset at industrial warm.
I had the same issue with my LeMonstre, even the bias moved at warm up.
If you have 1V DC at cold that is not a problem as long as your speaker's protection does not kick in.
Is not possible to put together your heatsinks to create some type of tunnel for your fan, that way would be much more effective. You can buy 5W metal film resistors and carbon films also.
I would buy 2R and use 2PC to get 1R 10W. Did you ever tried plate resistors like KOA etc. to me those acceptable also.

Ok so at first switch on the dc offset was:

The sankens were 919ma and the MJL's 418ma.

Stuck a timer on and after 35mins the temp was 41 degrees Sankens went down 30ma and the MJL's 35ma

It took almost an hour for both of them to get to 0V. at which point the temp was around 46degrees.

after two hours both heatsinks averaged about 47-48 degrees.

So yes it shows that dc offset is proportional to the temperature raise.

One more question do both transistors have to have equal levels of bias? For me to have it stable its like 0.60 on the npn and 0.62 on the pnp.

Last edited by vishalk; 28th September 2018 at 06:37 PM.
  Reply With Quote
Old 28th September 2018, 06:33 PM   #1623
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
Quote:
Originally Posted by sottomano View Post
I don't know your scope, but you'll need one with a certain bandwith (I suggest at least 20 MHz). DMM is not of much help.

I have a velleman hps140mk2:

Specifications
bandwidth: up to 10 MHz (-3dB or -4dB at selected ranges)
input range: 1 mV to 20 V / division in 14 steps
input coupling: DC, AC and GND
real-time sample rate up to 40 MS/s
AD resolution: 8 bits
time base: 250 ns to 1 h per division
auto set-up function (or manual)
probe x10 readout option
readouts: DC, AC + DC,True RMS, dBm, Vpp, Min-Max. (2.5%)
audio power measurement from 2 to 32 ohms
hold & store function
time and voltage markers readout
max. 100 Vp AC + DC
Monochrome OLED
power supply: 4 x 1.5 V AAA batteries (not incl.)
operating time: up to 8 hours on quality Alkaline batteries
for use on CLASS II pollution degree II installations
dimensions: 114 x 68 x 22 mm
weight: 166 gr
current consumption: max. 150 mA


Then you need a signal generator, or you can use your soundcard with REW.

I have both!

Drive your amp at different levels, with sine and square wave signals, with resistive and real loudspeaker loads. If the output shows other waveforms than the input (overshoots, high frequency content, ...), that is not good and shows that the amp is not stable enough. Do a Google search on "Amplifier Oscillation" and look at the pictures in the search results....

Ok sounds easy enough, ill do a quick search and see how to go about it

Sanken and OnSemi are pretty much state of the art. You may also try 2SC5200 and it's PNP counterpart from Toshiba, an excellent transistor.

Excellent ill order some

You need constant (high) hfe at higher currents, a fast transistor, cob as low as avialable.

There is no such thing as a "wonder-transistor", and the difference between those suggested is overrated in my opinion.

not looking for a wonder transistor just ones that other members use and enjoy so at least i can try and choose what i like.
  Reply With Quote
Old 28th September 2018, 09:21 PM   #1624
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
DSC_0984.jpg

DSC_0985.jpg

I tell you what you guys, this made such a difference. It felt so much easier to set the bias and dc offset up, infact i was able to get both NPN and PNP to match in bias.

Cant believe the difference changing the type of resistor made.
  Reply With Quote
Old 29th September 2018, 07:17 AM   #1625
Sadik is offline Sadik  India
diyAudio Member
 
Join Date: Feb 2015
I would suggest you to try these Power transistors also NJW0281G and NJW0305G. I am using them in my 30 WATT Jean Hiraga schematic by Dan. And they are sounding very beautiful.,,
  Reply With Quote
Old 29th September 2018, 10:02 AM   #1626
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
Thanks Sadik I just ordered those transistors again as I blew my last ones fiddling and learning, agreed they did sound lovely.
  Reply With Quote
Old 29th September 2018, 11:04 PM   #1627
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
DSC_0988.jpg


What a good day it was for testing, i was really able to put these amplifiers through their paces and they did not disappoint.

Ill keep it quick and simple.

Preamps:

Yamaha ca-600 (i like the mode function where it joins the Left and Right signals together so the preamp outputs share both signals) . This allowed me to test one amplifier at a time but getting both L/R signals coming through.

Diy Marantz 7 circuit Tube Preamp


Speakers:

Planet 10 onkens with MA alpair 7.3

Tannoy Berkeleys (i was very surprised how good it sounded with these amps)

Things really came alive when i used the big tannoys it gave a good impression of how well the amp performed and how the transistors used sounded.


Amplifer 1:

The MJL21193+MJL21194

Amplifer 2:

NJW0302G+NJW0281G

Both Amps were tested at 0.6A and 0.7A, allowed to be fully warmed and stable, i didn't want let the rail voltages drop below 16V. I will may 1A just to listen and test more, my thought was to eventually try and get a stable bias where my PSU you can handle the load and i get good measurements from my scope. I mean i tried 1.5A and it sounded strong, further tests showed no benefits cons were HEAT,PSU having a hard time and bad rms value tests from my scope. Just using 0.6 - 1A tests better for my current setup which is fine.

Ok i will continue this tomorrow as it's late!

Last edited by vishalk; 29th September 2018 at 11:08 PM.
  Reply With Quote
Old 30th September 2018, 06:26 AM   #1628
Sadik is offline Sadik  India
diyAudio Member
 
Join Date: Feb 2015
Hi Vishal,

You may have seen the below photo of my amp (Jean Hiraga 30 Watts) It was a complete DIY right from the PCB's to the Enclosure.
Click the image to open in full size.

But Now as the time has passed I too have updated my amplifier with Proper PCB's, Power Bank (4,40,000 uf Per Channel) and a Heavy Enclosure (Enclosure is a complete DIY) with More bigger Heat sinks. The Amp PCB's were made as per my layout from a PCB manufacturing company, Soft turn on & Protection PCB's were purchased as a complete assembled kits.

When i shifted to Proper power Bank there was a huge difference in the low frequency. The difference is on the better side, the low frequency is improved a lot the difference is like day & night.

When I was using Cap multiplier the lower notes were blurred and the intensity was very light. (but still it sounded very good in mids and high region)

Click the image to open in full size.


Click the image to open in full size.


Click the image to open in full size.


Click the image to open in full size.

Belive me this 30 Watter is a Real Monster. And so dose it looks now.


Sadik
  Reply With Quote
Old 30th September 2018, 07:20 PM   #1629
vishalk is offline vishalk  United Kingdom
diyAudio Member
 
vishalk's Avatar
 
Join Date: Mar 2017
Location: North London
Sadik that is wonderful man, i like how you also had the metal work etched something i would like to get done on future projects.

I am in the process myself of finishing my Hiraga Super 30w using Chokes and a big PSU, although i decided to build the le monstre as a test run!
  Reply With Quote
Old 1st October 2018, 02:47 PM   #1630
danieljw is offline danieljw  Australia
diyAudio Member
 
danieljw's Avatar
 
Join Date: Jan 2005
Location: South Australia
Send a message via MSN to danieljw
Great work Vishal and Sadik,

Some nice amplifiers being built !
  Reply With Quote

Reply


Hiraga "Le Monstre"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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Conversion of Hiraga's "Le Monstre" to a Circlotron tiefbassuebertr Solid State 13 30th May 2015 02:31 AM
Hiraga Monstre with SMPS? weissi Solid State 2 25th July 2008 09:44 PM
Hiraga 30W vs. Le Monstre JohanH Solid State 103 14th April 2008 10:27 PM
HIRAGA Monstre amplifier modules a333bt Swap Meet 5 14th October 2007 03:11 PM


New To Site? Need Help?

All times are GMT. The time now is 11:07 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki