M250 - 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 1st August 2007, 08:47 PM   #1
diyAudio Member
 
Join Date: Jul 2007
Default M250

Hallo i am a first year electritian aprentice and i am interested in building te 250W amp i ave tride a few books and learned that the amp is a push pull class b amp but i still dont realy understand the amp i only found amp's coupled with a transformer becuase of the better gain that it offered round about 30db i think it was.

my question is can any body please examen the scheamatic and explain what the verios sections do ens.

the info on the amp can be found from this link
http://marcusgun.com/
  Reply With Quote
Old 2nd August 2007, 01:43 AM   #2
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
A nice tutorial on amplifier design:

http://users.ece.gatech.edu/~mleach/lowtim/
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 2nd August 2007, 03:06 AM   #3
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
I suspect the transformer coupled amps that you found may have been Valve designs, and not solid state. The main reason that a transformer is use there is to isolate the speaker from the high voltage needed to drive the valves.

A brief tour of the M250:

T1 and T2 are configured as what's known as a "long tailed pair". Think of the bases of T1 and T2 as the + and - inputs on an op-amp. T3 is coupled up through LED1 to act as a current source.

The audio signal enters the base of T1 through some filter components (C1, R1 and C2). The waveform causes the currents in the collectors of T1 and T2 to change accordingly. This is then voltage amplified by T5 (with T4 functioning as a current source for this stage of the amplifier).

From there, we basically have a "current gain" section.. ie, to provide the same signal as through T5, but with more current behind it. The output transistors are T10-T13 for the positive half of the wave, and T14-T17 for the negative half. T8 and T9 function as "drivers" to run the transistors and provide them with the base current they need.

T18 and associated parts form what is known as a "VBE multiplier". This serves to regulate the "idle current" flowing through the output stage.

T6-7 and their associated parts function as a safety circuit called a "VI limiter". The bases are connected so that they sense the current flowing through T10 and T14. If this becomes too high, then T6/7 (as appropriate) turn on and "steal" the base current from the driver transistor T8/9. This in turn, turns off the output stage to prevent damage.


http://sound.westhost.com/amp-basics.htm This is a very good article, especially relevant here is part 2, where Rod explains how an amplifier like the M250 works.
  Reply With Quote
Old 3rd August 2007, 01:57 PM   #4
diyAudio Member
 
Join Date: Jul 2007
Thank you that was very help full i will go and check the pages that you recomended aswell
  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
m250 ldanto Solid State 22 13th March 2007 09:44 PM
p3a vs m250 john-china Solid State 0 23rd February 2006 05:17 AM
the m250 fity Solid State 0 24th January 2006 05:44 PM
Adjusting the M250 @fundum Solid State 2 8th July 2004 08:02 AM
M250 Cheese Solid State 1 13th November 2003 05:18 AM


New To Site? Need Help?

All times are GMT. The time now is 11:25 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