help me building this 2n3055 amplifier - 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 23rd January 2015, 09:51 AM   #1
diyAudio Member
 
Join Date: Nov 2014
Default help me building this 2n3055 amplifier

hello friends...
someone please help me to build this amplifier. will it work ? what changes this circuit will need to work on 12 V Supply and substitute for 2N3904 and 2N3906 as i cant find them in my town. i have bc557,558 and bc547,548. can i use MJE3055 instead 2N3055? please help me friends.

here is the link

90 W audio power amplifier based on transistor - Amplifier Circuit
Attached Images
File Type: jpg 90W-amplifier-circuit-diagram-276x300.jpg (19.7 KB, 239 views)
  Reply With Quote
Old 23rd January 2015, 01:38 PM   #2
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
BC557,547, and bc558,548, won't work. This appears to be set up for 120 ma current in the input transistors, and those are 100 ma max parts.
If 500 ma npn and pnp TO92 package parts aren't available, you could probably get away with TO220 or TO125 parts like BD139/140 or TIP31/32. Part gains are much higher these days than when most things were designed. At least the parts from ON semi I am getting. I don't know about the *****ese clone market parts, which operates outside North American and Europe.
There are probably lots of 2sc**** 2sa**** parts that will work, you need Vceo >35, Ic >200 ma, Pd >500 mw which are pretty common specs around the world for TO92 parts. I use MPSA05 and 55 for this sort of thing, although the gains of around 400 are driving me nuts on old design schematics. Also you need more ce (collector emitter) disk capacitors on the drivers and possibly the inputs on fast parts like they make now. (Ft > 1 mhz).
Datasheet conforming MJE3055 should be fine, although many people find clones don't have the SOA of the real parts.
This is going to be rather vile sounding with no crossover elimination parts. I suggest you look at the AX6 for a start, Retro Amp 50W Single Supply
but you would have to lower the resistor values on the input and VAS stages to make it work on 12 VDC power supply. You probably don't need an output cap as big as 4700, I find 3300 fine on 8 ohm speakers: Unless you are driving a sub-woofer.
You have to look back towards page one of the link article to find the schematic diagram. He has added a idle current control potentiometer to the layout for those of us that have different gain parts than he used, without updating the schematic diagram.
Don't forget heat sink and isolators on the output transistors, and I usually put bits of aluminum on the driver stage transistors too to eliminate future problems if I turn the amp up.
I build stuff on insulating board like NEMA C laminate 1/16", that I drill holes in, so I don't do circuit boards like the AX6 designer (Mike Slabovik?) offers the patterns for.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 23rd January 2015 at 01:58 PM.
  Reply With Quote
Old 23rd January 2015, 01:41 PM   #3
Batson is offline Batson  Turkmenistan
diyAudio Member
 
Join Date: Nov 2014
Location: AShgabat
What is your power supply?Do you have -/+25v supply?
  Reply With Quote
Old 23rd January 2015, 02:03 PM   #4
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Quote:
Originally Posted by Batson View Post
What is your power supply?Do you have -/+25v supply?
Boy, 99.99% of the posters on here really love burning up speakers don't they?
On a split supply direct connect amp, if you make one stupid bad solder joint PHHHHT!!!, your speaker coil insulation could be cinders.
Somebody building one of these probably hasn't soldered 100 good connections yet.
Output Capacitor amps are best for experiments, IMHO. Armstrong 621, Leak ST70, AX6, etc.Much more stupid proof. I had a ball of fire 6" in diameter when a solder joint pulled loose, no damage occured to my $150 speaker. Hooray for speaker capacitors. If you have a single supply and they never cross zero volts, I can't hear them, either. My hearing rolls off at 14000 hz due to Army service, your results may vary.
BTW, that 1 uf input capacitor on the OP design is a little light these days when 4.7 uf is $.08. Buy the bigger cap for more bass.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 23rd January 2015 at 02:15 PM.
  Reply With Quote
Old 23rd January 2015, 02:43 PM   #5
diyAudio Member
 
Join Date: Nov 2014
I can find bd 139/140. I have 12-0-12 5A power supply. what part should I change in this circuit in order to make it work with 12-0-12. thanks indianajo(nes) and batson.
  Reply With Quote
Old 23rd January 2015, 02:46 PM   #6
diyAudio Member
 
Join Date: Nov 2014
I build it with bc 548/558 and its not working... will use bd139/140. will update soon...
  Reply With Quote
Old 23rd January 2015, 08:24 PM   #7
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Was the voltage going into the output capacitor about 6? If not that is a sign something is unbalenced somewhere. 1/2 rail voltage is the desired operation point for the midpoint of the output transistors.
Did your BC548/558 get hot? Bad connections are quite common when you are starting out. Use a DVM and look for impossible voltages - ends of the wire different voltages on the component leads, Vbe not 0.6 v , Vce not between 2 and 2/3 rail voltage, wrong polarity etc.
You can increase the 100 ohms to 220 and also the 47 ohm, and maybe series the + and - 12 supply to make 24 single rail supply.
You'll need a high drive source like a CD player or transistor radio to use the actual circuit since it doesn't have a high gain input transistor. It doesn't have any global feedback either, which makes the sound rather primitive. The AX6 is a much better design. If you do have a split supply, you can fool with the power to the input transistor with the center tap to stabilize the operating point of the input transistor, without actually running the output transistor direct connect in the speaker toasting configuration. I'm working with a transformer with no center tap, so I don't have an actual design.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300
  Reply With Quote
Old 23rd January 2015, 09:21 PM   #8
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Here is a better circuit. You can omit a pair of output transistors if you like.
Click the image to open in full size.
  Reply With Quote
Old 24th January 2015, 04:39 AM   #9
Batson is offline Batson  Turkmenistan
diyAudio Member
 
Join Date: Nov 2014
Location: AShgabat
Here one of my circuits that i tested many times in many versions.It is very simple and powerfull.You can use your bc557,BD139,140 and MJE3055/2955
and with +/-12 volts you will get enough Good luck
Attached Images
File Type: jpg 20150124_093310.jpg (142.6 KB, 125 views)
  Reply With Quote
Old 24th January 2015, 04:46 AM   #10
Batson is offline Batson  Turkmenistan
diyAudio Member
 
Join Date: Nov 2014
Location: AShgabat
Quote:
Originally Posted by indianajo View Post
Boy, 99.99% of the posters on here really love burning up speakers don't they?
On a split supply direct connect amp, if you make one stupid bad solder joint PHHHHT!!!, your speaker coil insulation could be cinders.
Somebody building one of these probably hasn't soldered 100 good connections yet.
Output Capacitor amps are best for experiments, IMHO. Armstrong 621, Leak ST70, AX6, etc.Much more stupid proof. I had a ball of fire 6" in diameter when a solder joint pulled loose, no damage occured to my $150 speaker. Hooray for speaker capacitors. If you have a single supply and they never cross zero volts, I can't hear them, either. My hearing rolls off at 14000 hz due to Army service, your results may vary.
BTW, that 1 uf input capacitor on the OP design is a little light these days when 4.7 uf is $.08. Buy the bigger cap for more bass.
Thats why u measure output first.Then you connect speakers.
  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
Amplifier based on 2N3055 macgyver Solid State 595 13th January 2015 05:08 AM
the ultimate class A 2N3055 amplifier filippo22 Solid State 6 28th April 2014 12:02 PM
PCB for Amplifier with 2n3055/2mj2955 Gost22 Solid State 0 6th November 2013 05:20 AM
Famous 50w amplifier, with more MJ2955 2N3055 SERGIODS Solid State 3 16th February 2013 03:01 AM
Amplifier with 2N3055 Tekko Solid State 11 8th December 2010 01:43 PM


New To Site? Need Help?

All times are GMT. The time now is 11:13 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2