120 watt amp in 2 ohm loud with 2n3055 - Page 2 - 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 15th August 2013, 10:58 PM   #11
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
The SOA is only half the problem. The Hfe is only 5 at 10A. Yuck. This is the real limitation of 2 ohm loads with 3055's. You could parallel them on the circlophone and jack up the supply to 60V - but you'd need better drivers to take full advantage.
  Reply With Quote
Old 15th August 2013, 11:06 PM   #12
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
Bedini's little amps sounded good in their own way http://www.diyaudio.com/forums/attac...dini-25-25.jpg
  Reply With Quote
Old 16th August 2013, 03:32 AM   #13
diyAudio Member
 
Join Date: Apr 2007
Hello

Here's amp schematic who use the 3055 transistors and give a high output, I've simulated it and it's work good with low thd.

Bye

Gaetan
Attached Images
File Type: gif high power 3055 amp.gif (19.7 KB, 478 views)
  Reply With Quote
Old 16th August 2013, 03:34 AM   #14
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Quote:
Originally Posted by Hadighorbani View Post
i have BC, 2n5551, 2n5401, 2sc945, 2sa733 and ... too
As pointed by other members some decent drivers are necessary ,
adequate models can be TIP31B/32B , TIP41B/42B , BD241B/242B .
BD243B/244B , BD711/BD712 and eventualy if correctly cooled
BD442/443 can be used as well.

Also , what will be the usage ? If it s for public adress it doesnt
need to be as complexe as if it s for hifi use.


Quote:
Originally Posted by gaetan8888 View Post
Hello

Here's amp schematic who use the 3055 transistors and give a high output, I've simulated it and it's work good with low thd.

Bye

Gaetan
He will need a quasi complementary design , simple if possible...

Last edited by wahab; 16th August 2013 at 03:36 AM.
  Reply With Quote
Old 16th August 2013, 03:42 AM   #15
diyAudio Member
 
Join Date: Jun 2010
i have 30 pcs 2n3055 and 10 pcs tip41c
  Reply With Quote
Old 16th August 2013, 04:02 AM   #16
wahab is offline wahab  Algeria
diyAudio Member
 
Join Date: Nov 2009
Location: algeria/france
Quote:
Originally Posted by Hadighorbani View Post
i have 30 pcs 2n3055 and 10 pcs tip41c
If you dont have a complementary for the TIP41C , a TIP42C or even B
this can be solved eventualy with a triple emitter follower pair for the
positive side using 2N5551 + TIP41C + 3 X 2N3055 and a composite
PNP using 2N5401 + TIP41C + 3 X 2N3055 for the negative rail side.

I ll do some simulations to "test" the configuration with a generic
schematic and ill try to give you the results soon.
  Reply With Quote
Old 16th August 2013, 04:10 AM   #17
diyAudio Member
 
Join Date: Jun 2010
Quote:
Originally Posted by wahab View Post
If you dont have a complementary for the TIP41C , a TIP42C or even B
this can be solved eventualy with a triple emitter follower pair for the
positive side using 2N5551 + TIP41C + 3 X 2N3055 and a composite
PNP using 2N5401 + TIP41C + 3 X 2N3055 for the negative rail side.

I ll do some simulations to "test" the configuration with a generic
schematic and ill try to give you the results soon.
thank you so much
  Reply With Quote
Old 16th August 2013, 05:21 AM   #18
evette is offline evette  Canada
diyAudio Member
 
Join Date: Jun 2006
Send a message via Yahoo to evette
I could send you a few transistors if you needed them. Evette
  Reply With Quote
Old 16th August 2013, 10:19 AM   #19
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Here is a design that I simulated in Circuit maker,

QUASI Amplifier for Beginners

The schematic is in the next post.

I haven't built it yet but it is a basic classic design that may help you to get an idea about how to reach your goal.

The whole thread is worth a good read.

All I did was basically tweak a design that is already in the thread to perform well at the 1 to 2 ohm load range.

It is also biased quite high (250ma per device) as well for class A mode of operation at low levels but this can be easily adjusted for lower bias levels.

This is a very powerful design with high voltage rails.
It should be very easy to adapted for lower voltage rails for only 120watts of output (maybe).
I quoted maybe because it was tricky to get it to simulate properly at lower voltages.

I also did a design based on the JLH amplifier design for such low impedance's as well.
It was to use 8 (or more) pairs of 2N3055's on the output.

It was purely a Class A design and I believe the 100watt range was my target as well a low impedance for driving my ESL systems.

I found that by the curves the more output devices I used the more linear the circuit could be (lower THD).
This is because the devices HFE gets lower as they conduct more current as already mentioned.

I was actually going to use some 8 to 16 pairs of TIP3055's becuase I could get them for like $.40 a piece or so and their curves showed to be more linear than a normal TO-3 2N3055's according to the RCA semiconductor handbook.

I don't have that schematic handy at the moment and I thought that I had posted it.
But, I couldn't find it last time I went looking for it because I still want to build it.

I am sure that I have it in my archives somewhere though.
I will try to find it as there are a few other of my designs that I need as well and they are on another hard drive that is not hooked up at the moment

Cheers !!
jer
  Reply With Quote
Old 16th August 2013, 02:47 PM   #20
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"Assuming I had enough of them (and that they were free) I would use three in parallel per side and run off a +/-28V supply (20-0-20, 5A toroid). Use TIP41C drivers and 2N5401/5551 predrivers in a TRIPLE. Yes, a triple. The output schematic would look like the Phase Linear 400 with lower rails. It works with low gain transistors like the 3055, will drive 2 ohms, and it's (almost) foolproof. Standard diff pair front end and single ended VAS with a bootstrap (copy from the DX amp, it's as good as you need). "

Basically, I agree.


I would use only two pair of outputs though, and use another pair for drivers. This would look a lot like half the output stage of the McIntosh MC2300, rated at 300W into the 1Ω primary of its output autoformer.

I actually rebuilt an MC2300 with Motorola 2N3055s in the late 70s, they don't work well when you pour a pitcher of Coke into them while running!

After the rebuild, they only problem the club had was the dustcaps blowing off their 15" Gauss woofers.

McIntosh uses 0.33Ω emitter resistors on the outputs, and either 0.56Ω, 0.62Ω or 0.68Ω resistors on the drivers. The predrivers had 100Ω resistors.

You could download a McIntosh MC2100 schematic to see the general idea, although I too would use the DX amplifier front end (Mac used resistors for current sources pulled up to 100V supplies!). The Mac schematic also shows current limiting for short circuit protection.
__________________
Candidates for the Darwin Award should not read this author.

Last edited by djk; 16th August 2013 at 02:53 PM.
  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
2n3055 amp claims 200 to 220 watt seedseed Solid State 152 18th March 2014 01:24 PM
dean markley valve head 120 watt mondogenerator Instruments and Amps 19 25th February 2012 07:09 PM
peavey windsor 120 watt head schematic? guitar_joe Instruments and Amps 16 11th February 2011 04:15 PM
I need mono amp reccomendations - 800 watt RMS @ 4 ohm rocko1290 Car Audio 13 29th August 2006 06:04 PM
What is the best speaker for 120 watt and 80 watts martin88 Multi-Way 6 10th December 2004 08:09 PM


New To Site? Need Help?

All times are GMT. The time now is 04:12 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