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 4th June 2009, 04:10 AM   #1
diyAudio Member
 
sivan_and's Avatar
 
Join Date: Dec 2004
Location: Dxb / India
Send a message via Yahoo to sivan_and
Default Substitute 2N3055/2955

Am building an amp using readily available pcb of ETI480 amplifier, and i wish to substitute 2N3055/MJE2955 as i understand these are not audio specific devices ...what options i have..can i use MJE15001/MJE15002 or MJE15003/MJE15004 or even with MJ11032/ MJ11033 with better Ft, IC and Pd ?

ETI480 schematic:
Attached Files
File Type: pdf eti480app2_2.pdf (95.8 KB, 299 views)
__________________
SivanandBalan
  Reply With Quote
Old 4th June 2009, 04:45 AM   #2
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Given the nature of the design I would try to stick to transistors that are quite similar to the old 2N2955 and 2N3055. TIP series devices from TI come immediately to mind. (or modern versions in TO-3P packages)

Making unstudied changes to this design may result in an oscillator.
Compensation cap values would probably have to be tweaked for proper sq wave response and good stability.

Beta and ft are important in this design as is no doubt cob and a few other parameters.

Get yourself free LTspiceIV from the linear website and find the appropriate transistor models and model the amplifier.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 4th June 2009, 06:53 AM   #3
taj is offline taj
diyAudio Member
 
taj's Avatar
 
Join Date: Feb 2005
That circuit is strange to my newbie/inexperienced eyes. What's the purpose of taking the output from the collectors on that output section?

..Todd
  Reply With Quote
Old 4th June 2009, 08:03 AM   #4
diyAudio Member
 
Greg Erskine's Avatar
 
Join Date: Jan 2002
Location: Sydney/Australia
Useful information about this amp can be found here:

http://home.alphalink.com.au/~cambie/ETI480/ETI480.zip

regards
__________________
Greg Erskine
  Reply With Quote
Old 4th June 2009, 12:59 PM   #5
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Looks like another incarnation of the Tiger (Tiger, Tiger, burning bright....). That output stage is finicky to say the least. Substituting output trannies may or may not work. Even with modern 3055's it may still be troublesome. I would probably try to build it with MJ15015/15016, which are upgraded 2N3055/2955's. Similar characteristics, higher voltage.

MJ11032/33? 50 amp darlingtons??? No way would I ever go there.
  Reply With Quote
Old 4th June 2009, 07:18 PM   #6
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Default this is

another wonderfull sziklai ....

out stage that has some gain on his own.....

a few plus :
----more eficient than emmiter followers
----drives strange loads eazier
---- simple to make
----sziklai tents to be more "musical" than other topology but also this depents on the rest of the circuit and semis

a few minus ....

----it is pcb depending
---- it is unstable if abused
---- vbe multiplier has a god on his own ( thermal runaway)
---- Network arround drivers work as a sonic killer (there are better design ideas arround that )
---- modern transistors or faster and oscilation is arround the corner

----- the particular circuit will produce turn on thump i think

----- especially R15- 17 are the sonic killers but also keep the amp stable ...

----- the paricular amp has a reputation of


you may choose now

i love sziklai circuits ...but not the particular one ...there are more ....by far better than this one

if youre building something for casual listening go for a DX amplifier it is by far more acurate sharp and precise than this one only probably with a bit less drive abilty .... soundwise will outperform this one for breakfast and also can work with modern and powerfull semis

if your conquest is power this one will not do any way .....

if you allready have the pcb you might consider your shelf mods that will make the amp a typical ammiter follower and you are done !!!!!

happy sziklai regards
sakis
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 4th June 2009, 07:49 PM   #7
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
There is little wrong with 2n3055 and mj2955.

Maplin electronics did a kit in the 1980's which was very similar in design and it was 225WRMS and it was very loud. I used one for my disco and was always getting asked to turn it down !

I have to echo what others have said and be careful of stability problems if you put in different output transistors.

If the design is tried and proved then stick to it.

There is an endless stream of threads on here from people who tried updating amps only to find they have a good oscilator !
__________________
http://www.murtonpikesystems.co.uk PCBCAD50 pcb design software.
  Reply With Quote
Old 5th June 2009, 12:20 AM   #8
diyAudio Member
 
Join Date: Nov 2005
Location: Southampton
@ Sakis:

I would be interested to hear your thoughts on a well-implemented Sziklai output stage. I like the concept of it for many reasons but I'm struggling to actually design an output stage that will do what I want.

Particularly regarding the connection of parallel output devices. Which side of the output devices emitter resistor do you connect the driver if you have multiple output devices?

Can you suggest some examples of good Sziklai's to look at please?

Chris
  Reply With Quote
Old 5th June 2009, 05:10 AM   #9
diyAudio Member
 
kuldeepsingh's Avatar
 
Join Date: Aug 2006
Location: Chennai, India
Send a message via MSN to kuldeepsingh
whats the Wattage of this amp
__________________
. . .. ... ..... ........ ............. ..................... ..................................
My Blog
  Reply With Quote
Old 5th June 2009, 07:21 AM   #10
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Default first

Quote:
Originally posted by ceharden
@ Sakis:

I would be interested to hear your thoughts on a well-implemented Sziklai output stage. I like the concept of it for many reasons but I'm struggling to actually design an output stage that will do what I want.

Particularly regarding the connection of parallel output devices. Which side of the output devices emitter resistor do you connect the driver if you have multiple output devices?

Can you suggest some examples of good Sziklai's to look at please?

Chris
it would be wise to know your power figures .... whta do you expect ???? what is your needs ....

tell me that and i will let you know what i have in mind
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  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
PSpice Models for 2955/3055 JamesMI Solid State 18 2nd February 2014 06:36 PM
how hot is 2n3055 can go? milen007 Parts 2 17th February 2009 01:32 AM
swapping 2955/3055's for new on semi mjl4281A/mjl4202A ? Tensop Solid State 8 16th February 2006 09:25 AM


New To Site? Need Help?

All times are GMT. The time now is 08:44 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