ltp stage transistors - 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 3rd September 2008, 10:49 AM   #1
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Default ltp stage transistors

i come across these transistors and was wondering if they can be usefull in an LTP or other stages of audio .....

it looks to me that they have very fine specs but really wonder if can be used

BC 875-6-7-8-9-0
are complementary NPN -PNP DARLIGTONS + DIODE operatind at 100 v 0.8 w 200 MHZ and beta of 2000

what do you think ????

thanks
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 3rd September 2008, 11:06 AM   #2
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
too much of gain ?
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 3rd September 2008, 11:09 AM   #3
fotios is offline fotios  Greece
diyAudio Member
 
fotios's Avatar
 
Join Date: Feb 2007
Location: Δραμα - North Greece
Default Re: ltp stage transistors

Quote:
Originally posted by sakis
i come across these transistors and was wondering if they can be usefull in an LTP or other stages of audio .....

it looks to me that they have very fine specs but really wonder if can be used

BC 875-6-7-8-9-0
are complementary NPN -PNP DARLIGTONS + DIODE operatind at 100 v 0.8 w 200 MHZ and beta of 2000

what do you think ????

thanks
Saki, i don't think those bjts are appropriate for audio use. If you want big Vce, then a good type is 2SA970-2SC2240 of Tos. I have tried those with success. You can find from RS.

Regs
Fotis
__________________
Best Regards FOTIS ANAGNOSTOU
  Reply With Quote
Old 3rd September 2008, 11:46 AM   #4
fotios is offline fotios  Greece
diyAudio Member
 
fotios's Avatar
 
Join Date: Feb 2007
Location: Δραμα - North Greece
Default This is my list of preferable BJTs

First of all, i have not idea about mosfets and my experience it is limitted mainly in ONsemi devices.
According to use, i prefer these:
1) For P.A. amplifiers and according to supply level:

Small signal stages
MPSA06 - 56 or 2N5401 - 5551
VAS & Predrivers
MJE15030 - 31 - 32 - 33
Main drivers
MJ15020 - 21 or MJL3281 - 1503
Output stage
MJ1503 - 04 - 22 - 23 - 24 - 25

2) For Hi-Fi amplifiers

Small signal stages
2SA970 - 2SC2240
VAS & Predrivers the same as above
Main drivers
MJL3281 - 1503
Output stage
MJL21193 - 94

3) For low power applications such preamps etc:

BC550 - 560
D44H8 - 45H8

4) For bias in power amplifiers

BD135 or BD137

I have tried only the above devices, because i can find them (the same for you because Greece) very easy. You know as i think "BAKIS electronics" for OnSemi, Fischer etc etc.
I am in waiting to hear your news.

Fotis
__________________
Best Regards FOTIS ANAGNOSTOU
  Reply With Quote
Old 3rd September 2008, 01:30 PM   #5
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Default fotios

thanks for all these info .....

this is more or less what i use in my amps too

but these specs seemed to look like something really special and so i thought that might be used in some audio application ....

of course if so a circuit needs to be builted around them
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 3rd September 2008, 01:41 PM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
the MJE1503x series have far too much Cob for VAS duty.
Similarly the Power capability is wasted in VAS and pre-driver duty.

Use a low capacitance, lower power, medium hFE, high fT device in these locations.

Try 2sa1360/c3423 and many that are similar for VAS & Pre-drivers
__________________
regards Andrew T.
  Reply With Quote
Old 3rd September 2008, 09:02 PM   #7
fotios is offline fotios  Greece
diyAudio Member
 
fotios's Avatar
 
Join Date: Feb 2007
Location: Δραμα - North Greece
Quote:
Originally posted by AndrewT
Hi,
the MJE1503x series have far too much Cob for VAS duty.
Similarly the Power capability is wasted in VAS and pre-driver duty.

Use a low capacitance, lower power, medium hFE, high fT device in these locations.

Try 2sa1360/c3423 and many that are similar for VAS & Pre-drivers
Hi Andrew

Probably you are right in your suggestion. The problem it is where we can find 2SA1360/2SC3423 or similar in Europe.
As i have mentioned above, the problem it is the availability of components, for this reason we prefer OnSemis because are offered from most shops in Eu.

Regs
Fotios
__________________
Best Regards FOTIS ANAGNOSTOU
  Reply With Quote
Old 4th September 2008, 12:05 AM   #8
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Fotios,

I agree with AndrewT. I use 2SC3423 as VAS; Cob is less than 2pF, 200MHz, 50mA, 120V, outstanding device. I've found low Cob is the single most significant parameter for VAS selection. Capacitance across the depletion layer is very nasty; high dielectric absorption, variability with Vce, and multiplied by beta of course in common emitter.

I'm in a very different part of the world to you, but I buy from Peacock Electronics in Singapore. As you may be aware, the Far East pretty much controls the prices of semis in the world, and I find prices from this company very competitive. Expect to pay around 40c US for 1K+.

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 4th September 2008, 02:29 AM   #9
Bonsai is offline Bonsai  Taiwan
diyAudio Member
 
Bonsai's Avatar
 
Join Date: Jul 2003
Location: Taipei, Taiwan
AKSA is right - low Cob is critical.

In Europe, you can try the SOT223 BF8xx N & P types from Philips (I think they are NXP now)
__________________
bonsai
Amplifier Design and Construction for MUSIC! http://hifisonix.com/
  Reply With Quote
Old 4th September 2008, 02:38 AM   #10
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Few years ago I used for a custom amp transistors pulled from oscilloscope, they were 250V 200 MHz devices. I don't remember their names, but surnames were Toshiba.
__________________
The Devil is not so terrible as his math model is!
  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
Help understanding a driver stage with extra transistors rtarbell Solid State 1 24th July 2008 04:55 PM
Adding more transistors to output stage? bowdown Solid State 6 19th January 2007 08:15 PM
High voltage transistors for VAS stage rtarbell Parts 4 15th November 2005 01:13 AM
5 transistors output stage KCC Solid State 6 30th June 2003 02:52 PM
50 Output Stage Transistors? thylantyr Solid State 22 26th April 2003 11:44 PM


New To Site? Need Help?

All times are GMT. The time now is 12:41 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