Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

bc550 LTP values
bc550 LTP values
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 12th May 2020, 06:25 PM   #11
mchambin is offline mchambin  France
diyAudio Member
 
Join Date: Mar 2011
Ultra low noise transistor measurements.
Ultra low noise amplifiers
__________________
Transistor junction temperature is not transistor case temperature.
  Reply With Quote
Old 14th May 2020, 12:06 AM   #12
Mark Tillotson is offline Mark Tillotson
diyAudio Member
 
Join Date: May 2018
Location: Cambridge UK
Quote:
Originally Posted by peranders View Post
Do you have any datasheet that tells that?
Well I've built a test preamp using those transistors that detects the difference in Johnson noise between a 1 ohm and 3.3 ohm resistor as source, ie 0.2nV/√Hz of source voltage noise is not swamped by a ZTX851 or ZTX951

The transistors are actually designed as switching transistors with very low saturation voltage, which also happens to require very low Rbb.
  Reply With Quote
Old 14th May 2020, 12:47 AM   #13
sgrossklass is offline sgrossklass  Germany
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
Horowitz/Hill 3rd ed. lists a sub-2 ohm Rbb' for both... they're pretty much the closest thing to the legendary 2SB737 left for super low impedance work, if without the same high beta. Super low Rbb' high beta transistors all seem to have gone the way of the dodo these days.

If a sub-10 ohm Rbb' will do in your application, ZTX450 and 550 seem like a more sensible alternative. There's a whole range of parts if ca. 30 ohms will do.
  Reply With Quote
Old 14th May 2020, 03:30 PM   #14
donovas is offline donovas  South Korea
diyAudio Member
 
Join Date: Jun 2014
umm.. what about my ccs issue, guys?
  Reply With Quote
Old 14th May 2020, 10:17 PM   #15
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
bc550 LTP values
Try 1K R1 R2 because modern red Leds usually have more than the 1.6V forward drop shown in the schematic
  Reply With Quote

Reply


bc550 LTP valuesHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
BC550/560 Alienspecimen Parts 122 30th June 2020 11:31 AM
Bc550&Bc560cta vs Bc550&560ctu fairchild tonza75 Parts 1 23rd December 2016 04:49 AM
BC550 & 560's needed + 4558L Zero Cool Swap Meet 3 19th May 2007 07:00 PM
Where to get BC550/560C and MJE340/350 Dick West Parts 2 13th May 2005 11:42 PM


New To Site? Need Help?

All times are GMT. The time now is 07:17 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki