low noise replacement for BC547, BC557, BD135, BD136 - Page 2 - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

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 August 2012, 05:01 PM   #11
xslavic is offline xslavic  Moldova
diyAudio Member
 
Join Date: Feb 2011
Can sc1815 be considered a direct replacement for BC547 in audio applications,without changing the B base resistor?
  Reply With Quote
Old 4th August 2012, 05:46 PM   #12
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by xslavic View Post
Can sc1815 be considered a direct replacement for BC547 in audio applications,without changing the B base resistor?
In general yes. It's a "cooking grade" NPN like the BC547. Just make sure that you don't exceed the ratings in the data sheet.

No components should need altering to use it.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 4th August 2012, 07:31 PM   #13
xslavic is offline xslavic  Moldova
diyAudio Member
 
Join Date: Feb 2011
Default ok

I ment in this circuit,thanks!
Attached Images
File Type: jpg Super Iv.jpg (109.5 KB, 111 views)
  Reply With Quote
Old 5th August 2012, 06:52 AM   #14
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Yes, they would definitely be 100% OK for that.

[The circuit is a little unusual just seeing it in isolation. The inputs are very very low impedance (a virtual ground). Is it used as an I/V convertor from a DAC ?]
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 5th August 2012, 12:47 PM   #15
xslavic is offline xslavic  Moldova
diyAudio Member
 
Join Date: Feb 2011
Yes,I'll use it as I/v converter for dac , in dual mono ,and I'll need two of these as a result i think I get xlrafter the transistors at 3.16v if I'm not wrong but was afraid of the base resistor and the difference in freq 80 vs 300mhz
  Reply With Quote
Old 5th August 2012, 12:49 PM   #16
xslavic is offline xslavic  Moldova
diyAudio Member
 
Join Date: Feb 2011
Yes low impedance but I changed the 320 ohm Res to 195 to compensate for the higher output
  Reply With Quote
Old 5th August 2012, 07:28 PM   #17
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
The base resistors are OK left at 51 ohm. They isolate the opamp output from the B-C and B-E junction capacitance of the transistor and prevent any stability issues. The absolute value won't be very critical.

Absolutely no problem with the different ft of the transistors either.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  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
Low noise transistor and noise figure Real_Macgyver Solid State 28 27th July 2012 09:42 AM
Red LED noise. GK Solid State 5 14th December 2006 03:12 AM
anyone tried this for low noise 5v? mlloyd1 Digital Source 1 25th May 2006 12:06 PM
Hum and Noise with Ono rsbay Pass Labs 0 26th February 2006 12:51 PM
Noise Bukitoo Analogue Source 2 17th March 2004 02:37 PM


New To Site? Need Help?

All times are GMT. The time now is 07:49 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