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

Solid State Talk all about solid state amplification.

help with BJT preamp design
help with BJT preamp design
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 24th March 2003, 01:27 PM   #1
nobody special is offline nobody special  United States
diyAudio Member
 
nobody special's Avatar
 
Join Date: Oct 2002
Location: USA
Default help with BJT preamp design

I was going through my junkbox the other day, and thought I would throw something together to function as a preamp. I have a bunch of MPSA06 transistors, and various resistors, etc. So, I decided to make a simple current-sourced differential pair. I put the circuit together, but the gain I am getting is not symetrical on both outputs. So, I decided to add followers on the output (haven't done that yet, but thought it may help by taking the load off the differential pair). I don't know much of anything about designing with BJT's and I would appreciate it if some of you with more experience would look at my design and give me a shove in the right direction.
Some specific questions:
1. What is the best way to go about getting a symmetrical balanced output from a single-ended source?
2. How critical is matching between gain transistors in the differential pair, and is there a way to make this less critical?
3. I have taken into account the dissipation of the transistors, but is there an optimal current for this circuit? What is a typical Q current for a circuit like this?
4. What is a good way to lower the gain of the circuit? It seems like I am always running into this problem. If I use emitter resistors, it degrades the matching on the outputs of the circuit (right?) but if I don't use them, the gain is out of control, and the circuit clips with the full output of my cd player (2V max RMS).
Thanks,
-NS
Attached Images
File Type: jpg bjt_preamp.jpg (26.5 KB, 208 views)
  Reply With Quote

Reply


help with BJT preamp designHide 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
Preamp Design steevo Solid State 8 10th October 2007 09:11 PM
HELP PLEASE - with preamp design soundbadger Tubes / Valves 5 2nd October 2007 06:38 PM
Preamp PSU Design Help DoomPixie Tubes / Valves 18 5th July 2005 02:08 AM
Preamp design FBLEAGH Solid State 10 7th January 2004 10:29 AM
Preamp design Alex Solid State 13 11th October 2001 10:49 AM


New To Site? Need Help?

All times are GMT. The time now is 09:21 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki