Newbie Amp Design Question (Please Respond) - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 6th April 2005, 05:49 AM   #1
diyAudio Member
Join Date: Feb 2005
Location: Richardson, TX
Default Newbie Amp Design Question (Please Respond)

I've done a fairly substantial amount of reading in Self's Audio Power Amplifier Design Handbook , and I believe I have a quite good grasp on how each section works, etc. But looking through the book and every resource I have been able to find online, I can't find anything that tells me how to even START selecting specific component values and such. I would really like to design and build my own "blameless amplifier," but this seems like an insurmountable problem. Please help.

Thanks in advance,
  Reply With Quote
Old 6th April 2005, 06:24 AM   #2
Account Disabled
Join Date: Aug 2004
Location: Earth

I can probably help you as I was designing commercial PA amplifiers very similar to Douglas Self's designs - back in 1974 using MJ15003/4.

The one thing he glosses over and is a prime concern of mine is PSRR or Power Supply Rejection Ratio. Miller compensated amps are particularly prone and even his own example benefitted greatly, from memory, with THD dropping from 0.04% to 0.008% simply be adding a regulated power supply. If that isn't an indication of supply sensitivity I don't know what is.

The same occurs in many integrated OP amps where chip space is at a premium and capacitors consume real estate. The usually opt for the smallest on chip comp capacitor which is a miller cap and the PSRR to that supply side goes down the toilet. Rarely do they bring out a comp to ground pin.

The basic Self amp topology has great potential particularly with FET inputs, bipolar or CFP MOSFET outputs and comp from the Vas output to NFB return point.

Hope that helps.
  Reply With Quote
Old 6th April 2005, 06:37 AM   #3
diyAudio Member
Join Date: Feb 2005
Location: Richardson, TX
There was some great information in there, but I still don't know where to start deciding on values for each resister and capacitor and transistor, etc.
  Reply With Quote
Old 6th April 2005, 06:45 AM   #4
Account Disabled
Join Date: Aug 2004
Location: Earth
You need to identify the goals your amplifier is to achieve. Power, THD , crosstalk, budget.

Identify Type of output BJT or MOSFET?

work out supply rails Regulated or unregulated?

how many channels 2 to 6+ . If you want you could run them all off one power supply in one big box?

What quality source are you to use?
  Reply With Quote
Old 6th April 2005, 07:52 AM   #5
diyAudio Member
Join Date: Feb 2005
Location: Richardson, TX
hmm... looking at more schematics, most of the resistors and caps and such look predetermined. If this just leaves the transistors and rails and such, do I figure out how much power I want, and what rail voltages, and then pick transistors based on these values?
  Reply With Quote
Old 6th April 2005, 11:37 PM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
Self is good reading.
I second the removal of the Miller comp cap and choose a Leach or Cherry feedback topology or as amplifierguru suggests for HF feedback.
Read the tech notes in the ESP site along with the schematics etc.
Start with a lower voltage PSU (+-40v?) and save blowing up your transistors until after you have understood temperatures and why they happen, protection and how to implement and peak currents/voltages and their effects on components.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote


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
Newbie question re: "Proper" cabinet design Ken C Multi-Way 5 8th June 2004 07:14 PM
Newbie needs help. Basic PSU design and choke question. RockysDad Tubes / Valves 8 18th February 2004 05:37 AM
Gainclone & speaker design question. Newbie looking for help! matjans Multi-Way 13 19th October 2003 05:31 PM
I am so old I forgot my question, please do not respond ststone Everything Else 0 11th December 2002 04:04 AM
newbie post, but hopefully not a newbie question wiredcur Solid State 3 24th August 2002 10:49 PM

New To Site? Need Help?

All times are GMT. The time now is 01:59 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2