15W SE amplifier schematic - 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 11th April 2002, 03:04 PM   #1
diyAudio Member
 
Join Date: Feb 2002
Location: Bedford, TX
Send a message via Yahoo to SteveS
Question 15W SE amplifier schematic

I was wondering if some of the seasoned veterans around here could give me some comments on this design. What I am shooting for is about 10-15W class A and as simple as I could get it. Biasing the IRF540 pairs to 2A should get me there.

The power rail caps on the opamp were omitted for 'clarity'. Would I need to put filter networks on the bias and offset circuits even though I will be using regulated voltages (LM317/337)? Any comments or suggestions would be greatly appreciated.

Thank you,
SteveS
Attached Images
File Type: jpg 15-se.jpg (26.9 KB, 942 views)
  Reply With Quote
Old 11th April 2002, 03:06 PM   #2
diyAudio Member
 
Join Date: Feb 2002
Location: Bedford, TX
Send a message via Yahoo to SteveS
I failed to mention that my preamp will make up for the minimal gain shown.

SteveS
  Reply With Quote
Old 11th April 2002, 05:20 PM   #3
jam is offline jam  United States
diyAudio Member
 
jam's Avatar
 
Join Date: May 2001
Location: Auburn, CA, USA
Steve,

If you take the feedback from the output you could probably dispense with the input coupling capacitor and improve your damping factor and distortion specs. The assumption here is that you will no longer need the offset adjustment portion of the circuit.

Jam
  Reply With Quote
Old 11th April 2002, 05:31 PM   #4
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
Yep....

but I'm quite sure you will need a compensation cap if you take the feedback from the speaker output..


thijs
  Reply With Quote
Old 11th April 2002, 05:33 PM   #5
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
There is a dual power supply? Why?
  Reply With Quote
Old 11th April 2002, 07:17 PM   #6
diyAudio Member
 
Join Date: Feb 2002
Location: Bedford, TX
Send a message via Yahoo to SteveS
jam:
I must admit most of the inspiration for this design is from Monarchy's SE-70 amplifier. It too does not include the OP stage in the feedback loop and from what I'v read this give a touch more openess to the sound. I'm not a big fan of using feedback, so I thought why not give it a try. The SE-70 however uses a push-pull OP stage biased to class A.


tschrama:
The reasons for the dual power supply are:

1. I wanted a clean voltage source for running the opamp and biasing (input stage and current source).

2. I have a trasformer with multiple taps to accomodate.

3. It will give me more voltage output from the opamp to compensate for Vgs.

However, if you (or anyone else) has a good idea on a circuit to provide 23V from the unregulated legs I'm all ears.

Thank you,
SteveS
  Reply With Quote
Old 11th April 2002, 08:37 PM   #7
Banned
 
Join Date: Feb 2002
Location: Dallas,Texas
Default Class A

Untested for turn on thumps but should work. I will answer further questions that will be inevitable.

H.H.
Attached Files
File Type: zip classa.zip (10.0 KB, 259 views)
  Reply With Quote
Old 11th April 2002, 09:20 PM   #8
diyAudio Member
 
Join Date: Feb 2002
Location: Bedford, TX
Send a message via Yahoo to SteveS
H.H.:

You were right about the questions.

The diodes on the Mosfet gates and the diode/resistor bias adjust I understand, but what do the 'new' components in the input and feedback circuits do?

Thanks,
SteveS
  Reply With Quote
Old 11th April 2002, 09:46 PM   #9
Banned
 
Join Date: Feb 2002
Location: Dallas,Texas
Default ClassA

C1 1uF and R1 1Meg make the gain unity at DC and R4/R3 at audio frequencies

R6 and C3 filter RF out of input.

D1 and R9 set the bias current for output stage. Look at data sheet and or test for the gate to source voltage of mosfet at 2 amps. Zener voltage will equal Vgs+(2ampsXR9). Stay above 1 ohm for R9 for good thermal stability. Don't forget to test well before hooking up speaker. I would fuse 23 volts rails with 6 amp quick acting fuses.

H.H.
  Reply With Quote
Old 11th April 2002, 10:03 PM   #10
diyAudio Member
 
Join Date: Feb 2002
Location: Bedford, TX
Send a message via Yahoo to SteveS
H.H.

Thanks for the info!! You didn't happen to do any THD plots or anything, did you?

SteveS
  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
Trimodal amplifier schematic princesa Solid State 1 22nd January 2009 11:03 PM
5686 amplifier schematic Original Burnedfingers Tubes / Valves 1 23rd August 2006 02:55 AM
Take a look on amplifier schematic please viktor1986 Solid State 51 11th February 2006 09:35 AM
Schematic: Russound amplifier? ken.berg Solid State 0 21st April 2005 02:24 AM
Need a amplifier schematic mbates14 Solid State 3 13th September 2002 09:12 PM


New To Site? Need Help?

All times are GMT. The time now is 01:53 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