VSSA Lateral MosFet Amplifier - Page 3 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Vendor's Bazaar

Vendor's Bazaar Commercial Vendors large & small hawking their wares

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 15th December 2012, 04:51 PM   #21
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by dadod View Post
This what I've got with Bigun file.This is at quite low level, at higher level it is much worse.
dado
For such a simple amp it is still all very good, at your first sim at 1 kHz, H2 still -100dB.

Normal home usage with moderate to high efficiency speakers will do fine.

VSSA is ideal for an active speaker (2-3 channels per speaker), low parts count, direct connection to drivers, active crossover, etc.

If you would like to get lower THD add appropriate driver, plus two output pairs more ...
__________________
First One VSSA
  Reply With Quote
Old 15th December 2012, 04:57 PM   #22
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by lineup View Post
I setup the circuit from your diagram.
The DC-offset is very small, 12 mV.

The first thing I noticed is that circuit needs some compensation to be stable.
This was fixed with one 22pF from base to collector of KSA1381 and likewise 22pF around KSC3503.

The THD distortion at 1 Watt is remarkably low for such a simple amplifier:
THD 0.0002% at 1 Watt RMS.

Very nice amplifier
Yes, thanks lineup. It would be a shame not to share this amp among others, especially for young DIY-ers to start with some discrete amp built.

Agree, 22pF base collector compensation and 100pF parallel with input 10k also recommended.
__________________
First One VSSA
  Reply With Quote
Old 15th December 2012, 05:13 PM   #23
dadod is offline dadod  Croatia
diyAudio Member
 
dadod's Avatar
 
Join Date: Apr 2006
Location: Zagreb
Quote:
Originally Posted by Lazy Cat View Post
For such a simple amp it is still all very good, at your first sim at 1 kHz, H2 still -100dB.

Normal home usage with moderate to high efficiency speakers will do fine.

VSSA is ideal for an active speaker (2-3 channels per speaker), low parts count, direct connection to drivers, active crossover, etc.

If you would like to get lower THD add appropriate driver, plus two output pairs more ...
This is THD20k before clipping(this amp clips at 28 V p with +-35 V of power supply)).
dado
Attached Images
File Type: jpg TSSA-THD20k-before clipping.jpg (223.0 KB, 2718 views)
  Reply With Quote
Old 15th December 2012, 05:19 PM   #24
diyAudio Member
 
moschfet's Avatar
 
Join Date: Jul 2008
Location: Hannover
Quote:
Originally Posted by Lazy Cat View Post
It would be a shame not to share this amp among others, especially for young DIY-ers to start with some discrete amp built.
Yes it's a really little nice circuit and I think to publish it in a German forum. Especial younger people are searching often good and simple circuits. I will of course mention the author
__________________
Regards http://xipix.de/
  Reply With Quote
Old 15th December 2012, 05:19 PM   #25
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by dadod View Post
This is THD20k before clipping(this amp clips at 28 V p with +-35 V of power supply)).
dado
WOW that's very good, H2 almost -90dB just before clipping at 20 kHz. Very good simple amp this VSSA is. Thanks dadod
__________________
First One VSSA
  Reply With Quote
Old 15th December 2012, 05:27 PM   #26
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by moschfet View Post
Yes it's a really little nice circuit and I think to publish it in a German forum. Especial younger people are searching often good and simple circuits. I will of course mention the author
No problem, some resistors values still can be calibrated to optimal values, like OLG (470ohm, 10 ohm) vs. bandwidth (feedback resistors ratio), input/VAS bias etc, but in general as it is now, VSSA will work.

Also please invite German fellows to DIY Audio too.
__________________
First One VSSA
  Reply With Quote
Old 15th December 2012, 05:34 PM   #27
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Quote:
Originally Posted by Lazy Cat View Post
With only six transistors you can get genuine current feedback, high bandwidth amplifier, capable of driving 4 ohm speakers. PCB can be very simple and small too.
With additional pair of transistor for current source (and paralleled output), it can deliver up to 180W with better performance. And the best stability I have seen from all amplifiers I have simulated.
  Reply With Quote
Old 15th December 2012, 05:40 PM   #28
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by Jay View Post
With additional pair of transistor for current source (and paralleled output), it can deliver up to 180W with better performance. And the best stability I have seen from all amplifiers I have simulated.
All of them ever?
__________________
First One VSSA
  Reply With Quote
Old 15th December 2012, 05:45 PM   #29
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Quote:
Originally Posted by Lazy Cat View Post
All of them ever?
I mean capacitive load. Hehe And low impedance load too.

ADD: Simulated with 2 Ohm load and/or paralleled with 56uF, no oscillation even with 2V input (and no thermal runaway). Not sure with real measurement but never seen something like this before but the amp sounds good. I learned a couple of things from Marantz CFB amplifier.

My latest play is with your simplest BJT SSA. So only 4 transistors. But I used darlington output. Really "simple". And can be biased very low with acceptable performance.

Last edited by Jay; 15th December 2012 at 06:01 PM.
  Reply With Quote
Old 15th December 2012, 05:50 PM   #30
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
yeah that's what I meant too, so it can deliver off-phase currents better then other amps you've simulated, super
__________________
First One VSSA
  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
Really simple lateral mosfet amplifier Tekko Solid State 11 25th March 2013 06:31 PM
Magic - My first Lateral MOSFET Push-Pull amplifier shaan Solid State 44 7th September 2011 11:47 AM
2SK/irfp lateral vertical mosfet amplifier HELP ?? medogrizli Solid State 53 2nd November 2006 12:47 AM
200 Watt Lateral Mosfet Amplifier macgyver Solid State 32 14th January 2005 06:37 AM
200W Lateral Mosfet Amplifier macgyver Solid State 5 7th July 2003 07:49 PM


New To Site? Need Help?

All times are GMT. The time now is 10:36 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