Yet another amp - simple inverted with 10x gain, mosfet output stage - Page 2 - 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 16th June 2011, 08:27 AM   #11
WuYit is offline WuYit  Sweden
Banned
 
Join Date: Oct 2010
Another possibility would be a fairly high biased output compound la Hiraga and resistor loaded input. A great topology.
  Reply With Quote
Old 16th June 2011, 08:41 AM   #12
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Its the "Le Monstre" you are refering to?
  Reply With Quote
Old 16th June 2011, 09:07 AM   #13
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
Quote:
Originally Posted by sonnya View Post
You can drive it from a jfet buffer like in this paper:

http://www.tkhifi.com/div/Erno_Borbe..._articel_2.pdf
Sonnya
You have a nice amplifier there.

For input I think a two-NJFET solution
like the Borbely fetbuffer here is good:
.
Attached Images
File Type: png fet_buffer.png (4.7 KB, 755 views)
__________________
lineup
  Reply With Quote
Old 16th June 2011, 09:09 AM   #14
WuYit is offline WuYit  Sweden
Banned
 
Join Date: Oct 2010
sonnya,
yes, you could use that topology with emitter input.
  Reply With Quote
Old 16th June 2011, 09:11 AM   #15
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Hi Lineup.

That was exactly what i had in mind.
  Reply With Quote
Old 16th June 2011, 09:58 AM   #16
WuYit is offline WuYit  Sweden
Banned
 
Join Date: Oct 2010
sonnya,
now I`m getting confused, what are you actually aiming at?
  Reply With Quote
Old 16th June 2011, 10:33 AM   #17
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Hi WuYit.

Juma wanted a higher input impedance. And i suggested a buffer like the One Lineup pointed at.

You can get a high input impedance, but it will be on the cost of speed and offset.

The speed is mainly because it is a CFB design where in+ is grounded.

This amp sounded good, but did lack performance into difficult load as it used BJT outputs which loaded the VAS stage heavier as load was more lowimpedant.

- know the "Le monstre" It's a good and simple design. But it is only 8W and this one is a ~25W. Maybe it will end up as a Naim nait sized amp....

- Sonny
  Reply With Quote
Old 16th June 2011, 10:51 AM   #18
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
Quote:
Originally Posted by sonnya View Post
... Juma wanted a higher input impedance. ...
Sorry Sonny, there was a misunderstanding - I don't want anything. When I want something, I make it myself.

I just noticed that potentially fine amp could be sonically degraded by use of inappropriate buffers. I built and tested more than my share of amps and buffers (including those listed in Borbely's articles) and it's my opinion that slight change in your amp's topology (to achieve higher Zin) would be very beneficial. But it's your amp...

Keep up the good work
  Reply With Quote
Old 16th June 2011, 10:56 AM   #19
WuYit is offline WuYit  Sweden
Banned
 
Join Date: Oct 2010
If the input signal is a current then your topology is OK, if it is a voltage then the input stage should be changed. Thats the point.
  Reply With Quote
Old 16th June 2011, 11:39 AM   #20
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
Exactly.
If Zin of about 10k is enough and non-inverting topology is preferable, the easiest way to do it with this amp would be like this:
Attached Images
File Type: gif SonnyA-NI-HiZin.gif (9.2 KB, 723 views)
  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
Simple stereo gain stage ss007 Analog Line Level 156 23rd August 2013 03:52 PM
Wanted: Zero feedback 2-10x gain line stage...prefer symmetrical Ric Schultz Analog Line Level 14 26th February 2011 07:26 PM
Voltage gain stage for Non-NFB MOSFET current amp gripracer Solid State 50 23rd October 2009 02:37 AM
AMP with inverting output stage mosfet fab Solid State 112 28th January 2007 04:32 AM
Elektor op-amp front-end with mosfet CF output stage Dusk Elektor 1 5th April 2006 04:09 AM


New To Site? Need Help?

All times are GMT. The time now is 03:45 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