The Lawyer amplifier by Herbert Fu - 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 19th April 2005, 04:01 PM   #1
diyAudio Member
 
Join Date: Jun 2004
Location: HKSAR
Default The Lawyer amplifier by Herbert Fu

Does any one of you remember this amplifier? I happened to come across this when I am tidying up my machine. I remember that the output was something like irfp6??. His site is gone and I'm just wondering if any of you happened to have a copy of the material (he also have some wall horn material and others stuff). Or anybody knows whereabout is his site now?
  Reply With Quote
Old 5th January 2006, 01:40 PM   #2
FYC is offline FYC  Hong Kong
diyAudio Member
 
Join Date: Jan 2001
Location: Hong Kong
Hi, really by chance I spot this and I do not know if I can reach the poster being so late.

Yes, the website is gone as it had not been maintained for a while. The output devices is IRF610 and IRF9610 complimentory pairs.
  Reply With Quote
Old 6th January 2006, 04:39 AM   #3
diyAudio Member
 
Join Date: Jun 2004
Location: HKSAR
Hi FYC,

I've forgotten all about this already. So do you have a copy of the schematic? If so, would you please email to me or posted it here?

Tks
  Reply With Quote
Old 6th January 2006, 12:50 PM   #4
FYC is offline FYC  Hong Kong
diyAudio Member
 
Join Date: Jan 2001
Location: Hong Kong
Hi, I tried to post the circuit here:
Attached Images
File Type: gif redcircuit.gif (50.9 KB, 714 views)
  Reply With Quote
Old 6th January 2006, 05:38 PM   #5
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
What an interesting schematic, thanks for posting.
If anyone has/makes a layout for this one, i'd love to see it posted here.
__________________
The buck stops Here
  Reply With Quote
Old 7th January 2006, 09:47 AM   #6
clem_o is offline clem_o  Philippines
diyAudio Member
 
Join Date: Jun 2005
Location: Manila
47 ohm (R29) at the output - that should have a a few turns of wire around it, eh?! Probably what the asterisk means...

:-)

Cheers
  Reply With Quote
Old 7th January 2006, 12:08 PM   #7
diyAudio Member
 
Join Date: Jun 2004
Location: HKSAR
How much power can this amp. outputs? Can paralleling the outputs and raising the +-ve rail voltage raise the power? Can anyone provide the details?
  Reply With Quote
Old 7th January 2006, 12:20 PM   #8
jmateus is offline jmateus  United States
diyAudio Member
 
jmateus's Avatar
 
Join Date: Mar 2003
Location: US, New Jersey
Interesting amplifier.
Details? Any link?
The audio community would be interested.
__________________
JLH 2005, Cyrus and so on...
  Reply With Quote
Old 7th January 2006, 01:04 PM   #9
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
It is a fully symmetrical differential amplifier
using JFETS cascoded by bipolar in input and VAS.

And push-pull HEXFETS IRF610/9610 in output.

Uses two resistors to reduce total gain/feedback.
R24 and R25, both 50k in VAS.

Voltage supply is high for a headphone amp +-58 Volt.

So, all the active transistors are JFET/HEXFET.
__________________
lineup
  Reply With Quote
Old 7th January 2006, 02:19 PM   #10
awpagan is offline awpagan  Australia
diyAudio Member
 
Join Date: Nov 2004
Location: sydney
Quote:
Originally posted by lineup

Uses two resistors to reduce total gain/feedback.
R24 and R25, both 50k in VAS.

Voltage supply is high for a headphone amp +-58 Volt.

So, all the active transistors are JFET/HEXFET. [/B]

Silicon chip's Ultra Low Distortion amp uses similar to r24 r25,
excep they are 2 * 10k

allan
__________________
Indecision makes the world gone round.
Maybe
  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
Don Herbert, RIP SY The Lounge 5 28th June 2007 08:51 PM
Herbert Jeschke's TQWT with RS 40-1354, dimensions? gychang Full Range 18 13th September 2006 09:22 PM
Questions about how to decrease the PASS A-40 amplifier into a class AB amplifier. novtango Pass Labs 2 21st October 2002 02:50 AM
another DIY project - "Lawyer" phono amp FYC Solid State 0 1st March 2001 02:46 PM


New To Site? Need Help?

All times are GMT. The time now is 06:51 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