Anyone recognise these ? - 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 5th September 2013, 08:42 PM   #1
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
Default Anyone recognise these ?

Many years ago I built a pair of these from an article in Electronics Today International (I think).

Anyone recognise them and be able to send me a copy of the article.

The boards were home-brew, copies of the published boards.
Attached Images
File Type: jpg DSIR9567.jpg (672.0 KB, 420 views)
  Reply With Quote
Old 5th September 2013, 08:51 PM   #2
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
It's not clear in the photo but the Op-amp is an OPA604AP.
  Reply With Quote
Old 5th September 2013, 09:11 PM   #3
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
The reverse side looks like this.
Attached Images
File Type: jpg DSIR9568.jpg (569.5 KB, 390 views)
  Reply With Quote
Old 5th September 2013, 10:28 PM   #4
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
I think it's this:

HIGH QUALITY 100W MOSFET POWER AMPLIFIER By David N.J. White
Attached Files
File Type: pdf mos100.pdf (597.5 KB, 270 views)
  Reply With Quote
Old 5th September 2013, 10:34 PM   #5
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
Looks a bit like the Maplin DJ Amp kit from the 80's.
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 6th September 2013, 10:06 AM   #6
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
Jaycee, if it's not then it's pretty damn close - Thank you.

The only differences I can see are the choices of VBE multiplier and Driver transistors.
  Reply With Quote
Old 6th September 2013, 11:44 AM   #7
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
So, in a bi-amp system, which amp needs to be of the higher quality.

Bass or Mid/Tweeter.

My crossover frequencies are at 400 Hz and 3.8KHz.
  Reply With Quote
Old 6th September 2013, 03:21 PM   #8
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
The alternative driver transistors are actually mentioned in the article, so that's probably it. He also mentions that pretty much anything can be used as the VBE device, so I wouldn't be surprised if that's a BD139 that's been used.
  Reply With Quote
Old 6th September 2013, 03:31 PM   #9
diyAudio Member
 
Join Date: Dec 2005
Location: Kuala Lumpur
I agree, its the David White design. It's a strange way of using lateral mosfets, whose main advantage is that they don't need temperature compensation in the classic and very good, Hitachi circuit.
I was just reading the August 2001 Electronics World, where DW modified the Hitachi design to use vertical mosfets. Unfortunately he put a current source in the VAS stage current mirror
  Reply With Quote
Old 7th September 2013, 01:00 PM   #10
405man is offline 405man  Scotland
diyAudio Member
 
Join Date: Dec 2003
Location: South Lanarkshire near Glasgow Scotland
You could also concider one of the Quad 405 mods listed here

http://www.keith-snook.info/amplifie...0evolution.pdf

on Keith Snooks excellent web site

the Mod3 and 4 offer the lowest componant count, as the output stage is unbiased there are no thermal issues

Stuart
  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
Anyone recognise these speakers? deanxxx Everything Else 5 17th May 2013 11:34 PM
Anyone recognise these tubes... nickds1 Tubes / Valves 5 11th February 2013 06:59 PM
somebody can recognise this elna? netherlands Parts 4 23rd June 2009 03:18 AM
Does anyone recognise this 12AU7? sharpi31 Tubes / Valves 2 28th January 2008 10:11 AM
how does one recognise ..... alecwek Parts 3 22nd July 2004 08:27 AM


New To Site? Need Help?

All times are GMT. The time now is 06:32 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