JLH Headphone Amp - Page 11 - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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 28th February 2011, 11:22 AM   #101
diyAudio Member
 
Join Date: Dec 2010
Location: London
CORRECTION

Also JLH did some work on stabilised power supplies
- Power Supplies for Electronic Equipment Part 2 – Shunt and Series Designs
ETI
Apr ’94 p21
Source The Class-A Amplifier Site - JLH Articles
and here
John Linsley Hood ripple Eater - Rock Grotto Charity Edition
  Reply With Quote
Old 28th February 2011, 01:13 PM   #102
diyAudio Member
 
Join Date: Dec 2010
Location: London
ADDITIONAL

hotiron in http://www.diyaudio.com/forums/headp...ml#post2450241
and
synchron in http://www.diyaudio.com/forums/headp...ml#post2461130

Seem to have this JHL Class A headphone amplifier earphone AMP / preamp on eBay (end time 28-Feb-11 12:58:08 GMT)

Which now has been modified to this
NEW Ver JHL Class A Headphone amplifier PRE AMP KIT DIY on eBay (end time 23-Mar-11 05:43:37 GMT)

These are both JLH Circuit 1 from The Class-A Amplifier Site - JLH Headphone Amplifiers
Please note that on ebay they are called JHL and to find them you will need to use the worldwide search term under advanced or the left side of the screen.

I wrote to the company in China bai(DOT)du(DOT)com(AT)hotmail(DOT)com this morning it seems the modifications between the two PCB's are layout and component quality ... In a very fast reply there was a copy of the schematic for the new version if anyone is interested. The old one is a green PCB and the new one a blue PCB.

Thought these PCB's maybe a good starting point, your comments are very welcome ?
  Reply With Quote
Old 28th February 2011, 01:39 PM   #103
diyAudio Member
 
Join Date: Dec 2010
Location: London
Hart JLH Headphone Amp - Chiara

There seems to be a third design that can be found here JLH headphone amp

The kit and PCB can be purchased here Chiara
  Reply With Quote
Old 28th February 2011, 01:54 PM   #104
diyAudio Member
 
Join Date: Dec 2010
Location: London
Power Supplies for Electronic Equipment Part 2 – Shunt and Series Designs

Although the original article is not included, two updated designs can be found
1. By Greg Gerskine here JLH Add-on Shunt Regulator
2. Rock Grotto here JLH Ripple Eater Build and Support Thread

I hope this is all helpful ...
Miles
  Reply With Quote
Old 1st March 2011, 01:49 PM   #105
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
Default K170 CCS

Oh dear I've been experimenting again.

I had to mess around a fair bit to get the bias sorted out.
R6 sets bias current 110R = > 75R = <
Ive set bias at 50ma
And its sounding pretty damn good.
Offset is stil using LM336-2.5 and a 10K trim pot.
Attached Images
File Type: gif jlhphonesfig1.gif (7.9 KB, 1499 views)
__________________
If you give up easily Dont start!!
  Reply With Quote
Old 1st March 2011, 02:09 PM   #106
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
Default Unbelievable

Hi Miles, I just had a look at Alongs new board on ebay, and could not believe he had changed the input caps to foils and then bypassed with a ceramic.

My so called JHL has been shelved.
As I much prefer my stripboard version.
Don't know if it's because of the P2P like construction or what:
__________________
If you give up easily Dont start!!
  Reply With Quote
Old 1st March 2011, 03:08 PM   #107
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
Default New V Old

Here is a pic of my new perfboard K170.
And on the right is the symmetrical one I built Probably about 18 years ago when it was published in ETI.
Attached Images
File Type: jpg K170-2.JPG (457.0 KB, 1490 views)
File Type: jpg Symmetrical.JPG (392.5 KB, 1404 views)
__________________
If you give up easily Dont start!!
  Reply With Quote
Old 1st March 2011, 03:54 PM   #108
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
Bollocks Looks like I was beaten to this. I thought i had an innovation.
http://www.diyaudio.com/forums/headp...ets-servo.html
__________________
If you give up easily Dont start!!
  Reply With Quote
Old 23rd March 2011, 11:31 AM   #109
diyAudio Member
 
Join Date: Oct 2010
Location: Houston,TX
Hello HotIron. I too purchased the headphone amp off eBay. I was wondering if you could be so kind as to list all the parts you changed, part value and location on the board?
  Reply With Quote
Old 27th March 2011, 11:18 AM   #110
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
I have revealed all here look at the pic for location.
http://www.diyaudio.com/forums/headp...ml#post2450241
__________________
If you give up easily Dont start!!
  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
JLH headphone amplifier steveh49 Headphone Systems 8 14th May 2014 03:31 PM
JLH Headphone amp aethelbert Headphone Systems 4 13th July 2009 11:14 PM
JLH headphone amp with FET's and servo nelsonvandal Headphone Systems 17 30th August 2008 09:26 PM
PCB for JLH amp FaTTy Solid State 0 27th March 2007 04:40 PM


New To Site? Need Help?

All times are GMT. The time now is 09:33 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