World-Designs-Forum  

Go Back   World-Designs-Forum > DIY Projects > DIY Pictures
Register FAQ Members List Calendar Gallery Today's Posts Mark Forums Read

DIY Pictures Gallery of DIY project pictures

Reply
 
Thread Tools Display Modes
  #1  
Old 19th January 2007, 07:51 PM
MikeVA MikeVA is offline
Junior Member
 
Join Date: Aug 2006
Location: Shipley, West Yorks, UK
Posts: 8
Default KEL84 plus custom Headphone Adaptor.

My first DIY kit amp is this Kel 84. I'm very pleased with the results, with the exception of the amp lacking a headphone socket.

As a result I started thnking about a passive Headphone attenuator to run phones from the speaker outputs.

The Headphone adaptor is my first DIY effort - it incorporates switched speaker outputs and 8 Ohm 10 Watt resistors in each channel (as suggested by WD) as a dummy load.

It works very well and I'm very pleased with the result.


Mike.
Attached Images
File Type: jpg KEL84+HPA.jpg (123.4 KB, 225 views)
Reply With Quote
  #2  
Old 19th January 2007, 08:00 PM
asdylan
Guest
 
Posts: n/a
Default Re: KEL84 plus custom Headphone Adaptor.

you have a pm
Reply With Quote
  #3  
Old 19th January 2007, 11:29 PM
Greg.'s Avatar
Greg. Greg. is offline
WD Archivist
 
Join Date: Dec 2005
Location: Bristol, UK
Posts: 3,582
Default Re: KEL84 plus custom Headphone Adaptor.

Who has a PM? Please give us some text to compliment your pic of a nice looking build and headphone option.

Best wishes,

Greg
Reply With Quote
  #4  
Old 20th January 2007, 02:05 AM
MikeVA MikeVA is offline
Junior Member
 
Join Date: Aug 2006
Location: Shipley, West Yorks, UK
Posts: 8
Talking Re: KEL84 plus custom Headphone Adaptor.

Hi there I thought I had posted details with the pic but I'll try again.

The KEL 84 in the photo is my first attempt at a kit build of any kind. and I must say I'm very pleased with the outcome. The one criticism (for me at least ) is being unable to use headphones.

So, I spent some time researching options and came up with a very simple attenuation arrangement. A brief word with WD gave me the confidence to build an attenuator specifically suitable for my KEL 84, but also usable with other Valve or Transistor amplifiers.

The attenuator takes is feed from the KEL 84 speaker terminals, and so volume is controlled by the amps volume control.

It includes switched "pass through" speaker connections to allow selection of headphones or speakers.

It incorporates an 8 ohm 10 watt resistor across each channel to maintain a dummy load on the amplifier when listening to headphones.

I'm very pleased with this unit as it allows much higher percieved sound quality then with my speakers - largely due to an "L" shaped room with poor acoustics.

Cheers,

Mike
Reply With Quote
  #5  
Old 23rd January 2007, 01:33 PM
graeme
Guest
 
Posts: n/a
Default Re: KEL84 plus custom Headphone Adaptor.

hi, i was thinking of building a similar headphone switching box. I think i understand your description but any chance of a simple drawing of the circuit?
Reply With Quote
  #6  
Old 24th January 2007, 12:19 AM
MikeVA MikeVA is offline
Junior Member
 
Join Date: Aug 2006
Location: Shipley, West Yorks, UK
Posts: 8
Default Re: KEL84 plus custom Headphone Adaptor.

Yes, I'll post a diagram with the values shortly.

Reagrds,

Mike.
Reply With Quote
Reply


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
Forum Jump


All times are GMT +1. The time now is 03:33 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright World Designs