World-Designs-Forum  

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

WD Amplifiers For discusson of World Designs Amplifiers

Reply
 
Thread Tools Display Modes
  #21  
Old 23rd February 2020, 02:46 PM
Bonky Bonky is offline
Member
 
Join Date: Feb 2018
Location: Sheffield
Posts: 92
Default Re: KT88 conversion to integrated

Yes, thanks everyone; understood.

Best wishes,

Richard.
Reply With Quote
  #22  
Old 25th February 2020, 07:57 PM
Bonky Bonky is offline
Member
 
Join Date: Feb 2018
Location: Sheffield
Posts: 92
Default Re: KT88 conversion to integrated

My KEL84 has now been converted and is working perfectly ...no need for a pre-amp.

I did not do the 'earth-lifting' mod in the end. I decided to wait and see if the hum decreased with the removal of said pre-amp. I believe it has.

R
Reply With Quote
  #23  
Old 25th February 2020, 08:51 PM
Greg.'s Avatar
Greg. Greg. is offline
WD Archivist
 
Join Date: Dec 2005
Location: Bristol, UK
Posts: 3,376
Default Re: KT88 conversion to integrated

Richard, It would be cheap and easy to introduce an earth lift network anyway. Why not give it a try and see if things sound better?
Reply With Quote
  #24  
Old 25th February 2020, 10:42 PM
Bonky Bonky is offline
Member
 
Join Date: Feb 2018
Location: Sheffield
Posts: 92
Default Re: KT88 conversion to integrated

Yes, I could, but I've suddenly recalled that I disconnected the earth wire from the mains lead many months ago, relying on the grounding from the various leads going to/from the pre-amp. Now that the pre-amp's gone I think I'd better reconnect and see if I get an earth loop.

I'll take advice of course....

Richard
Reply With Quote
  #25  
Old 25th February 2020, 11:21 PM
bikerhifinut bikerhifinut is offline
Senior Member
 
Join Date: Jan 2006
Location: Penrith, Cumbria
Posts: 1,050
Default Re: KT88 conversion to integrated

I haven,t got a copy of the KEL84 build instructions any more since I moved mine on.
But I'd be very surprised if the KEL84 as standard didn't have the 10 ohm earth lift resistor/0.1uF capacitor fitted. That's why I was confused about all this about earth lifting on the WD amp. Any earth loop issues to my thinking will have been around the preamp.
As I remember it, the KEL84 was as quiet as a mouse on any source I tried with it.
Richard, get that mains earth connected ASAP! there's a reason for it!

Andy.
Reply With Quote
  #26  
Old 25th February 2020, 11:34 PM
Greg.'s Avatar
Greg. Greg. is offline
WD Archivist
 
Join Date: Dec 2005
Location: Bristol, UK
Posts: 3,376
Default Re: KT88 conversion to integrated

Well, Andy, I ‘ve checked the instructions, circa Peter Comeau era, and certainly he did not incorporate an earth lift network in the KeL84. Matthew may have subsequently changed this, but I have no idea.
Reply With Quote
  #27  
Old 26th February 2020, 08:14 AM
Bonky Bonky is offline
Member
 
Join Date: Feb 2018
Location: Sheffield
Posts: 92
Default Re: KT88 conversion to integrated

"Richard, get that mains earth connected ASAP! there's a reason for it!"

Don't worry ...it's first on my list this morning.

Edit: The amp WAS earthed after all...it was my pre-amp that wasn't. My poor memory!


Matthew wouldn't have sent me the two earth-lifting components if it had already been incorporated(?)

...I'll ask Matthew...but I think he's away for a couple of days.

Thanks again,

Richard.

Last edited by Bonky; 26th February 2020 at 02:56 PM.
Reply With Quote
  #28  
Old 26th February 2020, 05:39 PM
Matthew Snell Matthew Snell is offline
*****
 
Join Date: Feb 2006
Location: Totnes, Devon, UK
Posts: 108
Default Re: KT88 conversion to integrated

Just to confirm, KT88 is supplied with the earth lift, but KEL84 is not. No reason - other than inertia.

I haven't had any reports of hum in KEL84 in the last nine years. If anyone wants to chip in with "theory" on this it would be lovely to hear.

While I've occasionally suggested the earth lift for stubborn hum (so far always in other contexts/set-ups), I would never suggest disconnecting mains earth other than for diagnostic purposes and under controlled conditions.

... I hope that's clear!

Matthew
Reply With Quote
  #29  
Old 26th February 2020, 05:49 PM
bob orbell bob orbell is offline
Senior Member
 
Join Date: Nov 2009
Location: kettering northants.
Posts: 2,020
Default Re: KT88 conversion to integrated

I think that Bonky (Richard) my have been mislead by the earth lift and completely removed the earth cable from the chassis , I hope I am wrong, the KEL 83 has 0 volts and chassis earth common, the earth lift resistor and capacitor (in parallel) separates 0 volts and earth. Bob
Reply With Quote
  #30  
Old 26th February 2020, 06:01 PM
Bonky Bonky is offline
Member
 
Join Date: Feb 2018
Location: Sheffield
Posts: 92
Default Re: KT88 conversion to integrated

Quote:
Originally Posted by bob orbell View Post
I think that Bonky (Richard) my have been mislead by the earth lift and completely removed the earth cable from the chassis , I hope I am wrong, the KEL 83 has 0 volts and chassis earth common, the earth lift resistor and capacitor (in parallel) separates 0 volts and earth. Bob
Hi Bob, I easily get confused these days - but not on this issue, (except as I added to an earlier post of mine...I was wrong ... as the earth cable to the Kel was intact after all. I had taken it off the Shiit Saga preamp).

I am fully aware of the need to 'earth' such equipment - especially with such high voltages.

Expectation bias perhaps, but I think the amp without the preamp sounds better than it did before...And it looks better!

Thanks everyone,

Richard

Last edited by Bonky; 26th February 2020 at 08:24 PM.
Reply With Quote
Reply

Tags
find

Thread Tools
Display Modes

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 07:08 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright World Designs