Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 12th August 2010, 03:38 PM   #21
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Greetings back to you and thank you for the compliments.

The Williamson can make a nice amp, but requires very good output transformers to make it work without it oscillating. Not knowing the quality of the Chinese transformers makes this a gamble.

Using point to point wiring is fine.

Eli Duttman (see post above mine) is very knowledgeable and I would send him a private email on the subject and selecting a good schematic.

A Mullard topology would be better for you given the components you wish to use. This topology is more forgiving of the components, offers excellent fidelity, and is widely popular, which means you will have a greater set of resources at your disposal should you have issues or questions.

Quote:
Originally Posted by ptiJean View Post
Greetings from France,

This seems to be a very good work, a nice KT88 Williamson push-pull.

I'm actually thinking of building my own KT88 push-pull, with parts of a defekt Music Angel XD800 amp.

I wish I can reuse the wood+metallic case, the 4 Shuguang KT88 tubes, and the 4 transformers (output + power).

For the rest I'm actually browsing Internet to find a good scheme, and wish to avoid PCB and do direct-wiring.

Could you help me chose the scheme ? What's all about this Williamson ?
What differs it from others ?

I have Tannoy Definition 500 speakers with coaxial 8 inches polypropylene speakers and 8 inches boomer.

Thank you really alot,
Regards
  Reply With Quote
Old 12th August 2010, 03:47 PM   #22
ptiJean is offline ptiJean  France
diyAudio Member
 
Join Date: Jul 2006
Sorry for the question : can you give me Eli Duttman's nickname ?
I don't find a post above yours cause yours is now first
Thank you.

Last edited by ptiJean; 12th August 2010 at 03:55 PM.
  Reply With Quote
Old 12th August 2010, 03:56 PM   #23
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Sure!

It is actually Eli Duttman. He uses that name for his user name, so just do a search on the forum for that name and then when you find one of his posts, click his name and send a private email.

Best of luck!

Quote:
Originally Posted by ptiJean View Post
Sorry for the question : can you give me Eli Dutman's nickname ?
I don't find a post above yours cause yours is now first
Thank you.
  Reply With Quote
Old 12th August 2010, 03:58 PM   #24
ptiJean is offline ptiJean  France
diyAudio Member
 
Join Date: Jul 2006
Thank you, friend, I will do that !
By the way : do you have experience with Shuguang GEKT88 ?
Do you know other good KT88 ?
Thank you
Regards
  Reply With Quote
Old 12th August 2010, 04:03 PM   #25
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Sorry, I do not. Give them a try. I bought a set of Chinese Ruby tubes (KT88s) to use to bring up the amp with the idea to buy better ones when I got the amp running. However, the Rubys work great, so I just kept them in the amp. Maybe yours will do the same? Give them a try.

Quote:
Originally Posted by ptiJean View Post
Thank you, friend, I will do that !
By the way : do you have experience with Shuguang GEKT88 ?
Do you know other good KT88 ?
Thank you
Regards
  Reply With Quote
Old 12th August 2010, 04:47 PM   #26
diyAudio Member
 
richwalters's Avatar
 
Join Date: Sep 2003
Location: Alps:Tube amp designs over 150W, SMPS guru.
Quote:
Originally Posted by Loren42 View Post
The Williamson can make a nice amp, but requires very good output transformers to make it work without it oscillating. Not knowing the quality of the Chinese transformers makes this a gamble.
Oh yes; beginners luck--experience is the art of making things fit to work.

I've never had stability issues with Williamson concepts, perhaps it's because I design out and understand the instability bugs. In each and every case I can obtain an extra 15dB on top of nominal 20dB global nfb headroom when instability sets in. I agree with Eli Duttman that the o/p trannies are the awkward spec items, but think there has been alot of misunderstanding and unfairness retro about Williamson designs.......I ought to do a demo, an amp wind-up on the most awkward speakers and blow the cones out. Sonically, the optimised design sounds relaxed, and has never let me down when the Vol is really wound up.
The winter project amp (bits gradually being accumulated) will be another power double 150W WILLIAMSON using Sowter output transformers.
My Citation is far more dodgy to alien speakers esp with long cables; and on this I always keep it at home.
Perhaps I ought to slot in a Hammond tranny in my power design and see what happens.

richy
  Reply With Quote
Old 12th August 2010, 07:24 PM   #27
diyAudio Member
 
Join Date: Aug 2008
Hi, Loren42,

Very nice build. What is the BIAS voltage of your power transformer?
  Reply With Quote
Old 12th August 2010, 07:53 PM   #28
taj is offline taj
diyAudio Member
 
taj's Avatar
 
Join Date: Feb 2005
Hi Loren,

I notice you've eschewed convective cooling for the tubes. Does it all stay reasonably cool despite that?

..Todd
  Reply With Quote
Old 13th August 2010, 12:02 AM   #29
diyAudio Member
 
Join Date: Jun 2004
Location: Indiana
Quick question about Williamson stability. Is the issue the additional driver stage and the associated phase shifts? In other words, if one chose an output tube with more modest drive requirements and used a tube with more "stones" for the PI and went stright from the PI to the output tubes would the stability issues be solved?
__________________
If We The People refuse to hear the truth we will be ruled by liars.
  Reply With Quote
Old 13th August 2010, 12:16 AM   #30
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Quote:
Originally Posted by LinuksGuru View Post
Hi, Loren42,

Very nice build. What is the BIAS voltage of your power transformer?
Thank you. The tap is 80 VAC from the XPWR133 transformers.
  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
Stereo build- Mikael Abdellah's KT88 SE amp porkchop61 Tubes / Valves 119 3rd April 2011 05:41 AM
new build - abdellah SE KT88 vince76 Tubes / Valves 19 31st July 2009 10:07 PM
Cheap Williamson amp kit consort_ee_um Tubes / Valves 4 12th February 2007 10:25 PM
suggest a KT88 SE to build matthew2456 Tubes / Valves 4 5th August 2006 05:23 PM
Using KT88 to build a monster champ amp? G Tubes / Valves 2 13th December 2004 05:20 PM


New To Site? Need Help?

All times are GMT. The time now is 09:43 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