My KT88 Williamson Amp Build - Page 2 - diyAudio
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 10th January 2010, 02:58 PM   #11
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Quote:
Originally Posted by Bob_345 View Post
i wish i had skilz like that!
Thank you. Those skills were developed over a long time, but no reason you can't do it, too.

Then again, it helps to have a milling machine at your disposal.
  Reply With Quote
Old 10th January 2010, 04:19 PM   #12
diyAudio Member
 
richwalters's Avatar
 
Join Date: Sep 2003
Location: Alps:Tube amp designs over 150W, SMPS guru.
tube screens.. g1 on o/p tranny wwr ?
or am I ....?

richy
  Reply With Quote
Old 10th January 2010, 04:44 PM   #13
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Quote:
Originally Posted by richwalters View Post
tube screens.. g1 on o/p tranny wwr ?
or am I ....?

richy
Good catch! The schematic symbol is wrong, but the pin numbers on the symbol should be correct for the KT88 and that is how it is wired in circuit.

Pin 3 = Plate
Pin 4 = Screens
Pin 5 = Grid
Pin 8 = Cathode
  Reply With Quote
Old 10th January 2010, 05:35 PM   #14
jlsem is offline jlsem  United States
diyAudio Member
 
jlsem's Avatar
 
Join Date: Jun 2003
Location: Dallas,TX
Quote:
Originally Posted by Loren42 View Post
Very shocking. That was not the person I knew him to be at all.
Quote:
When I was in high school I was befriended by this really weird guy
To me he sounds like that person you knew him to be.

I'm sorry, I couldn't help it.

That's a really nice amp. I was just looking at a similar schematic in the GEC amplifier book a couple of weeks ago and was thinking about building one myself. It's a nice straightforward design.

Regards,
John
__________________
When an LP gets scratched it still makes sense; when CDs crack up they go completely senile and gibber incontinently. - Hugo Williams
  Reply With Quote
Old 10th January 2010, 06:07 PM   #15
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
I've updated the original schematic to fix the symbol for the KT88, so it should be correct now.
  Reply With Quote
Old 10th January 2010, 06:11 PM   #16
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Quote:
That's a really nice amp. I was just looking at a similar schematic in the GEC amplifier book a couple of weeks ago and was thinking about building one myself. It's a nice straightforward design.

John,

Williamson topology is "classic". The big issue with the topology is instability due to phase shifts. It's good news indeed that Loren has successfully executed Williamson style, while employing moderately priced O/P "iron". This project will add to the lore of Edcor trafos being an excellent value.
__________________
Eli D.

Last edited by Eli Duttman; 10th January 2010 at 06:12 PM. Reason: fixed verbiage
  Reply With Quote
Old 10th January 2010, 10:04 PM   #17
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Eli,

We have discussed a similar KT88/6SN7 amp on my Magnepan's on another thread- you had concerns over my OPT...Is the Edcor used here preferred over the Hammond 1650N I have?

Are you also in favor of connecting the 6SN7 plates via the UL taps here also as with the 1650N?
__________________
All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian
  Reply With Quote
Old 10th January 2010, 10:36 PM   #18
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Maybe dump/sell the Hammond 1650N and buy the Edcor CXPP100-MS-4.2K? Although I am intrigued with the "Exolinear Topology"
__________________
All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian
  Reply With Quote
Old 11th January 2010, 01:02 AM   #19
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Quote:
We have discussed a similar KT88/6SN7 amp on my Magnepan's on another thread- you had concerns over my OPT...Is the Edcor used here preferred over the Hammond 1650N I have?

John,

IMO, the Edcor CXPP100-MS-4.2K is preferable, if for no reason other than its 100 W. power rating. That rating implies the magnetic headroom needed, when GNFB is used, is available. The CXPP100-MS-3.3K might be a better choice with KT88 "finals".

The Hammond 1650Ns in your possession are (IMO) best mated with PP EL34s or PPP "12" W. types, like the EL84 and 6V6. The 1650N's 60 W. rating leaves little "wiggle room", when mated to KT88s. Doug Piccard's "exolinear" topology is the only thing I can think of, which allows you a 60 W. O/P using that "iron" and KT88s. How bad the freq. resp. aberations will be, I can't say. A no GNFB topology requires VERY linear O/P trafos and I have reservations about Hammond stuff used that way.

Even though both Williamson and Mullard style topologies are both "classic", I prefer Mullard. Mullard style is outright less vulnerable to instability than Williamson is. Loren is to be commended for a satisfactory execution of Williamson style, without employing extremely costly creme de la creme O/P "iron".
__________________
Eli D.

Last edited by Eli Duttman; 11th January 2010 at 01:03 AM. Reason: fixed tyo
  Reply With Quote
Old 12th August 2010, 03:24 PM   #20
ptiJean is offline ptiJean  France
diyAudio Member
 
Join Date: Jul 2006
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

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 11:54 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