Tubes for Lumley ST40 power amplifier? - 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 12th March 2006, 07:32 AM   #1
john is offline john  Philippines
diyAudio Member
 
john's Avatar
 
Join Date: Aug 2001
Location: pasay city
Default Tubes for Lumley ST40 power amplifier?

A friend is asking me to restore a tubeless Lumley ST40 tube power amplifier.

Anybody out there might own one ST40 who knows all the tube compliments?

Your help is kindly appreciated,

John
  Reply With Quote
Old 12th March 2006, 11:16 AM   #2
diyAudio Member
 
Join Date: Nov 2002
I did a search and turned up nothing. There are others that may have more luck.

If nothing is found I would suggest drawing up the schematic and posting it for all to view. This might not be a bad idea anyway.
  Reply With Quote
Old 13th March 2006, 12:48 AM   #3
john is offline john  Philippines
diyAudio Member
 
john's Avatar
 
Join Date: Aug 2001
Location: pasay city
Default Tubes for Lumley ST-40 power amplifier?

Thank you for your effort Sir.

I will try to draw the schematic diagram.
  Reply With Quote
Old 13th March 2006, 05:15 AM   #4
john is offline john  Philippines
diyAudio Member
 
john's Avatar
 
Join Date: Aug 2001
Location: pasay city
Default Tubes for Lumley ST-40 power amplifier?

I am still needing information on the types of input and phase splitter tubes. They can either be 12AX7, 12AU7 or 12AT7. These twin triodes I can try them out, But the Tube which is used as a screen regulator is the information I needed badly.

The ST-40 uses 4 EL34 tubes on the output stage.

The Tube (octal based) at the back of the Toroidal Power tranny is data I need. I assume this could be employed as a screen regulator. It got 6.3 volts filament at pins 2 and 7, The Grid (Pin 5) measures 307 VDC and pins 3 and 4 measures ( Plate and Screen) 480 VDC. Is this tube could be EL34 or 6550 or 6L6 ?

Your help is highly appreciated!

Thank You,

John
  Reply With Quote
Old 13th March 2006, 02:15 PM   #5
diyAudio Member
 
Alain Dupont's Avatar
 
Join Date: Sep 2003
Location: Paris - France
john,

Seen something about the tubes of a ST70 ; search on yahoo for Lumley ST70 amplifier
ECC ... don't remember.

Alain.
  Reply With Quote
Old 14th March 2006, 01:08 AM   #6
john is offline john  Philippines
diyAudio Member
 
john's Avatar
 
Join Date: Aug 2001
Location: pasay city
Default Tubes for Lumley ST40 power amplifier

Thanks Alain,

The ST70 uses 6650 and the ST40 uses EL34. The input and phase splitters are ECC82 and ECC83.

I am still uncertain about the octal based tube employed as a screen regulator located at the back of the toroidal power tranny. It could be an EL34 or a 6550?

Help anyone!

John
  Reply With Quote
Old 14th March 2006, 01:40 AM   #7
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
john, the designer is Ben Carter. His email is b(dot)carter(at)homecall.co.uk
  Reply With Quote
Old 14th March 2006, 02:42 AM   #8
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Default Re: Tubes for Lumley ST40 power amplifier

Quote:
Originally posted by john
Thanks Alain,

The ST70 uses 6650 and the ST40 uses EL34. The input and phase splitters are ECC82 and ECC83.

I am still uncertain about the octal based tube employed as a screen regulator located at the back of the toroidal power tranny. It could be an EL34 or a 6550?

Help anyone!

John

hi john,

perhaps you mean the ST70 uses EL34's while the ST40 uses 6550 which can use screen regulators, well, another 6550 for screen regulator will not be a bad idea, but a 6as7/6080 will be better, error amps used 9pin miniatures? plus a discharge type vr regulators right?
__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....
  Reply With Quote
Old 14th March 2006, 12:14 PM   #9
john is offline john  Philippines
diyAudio Member
 
john's Avatar
 
Join Date: Aug 2001
Location: pasay city
Default Tubes for Lumley ST-40 power amplifier?

Thank you for the information Arnold!

Hi Tony,

Lumley ST70 uses 6550 as an output tubes, while the ST40 uses EL34 as output tubes. It's puzzling for me since what tube should I use to the another octal socket which is employed as a screen regulator, since the Bplus is solidstate rectified. I am considering of plugging in on the either 6550 or EL34 if I can't source the schematic diagram or any information on the tubes that were employed on this rare amplifier.

Based on the voltages I have given above, what tube would fit the as a screen regulator?


John
  Reply With Quote
Old 15th March 2006, 02:07 AM   #10
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Quote:
The Tube (octal based) at the back of the Toroidal Power tranny is data I need. I assume this could be employed as a screen regulator. It got 6.3 volts filament at pins 2 and 7, The Grid (Pin 5) measures 307 VDC and pins 3 and 4 measures ( Plate and Screen) 480 VDC. Is this tube could be EL34 or 6550 or 6L6 ?
El34 is my bet in this case, at plate of 480 and grid of 305, your output could be around 340~350 which is fine.
__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....
  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
Ray Lumley m100 schematic needed antibill Tubes / Valves 0 18th March 2009 12:19 PM
High-power amplifier using transmitting tubes Michael Koster Tubes / Valves 39 14th January 2009 11:48 PM
Lumley M250 Woes HuggyBear Tubes / Valves 4 31st March 2003 10:04 PM
Lumley reference AuroraB Tubes / Valves 2 31st March 2003 08:30 AM
Assemblage ST40 Amp kit parts transducer Swap Meet 1 4th October 2002 05:10 PM


New To Site? Need Help?

All times are GMT. The time now is 03:26 PM.


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