Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

Raytheon / Western Electric JW-5755 / 420A
Raytheon / Western Electric JW-5755 / 420A
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 20th August 2014, 07:16 AM   #1
Westernelectric is offline Westernelectric  United States
diyAudio Member
 
Join Date: Jun 2013
Default Raytheon / Western Electric JW-5755 / 420A

Amazing replacement for Mullard Ecc83
/ 12ax7
Everyone That I had listen to the 5755 tubes in place of the Mullard old stock 12ax7 was blown away. What an awesome tube.
Best sounding tubes. All you have to do is switch a few wires on the tube socket and for 15.00 ea. you will get the very best sounding 12ax7.
I Rather pay 15.00 bucks then over 100.00 ea. for the best sounding 12ax7
This is one of the best discoveries ever.
I bought some Raytheon 5755 tubes and replaced all my 12ax7 vintage mullard tubes not only saved over 500.00 I Even think they sound better.
This is cool
Andrew
I bought some yellow branded Raytheon 5755 tubes think they are best
  Reply With Quote
Old 20th August 2014, 05:33 PM   #2
Palustris is offline Palustris  United States
diyAudio Member
 
Palustris's Avatar
 
Join Date: Aug 2006
Location: Cape Cod
I am glad that you enjoy the tubes, but to assert that they are general replacements for the 12AX7 ignores the fact that they have considerably different amplification factor, plate resistance, and transconductance.
  Reply With Quote
Old 21st August 2014, 12:27 AM   #3
Westernelectric is offline Westernelectric  United States
diyAudio Member
 
Join Date: Jun 2013
Default 5755 / 420a

I worked on many tube designs at the western electric plant . The 5755 / 420a tube is very close to the mullard 12ax7 ecc83 internally . Actually the Raytheon 5755 is the closest. The yellow print 1960's productions
Thanks for your input
  Reply With Quote
Old 21st August 2014, 03:49 PM   #4
smoking-amp is offline smoking-amp  United States
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Have you tried rigging a 6SL7 tube in the amplifier to compare? $10

Anyone have a datasheet with a Mu curve for the 5755?

The Raytheon datasheet isn't very complete:

http://frank.pocnet.net/sheets/138/5/5755.pdf

http://frank.pocnet.net/sheets/093/6/6SL7GT.pdf

http://frank.pocnet.net/sheets/093/1/12AX7A.pdf

5755 is a little lower rated than 12AX7A for some things, so some checking needed for an ampl.:
250 Vp versus 330 Vp
1 Watt versus 1.2 Watt
75 V Htr to K versus 100 V

Last edited by smoking-amp; 21st August 2014 at 04:15 PM.
  Reply With Quote
Old 21st August 2014, 04:31 PM   #5
smoking-amp is offline smoking-amp  United States
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Found a WE420A datasheet with a Mu curve:

http://www.westernelectric.com/spec_sheets/420A.pdf

Hmmm...., the WE420A/5755 Mu is varying from 60 to 78 over the operating range, worse variation than a 6LS7 or 12AX7. The steady increase in Mu across the grid voltage range like this has, would mean mainly 2nd harmonic generation.

You are listening to euphonic distortion.... or some cancelation with a later stage. (12AT7 will probably sound even better, and no circuit changes required.)

Last edited by smoking-amp; 21st August 2014 at 05:01 PM.
  Reply With Quote
Old 21st August 2014, 05:13 PM   #6
smoking-amp is offline smoking-amp  United States
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Late edits:
6LS7 above should be 6SL7

12AT7 would actually require a change (increase) in the cathode bias resistor versus the 12AX7.
  Reply With Quote
Old 21st August 2014, 05:18 PM   #7
jazbo8 is offline jazbo8
diyAudio Moderator Emeritus
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Quote:
Originally Posted by Westernelectric View Post
I worked on many tube designs at the western electric plant.
Got any good stories to share? Love to hear some insider scoop about WE!
  Reply With Quote
Old 21st August 2014, 07:55 PM   #8
Tubelab_com is online now Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
The 5755 was designed for dc amps, servo systems, and other applications where low noise, low drift and excellent matching between the sections are required. Low distortion was not a design criteria. It doesn't look like a drop in for many 12AX7 designs. The 5755 wants to be run at a low current and millivolt signal levels. A phono stage might be the only legitimate audio application. They don't work in a guitar amp.

I had a box full of WE and Ratheon tubes an could not find a design where they were measurably superior to other tubes even when the design was optimized for the 5755. I sold the box at a hamfest.

Most of the tubes that I had did not have a getter. It was stated that the activation of a getter could cause more problems than it solved on these specialized tubes.

Looking for something to stuff into a 12AX7 socket, try the 5751 especially the triple mica GE. It has less gain than the 12AX7 but more than the 5755. It drifts less over time that the 12AX7. This is good for LTP stages that are DC coupled to the next stage.
__________________
Tubelab, I blow stuff up so that you don't have to.

Last edited by Tubelab_com; 21st August 2014 at 08:03 PM.
  Reply With Quote
Old 21st August 2014, 11:46 PM   #9
Westernelectric is offline Westernelectric  United States
diyAudio Member
 
Join Date: Jun 2013
Default Raytheon 5755 with Getter

The 5755 / 420a must have a Getter . The very best one is the RELIABILITY CONTROLLED Raytheon made in 1962 thru 1969 . The 5755/420a without the Getter is not as good.
Thank you for all the interest.
  Reply With Quote
Old 21st August 2014, 11:51 PM   #10
Westernelectric is offline Westernelectric  United States
diyAudio Member
 
Join Date: Jun 2013
Default 5755 / 420a Data sheets

Remember there are many designs of the 5755 / 420a
the RELIABILITY CONTROLLED Raytheon 5755 / 420a with large getter is different from western electric clear top and Raytheon or Tungsol clear top.
Must have large Getter for the very best result to replace the 12ax7 ecc83
Thank you all for the interest in this topic. My passion is tubes. Any questions about tubes. Please let me know. I worked for Western Electric and been involved in vacuum tubes for many decades.

Semiconductors are cool ,but tubes are HOT!
  Reply With Quote

Reply


Raytheon / Western Electric JW-5755 / 420AHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for Western Electric components Jsullerot Swap Meet 9 11th October 2012 11:05 AM
Western Electric Transistors simon7000 Swap Meet 2 14th May 2012 10:59 PM
Western Electric 300B serengetiplains Tubes / Valves 4 16th December 2004 06:16 PM
Western Electric transformer contaxchen Swap Meet 0 22nd March 2004 02:54 AM
Western Electric PassFan Tubes / Valves 0 26th April 2003 01:09 PM


New To Site? Need Help?

All times are GMT. The time now is 02:15 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki