12AU7 Genuine or remarked - 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 27th September 2014, 10:04 AM   #1
yajnaS is offline yajnaS  India
diyAudio Member
 
Join Date: Jan 2011
Default 12AU7 Genuine or remarked

I bought some 12AU7 tubes which were sold as genuine, but I'm having doubts after seeing the tube.

Pictures of the tube:
Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.
  Reply With Quote
Old 27th September 2014, 10:27 AM   #2
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
What makes you think they are not as described?
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 27th September 2014, 12:29 PM   #3
yajnaS is offline yajnaS  India
diyAudio Member
 
Join Date: Jan 2011
The printing on the glass looks like modern ink. I washed the tube with soap and water and the printing did not come off. Every other tube I've ever had, the printing did not survive a cleaning.

There is also no etched date code or any other marking on the glass other than the ink lettering.

p.s. The pictures appear vertically squished, but if you click on the picture it will display properly.

Last edited by yajnaS; 27th September 2014 at 12:34 PM.
  Reply With Quote
Old 27th September 2014, 12:52 PM   #4
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

The fact that the printing does not wash off does not tell you much other than that old European valves used calcium based ink that did rub of easily.

OTOH, the fact that there's no acid engraving on the glass envelope ( there normally always is at least some code on it) should tell you that the valve is not made in the USA.
This is not uncommon since most of the Philips plants were all over the world and at the end of the valve era product was often traded inside these groups of manufacturers.

Going by the pics I'd say those are probably Sylvania/ECG but it's anybody's guess.

Cheers,
__________________
Frank
  Reply With Quote
Old 27th September 2014, 02:19 PM   #5
diyAudio Member
 
Join Date: Nov 2009
Location: Cortez, CO
It does look sloppily stamped. The "Electronic" looks like GE made it, but it doesn't have a manufacturer stamp, that makes it look like a second, or they cleaned a used tube, the lettering came off and they restamped it.
Anode looks kinda like a Sylvania.

Last edited by DeathRex; 27th September 2014 at 02:24 PM.
  Reply With Quote
Old 27th September 2014, 02:31 PM   #6
kmaier is offline kmaier  United States
diyAudio Member
 
kmaier's Avatar
 
Join Date: Jul 2007
Old authentic GE made tubes had etched stencil markings on the glass. They are likely remarked, just not sure by who. I prefer NOS 5814A tubes, preferably the old broadcast series, i.e., RCA Command or GE 5-star tubes. Sylvania tubes are generally excellent as well.

Regards,
KM
__________________
... just because you're paranoid, it doesn't mean they're not after you...
  Reply With Quote
Old 28th September 2014, 05:59 PM   #7
diyAudio Member
 
pmillett's Avatar
 
Join Date: May 2005
Location: Dallas (but I am not a Texan!)
Doesn't look like any GE 12AU7 tubes I have:

1. GE manufactured tubes virtually always have the type etched into the glass (along with a pattern of dots), usually/often in addition to it being printed
2. The plate structure is different than the tubes I have (3 ribs on mine)

Now, all that does not mean necessarily that the seller relabeled them - there was a lot of re-selling and re-labeling being done by the manufacturers themselves, especially towards the end of production. But I don't think this is what most would consider a typical US GE 12AU7...

Pete
  Reply With Quote
Old 28th September 2014, 07:28 PM   #8
diyAudio Member
 
Join Date: Dec 2010
Location: Amesbury, MA
I don't think anyone would pay for modern 12AU7's and spend the money/time to reprint on them and then sell them because NOS 12AU7's don't fetch any big money from what I have seen.

I have tons of American brand 12AU7's here are some pics. Like Pete said all of my GE's have 3 ribs.

In order;
Tung-Sol 12AU7A
GE white label 12AU7 horseshoe getter
GE made for CBS 12AU7
Sylvania 6189/12AU7WA
Unkown USA gold pins 12AU7A
Sylvania green label 12AU7A square getter

I can dig more out.
Attached Images
File Type: jpg P9280031.JPG (936.0 KB, 66 views)
File Type: jpg P9280032.JPG (680.1 KB, 51 views)
File Type: jpg P9280033.JPG (910.3 KB, 48 views)
File Type: jpg P9280034.JPG (912.5 KB, 46 views)
File Type: jpg P9280035.JPG (704.3 KB, 35 views)
File Type: jpg P9280036.JPG (939.6 KB, 30 views)
  Reply With Quote
Old 28th September 2014, 07:44 PM   #9
diyAudio Member
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
Send a message via Skype™ to JonSnell Electronic
The real question is; Does it work as expected? If yes, why worry.
__________________
www.flyingmole.co.uk For World Wide support for Flying Mole, Class D, Refurbishment and Repairs. www.jonsnell.co.uk
  Reply With Quote
Old 28th September 2014, 08:59 PM   #10
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
I suppose the question revolves around what he paid for them based on what he thought they were.

I dug through my stash of old and used tubes and found what looks like a very close match in terms of the getter and plate structure. I would guess that the ones the OP posted are relabeled late Sylvania or Philips ECG.. Not bad tubes..

I have attached two macros of the sample I found in my collection.

See post #7 - I think this is as likely an explanation as any. The ink Philips ECG used on the last few years of production is pretty durable.
Attached Images
File Type: jpg 20140928_163131_cr.jpg (458.6 KB, 48 views)
File Type: jpg 20140928_163142_cr.jpg (481.0 KB, 49 views)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  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
Are some parts genuine? Walkalone Parts 3 24th June 2014 02:47 PM
Genuine 2sa1360? jazz Parts 1 16th September 2011 03:02 PM
Preamp tube SRPP 12AU7 VS preamp tube Aikido 12AU7 = all use rec 6X5GT spiritm2r Tubes / Valves 1 6th March 2011 02:53 PM
Marantz 2600 Receiver...counterfeit (or remarked) transistors? EchoWars Solid State 2 29th May 2007 08:59 PM


New To Site? Need Help?

All times are GMT. The time now is 12:28 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