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Vacuum Tubes for Amps Tube Mfgr Codes

November 30th, -0001

Mic Kaczmarczik’s Tube Mfgr Codes Information

Tube Mfgr Codes


Vacuum Tubes for Amps

Tube Mfgr Codes

This directory contains USENET articles Mic has saved about guitars, equipment, pickup, techniques, players, and so on. Mic has graciously granted permission to post the stuff on the JT30 page on the off chance that it might be useful in the context of Blues Harmonica. Mic is not responsible for the content, just the collection.

Vacuum Tubes for Amps

Tube Mfgr Codes
From rcsigur–(at)–m.com Tue Dec 17 15:46:25 CST 1996
Article: 20311 of rec.audio.tubes
From: rcsigur–(at)–m.com (Richard Sigurdson)
Newsgroups: rec.audio.tubes
Subject: Re: tube manufacturer codes?
Date: Tue, 17 Dec 1996 20:23:26 GMT
Organization: Minnesota Regional Network (MRNet)
Lines: 43
Message-ID: <32b70997.--(at)--ortex.mm.com>
References: <32AC7E1F.7ED--(at)--edrose.net>
NNTP-Posting-Host: vortex.mm.com
X-Newsreader: Forte Free Agent 1.0.82


Gordon Trump wrote:


>Many years (25+) ago when I serviced consumer and pro audio and video gear,
>the tubes we bought for replacement use all had a 3-digit code on the side.
>”274″ was RCA and “312” was Sylvania and “337” was Zenith? This code
> Does anyone have a list of these codes? They ocasionally also
>appeared on other parts- like transformers, etc.
>–
>Gordon O. Trump Sales Engineer
>Red Rose Communications
>717.738.8441 voice 717.738.7030 fax


Gordon,


In the early 70’s I was a tech at a local Sylvania TV distributor and had a book
published by the EIA (trade association of domestic OEMs) which had a list of numbers
followed by the vendor. I wish I had a copy of that book today. The numbers you have
listed are correct.


Other OEMs are GE -188 , Westinghouse-337, Tung-Sol-322, Raytheon-280.
GE put 188 on tubes they made and labeled GE but RCA did not put 274 on RCA branded tubes,
but 274 was found on tubes they made for other OEMs including Sylvania and GE.


Zenith didn’t make their own receiving tubes but did have a CRT plant ( Rauland) and put
the Rauland number on those tubes. Sylvania made the majority of small tubes for Zenith,
and I believe they designed tubes for their specific needs.


Motorola, Admiral, and other smaller manufacturers bought tubes from who ever made tubes
that fit their specs. Those tubes had the set name (Motorola, etc,) labeled, along with
the EIA code stamped on the tube, along with a date code, such as 6812, meaning the tube
was made in 1968, 12th week.
Picture tube date codes were usually 2 years (color) or 1 year (b&w) from the date of
manufacture which indicated the end the warranty period.


With the majority of components for home entertainment product being made off-shore, most
of them don’t have EIA numbers. I have seen currently made CRTs with familiar 312 and 274
numbers on them though.


Richard Sigurdson
Sr. Eng. Tech. KMSP-TV/UPN9-Mpls/St. Paul
rcsigur–(at)–m.com





 

Index:

12AX7 Comparisons
12AX7 gain test
12AX7 vs 12AT7
12AX7 vs 5751
12AX7 vs 7025
5881 in Deluxe
5881=6L6GB
5AR4 data
5AR4 Typing
5V4 for 5AR4
62 Twin Speakers
6550s in Twin
6EY6 Characteristics
6EY6 close to 6V6
6EY6 rating vs 6V6
6EY6
6L6 GC meaning
6L6 Taste Tests
6L6 Types
6L6GC ID
6L6WGB vs 7581
6MB8 tube specs
6V6 6L6 swaps
6V6 duty cycle
6V6 NOS vs Sovtek
6V6 Ratings
6V6 Russian RCA Copies
6V6 to EL84 Cathode Resistor
6V6 Types
6V6=7408
6V6EH Taste Test
6V6EH vs RCA Blackplates
6V6GT Types
6V6GT vs GTA
6V6s in 6L6 amps
7408 info
7581A tubes
7868 equivalents
Amperex history
Best 6V6
Blue Glow Sylvania
Breaking in Tubes
Breathe on tubes
Brimar Special Quality
CEI 6V6GTs
Chinese 12AT7s
Chinese 6V6GTBC
Design Max Rating
EL34 coding explained
Euro Tube Code
Fingerprints
Fuzzy Cathodes
GE and Sylvania
Groove Tubes 6V6HD
Groove Tubes testing
Groove Tubes
GZ34 types
GZ34 Varieties
GZ37 vs 5U4
How Are Tubes Made
Hytron tubes
ID Tube Makers
Identify Tube Makers
Is Tube Matching Needed
LV Visseaux 6V6 Warning
M
Making Tubes
Mazda History
Metal 6V6s
micKtubes
More M
New US 6L6GCs
No More Chinese 12AX7s
Overvoltage Effects
Phillips 6L6GB JAN
Photon Noise
Real Mullard GZ34s
Relabeling
RTV Tube Damping
Ruby 6V6GTBC
Sovtek 12AT7EH 5751 Test
Sovtek 5881 Confusion
Sovtek 5881 data
Sovtek 5881 for 7027
Sovtek 5881 specs
Sovtek 5881
Sovtek 5881WXT
Sovtek 6CA7 problems
Sovtek 6L6WXT+
Sovtek Midget
Sovtek Online
Sovtek page
Sovtek Tube specs
SPICE tube models
Standby Switches
SV 6L6GC
Svetlana 6550s
Svetlana 6L6GC
Svetlana 7591A
Svetlana EL34 review
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Telefunken Tubes
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Tube Amp FAQ Feb 96
Tube Chickens
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Tube Data Page
Tube Data Web site
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Tube Manufacturers
Tube Mfgr Codes
Tube mismatch harmonics
Tube Naming Explained
Tube rejuvenation
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Visseaux 6V6
Vudu Tube Replacement
What Does 6L6GC Mean
What is 5881
What is 7027
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Why 6
Why Tubes Coated Inside
Worn Out GZ34s
YA tube page

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