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    Identify this tube?

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    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 12:31 am

    This is the 5AR4/GZ34 that came with my stock ST-70. Can anyone identify it? The only markings on the tube are a large "Realistic Lifetime", "5AR4/GZ34", and "Japan". I realize that's not much to go by, but...any guesses?

    I tried to put in an img tag, but that doesn't seem to work, so here's the image in my flickr feed:

    http://www.flickr.com/photos/100379403@N06/11660476675/

    and here's all the photos I took:

    http://www.flickr.com/photos/100379403@N06/sets/72157639221032943/



    Last edited by dougmon on Tue Dec 31, 2013 12:37 am; edited 3 times in total (Reason for editing : trying to insert photo)

    Maintarget

    Posts : 208
    Join date : 2013-02-10

    Re: Identify this tube?

    Post by Maintarget on Tue Dec 31, 2013 1:04 am

    You pretty much have identified the tube What more do you need?
    I'm sure you can goggle and find a specification sheet for it.

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 1:08 am

    Maintarget wrote:You pretty much have identified the tube What more do you need?
    I'm sure you can goggle and find a specification sheet for it.

    I actually have googled for this, and I've found some info, but no specs. What I was hoping is that someone could identify a possible maker.

    sKiZo

    Posts : 1287
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Identify this tube?

    Post by sKiZo on Tue Dec 31, 2013 2:43 am

    I figure it had to be either Mazda or Matsushita, and Mazda has a brown base.

    Here's the Matsushita version ...



    Probably made on old Mullard tooling ... does it have the "lifetime warranty"?

    DynakitParts
    Admin

    Posts : 181
    Join date : 2008-11-30

    Realistic Lifetime

    Post by DynakitParts on Tue Dec 31, 2013 8:08 am

    Assuming this tube has the Lifetime warranty labeling...

    Realistic (RadioShack) will still honor the warranty replacement of this tube if you believe it is defective, worn out, etc. They have no provisions to test tubes and most will not have any clue what this item is. A replacement will typically be a low cost China made 5AR4 tube provided by someone like Antique Electronics. The Japan marking as sKiZo states is most likely Matsushita or Mazda which are are both well made tubes and better than most new production 5AR4 rectifier tubes made today.

    Happy New Years...

    Kevin


    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 8:49 am

    sKiZo, DynakitParts: thanks for the help.

    I assume this tube has the 'lifetime warranty'. Now if only I could convince Radio Shack that it's a Mullard and has to be replaced with a Mullard!

    I'm assuming now that this is a Matushita. I'm a little leery of actually using it in the VTA-70...but what's the worst that can happen? I do keep a stash of 3 amp slo-blo fuses for fun occasions like this...

    I don't think the tube is bad, because up until recently I was using it in a stock ST-70. But I have no easy way to test it at present.

    thanks again!

    Jim McShane

    Posts : 154
    Join date : 2011-10-19
    Location : South Suburban Chicago

    Re: Identify this tube?

    Post by Jim McShane on Tue Dec 31, 2013 9:32 am

    Doug,

    Japanese 5AR4/GZ34 tubes are terrific!! Their post-WW II tube production was rebuilt by Mullard/Philips, so the quality was quite high. That's a FINE rectifier you have there!! Get it tested if you aren't sure of it, it looks to be in great shape. Don't try to get a new tube from Rat Shack unless it tests bad - you'll never get one as good quality.

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 11:43 am

    Jim McShane wrote:Doug,

    Japanese 5AR4/GZ34 tubes are terrific!! Their post-WW II tube production was rebuilt by Mullard/Philips, so the quality was quite high. That's a FINE rectifier you have there!! Get it tested if you aren't sure of it, it looks to be in great shape. Don't try to get a new tube from Rat Shack unless it tests bad - you'll never get one as good quality.

    Thanks! I was worried about it for a couple of reasons. First, the old Dynaco used to "pop" pretty loudly when I turned it off; but that's not necessarily the rectifier. Second, most of the flashing was black -- but further reading convinces me that that is not necessarily a negative thing. I'll probably give this tube a shot. Heck, I have safety glasses....  Smile 

    baddog1946

    Posts : 304
    Join date : 2010-02-03
    Location : Costa Rica

    Re: Identify this tube?

    Post by baddog1946 on Tue Dec 31, 2013 2:28 pm

    I have an original looking ST70 with a complete set of "Raytheon"(made in Japan) EL34's and rectifier with the same printed font, color and words on all of them.
    Except for the "Realistic Lifetime" it looks exactly like the one you have there.
    Although "Raytheon" is etched on the glass of the EL34's this tube looks like part of a set on mine.
    Looks like both tubes could have been made by the same manufacturer and possibly sold under different labels. Raytheon????......baddog

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 3:35 pm

    baddog1946 wrote:I have an original looking ST70 with a complete set of "Raytheon"(made in Japan) EL34's and rectifier with  the same printed font, color and words on all of them.
    Except for the "Realistic Lifetime" it looks exactly like the one you have there.
    Although "Raytheon" is etched on the glass of the EL34's this tube looks like part of a set on mine.
    Looks like both tubes could have been made by the same manufacturer and possibly sold under different labels. Raytheon????......baddog

    Entirely possible, though intense internet searches have led me to believe that mine is a Matsushita. But what with rebranding, etc., it's also possible that your Raytheon is re-labelled Matsushita. Or that mine is a Raytheon. Or that they're both some other factory, and we'll just never know.

    I did give this tube a try in my VTA-70, and it works fine. There _is_ a small 'pop' when I turn off the amp, but that was there with the Sovtek rectifier too, and I don't think it's worth worrying about.

    At any rate, this whole thread and my experience with the old tube has given me the idea that it might be a good idea to start saving for an NOS Mullard...just to have one. Of course, if this rectifier lasts a lifetime, that might not be necessary Smile

    Donkeyshins

    Posts : 19
    Join date : 2011-07-18

    Re: Identify this tube?

    Post by Donkeyshins on Tue Dec 31, 2013 4:53 pm

    Jim McShane wrote:Doug,

    Japanese 5AR4/GZ34 tubes are terrific!! Their post-WW II tube production was rebuilt by Mullard/Philips, so the quality was quite high. That's a FINE rectifier you have there!! Get it tested if you aren't sure of it, it looks to be in great shape. Don't try to get a new tube from Rat Shack unless it tests bad - you'll never get one as good quality.

    I totally agree. I've got a flat-top Toshiba 5AR4 that is as good and rugged as the Mullard 5AR4 that came with my Stereo 70 and tests beautifully. I've been saving it for something special.

    -D

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Identify this tube?

    Post by dougmon on Tue Dec 31, 2013 10:37 pm

    Just one last thing -- thanks for all the helpful responses, and Happy New Year!

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