Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Mike_J on June 13, 2021, 02:44:41 pm
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Thinking of getting rid of some of my amps. See little advantage to including a Mullard GZ34 with it. Wonder what the best 5AR4/GZ34 is for reliability and comparable voltage drop. Also, it would seem sensible to include diodes in line with the wiring to the tube if the information I have read concerning the reliability of current rectifier tubes is accurate. Any comments would be appreciated.
Thanks
Mike
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I don't know if there is a "best" GZ34 out there, and I've had some TAD's, new Mullard that have performed well.
I confess I am biased against JJ tubes with several failures recently (though not a GZ34/AR4). My experience may or may not mirror others . . .
With regard to the inclusion of diodes: the theory makes sense, and it is cheap and easy to do it, and I have started doing so. However, since I haven't had a rectifier fail in years, the problem seems a little remote. LOL -- of course, now it will happen next week!
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I don't know if there is a "best" GZ34 out there, and I've had some TAD's, new Mullard that have performed well.
I confess I am biased against JJ tubes with several failures recently (though not a GZ34/AR4). My experience may or may not mirror others . . .
With regard to the inclusion of diodes: the theory makes sense, and it is cheap and easy to do it, and I have started doing so. However, since I haven't had a rectifier fail in years, the problem seems a little remote. LOL -- of course, now it will happen next week!
Seems like when you are prepared for bad things to happen they are much less likely to do so. I was thinking about JJs when I wrote this. They seem to have a high failure rate. The Mullard Reissue does look like a likely choice as a replacement. Think I may have paid less for the original than what the reissue is going for but that was a long time ago.
Thanks
Mike
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i've heard enough good things about ruby/chinese 5ar4 that i picked one up when i thought i needed it (didn't, so it's waiting for future use). i always put in backup diodes. few pennies for some insurance why not?
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Never had any trouble with JJGZ34
and a vote for protection
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i've heard enough good things about ruby/chinese 5ar4 that i picked one up when i thought i needed it (didn't, so it's waiting for future use). i always put in backup diodes. few pennies for some insurance why not?
I suppose if backup diodes are installed the choice of rectifier tube is less important presuming the tube behaves reasonably closely to an old Mullard.