Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: scstill on April 03, 2023, 12:53:30 pm
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Just got my first tube tester - RCP 323.
Was able to get a copy of the manual and tested a few tubes.
Seems to be working good (I think).
I have a few operational questions not covered in the manual...
On some tubes during "quality" testing, the meter needle moves way past the green range.
Am I doing something wrong Or are these tubes just really good?
And when the throw switches are not being used when testing a particular tube should they be kept in the N (normal) position?
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This tube tester is not a scientific instrument. At the worst it is a museum curio in a very cool oak box but at the best it can simply tell you you if a tube works or not. You cannot quantify a tube's strength or match tubes with this unit. Be careful with the scroll chart--that paper is very brittle at this point. If there is a chart in the manual then use that to look up parameters. You will need to check and set line voltage every time--our voltage is higher now and this can pin meters. On the scroll chart if a tube parameter setting is blank, I would assume it is "N". I also see no control that sets bias nor do I see a "TEST" button but I am unfamiliar with this model. You can check new working tubes to get a relative reading for that particular tube and then compare it to other tubes of the same type. Erratic meter movement can also be because the switches need cleaning--you may need to hose the contacts with De-oxit. I would not check valuble and rare tubes with this instrument. Jim
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I bought mine so long ago, I can't even remember when. Was at a Hamfest for $10.00 USD. Like you, I've used it for testing good/bad/strength, but not for matching. Wasn't sure how.
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The most valuable feature of an average old tube tester is the Shorts function. You want to know, "Is this tube safe to plug into an amp?"
After that, there is a continuum that spans from "Fast & easy to use" to "Complete information of a tube's performance."
- If you're a nerd like me, you think you want "complete information."
- Once you have complete information, the challenge is figuring out "What does that mean?"
What people normally wind up using the most is the tester that doesn't take much time to set up & use, and gives an indication that "this tube is stronger than that tube."
On some tubes during "quality" testing, the meter needle moves way past the green range.
Am I doing something wrong Or are these tubes just really good?
You will probably need to figure out a different (lower?) position of the Shunt knob that keeps your strong tubes in the green. Perhaps your tester needs a slightly different setting there for the tubes you have.
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Interesting timing as I just saw a Precise model 116 tube tester in a local antique store. The little research I could find on the spot was that it is a service type machine that does basic go-no go testing. No way to try before you buy so I decided to ponder it and walked away. Price was well under half of this Reverb listing though:
https://reverb.com/item/16636139-precise-model-116-tube-tester
Any opinions on if this is worth grabbing? I also decided I really want a Whammy 5 to so I'm conflicted as all get out.
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looks like it has a transconductance test which seems a good thing.
But is that just an added scale or special test?
Wonder why it has so many same type sockets?
Might research the tester and see what is claimed.
I bought mine somewhat by surprise/mistake, with an ebay snipe much lower than should have won.
Of coarse I bought what turned out to be my fav acoustic guitar that way years ago (just lucky I guess)