RAT tube tester updates?

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ckniker
Posts: 7
Joined: Mon Oct 08, 2007 2:00 pm

RAT tube tester updates?

Post by ckniker »

Hi Stephie,

Any updates to your RAT tube tester?

Specifically, I've seen various references around the web that include changes to the schematic (by yourself) that allow testing of tubes with higher filament current requirements.

As an aside, I've acquired all the parts necessary to build the tester but have put the project on hold while working on a few other things. One of the things I've started working on in the background is a preamp that uses WE tennis ball tubes (that require filament current around 1A). Clearly, the RAT tester won't source this kind of current without some mods.

Thanks in advance,
Chris
sbench
Posts: 296
Joined: Fri Jan 28, 2005 3:45 pm

Post by sbench »

Somehow, that tester has come back to life. I've recently gotten some questions on it. No, no recent updates.

Somewhere in my pile of things to do on a rainy day is a new tube tester. I was going to put in a small PIC processor asnd a small display to print out the read values. Ahhh, but for some time. Maybe when I retire. :-)

On the specific questions, increasing the current capability should be relatively straightforward for the filaments. There's a 2 page schematic "update" somewhere (I think on Pete's site), but that's the last time I touched that tester.

Warmest Regards,
Stephie
martin manning
Posts: 2
Joined: Sat Mar 24, 2012 1:40 pm

Post by martin manning »

I am interested in this too. About a year ago I started to gather a parts list, locate sources, and began doodling a layout. I found that several components were obsolete, and some work would be required to redesign around available ones, so it kind of dropped down the priority list. Has anyone here built one recently? Anyone interested in working on an update and maybe doing a PCB for it?

BTW, nice to be here!

MPM
sbench
Posts: 296
Joined: Fri Jan 28, 2005 3:45 pm

Post by sbench »

Goodness. That tester seems to keep coming around. I have recently answered a few questions on it on my private email channels as well. :shock:

Actually, I think someone actually did a PCB for that. Try the geek zone forum at http://geek.scorpiorising.ca/GeeK_ZonE/index.php

If I recall correctly there's a thread in the tester section. I do not know the current status, though.

Since I designed that tester in the mid-late 90's it does not surprise me that some components have become obsolete. I still use my hand built version, though, and it has not failed yet.

Parenthetically, even though most of my energies are directed elsewhere (for personal reasons due to a more than dramatic change in my life), I still fully support Dave's forum here, and also support Geek Zone and occasionally monitor Google's rebirth of Rec Audio Tubes. So feel free to ask anything, and I'll try to answer it.

Warmest Regards,
Stephie <3
martin manning
Posts: 2
Joined: Sat Mar 24, 2012 1:40 pm

Post by martin manning »

Well, if production tubes were of universally consistent quality, or Hickok 539's in good working order were plentiful and cheap, or an Amplitrex could be had for a few hundred instead of a few thousand, probably noone would be interested ;^) I haven't looked at it in a while, so I'll have to dig up the notes I made. Thanks for the reply and offering your assistance.
BobMar
Posts: 3
Joined: Mon Jan 14, 2013 11:23 am

Post by BobMar »

I made this project years ago and a lot of tubes tested since then.
Few things in the diagram I never realized.
Whether the offer is still valid for your assistance?
Regards
sbench
Posts: 296
Joined: Fri Jan 28, 2005 3:45 pm

Post by sbench »


Hi,
Yes, I will help with any questions. As I think I mentioned, a lot of my energies these days are focused in other areas, but I do support this Forum. Right now I am in San Francisco with my sister who just had 12 hours of surgery, so I'm helping her with her recovery. So please bear with any delays in response.

Warmest Regards,
Stephie
BobMar
Posts: 3
Joined: Mon Jan 14, 2013 11:23 am

Post by BobMar »

Hi Steve
Sorry if I’m boring you, obviously you have important problems those days…
I accidentally saw this thread, and I was pleasantly surprised that from time to time that tester has come back to life.
I made this project years ago; design is really simple and easy to build anyone.
I have never overcome this trouble:
My problem with the RAT tester is that the g1 goes to positive respect to the cathode, even with low power tube.
In first 10 seconds at startup, grid come to about 10V+, and after this point suddenly drops to proper negative voltage.
At that time I was using diagram from your page, today it is no longer active.
Someone has copied your project and save them on Triode pages.

Reading these pages many years later, I saw that you have experienced the same problem.
In the text were the detail which in previous versions wasn’t present.
In the first versions of diagrams there was no LED that would show if grid is driven positive.
The same is with the (VR2)- plate current voltage adjust.
The main diagram with the text does not have these extras.
Can you find a diagram that matches the text?
Best regards.
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