Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

Tuning calibrating of my valve tester?

4/30/2006 3:18 AM
Satamax Tuning calibrating of my valve tester?
Hi everybody!  
Well, i've bought a valve tester  
I would like to understand more about it. How do i calibrate it? What test thoses µA relate to? Isolation, or emission? Both? Could i improve it, to calculate the transconductance and other parameters, beside isolation and emission?  
Thanks and best regards.  
4/30/2006 5:33 AM
Hi Max,  
Never seen that type of tester before, at a guess I would say it's an emission tester. I'm sure there's others on this forum who will pipe in soon with advice. If it's fairly old, I usually update the caps, check all resistors for drift, burn marks ect, clean all switches and sockets before putting it into service. See if you can download a schematic for it and check all voltages ect.  
Book Of The Day The Ultimate Tone, Volume III by Kevin O'Connor
Have you ever wondered if there is a better way to build a Bassman, Champ, Plexi, an 800, AC-30, Bulldog or Portaflex? Or you wanted to build an SVT with off-the-shelf parts? How about a master-volume amp that doesn’t change tone with the master setting? Everything you need to know is right here, including: proper grounding techniques, wiring methods, and mechanical considerations. Eighteen chapters cover the “iconic” amps everyone knows and loves, with schematics and layouts for each, along with the technical history of the product. Eyelet-board and chassis-mounted tube socket construction is used throughout, for easy servicing and modding. TUT3 is very accessible even if you cannot fully read a schematic and is a "must have" if you are going to build an amp for your self.

Note: The Ampage Archive is an Amazon Associate site. A small commission is paid to the site owner on any qualified purchase made after clicking an associate link such as the one above.
4/30/2006 8:28 AM
Thanks a lot Jack!  
Well, it's an emission and shorts tester. There's very few components in there :D About one diode, one or two resistors, the switches, and the multitap transformer :D I'll take a picture of the internals later.  
4/30/2006 1:28 PM
John Culp

If it's an emission and shorts tester, you can't test transconductance. You need a transconductance tester for that.
4/30/2006 3:12 PM
Thanks a lot John!  
Well, what brand of tested could i get cheap enough? I paid this one about 120 zoros, i'm keen on an AVO or a B&K , but realy i don't have the dough for one :D Therefor i thought i could may be modify or add components onto this one to be able to test and match valves.  
4/30/2006 5:44 PM
John Culp

I just bought off of eBay for $90 plus shipping an EICO 666. It doesn't exactly measure transconductance, but that's pretty much what its "dynamic conductance" testing actually is.  
There's a good section on various tube testers to be found at:
   Page 1 of 1