How To Make a 6V6/6L6 Bias Test Probe From a Cheap Multimeter

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In this video I go over how I made a pair of test probes for checking the bias of tube amps with octal output tubes in the 6V6/6L6 vacuum tube family (6L6GC, 6V6GT, 5881, 5871, 5992, etc.) To make your own you will need:
Cheap Multimeter
Broken 6v6 or 6l6/ New Octal Base
Amphenol Style Tube Socket
1" threaded PVC coupler
Super Glue
18 Gauge Wire
Heat Shrink
Solder
Tools:
Wire Strippers
Soldering Iron
Solder Pump
Drill
Small Clamps
Ball Peen Hammer or Similar (for breaking glass out of tube base)
This device measures a small amount of current at a high voltage so please use caution using these probes! Credit to Uncle Doug and Brad the Guitologist for giving me the inspiration to make the original bias probes i made several years ago. Thanks for Watching!

Опубликовано:

9 сен 2021

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Комментарии : 18

@jevinedric5390 2 года назад

Great video! Been meaning to make two of these DIY probes so I can measure a Silver panel Bassman that my uncle gave me. Your video showed me how to solder the wires on those hollow tube bases and get rid of the excess solder on the pins. More confidently in making them now and parts are on the way as I'm typing this. Thank you so much!

@DetroitWrecker666 Год назад

Nice job!

@slothtronix3047 2 года назад

There are a few clips out of order here, I’ll reupload when I get back in town, it’ll still be a little while

@scottpeters4401 2 года назад

I bought a Bias Probe device similar to this..it has a little switching box to select tube A,B,C or D….I only bought 2 probe cables,but was going to make 2 more…Mine has a 1ohm 2 watt resistor built into the cable between the socket and multimeter end…What is the purpose of the resistor,?….just wondering since yours doesn’t use a resistor,do I need it?

@omarcusihuaman4261 2 года назад

it would be best to measure the plate voltage with a more expensive multimeter instead of the cheap one? (for safety)

@Mikexception

My way is different - even do not have to pull tubes from sockets. it requires knowledge like Ohm law and Kirchoff law. After I have access to pins of socket, knowing DC amplifier supply voltage I check voltage drop on transformer and have enough data to calculate from voltages the flowing current and fast compare of both PP tubes bias in few seconds. Only additional thing which is requires is to measure the resistances of output transformer windings which I did even without any disconnecting them. .