How to Make Bias Probe Bases Out of Bad Vacuum Tubes - IMPROVED METHOD

Don't throw away your bad vacuum tubes! Make some bias probes instead. This probe is a step up from the ones I've made previously because it has a tap for the cathode. This facilitates plate voltage measurements for cathode biased tubes without opening the amp. You can also get screen current measurements and cathode resistor voltage drop measurements without opening the amp using Ohm's Law calculations.
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[@TheGuitologist]

NOTE: The hot glue at the end is optional. I did it as an experiment to see if it will melt when the probes are in use. I think the melting point of this high-temperature hot glue is above the temp of most tubes at the base. Silicone or epoxy are alternative options for filling the base.

[@kxmrock]

Very Cool, Next Video How to Use Them 🙂

[@dirtydanthesecretsauceman8519]

nice choice of podcast

[@pauldavis6356]

I was happy to see the hot glue considering you hadn't smoothed out the broken glass (with a Dremel and sanding bit) left behind after the modification you made to the tubes. Nicely done.

[@redkurn]

Cool, I have some tubes that were suspected bad/replaced for sanity sake since I'm not the original owner of my amps, got a nifty DIY for testing tubes that isn't expensive?

[@EwetoobSucks]

Ah ! The Old Smash And Grab !

[@normanmozley3659]

My dad was an E.E. from Purdue and served in the signal Corp as a 1st Lt. I grew up with 5y rectifying tubes, fenders etcetera in the 60s, we built a fuzz from popular electronics magazine in 1966, point is I always enjoy your podcasts and get what you are doing. KEEP UP THE GOOD WORK. Your friend in tone, Norman Mozley

[@TheGuitologist]

Thanks Norman. Keep the tube dream alive.

[@normanmozley3659]

No problemo, made loud to be played loud.

[@russell_szabados]

@The Guitologist I hope you, your family & friends are safe and weren’t affected by yesterday’s (Fri 12/10/2021) storms and tornados. All the best man.

[@cantyouhearmeknocking1961]

Impeccable solder work Brad.

[@bustedgut453]

All your base are belong to us!!! You rock Brad.

[@timothyb1559]

Probe version 2.0 is pretty sweet! I can attest version 1.0 works - I made one referencing your last video. I was a little sketched out using it for the first time but fortunately the services of the fire department were not needed. As an added bonus, the broken glass makes a great toy for kids of all ages! Christmas is right around the corner.

[@TheGuitologist]

The glass is also a nutritious snack for said kids.

[@timothyb1559]

@@TheGuitologist Right you are, sir. Back in my day, before they invented that fancy rock candy, we ate glass. And we liked it!

[@sski]

"As an added bonus, the broken glass makes a great toy for kids of all ages! Christmas is right around the corner." Irwin Mainway approves!

[@TheAxe4Ever]

@@sski Ah! When SNL was actually funny.

[@sski]

@@TheAxe4Ever Yup!

[@philshifley4731]

Very soothing video. Hammer to the glass was my favorite part. Thank you!

[@Chinaguitarsceptic]

Why did I enjoy the smashing so much? Great video bro

[@MrSmithvideo]

Why Mr Linzy, that was simply marvelous.

[@russl9029]

Hope you and your family are all ok and were not affected by the tornadoes! Very informative video as always!

[@jasonlee8497]

that was rather enjoyable and relaxing

[@strat0871]

Well done Brad.

[@ferit123100]

Great vid. I desolder the pins and pull the wire from each pin, that way you can solder the wires to the socket first then just slide into pins, solder and cut off extra. A little more work but I found it easier.

[@PrinceWesterburg]

Love what you're doing but you can break the glass base / cement then heat the pins and remove the remains of the valve envelope completely and put your own wires in which you presolder to the valve base used on top. Depending on the valve, this can be easier, it just depends on how much cement was used. Loved the MIDI Bach! :D

[@rexoliver7780]

At one time you could get “tube lifters” at any electronics parts place-even Radio Shack. Now that such places are gone-this is a good video to make your own. Used tube lifters to check bias on mod driver tubes for AM broadcast transmitters. The driver used EL34,6550,6146. The mod driver tubes drove big tubes like 4CX3000,5000 and 3CX2500. Used as mod tubes in 5 and 10kw AM transmitters. Now these are all solid state-no more “hot glass””fire bottle” fun. SS modules are boring!

[@liquidstar9]

hahahaha!!! i totally use a paint brush as a tiny broom/brush for stuff on my bench too!

[@AudioAtmos]

Very cool, Brad! Thanks!!

[@RHR-221b]

*What Sorcery is this?* *To the Ducking Stool with this Wizard!* AKA: Thank you for the illumination, Brad. Merry Christmas soon. All the best. Rab 🍻 😎 💡 🎯

[@georgerobartes5989]

Bad , bad naughty tubes . Take that AND THAT ! Reminds me how I was raised as a kid in East London ! Octal bases are also pretty good for making solid state rectifiers with UF4007s Caps and MOVs so you can keep that stuff on top of the chassis . When done just pot them in clear resin . If you have a 5v feed you can use that and a small resistor to run a red or Amber LED before potting so you get the fake glow of a heater element .

[@ShaneSG]

Though we are in Australia and only rely on the news to tell us what’s going on around the world , this morning’s news was about the severe storms over your state and neighbouring states and hope you and your family are safe , very sad hearing there was loss of life.

[@SteveHacker]

J.S. Bach’s Brandenburg Concerto #4! Excellent choice! 😊😊😊

[@philc.352]

How dare you, That was a perfectly innocent paper towel!!!

[@leemurphy6581]

awesome, you the man Brad

[@scottgarrett744]

Thank you... the first part of that felt good to watch. I've always wanted to smash the shit out of a tube, and the bigger the better 🤓

[@briansimpson8116]

Cool transformation

[@graywofel3755]

Hello Brain

[@harrismonnc]

Thanks Brad.

[@jebboceefus553]

An acceptable substitute for the smashing a messy booger amp with a bat request. We also end up with a usable tool in the end. Win win.

[@waynegram8907]

How can you get screen current measurements and cathode resistor voltage drop measurements without opening the amp up using these bias probe TAPS? can you show in your next new video how to do this

[@BustedJunkStudio]

Many years ago I made myself some of those and back then you could get new octal bases from Antique Electronics, I don't know if that's still true. They worked just as well but were a bit easier to fabricate with all that leftover glass out of the picture.

[@Pilotltd]

You can still get bases. Much easier, neater and far less mess 😎

[@TheGuitologist]

I have some of those. I just chose to salvage the bad 6550 bases to get my money's worth out of the fuckers. I had to buy them, after all.

[@BustedJunkStudio]

@@TheGuitologist Yeah, I sympathize with your take on them seeing what you went through. I never had a problem with them but that don't mean I'm immune. I think you have shown a great DIY method here that some tech's maybe would not think of right off the bat... quick and dirty!

[@Pilotltd]

@@TheGuitologist 🤣🤣

[@davelawrence946]

Hey dude, are you ok from them tornadoes? I know you live in Kentucky, but I dont know where.

[@freesk8]

Wonderful music. I love Bach! Would have been cool to see a little demo of how these neat little tools are used! Thanks! :)

[@jutukka]

Nice video. You could also show how to make an adapter which makes it possible to use EL84 tubes instead of 6V6 tubes. However It is a bit more complex to wire. And I have installed extra grid stopper resistor as well to make sure that EL84s won't oscillate.

[@TheGuitologist]

It’s doable.

[@baneverything5580]

@@TheGuitologist Brad, in the future I`d like you to be the one to repair my beloved Samick acoustic electric guitar if you are willing. She deserves saving for a future picker and I`d like to be able to perform with her again. I bought a new Dean koa wood acoustic electric and a very cheap 100 dollar one for alternative tunings during live performances in the future, but Traci is making me feel very guilty sitting in the corner alone and worn out. A drunk guy ripped the wiring out so there`s just a hole where she plugs in and the frets are gone. I wore her out over a 20 year period and she`s the guitar I learned on. If you agree and give me an estimate I`ll try to figure out the rest. I`m on a small disability income but have some money in the bank to use to get my trailer moved and set up and there should be enough left over to knock a dent in it. I want a good person to fix this guitar and that`s what you are. I know you care and will do it right. It would be cool if you made a video about the repair. When I was playing drums and singing in bands in the 1990s this guitar was the acoustic we used from around 1995 until 1999 I think, then it was given to me when I could no longer keep traveling and playing due to my mother getting sick. This guitar saved my life and got me through a very difficult time of severe depression. It`s a living being to me. I want it put back in good shape so someone will care about it and use it when I`m gone.

[@brianpartridge5654]

Hope all's well with all that wind round your parts?

[@timscarrow9151]

Hope You are O.K . Brad, Stay Safe.

[@AlphaOmegaCreations1]

Is that LWC i hear in the background at 19 seconds 👍♥️🇺🇸

[@williambock1821]

Great soundtrack!!

[@TheWarped45]

what ya got against the russia 6550 . I worked on a marshall jpm 50 a few days ago the b+ is 400 volts he's running 6550s the bias is set at 48 millivolts it sounds like total crap no overall volume some breakup after about 5 I was thinking the bias is too low I remember doing this mod about 15 years ago and I changed out a resistor to maybe 50k in the bias supply and running the kt88s at 74 millivolts and pulling about 50 watts " kt88s push pull 100 watts el34s push pull 50 watts" doubling bias on kt88s on a el34 setup.

[@JKSawShop]

Awesome how to tool build

[@ianwebb8066]

Damn you Brad give back my base

[@fichambawelby2632]

Brad: I hope everything is fine for you and yor family. I don't know exactly were are you located, but I've heard somewhere in Kentucky, and saw the bad news.

[@yernickle]

Did you avoid the tornados?

[@tolerbearALTII]

What wattage glue gun do I need for everything electronics?

[@gerardoromano3436]

Brad, It´s not safe to touch de plates and components inside the tubes, most of them have radioactive elements. very low , but not safe. Usually in old tubes (RCA, GEC, Tung Sol etc.) I dont´t know in current production ones. Sorry English is not my primiry language. By the way your content is awesome. Cheers

[@motorjock0478]

Brad, I'm not sure where in Kentucky you live, but I hope you and your family managed to escape the tremendous amount of destruction caused by the tornados.

[@KeritechElectronics]

OUCH, that hurt! You'd better wear gloves when handling the tube innards. Some toxic metals in there. Still, nice 6550 autopsy. I've got a bias probe from an old EL34 base just in case, but tend to use small cathode resistors on my amps so that you can measure the voltage drop.

[@programorprogrammed]

Caveman builds useful tool while brooding over some fear mongering.

[@joosboer1030]

I’d love if you showed us how to make a 6N2P to 12AX7 adapter. They are way cheaper, plentiful and need only minor adaptation to filaments to work

[@lowheadroom]

LOL “ALL YOUR BASE ARE BELONF TO US!”

[@mikescompany1981]

Super cool !

[@GJP1169]

What was the music you were playing its great

[@TheGuitologist]

(Let's Go) Brandenburg Concerto #4 - JS Bach

[@GJP1169]

@@TheGuitologist thanks

[@Twobarpsi]

@@TheGuitologist very cool subliminal...😎

[@nachom1971]

Next show us how to make a solid state diode rectifier tube out of a bad rectifier tube! Not the best but they come handy in emergencies.

[@Twobarpsi]

Great tip man 🤘!!

[@DarrenForbes]

Brilliant.

[@muskymike1885]

it's all about that base about that base no trouble

[@redactedname3459]

Based.

[@westelaudio943]

Based and redplated

[@danielsaturnino5715]

That was nice :)

[@nobodynoone2500]

I have a buncha amps that like crappier tubes that still work. Don't smash your low-testing ones, just the gassed and shorted dudes.

[@TheGuitologist]

Save microphonic ones too. They may work fine in some circuits and not others.

[@ZagrasNixillis]

What/who is that music? I love it

[@TheAxe4Ever]

We’re those the shit tubes that Antique Electronic Supply stuck you with and you had to eat the cost? Well, if they are, at least you made something useful out of them.

[@TheGuitologist]

Yep.

[@Twobarpsi]

Haha!! I was thinking the same thing 😂!!

[@RHR-221b]

@@TheGuitologist 👍 Stay free, B. R 🍻 😎 🌠

[@scottkalemusic1406]

Did you escape the storms bro

[@kengevers8738]

If you wouldn't mind, can you speed it up the video about 5x. Took too time out of my day. lol 😆

[@1683clifton]

Where'd you get your squid with the sweet ass roachclips?

[@andrewmules5191]

Can you do a video for an el84 probe plesae!!

[@916pickups]

Hope you and family are alright.

[@kxmrock]

Remember People, (Tube Amp Owners Should Already Know this) Make Sure The "Key way's" on both Pieces Line Up when You assemble This

[@edwardmonsariste4050]

Hope your okay through tornado hell.

[@gunsnwankers1]

Crowder power!

[@michaelhead875]

Bravo

[@mikecampbell5452]

Nice

[@toploadtele]

Almost as good as the women assembling tubes in the old manufacturing and training films. These old films have apparently become very valuable themselves!

[@jeremiahlyleseditor437]

Great Idea. You forgot to show the inter-connectivity of the pins.

[@TheGuitologist]

The pins connect straight across: 1:1 2:2 3:3 4:4 etc. Except the plate pins (for 6L6, 6V6 family of tubes), which are left open, and the cathode pin gets a small bent wire to hook on a probe later for measuring plate voltage and bias resistor values, etc.

[@georgeescaped6035]

asbestos or mica in the tubes?

[@TheGuitologist]

MICA

[@markinthemix6055]

Please tell me the name of this piece of music 🤩🤩🤩🤩🤩🤩🤩🤩

[@timothyb1559]

Speaking of bias probes, here's a fun trick - connect one multimeter probe to a tube cathode and the other to the plate and check for current. Proof of concept for the current limiter. It works! Ask me how I know.

[@DetroitWrecker666]

Sure beats the heck out of spending all kinds of cash on a probe.

[@bernhardnizynski4403]

The shattered glass is very dangerous!

[@FuquarProductions]

Brad, are you going to start practicing glass eating now?

[@TheGuitologist]

The trick is to completely pulverize into tiny bits before swallowing.

[@rockdaddy2168]

Who'd a thunk? You'd a thunk.

[@kenhancock8931]

FIRST THX BRAD :-)

[@thomasclarkharris9241]

Are you affected by the tornado just watching uk news

[@bkhawaii]

I'd add RGB blinking 3mm LEDs and turn them into Christmas ornaments. (((: (I'm a tube geek)

[@glenncollins4778]

I can tell who it is by the manicure.

[@richsmith9063]

Oh No......the Getters ....

[@mark64tanner]

👍✌😎

[@derangedhermit2879]

This video exposes the reckless degree of leaded solder smoke and flux colophony fumes that Brad so eagerly inhales. The channels most active viewers bearing witness, to the painful repercussions of neurotoxins cumulatively infecting Brad’s meritless political reasonings and demented ideologies in real time?…LoL…xD

[@kwacz]

smashed bad tubes with hammer. Bad!! your a bad tube!! bad tube!!

[@AlphaOmegaCreations1]

Zero Wing lol