[ronpod]

Thought my Clarinet burn-in was traversing strange ground when the right channel treble was boosted and the musical dynamics in the right channel became overly "lively." The high frequency "boost" was becoming fizzy but the left channel was not changing. I started to experience listening fatigue for the first time in a long while and thought that I would need to leave the room while the burn-in progressed. I strategically swapped cables and isolated the problem to the Cornet2. When I rolled the Mullards for the Telefunkens the problem resolved. At first I thought that the Teles were bad. Then I thought that there was nothing to lose by burnishing the pins on the tube and treatment with DeoxIT. That fixed the problem with the right channel and may have improved the overall sound.  These NOS tubes were made, what, maybe 40 years ago; no surprise that the pins could use attention! So I burnished the pins on all the installed tubes and those that I intend to roll.

[Dan_ed]

Hey, thanks for reminding me it is about time to clean my tube pins. I keep a pencil eraser and some alcohol swabs for just that task. It really does make a difference and takes only minutes per tube.

[tubesforever]

Hey Ronpod,

I am a hot rodder.  Burnishing means taking something raw and heating it to a temperature where it performs better in use.  For instance with new brake pads we will make repeditive stops from 60-70 mph to burnish the pads so they brake the car smoothly and consistently when we are out racing.

Whatever the right terminology is for NOS tubes, I  use 600 grit wet dry paper to clean the pins and then treat with Caig De-oxit.  If the tube sockets feel a little too nimble, I will power down and then use a jewelers screw driver to bend the pins sockets tight.  This is especially important if you are rolling a bunch of tubes.  Each has a different circumference and they tend to loosen the wipers grip. 

Many of our 12AU and 12AX tube pins are made of nickle so feel free to use 600 grit like I do.  Nickle is really tough stuff.  Nickle corrodes over time so cleaning them is important if you want consistent sonic results.

By the way, this is a superb post and I hope everyone take a minute to clean the pins and treat them.  Inspect the sockets.  Do they all have good wiper force for the pins?  This is an easy process and an easy adjustment and can save many hours of anguish when the real culpret is simply a poor connection.

Ronpod, you had one heck of a poor connection.  I am glad you sorted it out so smartly.  Some would have thrown out the gear.

On word of advice.  When I get to a point where I hear stuff that is weird, I generally grab the stock tube complement that Jim recommends for his gear.  I plug it in and take a listen.  I have had enough NOS tubes go south on me during my lifetime to know that I generally look at stuff other than the tube as the problem.   It is a good idea to use the stock complement of tubes as a base line to analyze the gear. 

Sometimes you need a reality check to make sure you don't waste time trying to fix stuff that is working just fine.  Fresh tubes is all it takes to point out a weak or disfunctional tube.  This takes all of a couple of minutes time.  Much better than busting open the box and looking over parts and pieces. 

I have contemplated purchasing a decent tube tester.  I just seem to spend my money on music instead of test instrumentation????  Jim Hagerman is to blame for that!  Shame on you Jim .

Cheers!

[ronpod]

Reminds me of using the burnishing file on the distributor points in the Bruce Anderson-modded 911 Porsche.

Dan_ed's excellent suggestion of a pencil eraser is a classic method of cleaning electrical connector contacts. Something about erasers work particularly well with copper for de-oxidizing the surface, and should work for nickle tube pins equally well. Burnishing metal is to make it polished and smooth.

The oxidation of the nickle tube pin must of acted like a dielectric between the pin and the socket. This capacitive connection may have caused a shift toward the high frequencies and caused a "bright" sound in that channel.

I'm just trying to get the hang of this modding and tweaking business.

[Bobzilla]

 Congratulations ronpod, you successfully troubleshot a difficult to find problem!

 Any non-soldered connection is suspect, and a poor connection can appear as a resistance, a capacitance, or even as a diode. Tough to find! (and imagine the thought process of "Joe electronics tech." troubleshooting "listening fatigue")

 Another tool one can use for cleaning connections is a relatively new dollar bill. It's flexible, surprisingly strong, and just abrasive enough to clean without scratching. This works especially well on relay contacts and soft metals such as silver and gold. 

[fatty]

Hi All !

NOS tubes and current tubes pins should be cleaned. I have found that after 30+ years that using 1200 grit sandpaper as a cleaning tool will clean off the oxidation followed up with TarnX. TarnX is a liquid product used for cleaning the tarnish from copper pots and pans as well as silverware. It is sold in most grocery and hardware stores. TarnX contains a mild sulfamic acid and must be cleaned off after using with either water or any electronics parts cleaners that come in a spray can. With the advent of the tree huggers and OSHA most so called electronics cleaners do nothing to clean the oxidation from copper or anything else. If you put any Caig product or Caig De-oxit on a copper penny you will see that it does nothing !! Put some TarnX on it and the penny will become nice and shiny !!

If you want to completely screw up your tube sockets and tube pins use Caig !! The heat will turn the pins into nothing more than a gummy mess. Do not use any so called performance enhancing products on tube pins even if they say it will withstand high heat. Just clean with 1200 grit sandpaper and TarnX. Then clean off the TarnX and you have brand new pins. TarnX is also good to clean oxidation from any connection, just use it sparingly and clean it off well afterwards.

[tubesforever]

Probably good advice about Caig De-oxit vs tarn-x.  I generally use the de-oxit to clean the metal and wipe off any residue.  I am not sure what is in de-oxit?  But I doubt it likes the high heat generated by tubes.

Thanks for the heads up.

[hagtech]

I had my best luck without using chemicals.  Takes a bit more daring, but a soft brass wire brush on my drill press sort of physically scrapes off the oxidation or whatever contamination and then polishes the pins.  Leaves no residue.

But hey, maybe I try the tarnx (I remember the commercials on tv).  Would be a lot faster.

jh