90 Years of Audio History, 90 Years of Care

[Michaels HiFi]

I’ve spent over three hours over the last two days gently working on the White Oak case of my 1935 Supreme Type 35 Tube Tester.

Not with sandpaper or harsh cleaners, but with layers of wood soap, Naphtha mineral spirits, cloth, non-scratch pads and time — slowly coaxing away nearly a century of grime.

Cleaning antique wood isn’t about “making it new again.” It’s about revealing the story hidden beneath the dirt without erasing the years it has lived. Every layer comes off a little at a time, and with each pass, the oak starts to breathe again, showing its grain, its warmth, its dignity.

It’s a trial-and-error process — too harsh a method and you scar the wood forever, too light a hand and you never get through the buildup. The art is in the balance, in letting patience do the work instead of force.

And when I finally sit back, tired but happy, I realize… this isn’t just a tube tester. It’s a bridge across 90 years, carried forward by love.

 

[JCS123]

Great project, Michael! If I might ask, what is the material next to the dial and on the eraser in the inset photo?

 

[Michaels HiFi]

Great project, Michael! If I might ask, what is the material next to the dial and on the eraser in the inlet photo?

The faceplate is metal.

In this oder of less to more strength I use:
Rinsless wash,
Then a waterless wash,
Then Clay bar strength wash;
Then panel prep spray (all with microfiber cloths), and then if need be I use the Magic Eraser.

The Magic Eraser will actually scratch shiny metals so I use that almost last and gently to make sure I've already removed much of the gunk and grime that made add additional scratches.

The easiest and quickest way would be to use a diluted APC on the faceplate, but that is too strong and will likely permanently alter the faceplate and or remove the lettering.

On the wood it's the same process of from least aggressive to more aggressive to see what is needed:

Guardsman All in one polish cleaner;
Guardsman Deep Cleaner;
Howards Wood Soap (lathers well with the blue pad);
Naphtha solvent (safe for use on antique wood).

On the wood I typically start with a rag, then will move up to a white non-scratch pad, then a blue non scratch pad (the wood soap lathers better with this), and the ultimately 0000 steel wool (very mild).

The leather handle gets about 20 applications of a 70/30 leather mix of saddle soap and conditioner.

After all that I will put a protectant on the faceplate and a polish on the wood. ALL products are silicone and wax free so there is no build up that actually will make long term care more difficult.

I used to detail ultra high end cars so I'm using those techniques and products learned on the tube testers.

If the tube tester has a metal case then it's a 15 step process of cleaners, compounds, polishes, and waxes.

 

[JCS123]

Thanks, Michael. But I am still wondering what it is sitting on top of the eraser in the inset photo (and presumably the same thing sitting on the faceplate next to the dial in the other photo). It looks like approximately the size of a cigar butt, only tan.

 

[Michaels HiFi]

Thanks, Michael. But I am still wondering what it is sitting on top of the eraser in the inset photo (and presumably the same thing sitting on the faceplate next to the dial in the other photo). It looks like approximately the size of a cigar butt, only tan.

Ah! Sorry I misunderstood.

That is what the magic eraser looks like after I used it on the tester faceplate vs. one in its original state of being new. That's how dirty one got.

 

[JCS123]

Yikes! You done wore that baby out!

 

[nc42acc]

With the age from 1935 will it test modern power tubes like the KT120?

 

[Michaels HiFi]

With the age from 1935 will it test modern power tubes like the KT120?

Hi - I don't believe KT 120's are on its chart. I run old tubes like 2A3's, 45's. 300B, 80's etc.

It seems I'm better off with older testers than "newer' ones. Reason being many companies removed the ability to test oder tubes that I need as they focused on "newer" tubes. Hickok was famous for this - their later ones remove the ability to test the older type tubes.

 

[Michaels HiFi]

Yikes! You done wore that baby out!

And me!

 

[Michaels HiFi]

Update - change of plans.

What started as a simple finish "refresh" has seen me go down the rabbit whole of full blown refinishing.

I've spent the day alternately sanding and lacquer thinner to make sure there is no old lacquer left that the sanding and Naphtha didn't remove.

First picture is using special tape from Japan and taping it up. Second pic is the current state after multiple sandings.

 

[nc42acc]

Is it fully functional?
Are there any modern current production tube testers that can test “audio” based tubes?

 

[Michaels HiFi]

Is it fully functional?
Are there any modern current production tube testers that can test “audio” based tubes?

Hi - yes fully functioning. Having said that is it all original so I'm going to have it updated with new caps and such as needed.

Arguably the best new tube tester is the Amplitrex at $3K. Though it does come with a lot of known issues. Even if I had the money I would not buy one.

I suggest people get a decent TV-7 and send it out for rehab and updating as it tests a super wide variety of tubes, easy to use, plenty of easy to find tube data, and easy to resell if you ever wanted to.

Here is a pic of one of mine: