New Vintage Audio Restoration HQ

[atmasphere]

If you keep this up there's a good chance it will look better than when it was new...

 

[Michaels HiFi]

If you keep this up there's a good chance it will look better than when it was new...

Well I just received the latest unit I'm going to try and learn to save.

It's a 1947 NRI (Triplett) Model 67.

I much prefer the testers from the 30's and 40's - much easier for me to try and learn than the 'newer' ones.

It's a metal case so it will be much easier to restore than a wood one falling back on my days of detailing cars.

 

[Michaels HiFi]

Bringing the original 1935 leather strap back to life.

I used the same products used on super-expensive saddles and such.

First deep cleaning - but carefully as the leather was brittle and could fall apart.

Then 20+ applications over several days of leather oil applying it heavily and letting it soak in (you can see it soaking in the photo). Keep doing this until it doesn't absorb any more.

Then a manual application of leather Baum to help seal in the moisture and protect the leather from the elements.

I probably spent more on product to try and save it than if I had just had a new one made. LOL

 

[atmasphere]

Had you considered having someone make a strap for you? If the leather is rotted it can give away without warning.

 

[Michaels HiFi]

Had you considered having someone make a strap for you? If the leather is rotted it can give away without warning.

I have and you're right - I would never trust them due to age. I think that would be an accident waiting to happen.

Even if the strap were fine, I wouldn't trust the screws that go into the wood. They are usually really small and possibly stripped in the wood from previous careless owners.

I never carry by the straps so it's more to preserve the originality and for the fun of restoration. I like the effort involved in bringing it back to life. It's a challenge for me.

Even with my metal military testers with metal handles - I always carry them like a pizza box as I never trust any handles/hinges/hardware that is usually 75-95 years old.

 

[Michaels HiFi]

Pretty excited about today's score.

After months of looking for the right one at the right price, I got a Weston 798 1940's tube tester.

Very different than Hickok's, many feel it's more accurate than the Hickoks. I can't say if that is true or not, however it DOES use a 5KHz signal feature, and the Weston testers place higher voltage on the plate of the tube which is supposed to give it more accurate readings.

I will also say when the FAA bought tube testers to be used in the towers and airplanes, they went with the Weston version, not Hickok.

It's right on that line of being new enough to test a very wide range of tubes I use, while still being old enough to get the variety of 4 pin tubes I have.

As testers moved into the 1950's, many of them dropped 4 pin sockets all tougher (think 2A3, 45, 300B). Or if they didn't drop the 4 pin, it was a secondary function so the testing of those tubes wasn't the most accurate.

This one has a very good faceplate, the owner sent me pics of it on the multimeter so I know it's accurate and working, AND - my favorite part - the outside metal case needs LOTS of TLC. I'll defiantly be working some magic on the case.

 

[atmasphere]

Pretty excited about today's score.

After months of looking for the right one at the right price, I got a Weston 798 1940's tube tester.

Very different than Hickok's, many feel it's more accurate than the Hickoks. I can't say if that is true or not, however it DOES use a 5KHz signal feature, and the Weston testers place higher voltage on the plate of the tube which is supposed to give it more accurate readings.

I will also say when the FAA bought tube testers to be used in the towers and airplanes, they went with the Weston version, not Hickok.

It's right on that line of being new enough to test a very wide range of tubes I use, while still being old enough to get the variety of 4 pin tubes I have.

As testers moved into the 1950's, many of them dropped 4 pin sockets all tougher (think 2A3, 45, 300B). Or if they didn't drop the 4 pin, it was a secondary function so the testing of those tubes wasn't the most accurate.

This one has a very good faceplate, the owner sent me pics of it on the multimeter so I know it's accurate and working, AND - my favorite part - the outside metal case needs LOTS of TLC. I'll defiantly be working some magic on the case.

Fabulous tester! I'd be tempted on something like that to give the case a nice vintage finish such as a wrinkletex battleship gray finish.

This is one I've had on hand for a while; not as nice as that but is a true transconductance tester:

 

[Michaels HiFi]

Fabulous tester! I'd be tempted on something like that to give the case a nice vintage finish such as a wrinkletex battleship gray finish.

This is one I've had on hand for a while; not as nice as that but is a true transconductance tester:
View attachment 34798

Yours looks really good.

To your point I find - especially with the wood cases - deciding which finish to go with the hardest part.

Should I use Liberon Finishing oil (I love this stuff)?
Liberon Teak Oil?
Custom blend of Tung / varnish / solvent?
Or a custom blend of BLO / varnish / solvent?
Or go wicked crazy and do Tung / BLO / Varnish / Solvent? (I prefer spar varnish over poly in all cases);
GF Seal a Cell?
GF Arm a seal?
Tried and True hard wax oil?
Waterlox?
Osmo?
Bunbleshutes hard wax oil?
A custom made hard wax oil blend?
Do I finish with a wax topping?
Should I do the 5 layer oil finish using sandpaper with each application to make an oil slurry to help fill the grain?
Should I use a grain filler on its own?
Shellac?
Something else?

I'm not a fan of the film varnish type look, so I would never final coat with a poly or lacquer.

And on, and on, and on. I spend as much time deciding what to do as I often do on the work itself. I love the experimenting to see how it all looks and turns out.

I've been looking at the Weston metal one, and I think what I may do is take the handle and hardware off to clean them up while leaving an open space to run through a multi-step polish regimen.

I have about 40 different automotive products to choose from, but I think in this instance I'm going to do:

Clean with APC to remove oils and grease,
Wipe with a paint cleaner to remove any residue,
Jescar compound with a wool pad;
Jescar medium polish with a medium foam pad;
Jescar fine polish with a soft foam pad;
Wipe down with paint cleaner to make sure there are no remaining oils from the polishes;
Hand application of 3D poly mixed wax;
Hand application of 2 layers of pure carnauba wax

My guess is it will restore it to a beautiful aged/used look vs. a brand new look. Sometimes I like to keep the character of the piece while refreshening and protecting it.

I love the challenge of the restoration.

 

[atmasphere]

The prewar test gear I've seen often had a finish that looked like spar varnish.

 

[Michaels HiFi]

The prewar test gear I've seen often had a finish that looked like spar varnish.

Correct. Seems like most of the wood pieces I've gotten from the 30's are an old version of lacquer which mimics today's Spar for sure.

It can be a pain to get off the military ones as every year they literally slathered on a new layer of it. Trying to remove 15+ layers without damaging the wood usually takes me 20+ hours.

The issue with lacquer is if you don't remove it completely, applying an oil finish will make is a sticky mess (as I've learned the hard way).

 

[Michaels HiFi]

Quick 40 second music vid of sanding down the Supreme 35 wood case after a chem strip and wiping with solvent.

Sanding with 180 grit to prep for oil application tomorrow. Case is white oak.

I'm going to apply the oil then wet sand with 220 grit sand paper to create a slurry.

2 days of dry time then repeat with 320 grit.

2 more days of dry time then repeat with 400 grit.

I'll reevaluate then to decide if repeat at 600 and 800 grit or go right to my oil/wax brew.

 

[Michaels HiFi]

The only thing better than getting one new-to-me vintage tube tester in a day? Receiving TWO on the same day!

One is the 1947 Weston and one is the 1936 Supreme Model 89.

 

[atmasphere]

That Supreme is in amazing condition!

Last night I began servicing my Precise 111. The interior of the cabinet smells like an old cabin. I assume that is due to mold but it looks fine. Any hints on treating the cabinet? Its wood with a tolex exterior which seems in pretty good shape.

The guts of the tester look good too. The meter is OK and the transformers are good, but it won't show the actual transconductance test. The tube rectifiers are good; I've tested all the resistors and replaced a couple that were off value and replaced a few capacitors that were clearly suffering. But that was just refurbishment and not trouble shooting. So I've got a bit of homework ahead yet.

 

[Michaels HiFi]

That Supreme is in amazing condition!

Last night I began servicing my Precise 111. The interior of the cabinet smells like an old cabin. I assume that is due to mold but it looks fine. Any hints on treating the cabinet? Its wood with a tolex exterior which seems in pretty good shape.

The guts of the tester look good too. The meter is OK and the transformers are good, but it won't show the actual transconductance test. The tube rectifiers are good; I've tested all the resistors and replaced a couple that were off value and replaced a few capacitors that were clearly suffering. But that was just refurbishment and not trouble shooting. So I've got a bit of homework ahead yet.

Thanks. I'm really excited about the Supreme.

I can definitely help with the inside of the cabs - they always smell terrible.

First, spray or wipe a water/vinegar mix on the inside and let it air out.

Then spray on several light coast of this: https://www.homedepot.com/p/Zinsser-12-oz-Clear-Shellac-Spray-408/100176744

You can get it on Amazon, Home Depot, Lowe's - where ever.

1) Shellac will stick to just about any inside cab well;
2) It's a fantastic odor sealer;
3) Make sure you do really light coats.

One can lasts quite a while if you turn it upside down to blow out the nozzle briefly after each use to keep it from clogging.

You COULD simply buy a can and use a foam brush to apply also. Note shellac dries in mere seconds so once you brush it on, don't go over it again or it will look bad.

Let me know how that works for you.

 

[Michaels HiFi]

As I’ve been scouring the wonder-web for new techniques to better understand and apply different finishes, I stumbled across the teachings of a fascinating craftsman — Tage Frid.

For those not familiar, Tage Frid (1915–2004) was a Danish-born master woodworker and teacher who played a monumental role in bringing fine European woodworking techniques to America. He was one of the founding editors of Fine Woodworking Magazine and a legendary instructor at the Rhode Island School of Design. Frid believed in mastering the feel of the craft — teaching not only how to do something, but why — and encouraged woodworkers to challenge convention and experiment.

So when I read about one of his more unorthodox finishing techniques, I knew I had to give it a shot. His method? Apply your oil finish to the wood, then immediately brush on a heavy coat of a 3-pound cut of shellac right over it. Then, without hesitation, scrub the surface with 000 steel wool — combining the two finishes into one smooth, rich surface.

Sounds crazy, right?
Well… I tried it today — and it worked great

The result was one of the best-looking finishes I’ve ever done. Smooth, deep, glowing — that subtle wood luster that looks like a real oil-in-the-wood finish and not the fake plasticky look of a poly finish. It’s like a shortcut to that French Polishing look that takes days (and a sore arm) to achieve.

I’m still experimenting — and learning how to make a proper French polishing pad to refine it even more — but man, is this fun. There’s something so satisfying about this.

[The picture is of a 90 YEAR OLD wood case of a tube tester I did today with the new technique.]

 

[Bones13]

My dad took a course that Mr Frid taught, and reproduced a few of his iconic works. Tage was a true master woodworker, and apparently a wood finisher too! My dad hated doing the finishing of some of his pieces, and would pay a professional to do the finish. (My dad was an orthopedic surgeon, so time was usually an issue prior to his retirement)

 

[Michaels HiFi]

My dad took a course that Mr Frid taught, and reproduced a few of his iconic works. Tage was a true master woodworker, and apparently a wood finisher too! My dad hated doing the finishing of some of his pieces, and would pay a professional to do the finish. (My dad was an orthopedic surgeon, so time was usually an issue prior to his retirement)

Wow! That must have been an amazing course.

Do you have any pics of your dad's work you can share with us?

Of all the dozens of videos and posts I've read, Frid was the only one to help me get great results using and learning to understand shellac. He was clearly a master of masters based on his life's accomplishments

 

[Michaels HiFi]

My new-to-me 1947 Weston tube tester arrived recently, and tonight was its big debut.

Powered it up — boom! — that beautiful green pilot lamp lit up like a vintage emerald.
Checking line voltage and......

Perfect. Good start.

Then I carefully consulted the tube chart, dialed in the settings for a Type 45, double-checked everything, inserted the tube, flipped the “Test” switch and…

Nothing. Dead.

No movement. No reading. No hint of life.

Now I know that 45 is solid — it tests strong on my other testers.

Okay, no problem, maybe that one was just feeling shy. I grab another 45, set it up, flick the switch and… same thing. Nada.

Hmmmm.....

I switch the settings over to a 2A3, drop that in, hit the test switch… and again, nothing.

At this point, I’m thinking, “Alright, something’s up with that 4-pin socket.” So I pop in a Type 80 rectifier (same socket) — it tests! But the reading’s off. Definitely not behaving as it should.

Next, I try a 6SN7 on a completely different socket — and it tests perfectly. The plot thickens.

I reach out to my West Coast Tube Tester Buddy and he gives me a few troubleshooting ideas.

After some testing and probing, turns out, one of the four internal prongs in the 4-pin socket — the ones that grip the tube pins — is missing or shifted. That explains why 4-pin tubes aren’t making proper contact, but the 6SN7 works fine on its own socket.

So… next step?

Open-heart surgery on a 1947 Weston.

 

[atmasphere]

My new-to-me 1947 Weston tube tester arrived recently, and tonight was its big debut.

Powered it up — boom! — that beautiful green pilot lamp lit up like a vintage emerald.
Checking line voltage and......

Perfect. Good start.

Then I carefully consulted the tube chart, dialed in the settings for a Type 45, double-checked everything, inserted the tube, flipped the “Test” switch and…

Nothing. Dead.

No movement. No reading. No hint of life.

Now I know that 45 is solid — it tests strong on my other testers.

Okay, no problem, maybe that one was just feeling shy. I grab another 45, set it up, flick the switch and… same thing. Nada.

Hmmmm.....

I switch the settings over to a 2A3, drop that in, hit the test switch… and again, nothing.

At this point, I’m thinking, “Alright, something’s up with that 4-pin socket.” So I pop in a Type 80 rectifier (same socket) — it tests! But the reading’s off. Definitely not behaving as it should.

Next, I try a 6SN7 on a completely different socket — and it tests perfectly. The plot thickens.

I reach out to my West Coast Tube Tester Buddy and he gives me a few troubleshooting ideas.

After some testing and probing, turns out, one of the four internal prongs in the 4-pin socket — the ones that grip the tube pins — is missing or shifted. That explains why 4-pin tubes aren’t making proper contact, but the 6SN7 works fine on its own socket.

So… next step?

Open-heart surgery on a 1947 Weston.

View attachment 34850

I'd be looking for a replacement on ebay. These are NOS and look like they need cleaning. You might want to measure the mounting ear dimensions (the center to center of the screws on either side of the socket) on the tester to see if these are correct.

 

[nc42acc]

I wonder if this tester is good enough to check the health of the tubes it is capable of testing?

Valve Tester MKII | Accurate valve-testing made simple

The Orange Valve Tester MKII makes testing preamp and power valves quick, accurate, and safe, now with expanded features and modular upgrades.

orangeamps.com