Vintage Lectrolab Model 20 Tube Amp

[tigerzilly]

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I just couldn't resist! Late 30s Lectrolab Model 20. 8" field coil speaker. Hope it's still good. Tubes are 80 rectifier, 6F6 power, and 6SJ7 preamp. Nice solid cabinet measures 11"×11"x5.5". Cool paint, bakelite handle, and fancy speaker cut-out. I didn't see much info on. It's all dusty and original just the way I like!

[loudthud]

Is that finish cracking original or is it the footprint of Father Time ? It looks so cool, I wouldn't think it was original as old as the amp is.

[tigerzilly]

Is that finish cracking original or is it the footprint of Father Time ? It looks so cool, I wouldn't think it was original as old as the amp is.

It appears to be the original paint design. Not cracking. Just some wear along one edge.

[52 Bill]

I've seen that finish before, I think that it is all original. Great find! Looks a lot like early National/Valco/Supro construction. It's also before they started using Homosote for the cabinets.

[tigerzilly]

Here are pics of the chassis and speaker. So far looks promising!

[Chuck H]

I've seen that finish before, I think that it is all original. Great find! Looks a lot like early National/Valco/Supro construction. It's also before they started using Homosote for the cabinets.

I think you meant 'Homasote'. I only know because I had to look it up I never would have known the original name of that product.

[Chuck H]

That power transformer has enough oxide that it's scaling. As long as it works well and doesn't get too hot you should probably remove whatever rust you can from the laminates with as little abrasion as practical and then spray it with some Rustoleum to slow the roll on that damage. Fortunately it's black now so you can do whatever you need to the end bells with little consequence since it would be repainted. I usually remove the end bells and spray those and the laminate/coil parts separate. It stinks a bit for the first dozen operations or so but I like to think it's a more thorough job of mitigating further oxidation.

[tigerzilly]

That power transformer has enough oxide that it's scaling.

I was working on it before seeing your recommendations. I wiped the dirt off with a soapy washcloth and dried with a towel. Then I brushed the PT and other rust spots with a brass wire brush. Lastly wiped it all down with mineral spirits.

[The Dude]

...... and do glue a dust cap on that speaker.

[tigerzilly]

...... and do glue a dust cap on that speaker.

Is it possible the speaker never had a dust cap? The speaker looks so good I'm afraid of screwing it up. I've heard field coil speaker didn't have them but not sure if that's true.

[Chuck H]

Plenty of field coil speakers had dust caps. Though it's not uncommon that they either didn't (or at least currently don't***) or just had a minimal sort of cover. There's no harm in adding one.

*** Since field coil speakers are typically an older design AND the amps made to work with them don't work without them (so the speaker must remain in sevice rather than be replaced) and those older designs commonly used hide glue (which gets more brittle with age) what we see in on line images may be a disproportionate number of missing dust caps rather than speakers that never had them. But it's hard to say.

I can't imagine the "tone" would be detrimented in any way and keeping dust out of the rare and irreplacable speakers voice coil mechanism would be the point.

[The Dude]

Anything is possible and I'd say, if you think there's a chance you could "screw it up", probably best to leave it alone. If it were mine, I'd glue on a dust cap whether it had one originally or not. I wouldn't want the gap getting full of dirt/gunk/etc. and ruining a cool vintage speaker.

Edit: I've many times found dust caps bouncing around between the cone and grill cloth after glue dried out and they came loose. I can't imagine someone would manufacture a speaker without a dust cap, but like I said, anything is possible.

[tigerzilly]

If it were mine, I'd glue on a dust cap whether it had one originally or not.

I went through my junk vintage speaker pile and pulled a felt dust cover off one. Trimmed it to size and used contact cement to glue it on. I didn't screw it up thankfully. No harm done and piece of mind that I listened to your advise.

[tigerzilly]

Finished the recap. Installed a grounded power cord and fuse. Powers up and sounds good. Not a ton of volume but not sure what I should expect. It wants to be turned up full in the breakup zone.

[tigerzilly]

Found a bad connection with the input jack. The amp came to life!