Loney lap steel guitar

[Harold Bishopriggs]

I recently purchased a believed to be a 1950s Valco/Loney lap steel guitar. Everything works but there is a pretty loud pickup hum. Nothing has been changed with the the electronics, is there a wiring diagram for these old guitars also is there anyway to quiet it down? Thanks very much

[Rob DiStefano]

There are typically sundry reasons for passive pickup noise. Most always it's the pickup itself, particularly if it's single coil, but it could also be the overall circuit itself, the wiring, the components. Have a good tech check it out.

[Noah Miller]

If it's a Valco steel then it probably has a hum-cancelling pickup. Can you post a pic?

[Harold Bishopriggs]

Hopefully these pics will tell the story. I’m ok with re-wiring if that will help.

[Harold Bishopriggs]

I’m hoping this will tell all.

[Rob DiStefano]

Whatever the passive pickup is - dual or single coil - the pots are full of corrosion and should be cleaned inside and out, or better yet replaced. My suggestion is to pull out ALL of the electronics and either service or replace them all.

[Noah Miller]

Ah - that's a Harmony-built steel with a single-coil DeArmond pickup. It will produce some hum depending on its orientation to the noise source. There may be additional contributions to the hum, but it's not going to totally go away.

[Rob DiStefano]

Ah - that's a Harmony-built steel with a single-coil DeArmond pickup. It will produce some hum depending on its orientation to the noise source. There may be additional contributions to the hum, but it's not going to totally go away.

If indeed it is a single coil transducer, it has a very odd build as what are the 1st and 6th strings are passing over??

[Noah Miller]

Ah - that's a Harmony-built steel with a single-coil DeArmond pickup. It will produce some hum depending on its orientation to the noise source. There may be additional contributions to the hum, but it's not going to totally go away.

If indeed it is a single coil transducer, it has a very odd build as what are the 1st and 6th strings are passing over??

Those are rivets; DeArmond used them to secure the cover to the base plate on some models. In this case they're also securing the pickup to the control plate - you can see where they come out on the underside of the plate, though one is partly covered by solder.

[Rob DiStefano]

Ah - that's a Harmony-built steel with a single-coil DeArmond pickup. It will produce some hum depending on its orientation to the noise source. There may be additional contributions to the hum, but it's not going to totally go away.

If indeed it is a single coil transducer, it has a very odd build as what are the 1st and 6th strings are passing over??

Those are rivets; DeArmond used them to secure the cover to the base plate on some models. In this case they're also securing the pickup to the control plate - you can see where they come out on the underside of the plate, though one is partly covered by solder.

So, the pickup sits on top of the control plate, with no height adjustment, and since the rivets sit under the 1/6 strings, the actual bobbin(s)/coil(s) must be forward or aft of the rivets (I'd guess?) along with a bar magnet or two?

[Noah Miller]

I wasn't sure how the magnet was situated either, so I found these pics of the same model being repaired. It looks like the coil is wound directly on the magnet (no bobbin). The rivets go through those notches on the ends of the pickup.

But yes, no height adjustment.

[Rob DiStefano]

I wasn't sure how the magnet was situated either, so I found these pics of the same model being repaired. It looks like the coil is wound directly on the magnet (no bobbin). The rivets go through those notches on the ends of the pickup.

But yes, no height adjustment.

Oh the horrors!!!!!

With sincere apologies to the owner, clearly the absolute worst single coil pickup design and build I've seen in over six decades of building passive transducers. If the plank plays well otherwise, replace ALL the electronics and be happy.

[Harold Bishopriggs]

Is there any chance of changing the wiring or capacitor to eliminate or reduce the hum?

[Noah Miller]

It's not a particularly unusual design among cheap old pickups; Danelectro's, for example, make this one look princely!

It's possible that the pots are somehow acting as antennae for noise, and it's possible that some ground connections aren't the best. But unless the hum is currently overpowering the signal from the strings, replacing the pots and reflowing the solder joints is probably going to make only a minimal difference. You could try shielding the control cavity, but since the pickup is entirely outside it, I'm still skeptical that it will do much.

[Rob DiStefano]

Is there any chance of changing the wiring or capacitor to eliminate or reduce the hum?

IF you are handy with a proper soldering iron, solder the pickup directly to the jack and listen - if the buzz has been reduced to acceptable levels, replace the pots and that funky cap. You may need to meter at least the volume pot to get a bearing on its value, for replacement of both pots. As to the cap, a simple .022uf would probably suffice.

My personal take is to immediately pull out and replace Everything, including that "pickup", but before doing so I'd measure the space between the control plate and the bottom of the strings to see what options there will be with finding a pickup that will fit. I would also measure the string-to-string spacing, just to know what pole piece pickups would be acceptable, but a bar magnet pickup such as a lipstick will cover all 6 strings and my even fit as it. There are also very slim height surface mount pickups used for jazz boxes that are quite thin (height wise). As a last resort, I'd remove the pickup and cut the plate to accept a pickup that would be mounted to the plank's body, and also allow height adjustment, which can be better than having a "tone control". This is all obvious conjecture, without having the lapper in hand, of course.

[Rob DiStefano]

It's not a particularly unusual design among cheap old pickups; Danelectro's, for example, make this one look princely!

It's possible that the pots are somehow acting as antennae for noise, and it's possible that some ground connections aren't the best. But unless the hum is currently overpowering the signal from the strings, replacing the pots and reflowing the solder joints is probably going to make only a minimal difference. You could try shielding the control cavity, but since the pickup is entirely outside it, I'm still skeptical that it will do much.

Yep, lotsa not-so-good pickup designs/builds from the olden dayze, and thankfully not so much today. With this pickup, notice the slack ballooning coil wire (microphonic heaven) and the fact that the 1/6 strings sit over only part of a large ceramic magnet (changes in Gauss rate to the strings).

IF the entire control plate and pickup cover are grounded, that's already a lotta shielding to control humbuzz. I'd look more at the pot corrosion both internal and external, and why I'd not think twice about replacing them, along with that weird cap. Then I'd find or build a passive pickup. All of this is relatively easy for me, it's what I do.

[Jack Hanson]

Looks like a prewar Gibson bridge. Relatively common on postwar 6-string lap steels from Harmony, Epitome...

...and others. When CMI decided to go another direction with their postwar lap steels, they sold off a boatload of prewar parts (bridges, control plates, P-13 pickups, etc.) to other entities.