Antique Doorbell, Julius Sax & Co - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

emeritus · 13th Apr 2014, 9:44 pm

I posted an extract from the "Trembling Bells" section of a GEC catalogue of 1892 here: [post #41]

https://www.vintage-radio.net/forum/...t=94738&page=3

There seems to have been a government standard specification for such bells, and GEC supplied individual components as well as complete bells.

Svenedin · 13th Apr 2014, 10:05 pm

I'm not sure what you mean by missing out the trembler. I'm reluctant to modify the bells in any way as I have discovered that they are rather collectable and fetch high prices.

Emeritus: thank you for the link. Very interesting. My bells have the wires from the screw terminals hidden in a groove in the backboard. The groove is filled with wax as is the back of each terminal. I will take a picture when I get the second bell down from the loft (I hate it up there and I'm putting off going up because the horrible glass fibre insulation makes me itch for days). I can't take a picture of the first bell because it is wired up and attached to the wall. I notice that the GEC bells have a "platinum pointed screw" and platinum points. I noticed that the screw on my bell is brass with another material let into the brass to make the electrical contact. I had assumed this was iron as it was very dirty but it cleaned up very bright. It could be platinum as well.

Herald1360 · 13th Apr 2014, 10:50 pm

Missing out the trembler means that with the bells in series, the wiring goes to the normal terminals on the first bell in line, then on the second bell the wires connect directly to each end of the coil bypassing the the trembler contacts. If the bells are identical this should work nicely but if their natural mechanical resonant frequencies are different, the second bell performance may be poor if its resonance peak is sharply defined as it will be being driven at the wrong frequency for optimum operation. It would be like trying to drive a swing or pendulum faster or slower than its natural frequency- possible, but takes a lot more power to do it.

Good quality early bells used platinum points as they were resistant to erosion and oxidation caused by the inevitable sparking. Nowadays there are other materials which are nearly as good and a lot cheaper!

Svenedin · 13th Apr 2014, 11:02 pm

Thank you Herald. If I understand this correctly the normally wired bell will "drive" the second bell at the same frequency and if the second bell is identical and hence has the same resonant frequency this will work. As I mentioned, I am reluctant to modify these bells as they are more valuable than I thought but it should be possible to connect a wire from the trembler assembly to one end of the coil and adjust the contacts so that they no longer make electrical contact via the points.

Herald1360 · 14th Apr 2014, 1:29 pm

If you're going to try it, leave the contacts adjusted as normal- if they don't touch the armature will be further away from the coil poles and will be harder to move. Just leave the trembler in circuit between one end of the coils and the bell terminal and use a piece of wire in parallel to short out the contacts. You may find that you can tune the slave bell ring to some extent by adjusting the contact position to preset the armature closer to the pole pieces.

Svenedin · 14th Apr 2014, 6:17 pm

Here are some pictures of the second bell. Almost identical but not quite. This one has the Sax logo, the trembler parts are nickel plated (not bare brass as in the first bell), the locking screw for the points is present (missing on other bell) and the coil assembly is screwed to the backboard with brass slotted screws not square drive ones. I am not sure which one is older. The second bell is in worse cosmetic condition (nickel plating poor on the bell) but functions very well.

Exactly the same design of the wires to the coils in a groove on the back filled with wax.

Tractorfan · 14th Apr 2014, 9:14 pm

Hi,
Yes, that's the same logo I saw on those stage light plugs I mentioned in post 11.
Cheers, Pete.

13th Apr 2014, 9:44 pm	#21
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,339	Re: Antique Doorbell, Julius Sax & Co I posted an extract from the "Trembling Bells" section of a GEC catalogue of 1892 here: [post #41] https://www.vintage-radio.net/forum/...t=94738&page=3 There seems to have been a government standard specification for such bells, and GEC supplied individual components as well as complete bells.

13th Apr 2014, 10:05 pm	#22
Svenedin Retired Dormant Member Join Date: Apr 2014 Location: London, UK. Posts: 19	Re: Antique Doorbell, Julius Sax & Co I'm not sure what you mean by missing out the trembler. I'm reluctant to modify the bells in any way as I have discovered that they are rather collectable and fetch high prices. Emeritus: thank you for the link. Very interesting. My bells have the wires from the screw terminals hidden in a groove in the backboard. The groove is filled with wax as is the back of each terminal. I will take a picture when I get the second bell down from the loft (I hate it up there and I'm putting off going up because the horrible glass fibre insulation makes me itch for days). I can't take a picture of the first bell because it is wired up and attached to the wall. I notice that the GEC bells have a "platinum pointed screw" and platinum points. I noticed that the screw on my bell is brass with another material let into the brass to make the electrical contact. I had assumed this was iron as it was very dirty but it cleaned up very bright. It could be platinum as well. Last edited by AC/HL; 14th Apr 2014 at 5:25 pm. Reason: Reference to Gas removed

13th Apr 2014, 10:50 pm	#23
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Antique Doorbell, Julius Sax & Co Missing out the trembler means that with the bells in series, the wiring goes to the normal terminals on the first bell in line, then on the second bell the wires connect directly to each end of the coil bypassing the the trembler contacts. If the bells are identical this should work nicely but if their natural mechanical resonant frequencies are different, the second bell performance may be poor if its resonance peak is sharply defined as it will be being driven at the wrong frequency for optimum operation. It would be like trying to drive a swing or pendulum faster or slower than its natural frequency- possible, but takes a lot more power to do it. Good quality early bells used platinum points as they were resistant to erosion and oxidation caused by the inevitable sparking. Nowadays there are other materials which are nearly as good and a lot cheaper! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

13th Apr 2014, 11:02 pm	#24
Svenedin Retired Dormant Member Join Date: Apr 2014 Location: London, UK. Posts: 19	Re: Antique Doorbell, Julius Sax & Co Thank you Herald. If I understand this correctly the normally wired bell will "drive" the second bell at the same frequency and if the second bell is identical and hence has the same resonant frequency this will work. As I mentioned, I am reluctant to modify these bells as they are more valuable than I thought but it should be possible to connect a wire from the trembler assembly to one end of the coil and adjust the contacts so that they no longer make electrical contact via the points.

14th Apr 2014, 1:29 pm	#25
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Antique Doorbell, Julius Sax & Co If you're going to try it, leave the contacts adjusted as normal- if they don't touch the armature will be further away from the coil poles and will be harder to move. Just leave the trembler in circuit between one end of the coils and the bell terminal and use a piece of wire in parallel to short out the contacts. You may find that you can tune the slave bell ring to some extent by adjusting the contact position to preset the armature closer to the pole pieces. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

14th Apr 2014, 6:17 pm	#26
Svenedin Retired Dormant Member Join Date: Apr 2014 Location: London, UK. Posts: 19	Re: Antique Doorbell, Julius Sax & Co Here are some pictures of the second bell. Almost identical but not quite. This one has the Sax logo, the trembler parts are nickel plated (not bare brass as in the first bell), the locking screw for the points is present (missing on other bell) and the coil assembly is screwed to the backboard with brass slotted screws not square drive ones. I am not sure which one is older. The second bell is in worse cosmetic condition (nickel plating poor on the bell) but functions very well. Exactly the same design of the wires to the coils in a groove on the back filled with wax. Attached Thumbnails

14th Apr 2014, 9:14 pm	#27
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: Antique Doorbell, Julius Sax & Co Hi, Yes, that's the same logo I saw on those stage light plugs I mentioned in post 11. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."