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What is the correct name for this?

Posted: Fri Jun 18, 2021 1:40 pm
by mrrgstuff
Sorry to be so vague, but I am sure I read somewhere about a device you could plug into your radio and then place underneath the needle of the soundbox when fitted on the gramophone.

The idea being that you could use your gramophone as a radio amplifier without having to remove the soundbox.

I believe the device had a small cup the needle went into, and this cup vibrated with the signal from the radio.

Is anyone familiar with such a device and know what it's called please? I'd like to find one, or details of one, but I don't really know what to search for. Thanks :D

mrrgstuff

Re: What is the correct name for this?

Posted: Fri Jun 18, 2021 2:17 pm
by emgcr
The one I have come across is called "Needlephone" by Rhamstine which I found on eBay (USA) quite recently. Unfortunately, although it looks as though it has never been used, it is not in working condition and I have not yet had to time to determine the fault but the coil might need rewinding. A friend has one which works well.

Re: What is the correct name for this?

Posted: Fri Jun 18, 2021 3:37 pm
by Inigo
Nevertheless, something is surprising. First they say no batteries are needed, but later in the instructions they talk about using a 67volt, or better 100 volt battery!!! What am I loosing?? :?:

Re: What is the correct name for this?

Posted: Fri Jun 18, 2021 4:28 pm
by mrrgstuff
emgcr wrote: Fri Jun 18, 2021 2:17 pm The one I have come across is called "Needlephone" by Rhamstine which I found on eBay (USA) quite recently. Unfortunately, although it looks as though it has never been used, it is not in working condition and I have not yet had to time to determine the fault but the coil might need rewinding. A friend has one which works well.
Thanks very much for all the details and the fast reply. That is indeed just the thing I was looking for. I guess they were a very transitional device and probably weren't being sold for very long, and hence rare. I wonder if there were any other brands. Thanks again :D
Inigo wrote: Fri Jun 18, 2021 3:37 pm Nevertheless, something is surprising. First they say no batteries are needed, but later in the instructions they talk about using a 67volt, or better 100 volt battery!!! What am I loosing?? :?:
The instructions are assuming you are using a battery powered radio, and although I really know very little about these I believe the B battery was the high tension battery. More voltage presumably meant more volume and that would make the the Needlephone work better. Thanks
mrrgstuff

Re: What is the correct name for this?

Posted: Fri Jun 18, 2021 7:03 pm
by Inigo
Ahaaaa, thanks for the explanation.. :)

Re: What is the correct name for this?

Posted: Fri Jun 18, 2021 7:19 pm
by recordmaker
I see what this is now it is a driver unit that the needle in the sound box sits in the little groove in the center and the device drives the sound box just like the record groove.
Hence the needle does not need changing and the type of needle makes change in tone.

This would need to be driven with a high impedance signal and these days a valve ( tube ) output transformer would need to be used to connect from a modern amplifier ,it is possible it does not need a battery unless this boosts the magnetic field of the driver coil hence the instruction to try the wires in reverse to see which works best.
And yes the B battery is the high tension battery ( A for filament low tension and C grid bias )
But as long as it has a magnetized core it may still work without DC bias as it is known.
I would expect this to measure up at 1000 ohms or so which could look open circuit on a continuity test but can be measured with many small multimeters these days.

Re: What is the correct name for this?

Posted: Mon Jun 21, 2021 3:17 pm
by AZ*
Here's some pix of one I bought at the Union show 15 years ago. It actually worked reasonably well. As stated in an earlier post, it does take a bit of power to drive it. I was able to attach a CD player to a keyboard amplifier and connect the external output of the amplifier to the Dulce-Tone needle gizmo. Imagine listening to ABBA's "Dancing Queen" through the horn of an HMV 32. :monkey:
93-Dulcetone-2.jpg
93-Dulcetone-1.jpg

Re: What is the correct name for this?

Posted: Mon Jun 21, 2021 7:02 pm
by Curt A
Your Dulce-Cone was made by the same company that made Genola toy phonographs... interesting.
Genola.jpg
Genola.jpg (24.61 KiB) Viewed 1055 times

Re: What is the correct name for this?

Posted: Tue Jun 22, 2021 6:17 am
by fran604g
AZ* wrote: Mon Jun 21, 2021 3:17 pm Here's some pix of one I bought at the Union show 15 years ago. It actually worked reasonably well. As stated in an earlier post, it does take a bit of power to drive it. I was able to attach a CD player to a keyboard amplifier and connect the external output of the amplifier to the Dulce-Tone needle gizmo. Imagine listening to ABBA's "Dancing Queen" through the horn of an HMV 32. :monkey:
93-Dulcetone-2.jpg93-Dulcetone-1.jpg
Very interesting, thanks for the images of this fascinating device!

Cheers,
Fran

Re: What is the correct name for this?

Posted: Tue Jun 22, 2021 3:58 pm
by mrrgstuff
recordmaker wrote: Fri Jun 18, 2021 7:19 pm This would need to be driven with a high impedance signal and these days a valve ( tube ) output transformer would need to be used to connect from a modern amplifier ,it is possible it does not need a battery unless this boosts the magnetic field of the driver coil hence the instruction to try the wires in reverse to see which works best.
....
I would expect this to measure up at 1000 ohms or so which could look open circuit on a continuity test but can be measured with many small multimeters these days.
Thanks - yes - I hadn't considered the need for an output transformer - but I can see this would be ideally suited to this. If I understand correctly it would be used in reverse to its normal configuration as in a valve unit it would be matching the impedance down to something like 4ohms for the speaker. However in this case the impedence of the modern amplifier is 4ohms and it has to be matched up to the higher impedance of the Needlephone. I guess it could be directly connected to a valve radio without the output transformer as both would be high impedance?
AZ* wrote: Mon Jun 21, 2021 3:17 pm Here's some pix of one I bought at the Union show 15 years ago. It actually worked reasonably well. As stated in an earlier post, it does take a bit of power to drive it. I was able to attach a CD player to a keyboard amplifier and connect the external output of the amplifier to the Dulce-Tone needle gizmo. Imagine listening to ABBA's "Dancing Queen" through the horn of an HMV 32. :monkey:

Thanks also for this. Interesting to see another design and also it would seem that even if the impedances aren't matched - using a more powerful signal can overcome the difference to an extent.