Early gramophone 'pick-up' questions

[poodling around]

1. I have noticed that some early gramophone 'pick-ups' have three wires and some have two and wonder why this is ?

Maybe the extra wire is an 'earth' to reduce sound 'hum' ?


2. One 'pick-up' in the photograph below is an HMV no: 15. Does any-one know when the HMV 15 was made and which gramophone it was used on ? It seems to be made of brass and is very heavy.


3. Also, can 'pick-ups' simply be connected via the phono input to a modern day amp ?


Thanks as always for any help you can give.

[Lah Ca]

In my limited experience with monaural electrical turntables:

Magnetic cartridges need three wires generally, two for signal--one for ground to reduce hum. Most magnetic cartridges do not produce a line level output and thus require some pre-amplification.

Ceramic cartridges generally need only two wires. They are not susceptible to hum. Most are comparatively high output and generally do not require special pre-amplification.

[poodling around]

In my limited experience with monaural electrical turntables:

Magnetic cartridges need three wires generally, two for signal--one for ground to reduce hum. Most magnetic cartridges do not produce a line level output and thus require some pre-amplification.

Ceramic cartridges generally need only two wires. They are not susceptible to hum. Most are comparatively high output and generally do not require special pre-amplification.

Thank you very much indeed Lah Ca ! So it seems that I can connect both of these pick-ups to a modern amplifier, including the HMV 15 if the amplifier has a pre-amp. Great stuff ! I will try that in the near future.

[Inigo]

The old magnetic pickups may need an adaptor (transformer?) because of impedance differences with modern amps.

[poodling around]

The old magnetic pickups may need an adaptor (transformer?) because of impedance differences with modern amps.

Ah, I see. Not always easy to do then.

Thanks very much Inigo.

[Hoodoo]

The ceramic cartridge will overdrive an amp made for magnetic cartridges. Turn the volume way down before you place the needle on the record.

[Curt A]

It seems to me that this style tonearm/pickup could be used freestanding (with the proper height mounting base standing next to the machine) on a cylinder phonograph... Am I wrong?

[Inigo]

Not likely. The inner movable parts (moving iron attached to the needle in the common pickups of that age) are prepared for lateral motion only. For use with cylinders some intrincated mechanism must be adapted... as in the other recent thread with one adaptation of a 1950s BSR ceramic cartridge attached to a cylinder reproducer and proper stylus. see viewtopic.php?f=11&t=56887&hilit=bsr

[Orchorsol]

The output from a very old pickup will be nearer line level. Connecting it to a magnetic phono preamp stage will probably overload it. Also nearly all phono preamps will apply RIAA equalisation, which you don't want with 78s.

[poodling around]

Thanks everyone. It all seems a bit too complicated for me - so I think I will put them away and admire them occasionally !