Vintage Speaker
Open baffle
The principle of the open baffle or rear open housing was formerly aisle and gait.
Also old radio radios were open at the back and provided with a perforated cardboard wall.
She did of course make fun of it, but at the time they wanted to leave the appliances completely open
because of the high tensions on the wheels then not.
Alnico as well as more modern materials such as neodymium can bring the pole plates into the so-called magnetic saturation,
which does NOT succeed with ferrite magnets.
This is not unimportant, because then the magnetic field of the voice coil can no longer modulate the magnetic circuit,
which reduces possible distortions.
AlNiCo Speaker
The AlNiCo loudspeakers come from radio and speakers from Grundig, Siemens, Telefunken, Loewe or SABA.
All broadband AlNiCo speakers were in the same factory Magnetfabrik Dortmund in Germany
manufactured in the early 50s.
They are built to the same high standard as all other professional appliances.
These are highly efficient speakers with ultra light paper membrane,
large round AlNiCo magnets with NT DEW CKS or Tigges sign on it.
Some speakers have no dust cap or the pairs have different colors and materials.
The speakers are made of magnesium, aluminum or steel.
The chassis are painted to prevent oxidation. If the chassis is heavily oxidized, then polish and paint it.
Technical data list
Field Coil Speaker
The field coil chassis was developed because at that time no sufficiently strong permanent magnets existed.
The amplifiers during this time had at most a few watts output power,
so that the speaker had to have a correspondingly high efficiency.
The magnet is replaced by a coil in the field coil system. Historically, of course, it was the other way round.
The coil must be traversed by direct current so that a magnetic field is created at all.
There were different versions with up to 20 Volt voltage, but also 90 to 200 Volt.
In addition to the field coil chassis, a suitable power supply must be purchased.
The Feldspulenlautsprecher come mostly from identically constructed radios and boxes of the marks Siemens, Telefunken, AEG,
all the fullrange speakers are manufactured in Germany.
They are built to the same high standard as all other professional appliances.
The field coil loudspeakers have an electrodynamic field excitation.
Since the chassis of the devices in question were (almost) identical, the field excitation was taken from the anode voltage.
These are highly efficient loudspeakers with ultralight paper membranes with a paper or Pertinax adjustable paper suspension.
Most loudspeakers usually have no dust cap, the loudspeaker chassis are made of steel.
The field coil requires a DC voltage from a range of 90V-120V.
The chassis are painted to prevent oxidation. If the chassis is heavily oxidized, then polish and paint it.
Field coil instead of permanent magnet
While most modern speakers are powered by a permanent magnet,
The magnetic field of a field coil is regulated by a current source.
Such electromagnetically driven loudspeakers already existed long before the today s loudspeakers,
which are driven by permanent magnets. In recent decades, the field coil speakers have been forgotten,
but now they are experiencing a revival, and rightly so.
Because unlike a permanent magnet, the strength of the magnetic field in a field coil can be changed at will,
quite simply via the power source. This allows the sound and timbre to be ideally matched to any room.
In addition, field coil loudspeakers have extremely low distortion compared to conventional systems.