Magneto Phone System
This private exchange phone system uses 1940's
vintage Magneto Phones
Bought on the used market and reconditioned, these phones work well as a
vintage
intercom.
Today there are 12 phones on this "private
exchange" system
It connects every Valhalla Farm building
using underground wiring
....and the main house with one on each floor to serve as an intercom.
The system is simple and requires little maintenance.
Our favorite is the Leich "901" phone but most any 1940's magneto ringer phone
will work with a system of this type.
One phone is even mounted at the main gate for visitors to use to gain access
Main house phone
Here's a shot of the gate phone.
More... on the Gate System
Phone in the new house, was purchased on EBay for $15.
This one had a sticker attached that said "6 long rings to report a forest fire"
901 Magneto phone in the MIL Apartment
Often these need to be reconditioned before they will operate correctly.
Disassembly and a thorough cleaning are often all that these phones need to be ready for use.
The Leich Electric Company manufactured early magneto and dial equipment for the telephone industry in the 1930s and 1940s.
Robustly made, these phones function as an intercom between the eight main buildings at Valhalla.
A short History of Leich Electric
Batteries are the preferred way to power the talk voltage due to the "pure DC" output of a battery versus an AC-Line power supply that could introduce hum into the system.
The car batteries require little maintenance. We connect a charger once a year to "top-off" the batteries. The general rule of thumb on this system is to have an additional battery for each 100 ft of branch line.
Six volts off of a defunct 12V car battery is just about right for a talk voltage.
This is essentially the same basic telephone that Alexander Graham Bell invented in 1876. A DC talk voltage in series with a carbon button full of carbon granules and on the other end, a permanent magnet with a winding that caused a diaphragm to vibrate and generate air waves. The varying talk current can even be observed on the small voltmeter.
When someone speaks into the telephone, the meter needle moves quickly in response to the words spoken.
These phones worked well to meet the needs of rural telephone systems, railroads, military bases or mines. This system is wired in a "common battery" configuration where all of the phones are on the same party line and when you turn the magneto crank, they all ring. Its very helpful in communicating "dinnertime
These phones are very robust and versatile and can be configured in several different ways.
"
Diagram of a Leich 901 with terminals identified and
typical hookup
Here's a shot of the garage Leich phone.
Note the small voltmeter used to monitor the DC Talk Voltage.
When you speak, the needle moves rapidly like a VU meter!
Note the white slip of paper in the top right. It lists the "ring signal" for each person on the system
Used service panel with a 66 Block.
The service panel is used as a "data closet" for distribution of telephone, internet and TV signals throughout the garage and MIL apt. The white box under the phone is a doorbell that chimes briefly when the main gate opens.
Magneto phone and touch tone phone in the woodshop.
The Leich 901 phone converts between desktop and wall mounting by virtue of the ingenious way the handset cradle is designed.
Utility building workshop phone.
Three old 12 V car batteries placed at the "ends" of the system provide "talk power" The magneto crank generates 75-100 Volts AC to ring all of the phones in the system simultaneously.
We chose to use the the classic Bell System "66 Block" as an interconnect point.
Available from telco supply houses, these are easy, handy and make nice solid connections using a special "punch down" tool.
Here's two more "66 Blocks" in the new house basement data closet.
66 Blocks are used here to distribute stereo audio, gate control and magneto intercom through the house.
Note the voltmeter in the upper RH corner to monitor the DC talk voltage on the system.
DirecTV units upper center,
Bottom row L-R: Generator Transfer switch, Leich 901, outside telephone NetWorx Alarm control panel
20W Solar Panel Experiment
Keeps the magneto phone system DC talk
battery fully charged
Here's a digital readout panel monitoring the DC talk battery voltage at the battery connected to he solar panel
Phone in upper equipment barn.
Note the local 12 Volt "Talk Battery" and also the "old bones" found under the pioneer house. The system's 1930 designers intended to have a talk battery at each phone when used in rural areas but we've found that using several old car batteries strategically placed at various nodes of the system provides enough DC to operate all phones, even the one at the gate, 500 Ft from the battery.
The old car batteries are down to about 8 volts and this voltage is probably what Leich designed for. At any rate 8VDC provides good volume and clear communication.
Here's a Kellogg Switchboard Co magneto phone from the
same 1930's time period.
This one is in the new house
upstairs bedroom.
Note the house energy monitor in the background
This phone is commonly called a "red bar" phone due to it has a red bar as
the visible part of the hook switch. It is out of view under the handset
Diagram rolled up inside one of the phones
Here's a Leich 901 in the basement office.
This is my favorite one
The sticker on the front reads:
WARNING This telephone subject to monitoring. Do not discuss classified. This unit evidently came from a military base.
Heck, there's even one in the Picnic Shed.
All wiring is underground using surplus "direct bury" armored 4 pair telephone cable.
Picnic Shed phone
This is great to call the main house when the picnic runs out of hot dogs.
More on the valhalla pavillion: Rock Concerts
Salmon BBQs
Lower Garage Phone
Note the old car battery on the left supplying about 8 Volts for the DC "Talk Voltage".
Projects Valhalla Home
What's New Switchboard
Restoration Project
08/15/21