1924 Michigan MRC-11 Two-Tube Radio Amplifier - WORKS! W. Tubes & Instructions.

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Item : This auction is for a beautiful working 1924 Michigan model MRC-11 battery-powered two-tube radio amplifier with two working Cunningham C-301-A UV-style short-pin tubes, and a modern copy of the instruction sheet. This is a highly collectible and rare early radio amplifier manufactured by Michigan Radio Corporation in Grand Rapids, Michigan, to match their MRC-10 one-tube radio and provide amplification so that a loud speaker can be used. Only a fraction of the customers buying a radio would pay the extra for an amplifier and a loud speaker, so even though the radios can sometimes be found today, few of these amplifiers are still in existence. Controls include a Stage Control that switches it to operate with either one tube, or two tubes if you want more amplification. There are also a 1st Stage and a 2nd Stage control that each control the filament voltage of one of the tubes. The instructions tell how to operate these controls, and how to connect the amplifier to batteries, to the radio, and to a loud speaker.Note: I am also selling a matching one-tube MRC-10 radio (as shown in the last photo) in another eBay auction - you can find it if you look at my other listings. This amplifier will allow that radio to power a loud speaker. Condition : Like the radio that this matches, this amplifier looks great with the slanted shiny black front panel, the unique looking operating levers, and the engraved white lettering, and it is especially good looking because it is in very nice condition.The front panel is aluminum with glossy black paint. It appears someone has rubbed fine steel wool (maybe 0000) on the paint and dulled it around the dials. This could be buffed out if someone wants to do that, but in most lighting situations it is not very noticeable. The brass name tag has also been buffed and is easy to read (see photo). The cabinet is beautifully refinished inside and out, and the wood is all in excellent condition. The chassis looks great, and the best part is that the rubber shock mounts that hold the tube sockets together have all been expertly replaced. Replacing these is no easy task since they are riveted, and whoever did this work did an outstanding job. The radio is being sold with two short-pin UV-style 01A tubes which would have been correct for the time period.I connected this to the matching radio (being sold in another eBay listing), to a 1920s high-impedance cone speaker, and also connected my power supply (speaker and power supply not included) to the battery wires (1.5 volts A+ for tube filaments, 67.5 volts B+, and 4.5 volts C-, as described in the operating manual. (It could also be powered by stringing 7 modern 9-volt batteries together to get 63 volts (close enough to 67.5), and using a D-cell battery for the A+ and 3 D-cells for C-) Each wire still has the original tag on it identifying what voltage to connect it to. I turned the radio and the amplifier on, and after a short learning curve I was listening to a radio station! Measurements : About 13-1/2 x 10 x 8 inches.Good luck bidding! Shipping : Buyer to pay calculated shipping.Contact me before paying if you want me to combine shipments !Local pick-up OK. Insurance : Free on shipments within the United States! Payment : Payment must be received within 5 days after contact. Minnesota residents will be billed an additional 6.875% for sales tax. International Buyers : Please check with your country's customs office to determine what import duties, taxes, or other charges will be prior to bidding. These costs are not included in the eBay item price or shipping charges. These charges are the buyer's responsibility. These charges are normally collected by the delivering freight (shipping) company or when you pick the item up – do not confuse them for additional shipping charges. Please see my ' About Me ' page for more information about international... read more

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