Arct/Sparton 686
DC Det/Amp Triode
1928

The 686 was a special tube made for Sparton receivers and used only in the Sparton Models 39 and 49. This tube had a five pin base with one pin unused. These tubes can be found both with and without 686 marked on the base. None have been seen with any manufacturer name present. Sparton also made their own version of this tube, the 486/686. The Sparton version had clear glass and a Sparton paper label.