Dynaco's A25 loudspeaker was amongst the most popular loudspeakers ever produced. More than 600,000 speakers were sold. They provided amazingly good sound for about $80 per speaker. This web page takes a look inside the A25, and speaks in particular about trouble-shooting.
The A25 is a two-way speaker with a 10" woofer and a 2.25" mid-tweeter. The crossover is quite simple, just a 5 uF capacitor in series with a variable resistor arrangement that feeds the tweeter. Please also note that according to some recent information from an Updatemydynaco customer, Ed Cameron, some of these speakers were built with 8 uF capacitors, rather than 5 uF. So, you may want to check to see which you have. The woofer connects directly to the binding posts, and the crossover relies on the natural roll-off of the 10" woofer. Here's a picture of the inside of the speaker showing the crossover and level control
