10uF 500VDC Sprague Atom TVA 1903 Capacitor, Length 1.625" x Diameter .75". This sturdy blue jacketed axial lead aluminum electrolytic capacitor is preferred by most craftsmen for authentic vintage guitar amp and hi-fi restorations. Many of the best sounding classic guitar amps by Fender, Ampeg, Magnatone, Valco and many others used Sprague Atom series electrolytics.