Selmer Treble-N-Bass Fifty

This vintage Selmer Treble-N-Bass Fifty came to us with some electronic issues.  It was more than a routine repair, so we consider it a restoration.  It looked great but had a bad power transformer, tired tubes, and suffered from oscillations.  The original filter caps were also positioned on top of the chassis, potentially exposing the user to dangerous high voltages.  We had the power transformer re-wound, went over the entire amp, installed NOS Mullard tubes, and fabricated a protective cover for the new filter capacitors.
© P.M. Sound Technology, LLC 
P.M. Sound Technology, LLC

​-Custom Built Tube Amplifiers
-Tube Amplifier Repair & Restoration
-Serving Washington, DC Area & Musicians Worldwide

(540) 718-2392​​



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Exterior view of the amp.
Rear of amp with back panel in place.
Chassis removed from cabinet.  The filter capacitors with exposed connections can be seen behind the preamp tubes.
Close-up of shock hazard presented by exposed filter caps immediately next to the preamp tube sockets.  
Custom fabricated filter capacitor cover with new filter caps installed.
Rear view of custom filter cap cover.  This is what will be visible from the rear of the amp and will pevent accidental shock.
New filter caps and custom cover installed on chassis.  Risk of accidental shock eliminated.
Rear view of amp with chassis installed after all work was completed.