Excellent Supertone 12 bass button accordion in BbEb made in Germany in the mid to late 1900’s. It is in very good condition. There is little wear anywhere. The wooden case is in nice shape with highlighted woodgrain and painted on decorations. The original bellows are tight and I believe either had no wear or were retaped by a previous technician because they look new. They feature very colorful papers. It has 21 treble buttons and 12 bass buttons. The low buttons on each row of the treble side are accidentals. The zinc reed plates have the ‘O’ marking which I believe were made by Dix. It has steel reeds. The original leather valves have been retained. Each was evaluated and either flattened or replaced. These provide very quiet valve action. It features no-tool access via swing clamps.

The bellows have new gaskets and new straps. On the treble side I removed the keyboard and added shims to space it out preventing rubbing of the buttons on the button holes. The original grill cloth looks nice. The 12 basses are fairly unusual and add nice variety including one additional minor chords. The configuration was odd but I rearranged to the more normal layout. The treble reedblocks had some bottom cupping so I sanded the bottoms to flat and then shimmed the ends so they are still held tightly. I have added an anti-resonance crossbar between the treble blocks to minimize undesirable ‘wah-wah’ effect.

The bellows gaskets and straps have been replaced. The original thumb loop in in place but I reversed it so as to not be in the way for shoulder strap usage. It is easily reversed back. It features two knobs instead of the normal accordion strap brackets. This allows using standard guitar straps. I will include a makeshift non-adjustable strap so it can be used immediately but an adjustable guitar strap should be procured. I have just tuned all 144 reeds using A=440Hz as the reference frequency. On the treble side the tremolo beat frequency is around 2 Hz for the lowest notes gradually rising to 7 Hz on the upper notes. Final tuning occurs in situ with the reedblocks inside the case.