Unknown Blaupunkt Chassis
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Hello, can anybody help me in identifying this radio? I am having trouble figuring out what tubes to place in the 4 rightmost positions near the power transformer. Does anybody have any more information on this radio? Thank you.
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Looks like a USA version of this:
or Riviera 2640
See also this USA model (similar but 2x EL84 B9A instead of smaller B7G EL95)
There are also models with only one EL95 or EL84. Examination of audio transformer wiring and tube base should show which (mono single ended, push pull, stereo or hybrid switchable mono-push-pull / stereo-single ended).
Likely it's from a big radiogram cabinet and stereo single ended.
Search: Radios Only, Germany, Blaupunkt, on Home page with photo and tubes ticked for 1957 to 1963.
Actually looks like it has a stereo decoder (2x single ended tubes near scale) maybe even with a stereo decoder (the two tubes in shielded part).
Earlier models, especially in Europe, that were stereo had no decoder. The stereo was only on gram or tape.
Most probably Blaupunkt 2531 USA is an early stereophonic console chassis (AF only, there is no provision for an MPX adapter). This is the predecessor of the Riviera USA 2633 MX.
The chassis has 9 tubes which are from left to the right ECC85, EF89, ECH81, EF89, EABC80, EL84, EBC41, EL84, magic eye EM84. The two tubes EBC41 and EL84 (2nd audio channel) are separated in the elevated "box" beside the lower EL84.
The remaining two bases (one 7-pin and one 9-pin mounted at the right) is the provision for connecting the speaker array (green dot) and the record changer/illumination (red dot) of the console. Danger: No tubes shall be put in there! Please refer to the schematic sch1c.pdf from the Riviera console mentioned above. Your chassis 2531 USA may be identical here.
Blaupunkt Riviera USA 2633 MX, audio and power supply
Update: The new model has been accepted and the forum thread is now tied with it.