Selmer Treble 'N' Bass 50 Reverb


A new and improved version of one of the most successful amps ever produced. 50 watts with such a wide tonal range that the amp is ideal for every use from Bass to P.A. Twin channel, four inputs and separate volume, bass and treble controls for each channel. Very smooth frequency response throughout the tonal range and superb performance without distortion at high volume levels.
Designed and manufactured by Selmer.
No. 7091. Complete with waterproof cover 81 gns.


SPECIFICATION NEW TREBLE 'N' BASS 50 REVERBERATION
Two channels (bass channel, normal channel).
Two inputs per channel (high impedance)
Volume, treble and bass controls on each channel.
Normal channel has reverberation, using the Hammond spring unit with a variable depth of reverb control. Reverb is switched in and out with a remote footswitch.
Power output: 50 watts r.m.s.
Mains input: 115V, 125V, 205V, 225V, 245V, 50 – 60 c.p.s.
Valves: 2 – EL34, 4 – ECC83, 1 – 6BR8.
Rectifiers: 2 – BY128, 1 – BY105
Hammond reverb unit type 4C
Separate mains and H.T. fuses.
Neon pilot light.
Output impedance: 7.5 ohms and 15 ohms by means of locking-type jack to prevent accidental disconnection of speaker lead.
Cabinet finish Black, Black/White sil, Black panel withWhite lettering.
Black and satin chrome trim.
Dimensions: 203/4" x 91/4" x 111/4".

IMPORTANT: These drawing and notes are provided for interest only and are not guaranteed to be accurate. Use at your own risk and discretion. The equipment shown contains lethal voltages and should only be worked on by people with suitable training and experience. Schematics and layouts are typical but will vary.
PRINTING

Wix (bless 'em 😖) have changed their image format - again - to avif just to make them awkward to print. Unless you want to buy a converter, the easiest way to make a hard copy is:
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Left click when the magnifying glass icon appears and wait for the picture to clear.
(On a touch screen, tap on the image). This will display a higher res file. -
Right click and 'save image as' to somewhere as an avif file.
(On a touch screen, touch and hold down to view the menu) -
Upload the saved file to your Google Drive.
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Open the file and use the print menu to make a hard copy or save as a pdf.
Selmer Treble 'N' Bass 50 Reverb Schematic

Selmer Treble 'N' Bass 50 Reverb Under Chassis Layout
(Update on mains indicator wiring in issue 2)


Selmer Treble 'N' Bass 50 Reverb Above Chassis Layout


Selmer Treble 'N' Bass 50 Reverb Tank

LEFT and BOTTOM LEFT: Rubber bands don't generally last for 50 years, so that rattling noise is probably the reverb tank destroying itself. This one's down to one spring (no sign of the other one). There should be two springs as in the bottom right picture.
The only marking on the original is 'JAPAN', so not much chance of finding another one. A suitable replacement would be an 8AC2C1B, horizontal, open side down.
Fit phonos to the cables and screw the tank to the bottom of the cabinet, not the cover box.
An MOD 8AC2B1B, with modified grounding, could be used as well.

