If you want to listen to original recordings by Charlie Parker, Bessie Smith or most Billie Holiday, you won't be listening in stereo. In the US, stereo lp's were inaugurated in 1963. Prior to that, all records were monophonic.
As more people discover just how great music on mono can be, they also discover an interesting and important fact- before stereo, every label had their own equalization curve (EQ.) When music is recorded, it must be compressed in the cutting process to make a record "master." When the record is played back on your home system, a corresponding EQ filter is used to restore the bass and attenuate the highs. With stereo, an industry standard known as the R.I.A.A. (Recording Industry Association of America) curve was established. Before stereo, phono preamplifiers had various settings or adjustments to tailor the bass and treble rolloff for each label and record. Without that ability, you may be able to play a mono record, but you won't be able to hear it properly. Because the bass, or the treble, or both, may be far off the RIAA EQ built into your stereo phono stage or preamplifier.
The solution is a dedicated mono phono preamplifier, and indeed there are a number of choices available that have either preselected settings for the most common labels (RCA, Columbia, Decca, and so on) or stepped attenuators to allow the necessary adjustments. None of these are optimal solutions.
The Monophonic is a handmade German mono phono stage using solid stage amplification which employs stepless adjustments in the most simple, user friendly way. There are only two knobs on the front of the Monophonic, which correspond to bass and treble rolloff. Each is numbered. A comprehensive list is provided of nearly every label existing prior to the introduction of stereo, showing two numbers, for example 5 and 4 (RIAA) or 5 and 5.5 (Columbia.) You simply consult the list, and dial in the code for your record. And if you feel that there is too much bass or treble for your taste or your system, you can with great precision dial in your preferred sound by ear as the knobs offer stepless adjustment instead of the usual stepped adjustment.
Only with the Monophonic can you correctly playback any mono recording precisely and effortlessly.
The Monophonic offers both MM and MC gain sensitivities ( 3.0mV, 1.0mV and .3mV) with optional impedance matching to the cartridge selected. It is supplied with a 110V or 220V wall wart type power supply. Size- 7" x 5" x 2.5"
Price (includes shipping in the US) $1500