P1 PHONO UNIT

The Mu­si­cal Tech­nol­ogy P1 phono pre­am­pli­fier rep­re­sents the ul­ti­mate in phono de­sign. In terms of both qual­ity and flex­i­bil­ity it can be con­sid­ered de­fin­i­tive; and should be com­pared to the best phono pre­am­pli­fiers avail­able re­gard­less of price.

The P1 is suit­able for use with any ex­ist­ing MC or MM car­tridge. Of­fer­ing a range of im­ped­ance and gain set­tings it is pos­si­ble to op­ti­mize op­er­a­tion for any car­tridge, even MC de­signs with out­puts as low as 0.1 mV. The sig­nal path is very sim­ple de­spite the ap­par­ent com­plex­ity of the cir­cuit. Each chan­nel is com­pletely sep­a­rated from the other and is con­fig­ured as 24 dis­crete tran­sis­tors op­er­at­ing in pure class A (!) in a com­ple­men­tary cas­code cir­cuit, with min­i­mal vari­a­tion of cur­rent and volt­age as com­pared to the bias value. This re­sults in ex­treme lin­ear­ity.

The de­sign is free of in­te­grated cir­cuits and over­all feed­back. RIAA equal­iza­tion is not ob­tained by a shaped feed­back net­work, but by a cur­rent pro­por­tional to the input volt­age sourced to a ref­er­ence im­ped­ance which yields volt­age that pre­cisely in­creases with fre­quency, some­thing that does not occur with pas­sive equal­iza­tion. The over­sized power sup­ply, housed in a sep­a­rate chas­sis, em­ploys a total of 4 ca­pac­i­tors and 18,000 µF of ca­pac­i­tance to min­i­mize noise and to en­sure un­re­stricted dy­nam­ics.

Trans­par­ent, dy­namic and well-de­fined sound is pre­sented against a very silent back­ground, even with very low out­put MC car­tridges.