Tag Archive for 'equalizer'

new ferralgraffa studio unit

an australian  client has ordered this stereo MB1 chassis  – versus  -  my sweet lady tube 2 way EQ . a great combo  .  he has supplied a beaut old ‘skin’ tolex covered ferrograph tape recorder case for it .  so im going to make this stereo mic/di/eq amplifier into that -  complete with on board 5 watt tube amp and the original 9X6 inch goodmans monitor speaker.   the new dual pultec MB1 tube mic  amp will  have variable input impedance. 30.150.600 ohms . alex has some real old ribbon mics .  and wants extra tonal front end augmentisation capability in general.  the big old meter switches between the two preamp outputs.  as does the EL84 single ended tube P.A. amp.   the 2 way tube equalizer  features as the MB1 alternative input source.  reverse engineered design from an american roberts (or rogers) stereo system. a unit that i repaired once really impressed me. the eq sound was so fat and deep. a very particular circuit built around the feedback of a single valve amplifier stage. ive added a preamp stage to it to enable an  effective rumble filter,  and hi/lo frequency switches to the bass and treble stages  to complete this massive sounding 2 way eq adjustment scope of this ferral graffa transportable 2 channel studio preamp unit .