Weak X100B Phono

K7JHG

Member
I don't think its a secret that the X100B is weak when it comes to the phono stage. I love this unit and it sounds extrordinary but the phono is not loud enough for me. I'm listening to a CD now and it is as loud as I would want it. The phono just isn't cutting it so I'm considering getting another Fisher with more metal in it but I really can't affor it.

My question is - is there anything that can be done to improve this and get more volume out of the X100B phono stage?

Thanks,

John
 
What are you using for a phono cartridge? MM goes in Phono HI, Ceramic goes in Low. I'd build a new board to replace the P.E.C. (CP1 & CP2) with new parts to start. Check the 12ax7 in position(s)V1 & V2. They might be weak.

There is a problem with the schematics between the 10001-19999 and the 20001-29999 versions. The Tape-Phono switch is reversed in one of them. One has pin 2 on tape, with phono on pin 3 and the other has tape on pin3 with phono on pin2. The C/R layout doesn't change tho. So something is wrong here. comparing the X-100 and the X100-C schematics to the X-100-B's the 20001-29999 schematic is BACKWARDS with regard to labeling. If the switch is in fact connected backwards you would get an incorrect equalization.

1st off Check the pinout from the PEC to the TAPE/PHONO SWITCH. Follow the lead from pin 3 of the V1 tube to the PEC. It should be on pin 1. Pin 2 should be on the Tape side and pin 3 on the phono side. If it's not the easiest solution is to reverse PIN 2 and PIN3 leads on the PEC. THIS IS FOR THE 20001-29999 series x100B. The schematic on the earlier 10001-19999 is correct. But doublecheck anyway.

The PEC is the same used on the 800-C. I just verified the pinouts on my 800-C. Pin 1 is from Pin 3 of V1 or V2 (left or Right Channels). Pin 2 to the TAPE side of the switch, and Pin 3 to the phono side of the switch. There shouldn't be a loop back to Pin 1 from pin 2 or 3.

Larry
 
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