09-06-2005, 01:01 PM
So far I can report that EH7868 tubes work well and sound good in my Fisher 400. I had the unit aligned and the output stage adjusted, the unit sounds fantastic. Neither of my 400s has ever sounded so good. I can not really compare them to NOS tubes because I never had the outputs balanced with a matched set of NOS tubes. My NOS tubes are not matched. Over the past year I replaced all coupling caps with orange drops and rebuilt the neg. power supply. I also replaced all the FM MPX diode bridges. (some one previously screwed them up.) The FM also now sounds excellent. I recommend to any 400 owners the EH tubes if you can not easily find matched NOS tubes, find a good tube tech and have it aligned. These receivers are a relative bargain after the usual work is done to them, The sound quality comes close to my modern tube pre and amp set up. After purchase restoration (by me), tubes and alignment total cost about $300. BTW the EH tube is not a rebottled EH7591. The bulb and plate structure is the same size and looks very close to NOS.