Phono coupling capacitors in Fisher tube receivers

[monkboughtlunch]

My Fisher 400 had its phono coupling capacitors switched out when I got it so I haven't heard the originals Fisher used.

Any comments on the quality of the original phono coupling capacitors Fisher used? What brand or brands were used and how did they sound?

 

[audiodon]

They're colloquially called brown turds.
The ones in the phono stage didn't have that much voltage across them, so they don't tend to crack and dry with age, as they do in other positions.
They were a decent functional cap. Nothing to write home about, but not a compromise cap either.

 

[ferninando]

my X100B is full of turds. They are all mylar. But not for much longer.
Soon in go PIOs and polypropolenes and new electrolytics.

 

[sony6060]

I have seen mostly ceramic type coupling capacitors in the phono and a few with the mylar type. The best mix of replacement capacitors without breaking the bank are to replace the original with one set of K40Y-9 & other set with vintage Sprague VIT Q. Both capacitors are of Mil-Spec glass sealed design. I increase the .022uf to .047uF and use the K40Y-9 in that position.

From a tube standpoint, many have verified the best tube in the phono are Brimar CV4004 or 12AX7 (same tube). Only use the Brimar 12AX7 plate design with one boxed end and the other end having a thin wing. Frankly, the other Brimar plate designs fall to the bottom of the performance list. If your Fisher has Telefunken 12AX7 in the phono section, selling the Telefunken will help finance the Brimars.

An alternate without breaking the bank are USA manufactured Westinghouse 12AX7 with the narrow short plate. The plate looks like mid '60s & 70s Sylvania. Some Westinghouse were build by other manufactures.

I tried many tubes in the phono section and others also heard the various tubes at the same time. All have come to the same conclusion.