Fisher 400 Tube Rolling

[streetwise]

I felt it was a good idea to start a thread to get ideas for myself and others as to what people are using in their 400. On my 400 I have original Fisher power amp tubes, no idea a variety for the tuner sections, phase inverter are rca branded tubes, tone amp and line amp I cant remember at the moment possibly a tung sol. Any thoughts where to start. I also have Dave Gillespie mods all over mine so certain tubes might be less worthwhile to roll from what I have read. My phono section has new Sovtek 12ax7LPS as Jim McShane recommended.

 

[larryderouin]

Tuner tubes usually don't affect SQ, except when they go bad. Same with MPX. Probably best thing to do is to match the tubes for phono(done) side to side, same with phase inverter, Tone and Voltage amp tubes. In other words, Make sure the Left tube for a circuit is the same as the right side. The RCA Tubes are usually good in the P.I. Believe it or not, FISHER switched from Telefunkens to Sylvania's about the time they changed to the late version of the 400. These are quite under-rated and sound quite good. They aren't as flat as Tele's and are quite musical. As for power tubes, Sylvania 7868's are right up there with the best of them.

Don't be afraid of using Russian tubes for the 12ax7's and 7868's. The 7868's have a slightly larger pin, and will limit you to the russian 7868's once changed over. Stay away from the Chinese 12ax7's. These are crap for HI-FI, but ok for Guitar applications.

I've pretty much got a tin ear, but I do match them left to right, and can tell (about 50%) when the tubes are different left to right. Keep the output's matched for tube draw as much as possible either thru matched tubes themselves or by individual adjustments.

 

[RS Steve]

I find that when you buy used Telefunkens to restore these receivers, the sound of all those dollars leaving your wallet can make for a much poorer sounding unit.

I installed new EH 12ax7's in my last 400 and have no complaints.

 

[arts]

I've never met a 400 that did not sound great,regardless of brand of tubes used

 

[larryderouin]

One more thing about the Voltage amp and Tone Amp tubes. As the 12ax7 is a "DUAL" triode, it means 2 tubes operating in a single envelope. The tube 1/2's should be matched as much as possible for these tubes as each tube does the Left and Right sides. All the other 12ax7 tubes will do one side or another. On the EARLY VARIANT (Serial <48001) these are V9 and V10 and on the LATE VARIANT (Serial >48001) these are V10 and V11.

 

[eduarsan1]

Depends how much you have in your wallet, I agree with Larry, EH tubes are good stuff, probably the only issue is.... the lifespan! no goodest than in the old school !!.