tlarwa
Vinyl Lover
This from Sony6060 in a different thread:
"Nothing is fundamentally wrong with the Fisher phono stage. IMO I believe these reports are hearsay. In fact, what is the difference in-between any 12AX7 phono stage? They are all the same with exceptions of the quality of parts and the RIAA tuning.
I can make a Fisher phono stage sound lousy or great with choice of the phono tubes and coupling capacitors. And, a dozen audiophiles with very high-end systems cannot not be wrong. One audiophile is a recording engineer with select master recordings and serious playback equipment.
Two tubes will perform. Brimar CV4004. These are with box plate on one end and a wing on the other end plus are very expensive. Close second place is Westinghouse USA manufactured 12AX7 with short narrow plate and only $30 per tube with diligent shopping. I rolled about every tube, even 1952 Sylvania 12AX7 tall black ladder plate that produced a slight smearing or say just not enough airy response.
Next, change out the phono stage coupling caps to K40Y-9. If a slightly softer presentation is needed, replace one set of K40Y-9 with Sprague Vit Q. Less than stellar LPs will sound a little better.
The last few percent in performance will come forth with a RIAA replacement using close matched metal film and K40Y-9. If organ music is your delight, change the response curve for a lower response. Going too low in response may have rumble possibly showing up. I have not made measurements, but the stock Fisher RIAA is likely good to 25Hz @ -3dB. 3dB is not a lot of fall off. I should measure it soon."
My Fisher 400 has the BizzyBee mods, and is a terrific performer. I don't typically use the phono stage, opting instead for my Parks Audio Budgie. But with the addition of a new-to-me AR XA table, I'm now using the 400's phono stage. I'd like to make it as good as I can. Tube rolling isn't an issue, and I will try to score some Brimar's or Westinghouse 12AX7's as recommended. As for the coupling caps, is that something I can do myself? I can solder decently, and have recapped crossovers, but have never worked on a receiver. Let alone a tube receiver ... and I don't want to electrocute myself. I also don't want to mess this beauty up! So what do you think ... should I tackle it or leave it to someone else?
Tom
"Nothing is fundamentally wrong with the Fisher phono stage. IMO I believe these reports are hearsay. In fact, what is the difference in-between any 12AX7 phono stage? They are all the same with exceptions of the quality of parts and the RIAA tuning.
I can make a Fisher phono stage sound lousy or great with choice of the phono tubes and coupling capacitors. And, a dozen audiophiles with very high-end systems cannot not be wrong. One audiophile is a recording engineer with select master recordings and serious playback equipment.
Two tubes will perform. Brimar CV4004. These are with box plate on one end and a wing on the other end plus are very expensive. Close second place is Westinghouse USA manufactured 12AX7 with short narrow plate and only $30 per tube with diligent shopping. I rolled about every tube, even 1952 Sylvania 12AX7 tall black ladder plate that produced a slight smearing or say just not enough airy response.
Next, change out the phono stage coupling caps to K40Y-9. If a slightly softer presentation is needed, replace one set of K40Y-9 with Sprague Vit Q. Less than stellar LPs will sound a little better.
The last few percent in performance will come forth with a RIAA replacement using close matched metal film and K40Y-9. If organ music is your delight, change the response curve for a lower response. Going too low in response may have rumble possibly showing up. I have not made measurements, but the stock Fisher RIAA is likely good to 25Hz @ -3dB. 3dB is not a lot of fall off. I should measure it soon."
My Fisher 400 has the BizzyBee mods, and is a terrific performer. I don't typically use the phono stage, opting instead for my Parks Audio Budgie. But with the addition of a new-to-me AR XA table, I'm now using the 400's phono stage. I'd like to make it as good as I can. Tube rolling isn't an issue, and I will try to score some Brimar's or Westinghouse 12AX7's as recommended. As for the coupling caps, is that something I can do myself? I can solder decently, and have recapped crossovers, but have never worked on a receiver. Let alone a tube receiver ... and I don't want to electrocute myself. I also don't want to mess this beauty up! So what do you think ... should I tackle it or leave it to someone else?
Tom