Hey gang, the disparity between the imaging of my cheap CD player fed through the line stage of my Fisher 400 and my TT fed through the phono stage has led me to wonder about the quality of the Fisher phono stage. I've had my Fisher gone over by Terri DeWick, so it should be generally up to snuff, but where does the phono stage sit in comparison to modern phono pre's? I'm using a Grado Gold on an AR XB for reference. Thanks, Nat.
Fisher 400 phono stage?
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audiodon
Addicted Member
Assuming that your turntable has a moving magnet cartridge, I'd suggest trying different tubes in the phono stage to round off the peaks in the upper bass/lower midrange and around 11k. I've had good luck with Sylvania 12AX7s in those positions.
In later 400s, Sylvanias replaced the Telefunkens as the preferred vendor of tubes new 400s came stock with.
If you've got a moving coil cartridge, even a high-output one, you probably are ready for an output phono stage. If it has variable output gain on it, you can run it into the tape mon inputs and adjust the gain until the gain is comparable between the tuner, aux input, and tape mon switch. Don't run tape mon with aux input running, even if switched off on the 400 because you'll hear bleed through.
In later 400s, Sylvanias replaced the Telefunkens as the preferred vendor of tubes new 400s came stock with.
If you've got a moving coil cartridge, even a high-output one, you probably are ready for an output phono stage. If it has variable output gain on it, you can run it into the tape mon inputs and adjust the gain until the gain is comparable between the tuner, aux input, and tape mon switch. Don't run tape mon with aux input running, even if switched off on the 400 because you'll hear bleed through.
audiodon
Addicted Member
Fisher branded usually says "Made in Western Germany", which means Telefunken. They have a bit of sparkle that reinforces the 400 in a positive way, but the circuit in the phono stage ages and turns reinforcement into exaggeration. So, with Teles in the phono stage (the two at the left front with tube shields), you get double reinforcement. Try some RCAs also. They tend to be a bit softer and may sound better in those positions.
TheRed1
Console Conservationist
You're comparing two different sources which isn't a very good test of the 400's phono stage. Try using a outboard phono pre-amp connected between your TT and the 400's AUX input vs. your current TT's signal path.
When I first got my 400 back from NOSValves I bought a Cambridge Audio 640p outboard phono pre-amp because I had read that Fisher's phono stage was a weak point of the 400. For some reason I never even tried my 400's phono stage. When I did eventually try it I was pleasantly surprised at how much better I thought it sounded than with a modern outboard pre-amp. Of course, my personal preference is for a warm and balanced sound. That might not be what you're seeking.
When I first got my 400 back from NOSValves I bought a Cambridge Audio 640p outboard phono pre-amp because I had read that Fisher's phono stage was a weak point of the 400. For some reason I never even tried my 400's phono stage. When I did eventually try it I was pleasantly surprised at how much better I thought it sounded than with a modern outboard pre-amp. Of course, my personal preference is for a warm and balanced sound. That might not be what you're seeking.
Thanks Red1. What I am noticing is a lack of focus, image clarity in the middle with the phono stage. I meant that comparing CD to phono, I would think that a cheap CD would be bettered by the higher quality vinyl setup. In some ways the vinyl chain is better, but it is bettered by the CD in terms of focus. In anticipation of responses, my vinyl is setup properly etc.
JonL
Lunatic Member
My experience is consistent with your expectation rather than your results -- in other words my decent vinyl setup sounds far superior to my cheap CD setup, most overtly in terms of focus and the ability to present well-defined and stable imaging throughout the soundstage. As an owner of a Fisher 400 that's not currently in use but which is tentatively earmarked for a future bedroom system (when I get a bedroom!), I'm interested in seeing how your situation evolves.
TheRed1
Console Conservationist
While I do think I understand what you mean by "focus" and "imaging" there is a subjective element to such terms that might lead to confusion. Do you think there might be a valid analogy between audio and photography with regard to these terms?
In digital photography when you "sharpen" you are increasing the contrast between adjacent light and dark areas or between different colors, shades, hues, etc. (I won't pretend I fully understand all the different processes, but I get the overall concept.) Is there an audio equivalent? Might "focus" and "imaging", in an audio context, be something we have become accustomed to because of the way digital audio is sampled and processed? Is digital audio "sharpened"?
I certainly don't know whether this is true or not but I suspect so. I think modern recording techniques like close miking tend to give exaggerated detail even with a purely analog signal chain. I'm not making a value judgment - I like to hear as much "focus" in my music as the next guy. I'm just curious what it is that we actually perceive as "imaging". I find it interesting that the terms we use to describe it are usually used in a visual context.
In digital photography when you "sharpen" you are increasing the contrast between adjacent light and dark areas or between different colors, shades, hues, etc. (I won't pretend I fully understand all the different processes, but I get the overall concept.) Is there an audio equivalent? Might "focus" and "imaging", in an audio context, be something we have become accustomed to because of the way digital audio is sampled and processed? Is digital audio "sharpened"?
I certainly don't know whether this is true or not but I suspect so. I think modern recording techniques like close miking tend to give exaggerated detail even with a purely analog signal chain. I'm not making a value judgment - I like to hear as much "focus" in my music as the next guy. I'm just curious what it is that we actually perceive as "imaging". I find it interesting that the terms we use to describe it are usually used in a visual context.
You might try replacing the PEC module in the phono section with a DIY unit made with higher quality components. The component quality of the caps and resistors in these PEC's is, I suspect, not that good. You're dealing with a very low signal level and a high gain circuit. The PEC is in the feedback loop where it will have maximum effect on the sound quality. Also make sure the selector switch sections that pass the phono signal are good and clean, again since it's a low signal level especially at the input switching section. Personally, I wouldn't be against redesigning the original circuit for something better.
Have fun,
John
Have fun,
John
My experience is consistent with your expectation rather than your results -- in other words my decent vinyl setup sounds far superior to my cheap CD setup, most overtly in terms of focus and the ability to present well-defined and stable imaging throughout the soundstage. As an owner of a Fisher 400 that's not currently in use but which is tentatively earmarked for a future bedroom system (when I get a bedroom!), I'm interested in seeing how your situation evolves.
And that has been my experience historically as well; i.e that the vinyl playback is superior. Hope I get things straight!
When I know the placement of an instrument is supposed to be in a given place and it appears to my ears to be less definitely in that place. Also there could appear to be less focus in the panning of a sound effect from left to right. With the CD player you can follow it with your ears, but with the vinyl the location is less exact (Your ear may have trouble following a consistent and specific pan effect).
I think is part of the solution as well. I've dealt with these in other units too and there was improvement when replaced with discrete components. Might take a little thinking to pull it off because you'll probably have to add a terminal strip for each channel to mount the new components.
Besides the RIAA eq in the phone stage, these things are also used on the back of the treble pots for the tone controls.
You guys are way over my head. Maybe a business op if you could design a drop in circuit that one could just solder in? Thanks for the responses.
Maybe but isn't there an audiodon mod for the aging PEC in the phone stage?
You're gonna make me beg...