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Vintage Asylum Classic gear from yesteryear; vintage audio standing the test of time. |
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In Reply to: RE: Fisher 500-C vs. Mcintosh 1500 receiver posted by geezerrocket on March 8, 2010 at 14:51:21:
Hi, geezerrocket:
I just wanted to mention that I knew Charlie Kittleson personally and over many years, and I was totally shocked when I received news of his suicide last year. There was no obituary posted anywhere that I was aware of, which struck me as most unusual.
Charlie really should have included at least some basic instructions with his "restoration kit". This stuff is quite basic, actually, except for "hot-rodding" the tuner by changing the time constant (not particularly recommended) and perhaps other power supply tweaks, about which I know little or nothing. I do know that Sheldon Stokes provides a nice board to completely replace the majority of the powre supply componentry, but I have not used that product yet. As long as the rest of the larger electrolytics are still working or testing well, that is okay by me. Besides, if you know how, you can remove the originals and restuff them with fresh caps inside and then reinstall on the chassis.
I stick with the basics: replace all coupling caps with equivalent values and slightly higher voltage rated parts, replace all small electrolytics and always observe proper polarity! The same goes for removing and substituting for the original selenium rectifier. You can use a full-wave bridge rectifier of equivalent value and I believe that part should have been in your kit from Charlie the K. If he did not include 10-ohm 1/4 watt "safety resistors" for the 7591-A tubes (cut the hard wire from pin 5 to ground and insert them in-place of the hard wire), then you should at least do that. When the new full wave bridge rectifier is installed the voltage will increase, so you need to change the normal 5.6 K Ohm dropping resistor attached on one end to the dual 1000 mf @ 35 vdc bias filter cap to something about half that value, but calculate what you need to arrive at -21.5 volts DC on the bias.
All of this stuff has been discussed quite frequently in this very forum, so feel free to research the topic!
Also: Jim McShane is an expert on these and other matters.
Lately, I have been removing and then opening up and cleaning out the original dual 1000 mf cap I just referred to. I re-stuff it with fresh caps of 1000 mf @ 50 wvdc each. (I have a huge bag of them if anybody else out there needs any!) Always replace the re-stuffed cap into the original paper insulation sleeving and then into the metal retaining clip. Insulate more with black tape if you wish, but isolate it from ground in that clip or you will be blowing lots of ugly smoke rings!
Please read up on the rest. The schematic is commonly available elsewhere.
Just as an aside: My personal experience with these various Fisher receivers is in favor of the overall sound of the 500-B, rather than the 500-C. But, the "C" offered so much more in the way of extra features: dedicated headphone jack on the front panel (with reversed channel orientation, by the way!) and that nifty remote speaker selecting switch.
The phono section is decent and could stand improvement, as others have noted. There are some of those weird yellowish encapsuled networks in the 500-C, which I believe have something to do with the tone circuitry or possibly the phono circuit. If that is true, if you were patient enough and could stand bread-boarding them as replacements, do so!
Richard Links
Berkeley, CA
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Follow Ups
- RE: Fisher 500-C vs. Mcintosh 1500 receiver - Marantzguy 17:50:19 03/08/10 (0)
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