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I know Mike and Eli have given you good advice. I have done a lot of work recently on H-K Citation I preamps, Cit. V and Cit. II amps. I also restored a Sansui 1000a receiver. It sounds like your tech put in supplemental power supply caps - to me that means that rather than search out replacement cans (if that is what is in an 800C) he wired some caps underneath in parallel. He also changed a resistor or two. If it were my amp I would replace all the coupling caps, all the power supply caps, change the grid resistors (there are only 4 of them, it can't be that hard and they only cost a dollar or so each). There must be caps on some sort of feedback loop and I would change them too. I would also test every resistor in the power suppply section and replace as necessary. They are pretty darn cheap. I would test all the tubes. I would expect that most of the tuner section tubes are just fine. I don't have the schematic in front of me, but if it has 12ax7, 12au7, or 12at7's in the preamp section it is quite possible they are fine too. I would expect that the power tubes are probably about done. Possibly the driver tubes as well - don't know the circuit. It's only about $80 or so for a quad of new EH output tubes. Setting the bias is no big deal. You need to find a tech that takes vintage equipment seriously. I would do it for you, but you don't want to be shipping big heavy things across the continent. Try contacting your local hifi group. There has to be one. Some sort of club. Try googling or asking on here in the vintage asylum. You will sooner or later find someone like Mike or myself who will tackle it for you for the cost of parts and a few hundred dollars labor. It is a nice piece that needs to be restored. The power supply and coupling caps are probably about done. The parts are not that expensive, but you don't want to just throw new output tubes in without making sure the power supply and coupling caps are up to snuff. Even if your problem is the output tubes, if you change them your coupling caps or power supply caps will probably fail sooner or later. Don't worry, you will find someone who enjoys working on vintage equipment if you dig around a bit. Boston is a big city! As for cost...the full complement of caps must be available for $75 - $150 - I think there was a fisher restoration kit being sold somewhere - google it. It will have all the caps and resistors you need probably. The tubes - probably $80 - $150 depending on what you need besides a quad of output tubes. The labor.. well a shop would probably charge you $75/hour and you are probably looking at 4 hours or so? Never worked on a Fisher receiver, but that Sansui was a bear. But if I had to do another one I could be pretty quick, so if you found someone familiar with Fishers I bet 3 - 4 hours is a reasonable bet. Or put it on ebay and find a rebuilt Fisher receiver or one of the many other fine vintage units out there. The long and short of it is that you could put $500 - $600 into it and have a restored piece that could be good for another 20 or 30 years - with the change of power tubes every 5 years or so. It will sound way better than most modern stuff!
'Replacing all the tubes' may mean, pocketing all the valuable Telefunken and Sylvania OEM tubes and putting in "new" but possibly inferior tubes, at great expense to you and profit to them.
I restored my Fisher 800C myself, but I had 'some' experience. I got the booklet from Fisher Doc (not sure he's still in business). He recommends NOT replacing original PS capacitors unless it's necessary. Mine worked perfectly. We put the amplifier on a scope and the signal was about perfect, so I even left in the German-made coupling caps so as not to alter (screw up) the sound. YMMV.
I'm not saying techs are unscrupulous, but as you surmised, that may not be the place to go. You shouldn't have to ship.
- sold my 800C (shown), and the new owner loves it, works great almost 2 years after.
Certainly a very valid response, as I have no experience with Fisher receivers. I agree, if the power supply cans are OK, then leave them alone. However, if they are weak it shouldn't be hard to find new cans for $25 - $35 each that are of very high quality. I bet Jim McShane has some. The EH output tubes are $80 for a matched quad from Jim. I also agree that most of the small signal tubes are probably just fine. I just checked and there is a guy on epay who is selling the entire cap kit for $85. I have no idea how good the original caps are and what kind of shape they are likely in. I leave that to people with more experience on Fishers. If it were mine I would replace every cap and put Russian PIO's in for the coupling caps, but that's me. But output tubes and a cap kit are only $165 for parts. Labour simply can't be that bad. 4 or 5 hours I will wager. Biasing has to be pretty simple. All you need is a DVM and a screwdriver I am sure...... I would guess he could do it himself.
Biasing on Fisher receivers is truly fixed. :> ( There's nothing to adjust. You check the voltage and tweak parts, if it's out of tolerance. Truly fixed bias imposes the need to buy VERY closely matched quads of O/P tubes. All 4 "finals" must be extremely close in both cathode current and gm. Yes, McShane can provide the sets needed, but he, or any other honest dealer, has to charge for the considerable work involved in the culling. Unfortunately, factory "matched" quads fail to "cut the mustard".
Wow, that seems like a pretty silly design. Still, I bet Jim doesn't charge more than an extra $20 or so to do it. If I had one of those Fishers I would seriously consider changing the bias scheme to at least a balancing pot on each channel.... Seems to me that even if you get a new quad that has been expertly matched there is no guarantee as to how far apart they will drift as they age. Of course I have a Sansui 1000a to fill my receiver need and the Citation II upstairs to REALLY listen to. I managed to score some EI KT100 type I's and am running it in triode. Very nice. I also have a Citation I and V combo in the basement that is sounding pretty good after all the McShane kits...... so I'd have to sell something to take on another project!
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