Harmon Kardon citaion 1 kit telefuken

I think you have something that is very very rare and collectable if it is in good or better condition. If the kit included the original unused tubes which I assume is why you put Telefunken in the title, then it's even more collectable. I would think you could sell it for a very good price that would give you the money you can use to buy what you want.
The guy with the most knowledge is probably Jim McShane who you can find on Audio Asylum, or under his web site name of McShane Design.

A collector item it is. A great sounding unit it is not. The parts are now so out dated that its 'sound' would not match most current offerings. VAS audio, has taken the design and put in new state of the art parts and produced a Citation I pre amp. I have one. Sound great.

You would certainly have to reform all the electrolytic filter caps and hopefully they are still good. Given the age I would doubt it, as they dry out with age. All I remember about it was the circuit was very novel for it's day. The output transformers were also quite good.

We have repaired, rebuilt and modified many of these over the years. Its my favorite vintage preamp, and IMO keeps up easily with most modern preamps once refurbished.

The electrolytic capacitors are all shot. Do not try to use them.

The selenium rectifier should not be used either. Replace it with a silicon rectifier. Consider HEXFREDs for the high voltage power supply.

Although some of the resistors and caps in that unit are collectible, the fact is that there have been advances in that area and there are newer parts that sound better (although the EQ caps should be fine). So its not a bad idea to consider new resistors and caps. In the phono section, some of the resistors require precision, and that fact should not be taken lightly- if you replace them, use the best parts you can find.