© Don Sachs, 2015
 
 
 
  Vintage Tube Audio
   Restoration and Repair
 
 
 
  
Harman Kardon Citation I Preamp
  Great line stage and the best vintage phono section there 
  is!
  Why restore a Citation I preamp?  Because it is one of the best phono sections around when 
  working properly!  The line stage is great too.  Beware all the shiny ones on ebay.  If the power 
  supply is original it probably still works, but a new supply will make the amp sound much better.  
  Also, if it has been shined up and all those signal caps are original it will sound so much better 
  with new caps and key resistors changed that you simply will be amazed.  Finally the original 
  volume pot fails on a high percentage of them.  You will notice a channel imbalance that may 
  disappear after you get the volume up to a certain point.  I have a replacement volume pot that 
  will make the unit sound much better and solve that issue.  Again, beware the shiny new ones 
  on ebay with all original parts.  Really, you are better off with a more used looking unit with all 
  new parts inside.  Are you going to listen to it or admire it?  The sonic difference is literally 
  night and day!  I know, I have rebuilt close to 40 of them and heard the difference with 
  different stages of restoration.  So if that shiny one on ebay has all new parts inside then go for 
  it.  If everything is original with maybe one or two new parts then think twice.  
  To restore a Citation I preamp takes approximately 15 - 20 hours.  I charge about $700 - $800  
  labor for this depending on which options you choose.  Parts run approximately $200 - $350 
  depending on your choices.  The base restoration includes:
  1.  The entire power supply is replaced with the McShane power supply kit.  This features much 
  quieter diodes and much more filtering capacitance to produce a power supply that is much 
  better than the old stock one.  You will hear better bass response, faster transients, and a 
  blacker background.  I adjust the resistance to the filament supply to make sure all tubes are 
  getting 11 - 12.5 volts DC.  The V5 phase and center channel tube is often over 14 volts in an 
  unrestored preamp.  The tube will not last long at those voltages.
  2. Changing all signal caps including the phono section.  A large number of key resistors are 
  also changed using a combination of modern carbon film resistors in the signal path and very 
  quiet metal film resistors for plate loading of the tubes.  
  3.  All the caps and resistors for RIAA setting of the turnover and rolloff switches are changed.
  4.  Improved grounding.  I change all ground wires and replace several key wires from the 
  boards to the switches.  I also replace the main shielded AC wire from the fuse to the power 
  switch on the front if necessary.  All of these changes lower the hum level significantly.
  Options:
  1.  Optionally all the caps and resistors in the turnover and rolloff switches are changed for 
  those who will be using the other settings.
  2. New RCA jacks.  This can eliminate a lot of hum problems.
  3. A new modern volume pot.  A signifcant number of Citation I preamps have volume pots that 
  are failing.  The symptom is that channel balance is off and will vary with the volume setting.  
  The new pot costs $19, has a loudness tap for the contour switch, and is an Alps Blue Velvet 
  copy (a conductive plastic pot).  Immediately you will notice a wider sound stage and more 
  clarity, detail, and air.  There is a significant difference...REALLY!
  4. I can install the Bob Carver MC phono modification for $100.  Phono 1 will remain a MM input 
  and Phono II will have switchable gain between MM and MC.
  5. The ultimate volume control!  I used to use the very good Gold Point 23 step 
  attentuators in the Citation I.  I have now managed to fit the excellent 48 step Khozmo 
  attenuators in very neatly and cleanly.  These have hard gold contacts good for 10,000 turns!  I 
  was able to get Arek, the fellow who makes the Khozmos to do a special version with a knurled 
  shaft to fit the original Citation I volume knob.  He even tapped the attenuator at about 70K so 
  the loudness contour switch still functions.  An example installation is shown in the photo at the 
  right.  The knob position on the front panel is exactly as with the original pot.  These are 
  expensive, but if the rest of your system is up to it you WILL hear the difference over any other 
  pot I have tried.  It is dead quiet, imaging is much better, and the channel balance is absolutely 
  perfect from the lowest to the highest volumes.  The Khozmo attenuator costs $179 and I will 
  install it for a package price of $225 if you send me the preamp.  If I am doing a total rebuild 
  for you then I will install it for just the $179 parts cost.  I can guarantee you that it will make a 
  very noticeable difference if the rest of your system is revealing.