Harman Kardon Citation II Rebuild

More updates.

I've been running the system every night and I'm much more confident that the thing is not going to fail or blow up.  I've also got the bias and something called the "AC Balance" all set.  The bias is rock solid (a good sign).  There is a different bias pot for each output tube, and a built-in bias meter (that uses current sensing resistors) to make things easy.

I have noticed one thing though.  When being run with the iPhone, there is a slight 120Hz buzz.  It gets worse with no input connected.  However, with a zero ohm input (dead short) the buzz is completely gone.  The input impedance is 1M, which is fairly high and would allow the pickup of all kinds of stuff.

I figure that I'll solve this little problem by using a very low output impedance pre-amp.  Something op-ampy is in order I figure.

This journey is not over yet!
 
errr - no. Then the preamp could not drive it (assuming that the preamp didn't have low output impedance)
 
oh - that's already there.  the input impedance of the amp is created by a 1M resistor between the input and ground.
 
mayfly said:
20742_303007677111_527102111_4624119_2477723_n.jpg
Click to expand...

Great work  :icon_thumright:
It's nice to see old amps coming back to life. If your friend does a good work you'll be surprised with the sound. Proac speakers are expensive but I like their sound a lot.

I'm waiting for the final photo of the stereo setup: Speakers, Rega and Manley... :rock-on:
 
It's a hi-fi amp, not a guitar amp. It's not supposed to color the sound. If it did, new components may have improved it over the ancient stuff.
 
mayfly said:
The rebuilding as begun! Here's the board with the new caps and jumpers on. I'm following the original assembly manual order to ensure I don't miss a step.

22042_245935322111_527102111_4337577_1841653_n.jpg


The new caps are a hell of a lot smaller than the old. So much so that the leads are almost not long enough! That's garden variety heat shrink on the leads BTW.
Click to expand...
Hi Mayfly,
I am in the process of rebuilding my Cit II amp and bought the McShane kits to upgrade. When you redid the turret boards did you replace the jumpers too? If so what gage and type of wire did you use for jumpers?
 
Hi there,
I did replace the jumpers as well - I actually stripped the turret boards completely. I believe that I used 20gua wire for the jumpers - essentially just stuff that I had around.

Too bad all those photos never made it to the new forum...
 
mayfly said:
Hi there,
I did replace the jumpers as well - I actually stripped the turret boards completely. I believe that I used 20gua wire for the jumpers - essentially just stuff that I had around.

Too bad all those photos never made it to the new forum...
Click to expand...
Thank you i will do the same. I'm replacing everything with Jim Mcshane kits, why go to all this work and not replace the jumpers...They just looked in perfect condition....but it could be the week link so i will replace
 
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