HK Citation-V ,B+ high

MickeySmile

Well-Known Member
I just finished fully restoration of HK Cit.V ( recap, swap out most of old resistors, pots and old wires). After done DC and AC balance adjustment, I measured the B+ (484 VDC), the voltage from wall is 125V.
According to Jim McShane page, the B+ is 440 - 460 VDC but in his notes: "Variations of 10-20% in the readings can usually be considered normal". Should I put in resistor for dropping B+ voltage or leave it.
Thanking you in advance for suggestion.

Binh
 
That line voltage is on the high side. In the past I have installed a current inrush limiter on these amps. This will drop a few volts from the primary side which translates to the proper B+ voltage. The V is a great amp, try 7733 tubes in the front end. I am using the new Tung-Sol 7581 tubes and am happy with them.
 
Jim McShane normally recommends using 2 current inrush limiters on the secondary side of the high voltage windings. This arrangement slows inrush to the filter caps and brings up the high voltage rail slower than the filaments. Perhaps you'd consider using the same thing for the V. Check with Mr. McShane for his recommendations.

Yes, I'd find a way to lower the high voltage given the AC line voltages. A variac is a good idea if you don't want to mod the amp.

Cheers,

David
 
A non invasive technique is to run your amp thru a 10 amp variac. That works if your only problem is the high wall voltage.
 
Jim McShane normally recommends using 2 current inrush limiters on the secondary side of the high voltage windings. This arrangement slows inrush to the filter caps and brings up the high voltage rail slower than the filaments. Perhaps you'd consider using the same thing for the V. Check with Mr. McShane for his recommendations.

Yes, I'd find a way to lower the high voltage given the AC line voltages. A variac is a good idea if you don't want to mod the amp.

Cheers,

David
I bought the restoration kit from Jim McShane long time ago and have followed all instructions. When I used variac at 110V and every high voltages are in spec. I ran it for straight 6 hrs and the power transformer just get warm.
 
That line voltage is on the high side. In the past I have installed a current inrush limiter on these amps. This will drop a few volts from the primary side which translates to the proper B+ voltage. The V is a great amp, try 7733 tubes in the front end. I am using the new Tung-Sol 7581 tubes and am happy with them.
Thank you HF-Guy, for your suggestion. I will add a current inrush limiter on primary side.
 
If current inrush limiter won't lower much HV then I guess 10A variac is a solution. Thank you primosounds!
BTW, if you use a variac then the inrush CL is redundant. Better to go full bore straight from the wall since the variac will allow you to make the slow voltage ramp up at your whim. I like to start at about 60vac for about 2 minutes then to 80 for 1 more minute then to 90 for another minute, then to the final voltage. You should also check you Citation 5 B+ at the initial test and reference that to the voltage on the variac. Also at that time check the heater voltages on the tubes to make sure they are within 10% of nominal. Good luck.
 
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