• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

kta preamp ls-1 srpp

kevinkr

Administrator
Paid Member
Please send me a PM with your email address and I will send you what information I can dig up at this late date.

This pre-amplifier was one of a very small number OEM'd for me in Hong Kong back in the late 1990s.

The power transformer is showing some evidence of thermal damage, noting that these units were not designed for operation on 50Hz.

I am not sure exactly how this came to pass but some of them ended up in Israel a decade or so ago.

The filament regulator should not be touching the 6U8A voltage regulator tube.


Design is not in the public domain so any information I provide is not to be shared.
 

kevinkr

Administrator
Paid Member
I would recommend that the HV electrolytics be replaced I suspect 1 or both of them are bad at this point. The burned resistor is in the HV supply and there are no current levels in normal operation that would cause the damage I see.

Would also explain why it is noisy. These were very quiet units. I used one in a secondary music system for a number of years before selling it to a friend here in MA who still has it last time I checked.

This particular unit is 20 years old. There was a matching phono stage.