JEDIA L2.2 - R.C.S./JD-MEDIA LX2.2 Service Manual

[terranigma]

Hi all,

I'm desperately trying to find service manual/schematic of the JEDIA L2.2 / JD-MEDIA LX2.2 / R.C.S. LX2.2 power amp. I asked to the manufacturer but they didn't respond yet. Have you any suggestions to find service manual of this particular amp please?

I need to figure out input stage topology because this amp seems much more prone to the interference comparing the other amps that I have dealt with. I'm also trying to figure out purpose and equivalent schematic of the HIC-VOLT21 proprietary daughter board/module at the input stage.

Thanks in advance.

 

[terranigma]

Hi guys, I found the schematic from a different model (L60AS) of the company. I'm trying to deal with interference problem which is excessive. Looking at the schematic, amplifier output topology is uncommon: collectors of the output transistors are at the output side, not at the power supply side. This way, manufacturer able to attach all output transistors to the heat-sinks without using an insulator. So, heat-sinks become part of the active circuitry. I think interference comes from the heat-sinks that acting like an antenna. When I ground heat-sinks using a 20-100nf capacitor, the noise noitceably suppresses.

What I am asking is, what should be the proper way to suppress the noise introduced by the heatsinks since they are on the active side?

Thanks.

 

[Sloebbie]

Her you find original schematics, hope you can repair this thing, it’s a marvelous amp

 

[terranigma]

Thank you @Sloebbie , I really appreciate. It seems the interference introduces from speaker cable of one channel. Amplifier seems not faulty but the environmental RF conditions make this amp behave this way. I'm still investigating.