Seimens tube amp mod

The channel switching mod to the old Siemens 6 S Ela 2427c installed. The optocouplers circuit board found a place.

Siemens 6 S Ela 2427c
Siemens 6 S Ela 2427c guts

Another view, on the left is the input jack, switch for channels and a remote jack for channels.

Siemens 6 S Ela 2427c
Siemens 6 S Ela 2427c guts

I removed the guts from the pilot lamp and installed the channel indicating leds in it. We can see the two new pots installed, a clean volume pot and a mids pot.

Siemens 6 S Ela 2427c
Siemens 6 S Ela 2427c front

Another view where you can see the new wiring to the old pilot lamp now acting as channel indicator.

Siemens 6 S Ela 2427c
Siemens 6 S Ela 2427c top

/Krister

SubZero TUBE-H5 repair

Got this one in for repair, would not make a sound.

SubZero TUBE-H5 repair
SubZero TUBE-H5

Sometimes it’s an easy fix, when opening the back I found the 12AX7 preamptube at the bottom of the chassie. Just put it back in place and it was ready o rock.

I opened it up and took a look at the circuit. Besides from the single 12AX7 preamptube and the EL84 power tube there’s two JRC4558 opamps on the circuit board, so what we got is a hybrid of solid state and tubes.

SubZero TUBE-H5 repair
SubZero TUBE-H5 circuit board

/Krister