The plan is to use this thread to document my integration of a Zenductor 2 stereo pair into a Modushop Galaxy 1GX388 2U chassis.
Except for removal of the tall Mosfet heatsinks, relocation of the transistors to the chassis sidewalls and reuse of the speaker posts I tried to leave the Zenductor 2s unmodified, and make the assembly as modular as possible. DC power and RCA input connections are via connectorized jumper cables. A preamp mounted to the front panel can be optionally looped into the signal path via rear panel RCA input and output connectors. I integrated two digital bias current displays and a large illuminated push button power switch into the front panel.
Heatsinks and transistors after removal:
They look a bit sad, with their legs cut off. Will they ever run again? ;-)
The amps just fit with the jumper cable connections:
Transistors mounted on sidewalls (1.4 K/W heatsinks, tested in https://www.diyaudio.com/community/...galaxy-1gx388-2u-chassis.426972/#post-7997356):
A quick test to see whether the Mosfets survived:
The 3-digit display shows the bias current. All four transistors survived, and get warm, but not hot. Definitely an improvement over the original heatsinks.
A thermal image:
Lots of filing for the bias display cutouts:
It's been a while since I had to do 'precision filing'; maybe I'll fill the gap later.
Almost finished (except for the preamp connections):
With top cover:
Rear panel, still with empty holes for preamp connections:
Except for removal of the tall Mosfet heatsinks, relocation of the transistors to the chassis sidewalls and reuse of the speaker posts I tried to leave the Zenductor 2s unmodified, and make the assembly as modular as possible. DC power and RCA input connections are via connectorized jumper cables. A preamp mounted to the front panel can be optionally looped into the signal path via rear panel RCA input and output connectors. I integrated two digital bias current displays and a large illuminated push button power switch into the front panel.
Heatsinks and transistors after removal:
They look a bit sad, with their legs cut off. Will they ever run again? ;-)
The amps just fit with the jumper cable connections:
Transistors mounted on sidewalls (1.4 K/W heatsinks, tested in https://www.diyaudio.com/community/...galaxy-1gx388-2u-chassis.426972/#post-7997356):
A quick test to see whether the Mosfets survived:
The 3-digit display shows the bias current. All four transistors survived, and get warm, but not hot. Definitely an improvement over the original heatsinks.
A thermal image:
Lots of filing for the bias display cutouts:
It's been a while since I had to do 'precision filing'; maybe I'll fill the gap later.
Almost finished (except for the preamp connections):
With top cover:
Rear panel, still with empty holes for preamp connections:
Attachments
Last edited:
The preamplifier (from ebay, using two NE5532 op-amp chips) is all wired up and works. As hoped, it puts out a little bit more than my Bluetooth receiver. For some reason the volume when streaming from a Macbook was insufficient. Must be an Apple thing?
The preamp gets looped in via two external 8 inch RCA jumper cables, which makes it easy to remove it from the signal chain.
Unfortunately one of the green 3-digit displays already fried itself and had to be replaced. At some point I'll probably switch the other display to yellow as well.
A recalibration of the voltmeters is probably in order as well.
The preamp gets looped in via two external 8 inch RCA jumper cables, which makes it easy to remove it from the signal chain.
Unfortunately one of the green 3-digit displays already fried itself and had to be replaced. At some point I'll probably switch the other display to yellow as well.
A recalibration of the voltmeters is probably in order as well.