Aurora Jupiter Guitar Preamp Build Log: Part III

This is the one where it actually starts to get interesting for most people.

It LIVES! After some initial voltage testing and a shocking first start-up where a high gain preamp could only produce shimmering cleans we finally start moving.

The clean issue above was due to the shielded cable on the gain pot shorting so it was a nice fast fix.

The front panel control wiring is a little messy and very boring and black but it’s only temporary for this testing anyway as it will all be removed and redone once I start adding the Focal Point 5 Band GEQ, Boost, LND150 effects loop and DI out boards.

The boost for this one is going to be similar to the ZW-44.

And finally onto the pictures. First up we have the first power up. The main SMPS has an EMI shield but I removed it so I could dial in the B+ voltage.

First power up for voltage testing.

And here we have a semi complete preamp capable of creating sound. Note the presence control isn’t installed as that is a push pull pot used for activating the Focal Point GEQ so that will be installed in the next post.

First audio testing.

And finally here is a quick reamp using the same Numbskull DI’s that are on the Ultra High Gain Preamp page for easy comparison of the differing tonalities of each design. On the left channel it was done using Voshkod 6n2p-ev valves and on the right Psvane Ecc83s.

Aurora Jupiter Preamp first audio test.

I probably wont be able to get back to this until next weekend but I can’t wait to hear and show off the complete thing.

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