ZEROZONE PRT05A-CJ Indicator Lights Relocation

A few days ago I purchased a very lightly used Chinese tube preamplifier to use with a PassLabs First Watt F5v2 power amplifier. I had been looking at these very inexpensive :clone” preamplifiers for some time. When this one popped up in the classifieds for $200, I couldn’t resist.

Like all HiFi equipment I acquire, I had to “Pop The Top” to see what I actually bought.

I was blown away by how well this unit was assembled. For a <$500 preamp (Shipped from China), it has some of the best electronic construction I’d ever seen!

But there was one thing that drove me crazy. The selector knob on the front has no stops. It simply goes round and round with a detent ever couple of degrees.

That’s all well and good, because the inputs are relay controlled which I like. But there is no way to really see which of the four inputs you selected…

Unless you take the cover off and on a front mounted circuit board there are 5 nice blue LEDs……One for power on Standby….And the other four indicating source selection…..ALL ON THE INSIDE!

I guess this was a cost saving move on ZeroZones part……But it needed a modification

So…Because there were a number of devices glued onto the front panel, removal of the front panel to drill 5 holes for the LEDs was impractical.

Plan “B” was to make a template for the holes and drill them by hand.

Very accurate measurements were taken and a piece of aluminum was put into the milling machine and 1/8″ holes drilled…

This template was then affixed to the front panel and five holes drilled by hand

The LEDs were de-soldered from the circuit board and resoldered on the other side.

They fit perfectly and now I can easily see my input selection

Loving this set up with the Pass Labs First Watt F5 v2 amplifier…….

If anyone wants to do this to their ZeroZone preamplifier, send me an email and I’ll let you borrow the template I made. But return it so another can use it. Will only cost you postage.

Thanks for reading! Be sure to visit my full web site for more “Garage and Workbench Nonsense”


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