Tips and Troubleshooting

August 6, 2014: I've started this page to include usage tips and troubleshooting for HPF-Pre. Most of this information is learned from working with customers.

Shipping Series 1 and 2

A few HPF-Pre's have been shipped from one person to another. Please do not ship an HPF-Pre Series 1 or 2 in one of those padded mailing envelopes. The package is just the right size to go through the automatic letter sorting machines, and get crushed. A small cardboard box is the preferred way to ship your HPF-Pre. Also, US Post Office first class mail is the cheapest way to ship, and now comes with tracking. You don't need the tracking label any more, just ask the clerk for tracking.

Crushing Series 1 and 2

Direct, hard impact to the knobs on Series 1 and 2 can damage the pots. Series 2M addresses this issue by replacing the plastic box with die cast aluminum. Series 1 and 2 should be rugged enough for normal use, but the metal box is arguably more rugged.

No sound: Series 2, 2M, and 3

If you just received one of these preamps, the phase switch can get into an "in between" position during shipping, resulting in no sound. Please make sure it's definitely in one position or the other when using the preamp. This has happened to a couple of customers.

How's that LED battery indicator work?

It's only supposed to give off a brief flash if your battery is good, otherwise nothing. It operates from the output jack. The LED is not expected to stay on.