Quick note on using a Revox B77 with a Presonus Firestudio Project – potential impedance mismatch!

I’ve been using my Revox B77 with various audio interfaces and operating systems for a while, and this week I’ve restarted tape imports for a long-running project that needs to come to a final conclusion – at least on the ingest stage.

Various factors, not least compatibility with Mac OS X El Capitan, have forced me into using my Presonus Firestudio Project as the analogue-to-digital converter for this stage.  It’s not ideal for a number of reasons, but it gets a job done, without too many sonic compromises (especially when compared with the vagaries of the source material) and so I suck it up and move on with life.

One important thing has come to light this time around though… My B77 *really* doesn’t like feeding Channels 1&2 at line-level, which are labelled as “instrument” (presumably Hi-Z, high impedance) inputs.  Its output preamplifier runs out of headroom rather quickly and ends up giving horrible clipping, especially with the outputs wound up to give something approximating “line level”.

Plugging into any other channel line input (3 through 8) does reduce the recorded signal level as seen by the DAW software, but also gets rid of this clipping.  Lesson learned.

I’m left wondering if this is an expected quirk of the B77 electronics, or whether it’s a quirk of my specific machine?  I don’t (yet) have time to go poring through manuals to find out for sure – but I can’t say this result surprises me!

Still – onward and upward!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s