Questions & Answers

R32 Front Panel Headphone Low Output Level

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asked Mar 2 in StudioLive Series III by jklinetob (160 points)
Using Westone UMPro30 IEMS @56ohms and/or HD280pro @64ohm.

Brand new R32 mixer, initial issue and has never worked correctly.  Device and UC firmware up to date.

No matter how I route the hdph mix in UC (mains/aux/solo) the signal is very weak, when crank the output above 75% or so get a nasty distortion.  Also tried routing as Solo and boosting the Sole level pot in UC for +3-6db, level higher as expected but extremely distorted.

To be clear this is happening in a quiet space, I'm not looking for extreme levels and I have the gear for that when needed.  The R32 amp is spec'd for 100mW@60ohm, that should be beyond plenty loud for most any application.

Aux/main outputs on the back are hot/clean and work perfectly with speakers or routed to an external hdph amp.  I can work around it for the meantime but like the convenience of the front panel jack, just need it to work.

My question:  Is there a software pad or something similar engaged that I'm missing or do I have a hardware issue with the R32's built in hdph amp?

1 Answer

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answered Mar 3 by jklinetob (160 points)
Traced the issue to a headphone extension cable.  Amp is fine and LOUD.  Here's what I found for anyone else having a similar issue.

Was using a coiled hosa hpe325, the output with this cable is low on the 32R but always fine through UA apollo.

Plugged phones straight in, much hotter.  I did not do this before, SHAME on me.

Tried straight hosa hpe310 and get the hotter signal.  The straight/coiled effect is noticeable through UA apollo and through an external hdph amp, but not to the same degree, maybe 3db-ish.  Apollo's hdph output is 300ohm, compared to 60 on R32.

Can't find data on the hosa cables but it's reasonable to think that the coiled cable has higher impedance and is mismatched to the 32R's hdph amp.

Lesson: signal path, halfway>test>halfway>test.
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