Problems with Otari MX80

[thekeepsake]

Hi,

My partner and I have been having the following problems with my Otari MX80:

When we track vocals, they get this very strange warbly distortion. Kind of like a ring modulator sound or a very fast tremolo. Not in a good way at all. We checked the alignment and the machine is properly aligned to +6 IEC, but this happens at 15 and 30 ips.

Other things that may be related:
-Guitars sound super mid-rangy lately
-Cymbals extra harsh

We are hitting tape at proper levels. The distortion doesn't sound pleasant like tape distortion and it sounds like transient exaggeration rather than loss.

What are some things we can try? We've tried the following:

Switching cables
Switching mics
Switching pres
Switching channels
Switching cards

[thekeepsake]

I have some more information:

We notice the problem while getting signals, not just during playback.

I'd say it sounds like it's just decaying really quickly, maybe that's what lets the brittle/sharpness dominate

I recorded some guitar on it today and then plugged the pres into my ad16x. the tape one definitely sounds terrible. i can post samples later if anyone is interested in helping us.

thanks!