EMT JSD High Output - Charlie Byrd Direct Cut

1. This distortion happens when the Audia's output is sent to the Pass. It occurs whether the connection is RCA or firewire/XLR.
2. The distortion does not occur when the Audia's output is sent to a headphone amp.
3. Therefore, this distortion is originating in the Pass (or the speakers, though that's unlikely IMO).

As I posted originally, lack of headroom is unlikely to be the problem. Atmasphere (who builds amplifiers and understands these matters better than I) has frequently posted that preamp circuits with slow slewing rates can exhibit distortions that sound much like mistracking. Slewing distortions are most audible on dynamic peaks with hard blown horns, strong vocals, etc., and they have little to do with a preamp's overall headroom or lack thereof. SS circuits, especially less expensive ones, are more prone to this.

Based on the information provided, this would be my guess. You could confirm by substituting another component for the INT-150 (perhaps higher end separates).

The distortion is with RCA connection too.
The distortion is on the preamp out`s of the Pass too.
Yes, the distortion is generated in the Pass.

Do you read this?
I connect a Focusrite Firewire Interface to the Audia Pre Outputs with XLR cables. This audio interface accepts +16dBu. It clips a little too!

The meter of the Focusrite was red when the trumpet plays.
So the Audia had about 14V at the outputs.

If you go to what you list as chain 1 and swap just the cartridge (Put the AT in place of the EMT), the system should play fine. Even if you don't plan on using your setup this way, it will be a good check to make sure that nothing in the system is damaged.

Going back go chain 1 as you list it. There is one simple thing you can try. I would give it a 50/50 chance of working. Remove the xlr IC's going into your Pass, install the jumpers between pins 1 and 3, and use a pair of single ended rca IC's instead. Going single ended will lower the gain of your source, and may be enough so that you can use your EMT. This is something that you really should try. I think it has a good chance of working.