Greetings:
 
The title hopefully says most if not all of the basic issue and here are the details:
 
I'm using a Focusrite Scarlett USB audio interface, with Toontrack EZ Mix in the FX bin.  With Input Echo (I think it's called) greyed out I get the dry signal from the Focusrite.  When I click the Echo button I get the EZ Mix sound but it includes the dry sound.  I A/B's that sound with the recorded track to confirm.
 
I would like to just hear the EZMix sound during practicing and recording, and have looked in Preferences and various other menus but cannot see a solution.  It feels like one of those "d'oh" issues but I'm now stumped.  
 
Thanks very much.  Oh, 2017.04 Sonar, and updated EZMix software and Focusrite drivers.  Hopefully that's all you need.

This will be a setting in your focusrite audio control panel. It is probably giving you "low latency direct monitoring" and you'll want to disable that.
 
EDIT
 
Actually, the PDF manual seems to indicate there might be a hardware switch on the front panel to set "Direct Monitor" from ON to OFF. I guess this depends on your exact model
 

stickman393
This will be a setting in your focusrite audio control panel. It is probably giving you "low latency direct monitoring" and you'll want to disable that.
EDIT
Actually, the PDF manual seems to indicate there might be a hardware switch on the front panel to set "Direct Monitor" from ON to OFF. I guess this depends on your exact model

Stickman:
 
Thanks for taking the time to write.  I have the Focusrite Scarlett 2nd Generation 18i20 and no such hardware switch exists.  But the PDF says the following which conuses me a little:
 
"When using Direct Monitoring, ensure that your DAW software is not set to route any inputs (what you are currently recording) to any outputs. If it is, the musicians will hear themselves “twice”, with one signal audibly delayed as an echo."
 
I don't experience any actual "echo", just what sounds like a mix of dry input and EZMix.  But if I follow this advice and don't route the input sound to an output it seems I won't hear anything at all even with EZ Mix engaged (I'm not in the studio at the moment and perhaps it will become obvious if I try that).  
 
EDIT:
 
Upon further reading in the Focusrite "Control" software manual, it appears Direct Monitoring means exactly that -- the dry sound goes directly to the speakers/headphones, and any FX (such as EZMix) is not heard.  That is the exact opposite of what I'm trying to achieve, which is hear only the EZMix amp simulation.
 
If these comments trigger any further insights they are greatly appreciated.
 
Steve

+1000 to this

When I first started I spent many months with direct monitoring turned on - so when playing I always heard the "dry" guitar sound

It was really subtle (especially on cleaner guitar tones) and I just thought the amp models were not very good

When I sussed it out and turned direct monitoring off it was a revelation and my performances improved dramatically as I was hearing the proper amp sound as I played

Focusrite has several manuals for the 18i20 (can't say they don't provide information! ) and finally found out how to silence the direct signal by muting it in Focusrite's Control Panel software.  What a difference it makes.  After trying a test recording I was pleased to find that on playback turning off EZMix left just the dry sound being the recorded sound, so I could easily change EZMix (or other amp sim) sounds.  Cool! 

Yep, direct monitoring is there for those times when your buffer has to be set higher to avoid underruns due to a project becoming big or complex. It's very useful if, for example, you need to add/redo some vocals once a project has got to an advanced stage and you need to monitor your vocal without latency. Other than that you should always have direct monitoring disabled. It is a very handy feature to have though when you need it and I think Focusrite have some real-time plugins that can be used with direct monitoring, such as reverb, compression etc. so you can setup a nice monitor mix to help set the mood for your performance - at least they do on their older interfaces.

I have a Focusrite as well, go in to the control panel of focusrite's interfaces and select DAW recording.
just test it out and see if it helps. I see no difference between direct recording and DAW recording unless im using an old IBM with 10,000 tracks.
Never mind I see you figured it out.