do effect pedals with amp sims/modellers make your actual speaker amp sound bad?

I’ve experimented, and generally haven’t been happy running a sim directly into my amp.
I have been happy running it into the efx return on my amp, bypassing the pre-amp and just hitting the power amp w/ the amp sim.
Then you have full control of sound w/ sim without having to try to balance two preamp sections, or w/o having to get just a dedicated power amp.
(Edited last sentence for clarity.)

 

cab IRs are what make the sound muddy when running a modeler into a amp+cab, not amp/preamp sim.
you can stack amp/preamp without problem (except od/distortion but is it really a problem ...?) but never use an IR with a real cab

 

They can make things sound worse or better depends on how they are adjusted.

 

This has been my experience with a Zoom B3. It depends on the amp being modeled and it's cab but IME I'd say less is more when using a cab sim along with the amp model when playing through a typical bass rig. It also help to adjust the amp EQ so the response is flat or as flat as possible. I haven't found it to be muddy as much as just not all that good in some cases.

If the amp has a post EQ effects loop I'd use that and expect better results by avoiding the amps preamp section completely.

 

I simply use my ZOOM B3 for the effects alone and run it in the effects loop. I have used it as a pre-amp and run it straight into the effects return with satisfactory results. My new Fender Rumble Studio 40 is far superior to the ZOOM's amp models; cabinet simulations, and effects. The ZOOM B3 is now up for sale.

 

Amp sims/modellers vary in price and Quality.

 

IR = Impulse Response which is a method to meassure and emulate speaker response. In a normal bass rig, the signal path is preamp->poweramp->speaker. A sane way to use your gear would be modeller with speaker sim/IR turned off->poweramp of your bass amp (effects return)->speaker. Connecting two preamps or two speakers in row would lead to somewhat strange and complicated response/tone.

 

My question is why would you use an amp sim while using an amp?

You wouldn’t soak your signal in reverb, in a hall with a natural ambiance and expect it to sound good...