Bass 400+ as preamp only?

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cho

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I am interested in using my Bass 400+ as a preamp, without a speaker. Is there any reason I can't just remove all the power tubes, and run the amp safely, using one of line outputs? Has anyone tried this? How does it sound? Which would be the best output to use into a board: balanced out, slave out, or effects send?
 
I answered my own question by reading the manual:

"If you wish to use only the preamp section of your Bass 400, you can use the Effects Send jack as a preamp
output; be sure to set the Effects Blend at 10 and the Master to 0. This will prevent signal
from driving the power section, so running the amp without a speaker or load resistor will be OK."

Now my only question is: Is it OK to pull out all the power tubes and operate the amp without them?
 
Based on what I have read about Mesa Boogie amps over the last 8 years, do not pull the power tubes. Always run the amp with tubes installed.

I have a 395 that I only run on one side, the other side is on standby with volume on 0 and presence on 10. I don't believe you can do this same set up on a Bass 400+ (I have a Bass 400) as I would think the preamp won't work if the amp is on standby.

Also, you should run a speaker cable from the speaker out to a matching rated speaker cab to be safe. You will be running the entire amp and even thought the power amp is not seeing any signal, it is still running and if anything were to create a signal to the power amp without there being a load, you wouldn't know until it was too late.
 
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