A classic design. I've got one. Sounds great going from the speaker out of a tube amp into the PA. That way you get the whole amp sound and not bypassed or just the preamp. Badass!
NOTE: The vast majority of tube amps can't be run without a speaker load without doing catastrophic damage to your amp if it goes on too long? How long is too long? I don't know. I never did it long enough to find out!
Yes it's nice in that it's active and can use either a 9 volt battery or phantom power at your XLR input...
"The Type 85 simply works. Provide 48 V Phantom power and the Type 85 will automatically use it. If you don’t have Phantom power, the Type 85 will run for about 400 hours from a single internal 9 V battery. The Type 85 doesn’t have roll off switches or effects. Adjusting the frequency content of a sound source is an artistic decision best done at the mixing location where you can hear the results and easily make changes."