Tuesday, October 7, 2014

Fun New Design: Newcomb E10B Rack Mixer Amplifier turned into Ultimate Vocal Amp!

Newcomb E10B, Tablebeast Modified TB-E10B Mixer Amplifier:

So I have this friend that is a singer. He is loud. I mean he is LOUD. LOOOUUUDDDD. Seriously every single time I sound check him, no matter how loud I can get him to check, he will always come back and go louder later in a show or session. So, I wanted to devise an amp that had a genuine brick wall for this guy. And a wall that will compress using amp compression rather than a true limiter or compressor. I also wanted to have a few other unique abilities. I wanted a mic level input for one channel, a balanced line level input (that fed the same circuit as the mic input, but with a 1:1 input transformer instead of a 1:15), and an unbalanced bridge input. The mic input is for a "drive mic" that can be set up as an effects-free overdriven sound (for screams and contrast vocals). It can also be used as a DI or a mic on a guitar for solo performances. The balanced line input is fed by a Voco Loco. The singer uses guitar pedals with this neat device and the output of it is balanced XLR so it feeds right into this input. The last input, the bridging one is simply for playback input for when he is practicing and working along with his iPod. So its nice and clean no matter what.

This thing also has two outputs. One of them is the speaker output of course, but the 1/4" speaker jack has a built in dummy load so you can run it it with or without a speaker attached. The OTHER output takes the 75 volt speaker tap that is normally unused and taps it, feeds it to a pad, and then to a 600:600 output transformer. This output transformer is the main output and the signal that the singer gives to the sound guy. One last feature is a footswitch with local switch override. This goes to the feedback circuit and literally turns the feedback loop on and off. That way you've got a clean sound and a gnarly driven sound that is easily switched back and forth to with no popping.

So, all together the singer can create a complex tone himself and have it be consistent throughout all venues. He gives the sound guy one cable that has his finished sound ready to go.

Oh yeah, I'll get some better pics, it has a nice mural and a custom case for it now.


  1. Replies
    1. Pretty much any of those old mixer PA heads will work as donors for this thing. I would stick to lower watts because then you have less of a dummy load and pad to mess with. So anything with two mic inputs and a phono or line input and a 75 volt tap on the output transformer will give you the same capabilities as this one. So don't get hung up looking for a Newcomb if you want to build something like this. A similar device could easily be built in my Akai monoblock format as well for instance. I'll provide some more pics, schematics, and info soon.

  2. Are you still/currently accepting donor projects?