Ampeg SCR-DI

It works great and colors the tone wonderfully.
The ultra low is very useful to get a big warm sound and stay out of guitar frequencies.
The ultra high adds bite.
The EQ is solid and usefull.
Plugging headphones or computer speakers into it makes it a great practice amp replacement, and aux in adds further features like playing along with music from your phone or computer.

The drive is ok, not great. Its mid sounding and bites. Very vintagey and fuzzy. You might like it or not

There is one problem. If you have a very hot output you will clip the preamp. There is a trim pot inside the pedal to adjust it but makes the preamp much lower volume than bypass, which must be compensated by either upping the volume of the preamp or leaving the trim pot in passive mode and lowering input volume on the bass or i do it with an compressor. Problem comes around only with VERY HOT output active basses, but it is there.

I recommend the product very much.

Very useful to widen the frequencies of your sound.
You have all the characteristics of a DI box plus two circuits (the clean sound and the overdriven one) which give you the possibility to switch (through the bypass) among three different sound while you are playing.
The clean sound with bass, mid and low filters it's like you had another amp to regulate as you prefer; further, you have two filters (Ultra Lo, to add more body and punch - Ultra Hi to add more definition): in this circuit you recognize the master tone of ampeg amplifiers.
If you want to overdrive the signal you can use the scrambler channel, that allows to decide the amount of drive and the mix with the clean tone.
I do not appreciate the scrambler (overdriven signal) when it's plugged in directly to the audio interface (too much mid frequencies).
I use it mainly through the clean channel, to record in studio, and it gives me a very full, clear sound.