D.A.V. Electronics BG1 by Sim
This was my first real pre upgrade, I use it along side my RME ff800 pres and some Focusrite octopre's. And boy was it an upgrade it's like a new pair of glasses for your ears.
I paid £250 for mine used and they cost £510 new and tbh they are light weight but rock solid so second hand is a good option for anyone trying to save pennies. This little unit packs a punch with some nice features.First off you've got 3 stages of high pass 22hz, 33hz and 68hz thats more than enough for any mic pre. After that you've got a 26db PAD perfect for record lud signal sources like close miced drums. It's got a 26db-59db in 3db's step on it hi quality stepped gain pot which is very accurate. And you get a phase reverse on channel 1 only. The only let down is the phantom power switch that controls boh channels so you can't run a ribbon and condenser at the same time which is annoying. One other thing is the lack of a power switch which is a pain as you have to switch it of by the mains. You get to leds for gain metering one for clipping and one at -3db. Which is plenty if your running straight into an interface any way.
The best thing about this pretty is if you run in into clipping a little bit it doesn't distort and adds a bit of character to you signal. The pre it's sounds clean with little but of character. I would say it has a little bit of the larger than life sound and it polishes your signal up nicely apart that it for most part clean gain until you clip hard which is difficult as the output will get to high for your interface.
People say this really competes with pricey units in the £800+ band I wouldn't know as I don't use expensive pre's often enough to comment. For £350 second hand I really can't think of anything better. This pre doesn't pretend to be something else, it is what it is. With it's history and pedigree it just makes the cut unlike some similar priced pre's.