Review on 🎶 Enhance Your Sound Quality with Behringer Microphono PP400 Ultra-Compact Phono Preamp in Silver by Jennifer Young

Before I bought this amp I thought about building it myself. There are many phono preamp designs that are easy to find with a google image search. Many of the best have two op-amps per channel, plus some other active discrete components (transistors). I even looked at the service manuals for new and old receivers, as those manuals show the circuitry of the phono stage built into the receiver. So, curious to see what I find inside this device, I removed the cover. The scheme used is not special. It consists simply of one op-amp per channel and some passive components. Good, I thought. "It's a bit mediocre, but let's plug it in." I connected the RCA jacks and then applied power. I was listening to radio through the receiver when I turned on the phono stage. I heard a thump from the speakers! I thought it might just be a short burst caused by FM signal interference since the antenna was close. I then tried turning off the preamp by unplugging ONE RCA plug and powering the preamp. Well, now only one side knocks. I tried swapping the connected RCA jack and now the other speaker makes a muffled sound. Hmm, what's going on here? I measured the voltage coming out of the preamp's RCA output and it was over 10 VOLTS! The voltage present at the receiver inputs should never exceed about three volts. (I bet that's why these units have a lot of reviews reporting crashes! I'm wondering if the preamp is failing or if it's causing the input of the reviewer's receiver it's plugged into to fail.) Apart from this strange (and unacceptable) surge protection performance seems to make the device work adequately. However, I am amazed at the longevity of the receiver input to which the preamp is connected. What I like about this device is the metal body. Otherwise, the device would be very sensitive to interfering signals, and this metal housing allows for less tidy placement than other devices and cables. There are no rubber feet (or any feet) or anything like that (http://www.amazon.com/Waxman-4215395N-Round-Bumpers-pieces/dp/B001WAK6DS/ref=sr_1_1?ie=UTF8&qid=1420770182&sr=8-1&keywords= rubber+feet) must be used to prevent the device from slipping and to protect the furniture on which it is installed. Build quality is pretty good too. In addition to the metal body, the circuit board is grounded on both sides, the soldering is solid, and the device uses mounting screws instead of self-tapping screws. The preamp is also aesthetically pleasing. I don't particularly like having so many electrolytic capacitors placed in the signal path, but the practice is not uncommon. I just don't know what scheme is used. I have to listen for a while and weigh the risk of damaging my receiver's inputs to decide if it's a steward.