alvin1118 0 Report post Posted December 12, 2008 got these PCBs some time back, 2~3months ago i guess I was too busy, finally got time to assemble them ... They are part of NeoMini family, Virtual Ground Kit, Stereo Preamp and Mono Preamp Most Opamps need dual voltage supply, conventional battery only provides +V and 0V. To achieve dual voltage out from a conventional DC source, a virtual ground is needed. What is does is to split the DC voltage into +50%V, 0v, -50%V. if you have a 9v battery passed in a virtual ground circuit, the output will be +4.5v, 0v, -4.5v. NeoMini Stereo Preamp NeoMini Mono Preamp Yupz, they are SMALL, about half of credit card size. Opamp based, can be used as headphone amp. Found some used components in my rack, yeah, just use them for this headamp experimental project :b Finishing....hmm, less than 20mins of work. LOL Why built both stereo and mono preamp? haha, wanted to build a 3-channel headamp, R&L and active ground channel. Source will be my ROE NeoMini USB DAC Pump in Vdc source from wall wart adapter 18v into virtual ground, output +9v, 0v, -9v are connected to +vcc, gnd, -vcc of the PCB; happy singing now Hmm...I miss SMRT... aint they look like a....... train? lol With DIP8 socket, you can rooooooll the opamp on both stereo & active gnd based on your personal preference sounding Share this post Link to post Share on other sites
