For some reason today I decided to modify my Vp312. When I builded it I left out R3, 150K. And I decited to put it on it. Nothing major, I did the job, plugged into my lunchbox with no opamp and R5 smoked. Seems weird to me, since the pre was perfectly fine without that R3.
I just replace R5 but didn't plug it back, and I removed R3 since I lived without it till now.
Before i plug in it again, could be I burned other stuff other than R5?
Hi this is my first build and I m not getting signal with LDC mics. Phantom power led is lit when turned on but there is only 4.8v at XLR pin 2 and pin 3 and with no load it measures 12.6mA. All my dynamic mics are working so I assume there is nothing damaged in the input transformer. My shure sm94 SDC has signal but crackles a bit. My rack is a brand new midas L6.
Just finished my first build of a VP312 VPR-Litz, no problems, works great. I had to ignore the recommendation from Jeff to bring it up with a known good DOA, since I also built the CA-0252 kit, and that's all I had, but all the static checks of the VP312 were good, and it seemed to power up in the rack ok without a DOA (i.e. no smoke or fire). So I just plugged in the DOA, powered up the rack, and held my breath. All good...
Kudos to CAPI for clear documentation, and a well packed and labeled kit. I would maybe hesitate to recommend the CA-0252 kit for a first time DIY builder (I think Jeff has stated the same), but if you have decent solder skills and the right tools (REALLY important!), the VP312 is a straightforward build. The CA-0252 is really no harder, just things are a little tighter, and poor soldering skill is more likely to cook a transistor than a passive.
I've tested a bit with a couple of different mics, on different sources, and overall I'm very pleased with the sound. It's certainly got a desirable 'color' that I don't have with any of the other pres I own.
I've got a second one to build now, and I'm thinking of taking some photos and creating a more formal, VP312-specific (Rev B) build guide if anyone has any interest?