Cpartipilo
Active member
i posted this on the gearslutz but got no interest, since most DIY's deal with these issues maybe i can find help here.
I bought a new desk for my home studio and some new equipment, when it was time to put it together i found this issues.
Preamps: Toft afc-2, Trident S20 and Studio technologies Pre-Eminence
All 3 exhibit the same issue. When plugged into power only and the output to my digi 003 there is no RF or noise whatsoever, when i increase the gain all the way i hear the regular gain hiss. As soon as i plugin a mic cable in the mic input i hear this terrible buzz, if i move the cable enough i hear a faint radio station in the back when at full gain but the buzz is the issue, sometimes moving the cable it goes away for a bit but most of the time is there.
When i connect a transformerless mic (at 2020) sometimes it stays the same or gets worse but when i connect a transformer based mic (mk-219) there is no buzz or a DI for that matter, no buzz either. i have tried lifting shields at both sides, lifting AC grounds, different cables, etc. and it's driving me crazy.
I have a presonus VXP, RNP and Earthworks lab101 that do not get the buzz, i have the digi003 tied to a Presonus Digimax FS and i don't get the buzz in any of the digi pres or the FS pres.
Now a little more info, following some advice from Jim Williams i connected a small capacitor at the mic cable from hot to ground and it took the noise away in the toft and studio tech pre-eminence in some instances like when the phanton was on, etc. still not a clean solution.
Another curious thing, while messing with the condensor in the Toft pre i accidentally shorted the hot to the case with phantom on, saw a little spark and thought i had killed something. curiously now the preamp is silent as it should be, when i connect the AT2020 i hear a little buzz for about half a second and it goes away. like if some rectification circuit kicked in. Still the other 2 pre's are driving me crazy, especially the Trident S20.
To make sure it was not a ground loop i connected my headphones to the S20 and unplugged everything else from the wall and the same noise was there. no change at all from when plugged into the interfaces.
Sorry about the lenghty post but does anyone has any recomendation as to what to try? maybe i just have dirty AC or ground in my place. I don't know how to check for that. i have a scope at home but i still don't know how to use it properly, if someone directs me i can get some measurements to discuss.
i'm frustrated :-\
Thanks in advance!
I bought a new desk for my home studio and some new equipment, when it was time to put it together i found this issues.
Preamps: Toft afc-2, Trident S20 and Studio technologies Pre-Eminence
All 3 exhibit the same issue. When plugged into power only and the output to my digi 003 there is no RF or noise whatsoever, when i increase the gain all the way i hear the regular gain hiss. As soon as i plugin a mic cable in the mic input i hear this terrible buzz, if i move the cable enough i hear a faint radio station in the back when at full gain but the buzz is the issue, sometimes moving the cable it goes away for a bit but most of the time is there.
When i connect a transformerless mic (at 2020) sometimes it stays the same or gets worse but when i connect a transformer based mic (mk-219) there is no buzz or a DI for that matter, no buzz either. i have tried lifting shields at both sides, lifting AC grounds, different cables, etc. and it's driving me crazy.
I have a presonus VXP, RNP and Earthworks lab101 that do not get the buzz, i have the digi003 tied to a Presonus Digimax FS and i don't get the buzz in any of the digi pres or the FS pres.
Now a little more info, following some advice from Jim Williams i connected a small capacitor at the mic cable from hot to ground and it took the noise away in the toft and studio tech pre-eminence in some instances like when the phanton was on, etc. still not a clean solution.
Another curious thing, while messing with the condensor in the Toft pre i accidentally shorted the hot to the case with phantom on, saw a little spark and thought i had killed something. curiously now the preamp is silent as it should be, when i connect the AT2020 i hear a little buzz for about half a second and it goes away. like if some rectification circuit kicked in. Still the other 2 pre's are driving me crazy, especially the Trident S20.
To make sure it was not a ground loop i connected my headphones to the S20 and unplugged everything else from the wall and the same noise was there. no change at all from when plugged into the interfaces.
Sorry about the lenghty post but does anyone has any recomendation as to what to try? maybe i just have dirty AC or ground in my place. I don't know how to check for that. i have a scope at home but i still don't know how to use it properly, if someone directs me i can get some measurements to discuss.
i'm frustrated :-\
Thanks in advance!