g9builder
Well-known member
Hi All,
Just wanted to share with you all my first attempt at a p2p project - a dual slowblow micpre.
http://s1209.photobucket.com/albums/cc394/g9builder/
I am a newbee to this game having before this project only built 2 G9's. They went pretty well and any problems I had were answered by great folks here. Many thanks!
I wanted to try and build one of these pres (based on the Don Hicks Slow Blow) and as there were no pcb's availiable I thought I would throw myself in at the deep end and try point to point. ;D Well six months later and plenty of head scrathing but I finally made it. I do however have a small problem and am seeking the help once again of the good folks here to help me fix it?!!
As you will see from the pics its not the neatest thing inside the box and when I do my next project there are definately things I will do differently. I am also yetto implement the phase switch on the unit. I will do this as and when I decide to add output iron.
Anyhow my problem is this - noise!!
If I use the DI it works great and is almost noise free - (as good if not better noise wise than my G9's just a faint noise in the background but totally useable)
BUT - When I use the Mic input i get noise and pretty bad. Its not just mains hum either. it makes no difference If I select line/mic or 48v either and the noise increases with the gain knob. The pre still works and passes audio but just unusable as the noise is too great.
Therefore i obviously have a problem with the input stage because the only things in the circuit before the Di input is basically the transformer and the resistors for the 48v.?
I find it stange that it can be so quiet on the di but go through a transformer before it and its a noisey as hell. Same on both channels.
Like I said i'm a newbee and so maybe I'm missing something ? Any suggestions before I spend the next 6 months trying to eliminate the noise.?
Just a quick thankyou also to all at this forum - there is no way in hell I would have been able to undertake this project without this facility here to search and find answers!! many thanks to everyone. Oh and big thumbs up to grand mater Audio for the front panel -looks great. Just a shame about the noise... ???
Cheers
ian
Just wanted to share with you all my first attempt at a p2p project - a dual slowblow micpre.
http://s1209.photobucket.com/albums/cc394/g9builder/
I am a newbee to this game having before this project only built 2 G9's. They went pretty well and any problems I had were answered by great folks here. Many thanks!
I wanted to try and build one of these pres (based on the Don Hicks Slow Blow) and as there were no pcb's availiable I thought I would throw myself in at the deep end and try point to point. ;D Well six months later and plenty of head scrathing but I finally made it. I do however have a small problem and am seeking the help once again of the good folks here to help me fix it?!!
As you will see from the pics its not the neatest thing inside the box and when I do my next project there are definately things I will do differently. I am also yetto implement the phase switch on the unit. I will do this as and when I decide to add output iron.
Anyhow my problem is this - noise!!
If I use the DI it works great and is almost noise free - (as good if not better noise wise than my G9's just a faint noise in the background but totally useable)
BUT - When I use the Mic input i get noise and pretty bad. Its not just mains hum either. it makes no difference If I select line/mic or 48v either and the noise increases with the gain knob. The pre still works and passes audio but just unusable as the noise is too great.
Therefore i obviously have a problem with the input stage because the only things in the circuit before the Di input is basically the transformer and the resistors for the 48v.?
I find it stange that it can be so quiet on the di but go through a transformer before it and its a noisey as hell. Same on both channels.
Like I said i'm a newbee and so maybe I'm missing something ? Any suggestions before I spend the next 6 months trying to eliminate the noise.?
Just a quick thankyou also to all at this forum - there is no way in hell I would have been able to undertake this project without this facility here to search and find answers!! many thanks to everyone. Oh and big thumbs up to grand mater Audio for the front panel -looks great. Just a shame about the noise... ???
Cheers
ian