Spino
Well-known member
Hi,
I wanted to build myself a mic pre in 500 format and I chose the 169 because:
- A very close colleague of mine had a very well kept 169, I worked on it for a long while, he had all the docs and some spare channel strips too.
- Some years ago, back when the idea came up, there was only one board out by audiox for the 169 pre.
- It's a very interesting learning experience, though frustrating at times.
- The original manual is extremely well written and very interesting to study and learn.
As you can see I was lazy enough to keep the original negative on top positive on bottom layout. I stripped the bass cut to keep things simple, originally it's after the pre anyway; and I put a drv134 to balance the output.
any comment on the schematics are more than welcome, I'm no electronic engineer and my knowledge of electronics is restricted to calculating the gain on an opamp loop and calculating a RC filter with a webpage. In particular, the choice of decoupling & bypassing caps and bias resistors have been pretty much close to casual.
likewise, I was wondering if anybody uses the separate AGrnd and PwrGrnd on the 500 series, as I notice most of the boards here are built with only one main ground - but I have no informed idea whatsoever on what should go on the different grounds so I routed everything toghether anyway.
The idea is making a bunch of about 5 cheap boards from a Chinese manufacturer and see if they work.
If they work (big IF) I'm probably going to keep 2 and I will have the remaining 3 to share, with frontplate, L bracket and mouser cart.
I wanted to build myself a mic pre in 500 format and I chose the 169 because:
- A very close colleague of mine had a very well kept 169, I worked on it for a long while, he had all the docs and some spare channel strips too.
- Some years ago, back when the idea came up, there was only one board out by audiox for the 169 pre.
- It's a very interesting learning experience, though frustrating at times.
- The original manual is extremely well written and very interesting to study and learn.
As you can see I was lazy enough to keep the original negative on top positive on bottom layout. I stripped the bass cut to keep things simple, originally it's after the pre anyway; and I put a drv134 to balance the output.
any comment on the schematics are more than welcome, I'm no electronic engineer and my knowledge of electronics is restricted to calculating the gain on an opamp loop and calculating a RC filter with a webpage. In particular, the choice of decoupling & bypassing caps and bias resistors have been pretty much close to casual.
likewise, I was wondering if anybody uses the separate AGrnd and PwrGrnd on the 500 series, as I notice most of the boards here are built with only one main ground - but I have no informed idea whatsoever on what should go on the different grounds so I routed everything toghether anyway.
The idea is making a bunch of about 5 cheap boards from a Chinese manufacturer and see if they work.
If they work (big IF) I'm probably going to keep 2 and I will have the remaining 3 to share, with frontplate, L bracket and mouser cart.
