ytsestef
Well-known member
Here it is, the 9K "stripped down" with no +48V, no pad, no phase rev. and only 6 position gain switch, ranging from +34 to +46 dB, controlling both channels simultaneously (one pole per channel, "gain A" is fixed). Its purpose is to make up for my summing mixer's -40 dB loss. The paint job went pretty good, but I changed the marker over the one I used in gssl and it wasn't quite comfortable, so the labelling is not really that good compared to my gssl. Sorry for the crappy quality of the photos, too. Oh well:
And a photo with its happy DIY companions That makes three of them in two month's time (since I registered in the forum)
Here are the resistors I used for the gain switch:
============
6STEPS (34-46dB in 2.5dB steps)
Gain A (Fixed):
Ra 82R 28dB
Gain B:
Rb 294R
Res. Gain. Total Gain. Actual Resistor
Step1 952R 5.4dB ~34dB 953R
Step2 477R 7.9dB ~36dB 475R
Step3 278R 10.4dB ~39dB 280R
Step4 176R 12.8dB ~41dB 178R
Step5 117R 15.3dB ~43dB 118R
Step6 0 17.8dB ~46dB
============
And the equivalent drawing:
For a detailed record of my struggle see also:
http://www.groupdiy.com/index.php?topic=4731.msg438100#msg438100
It sounds AWESOME, and I want to thank everyone for advising me to use that particular preamp as gain stage for my passive summing mixer. It is what I wanted, only better!!
Worked on first powerup, too!! Absolutely no troubleshooting was required. No hum , no noise, everythink worked right away. One moment I am checking the voltages, and the other one I find myself mixing with it! Talk about lucky...
Feel free to add it to the finished projects META if it does qualify
And a photo with its happy DIY companions That makes three of them in two month's time (since I registered in the forum)
Here are the resistors I used for the gain switch:
============
6STEPS (34-46dB in 2.5dB steps)
Gain A (Fixed):
Ra 82R 28dB
Gain B:
Rb 294R
Res. Gain. Total Gain. Actual Resistor
Step1 952R 5.4dB ~34dB 953R
Step2 477R 7.9dB ~36dB 475R
Step3 278R 10.4dB ~39dB 280R
Step4 176R 12.8dB ~41dB 178R
Step5 117R 15.3dB ~43dB 118R
Step6 0 17.8dB ~46dB
============
And the equivalent drawing:
For a detailed record of my struggle see also:
http://www.groupdiy.com/index.php?topic=4731.msg438100#msg438100
It sounds AWESOME, and I want to thank everyone for advising me to use that particular preamp as gain stage for my passive summing mixer. It is what I wanted, only better!!
Worked on first powerup, too!! Absolutely no troubleshooting was required. No hum , no noise, everythink worked right away. One moment I am checking the voltages, and the other one I find myself mixing with it! Talk about lucky...
Feel free to add it to the finished projects META if it does qualify