kmakdaddy wrote:
Hi I am a first time builder with nearly zero electronics experience or knowledge. I have started down the path of my first build with this little Preamp. It will be running a pair of Genelec 8020B’s that have a 10k input impedance and a Yamaha YST-515 sub that I am not sure of its specifications.
I have a couple of questions that I hope this group might be able to help me with.
Should I run a 3rd preamp channel for the sub ? If so what should I be thinking about if I do this ? If not and I just run it off the left Chanel of the preamp is there anything that I need to do here ?
Also for the bridge rectifiers on the power supply am I better with the one piece units like I have used or building out of MUR860 diodes ? I am not worried about the few extra $ to change it if the diodes will make any real change.
For the voltage reg on the heater side of the PSU I have scavenged a neat little heatsink / EMI shield to mount it to. Currently I have the regulator insulated from the heatsink should I remove the insulator and have it grounded to the heatsink. The heatsink will be grounded probably back to the - of the heater output.
On the bridge rectifier on the HV side you can see that I have mounted the caps sitting above the rectifier is this a problem at all ?
I have started with building the power supply of the wall wart variety. I have relied on the knowledge of the guy at Jaycar for the finer details of the components. And I know very little about what I am doing so if you don’t mind I would love some harsh yet helpful criticism from the group.
A couple of notes that are fun or relevant.
The board it is all mounted to is 3mm acrylic. I have used a 35w CNC Laser to cut all the mounting holes for the components and I have used the laser to cut tracks into the board and run 27AWG copper wire laid into these tracks to interconnect components. I have run the interconnects in an arc from point to point to avoid any parallel wire runs.
The next stage is to solder it all together and test is and if all goes well I will start on the actual preamp stage.
Thanks for any help or advice that you can offer.
Marc
The diodes helps little bit with sound quality the fast revocery ones allow less supply noise, Using the heatsink to condcut electirc is very bad idea, when heat conddductivity is not a prolbem the heat sink needs to be isolated from device.