Tonight I found out it is a really good idea to ground the shaft/body of the rotary switch in order to eliminate pick up of 60Hz and its harmonics. I noticed moving my hand closer to the metal knob on this switch resulted in a >20dB increase in 60Hz spectra and the addition of somewhat lower level harmonics at 120Hz, 180Hz, and 240Hz.. I grounded the switch with a piece of 28ga wire between the lock washer and the body of the switch and grounded it to the board ground. This totally eliminated any pick up with no noticeable line frequency or related spectra. (My case is totally shielded on the top and bottom, but not sides, front or rear - and does not appear necessary to do so.)
Posted 18th March 2010 at 12:28 PM byjtktam (Newbie audio DIYer)
I have been side tracked lately. not enough time to do the F5 like I wanted.
I ended up digging up the BOM for mini aleph and ordered the parts for that.. started to solder the parts and found that I needed to soldier mount the resistors because they are way too big for the PCB
I need to double check all the blank spots, clean up the flux on the board and start on the power supply..
Posted 18th March 2010 at 11:30 AM bywintermute Updated 18th March 2010 at 12:33 PM bywintermute
I have been spending an inordinate amount of time using LTSpice lately. The more I use it the more I like it! For someone like me who is somewhat challenged mathematically, and who's electronics theory knowledge level is well below where it should be (to be doing this sort of design anyway), I've found LTSpice is an invaluable tool!
It basically lets me experiment with what I think might work, and then tweak things until it works well (in the simulation) which will hopefully result in a relatively painless implementation once I start soldering.
Having said that, I know that as a simulation it has it's limitations, and at this stage I have not actually built this power supply so it might not actually work!!
The reason I have decided to embark on this design exercise is that I needed* a dual rail regulated supply for my B1 crossover project, and I felt that I wanted something pretty simple that would be able to deliver enough current to power the...
I decided to document all my successful speaker projects. Here is the link http://boogieelephant.blogspot.com/
I plan to add a few more projects to that blog
Apply 16Vdc through 100k resistor and measure how the resistor voltage varies with time. The resistor voltage is a rough indication of the cap leakage+charging current.
Once charging is substantially over the remaioining current is predominantly leakage +-a little bit of chage/discharge current depending on the stability of the supply.
The apparent leakage is very much affected by the DC supply voltage. A good regulated DC supply that is held at constant temperature will help a lot.
You may find that 6hours at 100k gets to within 105% of the ultimate leakage current. But tell us what you find.
You can reform a bank of caps using one resistor to feed each capacitor.
Measure across each resistor to see how similar or different the caps are.
Use RG58 on all your shunts for sense wiring. Use as thick main ''force'' wiring as you like. Remember that the sense nodes are voltage nodes, don't worry about gauge. Their mission is to skip the voltage drop on the current carrying force wires and ''see'' the remote nodes directly. I believe that you will see less stuff on your scope in difficult termination situations if you shield your sense wiring. If you need extra thin and flexible enough, see about Belden (RG style) 179DT also, which I like for signal too BTW.
