You ask good questions! I don't have all the answers right now but will try to provide some insight.
canidoit said:
Do you know how much current does your model take up? I have a space left on my original lunchbox next to the power supply, but I do not know if I have enough current left???? Will this be advisable to be installed near the power supply?
Haven't figured this out yet. Shouldn't be too bad. If memory serves, a loaded 2520 draws about 800mW. There are two of those. Add 4 discrete voltage followers and the LED in normal operation. In bypass, also add the two relays at 500mW each (although, the unloaded 2520 will be about half at this point). So a totally rough guess, 3-4W on the very conservative side? Of maybe call it about 200-250mA? I'll get some better numbers on that.
canidoit said:
Also, is your HF and LF functioning the same as the original? I thought the switch was to go from Shelf to Lo/High pass filter and not Shelf to Peak. That's what API told me when I emailed them on how the 550A switches work.
Yes, exactly the same operation as the original. If you look at the front panel pic on the first post, you'll see the peak/shelf switch for the HF and LF. In the middle is the Filter switch which enables a bandpass filter from 50Hz to 15kHz. That's actually one of the things still on my to-do list. The HPF side of the bandpass filter is a little steeper than I'd like it, although it may be OK as is.
canidoit said:
What will be the callibration process for this unit and will this be newbie friendly in terms of build manual, BOM and support?
What is the degree of difficulty on this, in regards to other builds?
Calibration is the easy part - there is none unless you want to tweak with the gain structure. If you build it as-is, just fire it up and go and it runs at just about unity. I made provision to alter the output level just as in the original by adding a resistor between pin 8 (In-) and a pad on the board. I can't image many folks will want to do this and I haven't even tested it yet.
As for the build, there will be a manual, BOM, and support via a thread here. It actually isn't a complicated item to put together. The difficulty comes in the fact that there are a LOT of parts in different values and it is extremely easy to put something in the wrong place. Finding your mistake after the fact will be a painful affair. I've gone beginning to end on a couple by now and it still takes me about 8 hours to put it together.
To be comfortable building it, you should be able to look at doing something along the lines of a DOA with confidence. There is a lot of real tight, small work and again, it's easy to make a mistake. I will endeavor to make a very clear manual. Just work slowly and patiently and I think anyone with decent soldering skills could build this. It's not electrically complicated, just mechanically so.
Brian
![[silent:arts]](https://cdn.imagearchive.com/groupdiy/data/avatars/m/0/172.jpg?1620371656){kind=avatar}
